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72Hondo

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Motors done 327 SBC - I think it made around 420HP and 380-390trq. I'll have to look at the dyno sheet.

Build sheet (yes I took out the name for now) first time using this builder. Everything look good? A tad out of my league with those numbers.

IMG_2889.jpg
 

SBMech

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Motors done 327 SBC - I think it made around 420HP and 380-390trq. I'll have to look at the dyno sheet.

Build sheet (yes I took out the name for now) first time using this builder. Everything look good? A tad out of my league with those numbers.

View attachment 536949
I'm curious as to why on a blown gas motor you would not use the 2.02 camelhump heads instead of the 1.94s ?

If you are stuffing it, you want it to flow as much as possible IMO.....

After looking at the numbers...420HP for a blown dual carb 327 seems pretty weak... You can make that NA pretty easily..most HP 327's were rated at 370HP and dyno'd at 415ish in the real world back then.

Shit the 302's in the Z28's were rated at 290 and made over 400 on the dyno when tested.

Both of those examples used a Duntov 30/30 cam and were NA.

I would want to think that it should make more than 500HP.
 

AzGeo

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Do you mind if I ask about the 'valve timing', and total spark lead on boost ?
 

72Hondo

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Builder said he thought it would be up over 500 also. The carbs are hurting me. I know, this is a know fact. It seems there is no absolute way to make to carbs work on a 144, not sure why B&M made that adapter. We spent over an hour on the dyno just playing with the carbs. It seems to be a trade off, looks vs performance.

I'm going to send both to C&J and let him work his magic, if anything.

No idea on the humps - thought it had the bigger valves but I guess not.
 

72Hondo

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Do you mind if I ask about the 'valve timing', and total spark lead on boost ?
Forgive my ignorance;

Spark lead - timing? We tried all sorts and even ran it way up to 40* it I got nervous and we decided to drop it to 36* I think.

Valve timing - cam specs? I'll have to look those up.
 

BDMar

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To answer your question, the bearing clearances, piston clearance, and ring gaps are all in the correct range for a boosted application.

Really need to know how much boost and camshaft design. HP number is low for a boosted engine.
 

obnoxious001

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To answer your question, the bearing clearances, piston clearance, and ring gaps are all in the correct range for a boosted application.

Really need to know how much boost and camshaft design. HP number is low for a boosted engine.
And even more important, perhaps, is how tired or fresh is the blower and how much heat is in the intake charge.

I would put a mild, pump gas blown 333 (.040" over 327) maybe just below 500 hp if everything was right, but the power actually depends on how much air and fuel you can put through the engine. A heated intake charge will show more "boost" pressure, but the air is actually less dense so you can't burn as much fuel in a proper air/fuel ratio to make good power. Larger valves, use of the proper cam could help with more airflow.

Knowing boost is an indicator,, but would really like to see dyno sheet with bsfc numbers as well as exhaust temps. I don't believe you should have to have the timing up to 36 degrees with a boosted (blown) recreational engine.

Last year I had someone bring an engine to me that someone selected parts for, someone else built and someone else dynoed. It lasted just over an hour in the boat. A look at the dyno sheet showing very high exhaust temps, combined with no intercooler and too much static compression caused his problem.

If you have the dyno sheet and cam specs,, please share with us.
 

72Hondo

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Blower was overhauled 1 - 2 years ago, less than 30 hrs on it since rebuild. I'm starting to think I'm leaving a ton on the table. Cam is a repo 30/30.

The final dyno sheet is at work but I do have the first one. This was straight from rebuild no changes at 32* timing (hard to take a picture of) I'll just give the last line until I can get it scanned.

RPM - 6400
CBT - 337.6
CBHP - 411.4
FHP - 103.8
VE% - 51.1 (I thought blowers we close to 100?)

ME% - 79.2
FA - 192.8
A1 SCFM - 295.0
A/F - 7.0
BSFC - .49
CAT - 77
BSAC - 3.43
 

AzGeo

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Was there a "boost level measurement" taken, or taken across the power band ?

EGT's ?

What did the carbs have in them for jets, PVs and set up during these pulls ?

Did you do a 'leak down test' after adjusting valves and before dyno pull ? Valve adjustment problem ?

My history with B & M blowers is in the marine field, and while Dick and Mike Landy did their dyno tests, we did many water tests for them .

Mid to late 80's, we ran a few different combinations on boats and found the "144's and the 177's" run hot as hell . Inlet temps ran; 144's @ 5 lbs 450 (F), @ 8 lbs 550 + (F), and 177's on small blocks only dropped 50 to 100 degrees on the same motors . Don't ask about big blocks . This is before they came out with the "250 blower", which after testing them, I have no comment .

Example; If your target EGT (which is all we had back then) is 1500 degrees (F), and your inlet air temps are 500 and 550, (no matter what the boost level) the 'thermal efficiency of the gasoline has been ONE THIRD LOST' by using HOT INLET AIR . (1500 (F) - 500 (F) = 1000 degrees of usable thermal transfer)

Two lobe rotors do not 'cool themselves' as easily as three helixed lobes do, when using 'fuel and air flow' to control 'case and air flow temps' . Two lobes must 'run at higher speeds' to reduce the 'pulses' they create, VS a standard GM helical - roots type blower .

I think you just have a fundamental assembly problem here, before you start working on the 'tune up' . Unless the carbs are just all f--ed up, I would go over everything


and do a leak test . .................

When you go back to the dyno, get an 'idle in gear setting' from your last test .

Let the motor idle, running temps, (reasonable idle, around 750/850 RPMs) slowly LOAD the motor and check ALL READINGS, until you get up around 50/75 lbs with a two blade prop and gears under 18's . And if you run a three blade prop (under 18 gear) go up to 80/125 lbs of load .

You can now SET YOUR IDLE for in gear use . Remember to have 'enough accelerator pump shot, right off idle, so it never backfires .

Let us know what happens ...........
 

Uncle Dave

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Builder said he thought it would be up over 500 also. The carbs are hurting me. I know, this is a know fact. It seems there is no absolute way to make to carbs work on a 144, not sure why B&M made that adapter. We spent over an hour on the dyno just playing with the carbs. It seems to be a trade off, looks vs performance.

I'm going to send both to C&J and let him work his magic, if anything.

No idea on the humps - thought it had the bigger valves but I guess not.

I fucked with a B&M 144 and single carb SBC for years and never did get it right.

That 144 straight paddle rig chuffs air and heats it up- terrible in parker in the summer.

C&J is great ran best with their setup, but the blower is junk.

I was 100X happier just building a 500/500HP/Tq NA 406 and it just worked beautifully and would shit all over my 383 bm-144 combo, and lasted for a decade at either idle or WOT continuously.


UD
 

72Hondo

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The boost was 5lbs, I do not see any EGT readings on the dyno sheet. I've reached out to the builder to see if he can pull them and any other info.

One thing that worried me was we kept putting smaller jets in it during the dyno until we got to the smallest ones on the secondary side. Per the build - it's making more power so it likes it.

Yeah but I don't want to live on the edge. He's the professional though. The dyno sheet says A/F ration 7, that can't be right, shouldn't it be up around 11?

I'm going to send the carbs off to C&J and see if they can play with the carbs. There carter 450's. Everyone has begged me to move to Hollys, but there's a sentimental reason behind it.

From all the talk in here, gives me a knot in my stomach that I got taken. Though this builder came recommended from other boat guys.
 

OCMerrill

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The boost was 5lbs, I do not see any EGT readings on the dyno sheet. I've reached out to the builder to see if he can pull them and any other info.

One thing that worried me was we kept putting smaller jets in it during the dyno until we got to the smallest ones on the secondary side. Per the build - it's making more power so it likes it.

Yeah but I don't want to live on the edge. He's the professional though. The dyno sheet says A/F ration 7, that can't be right, shouldn't it be up around 11?

I'm going to send the carbs off to C&J and see if they can play with the carbs. There carter 450's. Everyone has begged me to move to Hollys, but there's a sentimental reason behind it.

From all the talk in here, gives me a knot in my stomach that I got taken. Though this builder came recommended from other boat guys.

Personally your going to have a VERY hard time making those carbs work properly. I suspect they never have.

The motor is way over carbureted. So if you want to keep your nostalgia you're just going to have to trade off the correct tune.

Your AF should be around a low 12 to high 11 number given the light boost. Under boost you should retard spark advance or at least lock it out. Wish you the best. I built engines for a builder some many moons ago and if nothing else stuck it's the desire to keep carbs that just don't work for the application. Many hard fought hours trying to force it.
 

AzGeo

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metering rod carbs ......

IF you must run dual carbs, you need to see EXACTLY what kind of vacuum is at the base of those carbs throughout the RPM range . The base of the carb 'sees' the vacuum, which makes it function well or not .

Metering rod carbs move the 'lean/rich primary metering rods' with high or low carb base vacuum . BLOWER carbs don't always work that way, and in fact they often work directly opposite of an unblown motor .

Guys use Holley carbs on turbos/blowers because the primary 'power valves' (even secondaries) can be easily 'externally indexed', to what I call the 'load side' of the intake .

Your carbs (both primary metering rod wells) can be 'indexed', but it is a bunch more work than a Holley .

Your comments about 'reducing the secondary jets' indicates to me that the primaries of both carbs were 'flooding the intake' due to very low carb base vacuum ............
 

72Hondo

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So is it the carbs or the carbs? Lol

Why would B&M make that adapter if it hurt so much? Snake oil?

So dual Holleys would equate to poor performance also?

Let's say I found a good pair of 450 Holleys, same result?

If I remember right, before it was rebuilt 10-12" of manifold pressure, but that's at idle, starts boosting at 3500 RPM up to 5 at 6k.
 

AzGeo

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I wish you had a little more info from the dyno runs and how it is 'set up' overall .

Two carbs make A BIG HOLE in the top of that blower, when opened up .

Also, if it was running 'well under peak power' and still making 5 lbs of boost, I have a whole bunch of other questions to ask .

From what I understand; "vacuum powers a carburetor", a strong signal helps make smooth functions and good atomization, a weak vacuum signal needs compensation (parts and adjustments) and takes much more 'tuning' to run correctly .

Was the 10" to 12" on the same gauge that gave '5 lbs of boost' ? If so, that is not the vacuum I need to know about . (load side) I'm talking about at the carb bases at all RPMs .
 

rivrrts429

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Doing the math your setup lands somewhere around 820cfm needed. I think you're close with your carb cfm but you might want to switch to a single carb to get a performance baseline between the two.

You're not making boost until late in the power curve. I'd want to see more boost earlier. What size crank and snout pulleys?

As it sits the blower is replacing about the same amount of horsepower it takes to turn it. There's no return on your investment. The motor builder should've caught this on the dyno so whatever you do don't take it back to that dude.

So much more info needed. I think you have a couple tiny issues that are combining into one big one. No way a motor builder thought those numbers were acceptable and yet he already cashed your check?

I'd also take that blower in unless you yourself were there when it was rebuilt two years ago. Check to make sure it's turning and has oil in it first LOL.
 

SBMech

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If this was my build, all nostalgia aside, I'd slap a couple of these on it and work from there.

https://www.holley.com/products/fuel_systems/carburetors/hp/classic_hp/parts/0-80507-1

You can have them flowed and ported to meet your exact requirements, and they are way easier to deal with than your original carbs.

But like others have said, there is a lot of information missing.

I think rivrrts429 said it best so far...anyone who took your money to build this is not someone you want tuning it as well...:(
 

OCMerrill

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The V.E. should be in the 80%+ range for a well built HP engine. I like the tune it will a single carb and know what it takes to make it run right.
 

72Hondo

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Doing the math your setup lands somewhere around 820cfm needed. I think you're close with your carb cfm but you might want to switch to a single carb to get a performance baseline between the two.

You're not making boost until late in the power curve. I'd want to see more boost earlier. What size crank and snout pulleys?

As it sits the blower is replacing about the same amount of horsepower it takes to turn it. There's no return on your investment. The motor builder should've caught this on the dyno so whatever you do don't take it back to that dude.

So much more info needed. I think you have a couple tiny issues that are combining into one big one. No way a motor builder thought those numbers were acceptable and yet he already cashed your check?

I'd also take that blower in unless you yourself were there when it was rebuilt two years ago. Check to make sure it's turning and has oil in it first LOL.
Blower was rebuilt by BDS, you'd think they knew what they were doing. Upper pully is 5" haven't taken a tape measure to the bottom.

Sad thing was dyno time was $700-800 alone. Only dyno in the area, that I aware of.

So we know this is a carb problem but can it rob that much power? The 7 A/F ratio scares the crap out of me. Isn't that really lean?

Asked for the required info from the builder, no answer, won't return calls.

Anything else I can provide to help?
 

72Hondo

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I wish you had a little more info from the dyno runs and how it is 'set up' overall .

Two carbs make A BIG HOLE in the top of that blower, when opened up .

Also, if it was running 'well under peak power' and still making 5 lbs of boost, I have a whole bunch of other questions to ask .

From what I understand; "vacuum powers a carburetor", a strong signal helps make smooth functions and good atomization, a weak vacuum signal needs compensation (parts and adjustments) and takes much more 'tuning' to run correctly .

Was the 10" to 12" on the same gauge that gave '5 lbs of boost' ? If so, that is not the vacuum I need to know about . (load side) I'm talking about at the carb bases at all RPMs .
I get where you want the reading from. No that was not where the reading was taken from.

Best I can do from the dyno runs.

[video=youtube;CujYHzV2Yzo]http://www.youtube.com/watch?v=CujYHzV2Yzo[/video]
 

rivrrts429

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Blower was rebuilt by BDS, you'd think they knew what they were doing. Upper pully is 5" haven't taken a tape measure to the bottom.

Sad thing was dyno time was $700-800 alone. Only dyno in the area, that I aware of.

So we know this is a carb problem but can it rob that much power? The 7 A/F ratio scares the crap out of me. Isn't that really lean?

Asked for the required info from the builder, no answer, won't return calls.

Anything else I can provide to help?
Your cam card and and dyno sheets would help tell the rest of the story. We can't even tell where and what RPM's the power is being made.

I'm assuming you're running hydraulic lifters?

I've been thinking about this build and it has me scratching my head. I agree with a lot of the posters in this thread but there's just too much info missing. This should be a 500hp build.

Do you know which heads and flow numbers? My gut is telling me that your cam and/or valvetrain has a story to be told. It's hitting a wall early in the curve and choking itself. Good news is that it's an easy fix if it is.
 

rivrrts429

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That little blower is only going to make a lot of boost without creating heat, maybe 7-8 lbs. OC Merrill touched on it earlier.

I think you have a cam that is making power from 2,500-5,000 when you probably need one from 3,000-6,000. 3k-6k is probably where that package will live it's life on the water and you have a cam built for flying down the freeway. Gonna need a longer exhaust duration to get that hot gas out too.

I don't know much about the little blowers and small blocks but the theory works pretty universally when pumping air into a motor.

Keep us posted when you get the info. This is a pretty neat little build but as unique as it is you have a couple little things working against you to make it work right.
 

AzGeo

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some say that cam is .485"/254, .485"/254 on 114 centers .

IF this is true, the lack of LIFT will make the 'boost numbers larger', and prevent the motor from breathing better, up top .

BUT, the blower or cam cannot make up for the lack of 'breathing' .

Seven to one A/F is unacceptable, and yet the dyno operator 'can't won't' offer any insight as to what was going on during the 'pulls' ?

YES, I feel that either you 'didn't ask for help', or some of your 'experts' just wanted your money .

If this is an 'owner-builder', then it is what it is, but if this is a, 'paid for a whole professional package', then "I would clean and reload" .................

TOUGH to see all that facts when you state; "these carbs for nostalgia/sentimental reasons" .

I gave my thoughts on why the carbs are rich, but you need to choose to 'discuss this here, with ONE REAL shop, or keep throwing money at it', until it does run .
 

AzGeo

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That little blower is only going to make a lot of boost without creating heat, maybe 7-8 lbs. OC Merrill touched on it earlier.

I think you have a cam that is making power from 2,500-5,000 when you probably need one from 3,000-6,000. 3k-6k is probably where that package will live it's life on the water and you have a cam built for flying down the freeway. Gonna need a longer exhaust duration to get that hot gas out too.

I don't know much about the little blowers and small blocks but the theory works pretty universally when pumping air into a motor.

Keep us posted when you get the info. This is a pretty neat little build but as unique as it is you have a couple little things working against you to make it work right.
That LITTLE BLOWER makes a TON of HEAT, at all boost levels .

It runs at either 45% OVER crankshaft speeds, or 55% over on the smaller 8lbs pulley.

It will need at least .5 A/F ratio RICHER (than a normal blower), just to live at 5lbs .
 

rivrrts429

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That LITTLE BLOWER makes a TON of HEAT, at all boost levels .

It runs at either 45% OVER crankshaft speeds, or 55% over on the smaller 8lbs pulley.

It will need at least .5 A/F ratio RICHER (than a normal blower), just to live at 5lbs .
I was being a lot more gentler but you're absolutely right lol

Not trying to knock the guys build as it's more sentimental but at what point does function and efficiency over rule that?

Personally I wouldn't have chosen that blower and would've ditched it all together and gone n/a on a 327. He's taking the difficult route but the view might just be worth the climb for old school cool factor when he figures it out.

I love roots blowers even though I know there are more efficient designs today but they just scream cool. It's why I have a 1071 on my jet bote. I can sympathize with his effort regardless of the type of huffer.

I still think it's cool he's going to try and make it all work and I hope he sticks with it. I don't think it's all that difficult or expensive of a fix but he needs to know what he has and find a tuner with a dyno that wants his same goal. Not the one that pushed the sticks and took his money the first time around.
 

AzGeo

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I'm just sayin' that there are a few major problems, and then it will take a number of minor corrections to get it near 'running good for a blower motor' ..........

He knows it's not right, so let's all go the right direction, and start 'winning' . HA HA
 

SBMech

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I still think this is all flow related with some shitty carbs.

As stated on the build sheet the "builder" ran with the .194 valve camels or just stole the original .202 humpers and recorded his theft in the build sheet.

:(

IMO the B/M blowers are horrible even in automotive applications.
 

72Hondo

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Okay some blame lies on me for not asking the right questions.

Back story.

The motor cracked due to freezing water, freezing temps (100% my mistake, won't argue) its a 327 small journal, not the easiest to find but I found one in CA and had it shipped out here.

Called the engine shop asked about rebuilding, machining, checking everything, dyno etc.

I wanted to reuse everything as the only issue originally was cracked block. I told the builder, check everything, if something doesn't look right, let's change it. I'm not sure if the Cam is right, so let's look at that.

The build went together smooth, the block was gone to .30 over, crank was good (forged) and studded in the block. Rods and pistons checked out good (forged). The builder "checked with his dad, the cam guru" and the cam should be right for this build. I told him to check the PR for straightness and lifters. Being we reused them, when I took them out each was put into a bag of where it came out from (I was taught they MUST go back in where they came out). It's a 30/30 came with solid lifters, 1.5 rockers. Again I was told no issues going together. He did call up and say I'd like to change the valves out to SS. OK that's something that was on my list. No mention of going bigger or working the heads.

Everything else went together no issues (that I'm aware of).

Dyno day - everything hooked up, ran it, etc. it's running rich let's step down the jets and play with the timing. An hour later, 427HP and I quote "everything on the money. The carbs could use some tweaking but other than that I think we got it"

About 6 months later I picked it up. (Sent out of town for work). About $3500 later this is where we are at. One thing I found extremely odd, big bold letters on the invoice "no warranty on motor". I asked why no warranty? "If something was going to break it would have broken on the dyno. Plus parts are reused" but didn't you check everything out? "Trust me this is a standard in the industry. Don't get me wrong, if you have a problem give me a call and we'll work through it."

I thought to myself, wow, builders don't want any accountability.

Anyway, here is the rest of the build. Maybe I am to blame for trusting the builder too much.

IMG_2891.jpg

IMG_2892.jpg
 

72Hondo

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Now on to the fix.

Do I find another builder and have him go though the heads and valve train, possibly cam? Go with Holleys? Sell the blower and go with a 671? I have the C/R (I think). My goal was to try and get back on the water this year after about a 3 year hiatus. But everyone is agreement here, this motor is not right, how it sits. I stated to the builder, I'd like power with reliability and longevity, if possible.
 

rivrrts429

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I'd rip that dual carb setup off and try a single 750 or 800 instead. It's what that blower wants.

That upper pulley looks a little large, hard to tell. I'd try something in the 3" size for the upper to spin it up to maybe 7lbs ( I have no idea what size pulleys come in for that package).

Hit the dyno with those two changes. You're not that far off from 500 hp which I think is what this package should make. Call around and discuss with a different motor guy that has a dyno and has done similar packages.
 

SBMech

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I'm wary of any builder who does not stand behind their work.

My machinist gives a 12 month warranty on all the stuff he does for me, regardless of if parts are used or not since I always go with HIS recommendations.

If he says something is broken, we replace it etc till he is happy about what we are doing.

That being said, the work and receipts you showed are incredibly inexpensive for the amount of time that it takes to rebuild an engine properly....

Then again that might be part of the problem.
 

AzGeo

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What kind of boat is this going into ?

Just wondering with a car pan and pickup, small capacity, and no oil cooler, with a blower on top, I have questions about 'hot oil breakdown', in a boat .

From what I remember, these 'small blowers' run hot and up to about 5000 RPM (crankshaft speeds) on a motor under 400 inches, and "5500 is on the downhill side of power" .

Having built a few of the "P A W blower 355/377/383 kit motors" for customers back in the late 70's into 80's, I used a single 850 Holley .

I think they ran; 72/74 primary jet, 2.5 INDEXED primary power valve, secondaries had NO power valve with 80/84 jets . #33/35 nozzles, with the stock 'cams' on #1 . They both need a GOOD SHOT, but not a hosing down .

We even used 'spread bore 6210 Holleys' (650 CFM) on the 2.8 V6's with B & M 144's .

Knowing what vacuum signal the carb bases SEE, if very important, until you go with 'an indexed PV' in the primaries .

START with the 'spark advance' at 32 degrees TOTAL, until you get it running correctly . (change the advance rate and travel inside the distributor) example; 12 initial, plus 10 X 2 in the curve = 32 total all in at 2000 RPMs .

I don't LOCK them because it can be hard on starters when the motor is hot .
 

OCMerrill

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I'd rip that dual carb setup off and try a single 750 or 800 instead. It's what that blower wants.
If he can make 500 hp with that 327 at 5 - 6 lbs of boost I would call it complete. With proper AF I think he can. All this harping on the builder is hideous except for the DYNO time that was loaded with red flags, unless I missed something in the conversation.

If that engine was run extensively on the dyno at 7:1 A/F then where is a good chance the rings will never seat. Washed. This is what the builder should have told his customer....your parts produce X and your NOT good to go...but it runs. Now what other carbs do you have?
 

rivrrts429

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If he can make 500 hp with that 327 at 5 - 6 lbs of boost I would call it complete. With proper AF I think he can. All this harping on the builder is hideous except for the DYNO time that was loaded with red flags, unless I missed something in the conversation.

If that engine was run extensively on the dyno at 7:1 A/F then where is a good chance the rings will never seat. Washed. This is what the builder should have told his customer....your parts produce X and your NOT good to go...but it runs. Now what other carbs do you have?

Agreed.

I think the builder is getting harped on because he didn't see an issue or is unresponsive. I've been under the impression that the OP has reached out to him with no help in return.
 

72Hondo

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Going in a 18 ft jet.

I have no problem being told, your shit sucks, try it with this. It looks as if a dual carb set up can never work properly on this 327. Which sucks cause I liked the look. But my issue is I put all my faith and trust into the build to tune it right, why dyno it then? And being told it's pretty much on the money then being told here, it's fucked.

Live and learn I guess. First rebuild, first dyno.
 

rivrrts429

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Going in a 18 ft jet.

I have no problem being told, your shit sucks, try it with this. It looks as if a dual carb set up can never work properly on this 327. Which sucks cause I liked the look. But my issue is I put all my faith and trust into the build to tune it right, why dyno it then? And being told it's pretty much on the money then being told here, it's fucked.

Live and learn I guess. First rebuild, first dyno.

It's not fucked, brotha. This shit can be worked out and your 80% of the way there.

Two carbs doesn't mean twice as good always. Everything has to work together and no two carbs are alike. Trying a single is an easy approach which is why I mentioned it. If A/F changes or hp/tq changes it's all data to use for the next change. You have a baseline so now let's improve upon it.

I think there is meat on the bone to make some changes with what you got and get closer to the number but knowing where it made power in the curve is critical to knowing what you have inside your bullet.
 

72Hondo

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Going single carb will be my next step, finding a dyno operator, a bit tougher.
 

rivrrts429

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Going single carb will be my next step, finding a dyno operator, a bit tougher.
It will be worth the drive and time to find a better tuner. Remember, we don't learn from what we did right. It's usually what we did wrong and know what to do and what to ask next time.

People pay $20k to learn this at a trade school. You're paying a fraction of it and getting a better education. The glass his half full bud.
 

SBMech

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There is a lot of info missing here to make a good call on what the final output should be for your 327.

Does it have the 64cc 186 heads off a fuelie or the 327 L79 461 heads with 59cc chambers? I suspect neither with the .194 intakes.

Was it an original 3849347 30/30 cam or a repro? What was this in before it lived in your boat? I see no valve adj spec so this is a hydraulic cam?

Dynamic Compression Ratio?

Here's a good article on DCR and the difference between DCR and Static Compression Ratio...IE the 10-1 etc that most people use.

http://cochise.uia.net/pkelley2/DynamicCR.html

The original version of the Duntov 30/30 made HP from 3kish to around 6k if I remember right, most of it between 4500 and 6k. Makes hardly any torque down low.

The 30/30 is thrown around a lot but most people are unaware there were a few different versions, the L79 and the L46 were both hydraulic cams but were still called the 30/30.

The real ones came in the Camaro 302 both the MO and the DZ from 67-69, the LT-1 and the L72 and were all solid lifter cams. The "offroad" version is the racing cam.

Getting a complete view of what you are working with will help IMO.
 

OCMerrill

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It will be worth the drive and time to find a better tuner. Remember, we don't learn from what we did right. It's usually what we did wrong and know what to do and what to ask next time.

People pay $20k to learn this at a trade school. You're paying a fraction of it and getting a better education. The glass his half full bud.

I learn from doing it wrong several times in a row.



BTW I'm going to need a zip boom rental in the near future. PM me your info. Rather it be you than United.
 

72Hondo

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One of the dyno sheets. Might be kind of hard to read.

IMG_2895.jpg

IMG_2896.jpg

IMG_2897.jpg
 

72Hondo

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Would an 850 singly Holley be a good place to start?

I know AZ gave a full rundown.
 

SBMech

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Something a little smaller actually IMO, like a 750. 850 maybe if it had the big valve heads.

Blower carbs need to be setup for the blower, with lower signal vacuum they work differently as AzGeo said.

It's over carbed at this point, switching to something you can manage and see the AF ratio get much closer to where it needs to be will help tremendously.

Pop the valve covers and give us some casting numbers to see what heads it actually has on it, and the block casting stamps too...it will help identify what you are really working with.

Some of the "double hump" heads were simply passenger car heads, nothing special and as such were not performance pieces, if you can give some history about the motor maybe we can help you figure out where to go from here.
 

72Hondo

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Been a long time coming but found a nice 750 SC carb. Not sure about the difference between a boost referenced vs not.

Holley's are new to me. Seems like there's a tone to tune and change vs the AFB's.

Where's a good place to start with PV's and jetting?
 

AzGeo

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Running a single it needs to be "indexed" in the primaries, no power valve in the secondaries (plugged if needed) and good sized jets in the secondaries .

I would start by making SURE that the spark timing advance goes no more than 32 degrees total . If possible I would set it up to crank at around 12/14 degrees, and as soon as the motor is idling, all the advance comes in @ 32

This way you will not have "hot starter drag" against a LOCKED 32 degrees .

After you get/make the carb "indexed", I would start at 74/75 primary jet, with a 3.5 power valve (indexed) . Secondaries, I would start at 84 jet .

Two idle mixture screws on the carb, start at 2 turns out . Four idle mixture screws on the carb, start at 1 1/2 turns on each . If it is "surging hard", turn all the idle screws in 1/4 turn (at a time), until the idle smooths, but not "lean fast", just "fat smooth" .

I want it to "start and run", so you can get some vacuum/boost measurements, and some plug readings, on your first run in the water .

I start out rich and lean down > to where it makes power and won't burn up .

With this method, and considering there are many variables I don't know about your whole deal, I could guess that you will end up with 71/72 primary jets, 2.5 PV, secondaries around 82/84 .

In "theory" the open power valve will give 20% enrichment to the primary jets, and so this is why the secondaries have so much more jet in them (without a power valve) .

I would not run this single carb deal without INDEXING the primaries, because no one knows the vacuum levels at the carb base and blower top when on boost, WOT, or in between .................
 

72Hondo

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Appreciate the info. But I sent it off to C&J to tune. When it comes back I'll see about finding a dyno tuner
 
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