Winter bbc freshing up

[rider68]

My son and I pulled the engine and trans today from our whaler. The engine had some valve train noise and found some material I did not like when I cut the oil filter. So we are gonna check it out and make it like new. It is a bbc with 8-71. Had to remove blower to remove the engine from the boat. I have never posted a thread before but thought some of you diy guys would like to see. It will be slow cause I don't want to rush the disassembly. Im trying to get my son to pay attention to see if he a can find what the problem is with the noise and filter material. Not really trying to make any more power just want it realiable.

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[sintax]

thats awesome! I'll follow along on the R & R.

I did the same exact stuff with my dad when I was his age. We never did a car engine together, but we did tons of go-karts and motorcycles and general auto maintenance. Trust me, he'll remember it all and will shape him. The troubleshooting methodology he taught me applied equally to my daily work in technology every day, its not just turning a wrench.

 

[rider68]

Ok looks like it hydrolock #4. That plug was wet with oil. Bent a push rod on the intake. Also slight rust in the top of the bore. The intake rocker adjuster nut backed off also. The axle of the intake lifter roller started walking out also. Had to push it back in to remove the lifter from the lifter bore. We will finish the bottom end later. I want to see if #4 rod is bent.

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[obnoxious001]

May I suggest using one piece pushrods when you put it back together, rather than the stock ball end style. I use them on everything I build, sometimes thicker wall than the common .080" if it's something with more power or being raced.

 

[rider68]

May I suggest using one piece pushrods when you put it back together, rather than the stock ball end style. I use them on everything I build, sometimes thicker wall than the common .080" if it's something with more power or being raced.

Thanks for the advice, will do. I build large diesel engine at my shop for my living. So being inside engines is nothing new. But this is my first supercharged big block. I have built some decent NA bbc stuff in the past. I will be asking some questions before assembly. But I will do my research first. Like ring end gaps for blown application, and piston to bore clearance for marine application. Thanks again for the help. I took a closer look at the bent pushrod after you said something and found cracks coming out of where the ball end must be pressed into the tube.


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[obnoxious001]

Piston rings normally come with a sheet that gives a multiplier for the bore size, and various types of engines.

How did the exhaust lifter look for that cylinder, and was the valve lash correct on #4 exhaust?

 

[rider68]

Ok got the pan off and rods and pistons out. A little background, I did not build this engine it was in the boat when I bought it. Supposed to be some badass engine builder but now after what I see I call bs. It had studied mains and heads but stock rods with pressed pins. Speed pro dish pistons. Trying to id the crank. Has YT marking on it. .020 rods, .020 mains. The main bearings look shit. The pressed pins stock rods was a shock. My son is really enjoying this project.

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[rider68]

Piston rings normally come with a sheet that gives a multiplier for the bore size, and various types of engines.

How did the exhaust lifter look for that cylinder, and was the valve lash correct on #4 exhaust?

It has a hyd roller. So lash was zero. But seemed close to 1/2 turn past zero lash. Exhaust side looks ok. I was going to replace that set. I was worried because the axle walking out on the intake roller.

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[obnoxious001]

Ok got the pan off and rods and pistons out. A little background, I did not build this engine it was in the boat when I bought it. Supposed to be some badass engine builder but now after what I see I call bs. It had studied mains and heads but stock rods with pressed pins. Speed pro dish pistons. Trying to id the crank. Has YT marking on it. .020 rods, .020 mains. The main bearings look shit. The pressed pins stock rods was a shock. My son is really enjoying this project. View attachment 949691 View attachment 949692 View attachment 949693 View attachment 949694

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Press pins is not super terrible. What size rod bolts? I would still op for an upgrade. Eagle is making an I beam rod, full float, rated at 850 hp for less than $400 a set. The "YT" is an imported crank, trying to recall the brand name they went under. If the crank will not just polish up to run again, I would seriously consider buying a new one. At the very least you want to mag that one since it's been run with a blower. The 20/20 crank is ok, but apparently it's had a hard life already if it's been ground a couple of times.

 

[obnoxious001]

It has a hyd roller. So lash was zero. But seemed close to 1/2 turn past zero lash. Exhaust side looks ok. I was going to replace that set. I was worried because the axle walking out on the intake roller.

I asked about the exhaust valve because many times a problem with the exhaust will cause the intake pushrod to bend. You are correct that those lifters have reached the end of their safe lifespan.

Since you may want to replace the crank, along with pistons and rods, may as well put a 4.25" stroke in it and build a 496. I know you said you didn't really want more power, but the parts would cost the same as building a 468.

Another tip, instead of just automatically boring the block to 4.310" (.060" over), many times I will have the shop hone all eight cylinders to match, say to 4.285" or whatever it takes to clean up, thus leaving thicker cylinder walls and more material if the engine needs to be rebuilt again.

I don't know whose number that is on the camshaft, so don't know the specs. Depending on what it is now, It's possible to have someone regrind that cam to something that may work better. I would hazard a guess that the guy's cam selection may have been a shot in the dark based on some of the other components.

 

[rider68]

Press pins is not super terrible. What size rod bolts? I would still op for an upgrade. Eagle is making an I beam rod, full float, rated at 850 hp for less than $400 a set. The "YT" is an imported crank, trying to recall the brand name they went under. If the crank will not just polish up to run again, I would seriously consider buying a new one. At the very least you want to mag that one since it's been run with a blower. The 20/20 crank is ok, but apparently it's had a hard life already if it's been ground a couple of times.

The rods are 3/8 bolts. I have a set of scat H beams with cap screws 7/16. They have been resized. Also have a chevy 7416 crank ground 20/30 but it would need cut for a second key on the hub. I hope the YT crank will be ok. We should have the crank out tomorrow.

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[rider68]

I asked about the exhaust valve because many times a problem with the exhaust will cause the intake pushrod to bend. You are correct that those lifters have reached the end of their safe lifespan.

Since you may want to replace the crank, along with pistons and rods, may as well put a 4.25" stroke in it and build a 496. I know you said you didn't really want more power, but the parts would cost the same as building a 468.

Another tip, instead of just automatically boring the block to 4.310" (.060" over), many times I will have the shop hone all eight cylinders to match, say to 4.285" or whatever it takes to clean up, thus leaving thicker cylinder walls and more material if the engine needs to be rebuilt again.

I don't know whose number that is on the camshaft, so don't know the specs. Depending on what it is now, It's possible to have someone regrind that cam to something that may work better. I would hazard a guess that the guy's cam selection may have been a shot in the dark based on some of the other components.

The hyd roller lifters are howard's. Trying to see if the can is also. I will be bring home my dial bore gauge form work. I want to show my son how to use it. Then we can see how much bore wear we are dealing with. I agree on the piston size. If I don't have to go to .060 over I won't, unless pistons are crazy expensive. I'm open to cam swap but would like to know the specs on this one first.

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[rider68]

Got the crankshaft out. The main bearings look horrible compared to the rod bearings. Need to bring my measuring tools home from work to figure out what is going on here. On all pictures #1 is bottom of picture going order from there up.2nd picture is odd rods 3rd is even rods

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[rider68]

Also #1 main journal has slight did coloring like possible burn mark. Can't feel anything with my finger nail. I thought possible from blower belt to tight but it had 1/2 inch deflection on tear down. It looks like maybe bearing material transfer. Also some color on thrust. But it had end play.

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[snowboat]

Maybe on their last "rebuild" they just rolled in rod bearings.

 

[obnoxious001]

Also #1 main journal has slight did coloring like possible burn mark. Can't feel anything with my finger nail. I thought possible from blower belt to tight but it had 1/2 inch deflection on tear down. It looks like maybe bearing material transfer. Also some color on thrust. But it had end play. View attachment 950135 View attachment 950136

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I would say 1/2" deflection may be considered a bit tight. Threads on that one flywheel bolt hole don't look so spiffy. If that crank is already 20/20, I think a new one should be in your plans.

I drove up to Havasu yesterday and looked at a GN race engine that had the mains fail, but the rods were alright still. I scratched my head some, called someone I knew and asked him. His reply is that he has seen engines that aerate the oil do that to the mains and have the rods survive.

 

[rider68]

I wondered if the crank was flexing from driving the blower. If look at the main bearings the tops took most of the wear on #1 and #4 then it also wore heavy on the front side of the thrust. Almost like the crank was getting pinched between #4 and the thrust on #5.

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[obnoxious001]

What's the date on the back of the bearings, and what do the thrust surfaces of the rear main look like?

 

[rider68]

Here is a pic of the back of the bearings. Also got a chance to show my son and daughter how to use the dial bore gauge. Worst cylinder was .0025" taper. Took heads, block and crank to the machine shop to get checked out. I'm worried about the crank.

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[obnoxious001]

Here is a pic of the back of the bearings. Also got a chance to show my son and daughter how to use the dial bore gauge. Worst cylinder was .0025" taper. Took heads, block and crank to the machine shop to get checked out. I'm worried about the crank.

Before I would spend money to grind a 20/20 crank, I would replace with a new or at least better one, particularly since it's a blown engine.

 

[jeteater1]

My buddy crank grinder Howard, won't go past 15 for marine applications.

 

[rider68]

Before I would spend money to grind a 20/20 crank, I would replace with a new or at least better one, particularly since it's a blown engine.

I understand what you are saying. Just trying to make sure I know the condition of all the parts I have before a buy any more. I have been looking at 4.25 stroke kits. I was wondering what is the correct method for controlling end play on a hyd roller cam when using a cam driven water pump. There was no shims or anything else to control end play. Also do I need a bronze distributor gear. It does not have one now.

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[obnoxious001]

Cam end play may be controlled with the water pump, either by shimming the cam drive, but you say it is not shimmed, or moving the coupler on the water pump shaft. I find a far better way is by machining the timing cover for a Torrington bearing. It will take you some time to get it set up right. I have a couple of different guys who can mill the timing cover for me once I give them measurements and instructions.

If you don't have a bronze gear now, likely you don't need one. Is it a two piece camshaft, or possibly one of the Sadi cast core cams?

Normally I won't just buy a "kit". I prefer to have Racetec build my pistons and buy the individual pieces that suit my needs.

 

[rider68]

Ok so much for winter. I finally started assembly of this engine. It has new race tech pistons, with scat H beam rods that I all ready had. Degreed the cam. Then had to figure out cam end play. After several ideas. I came up with this. I had to buy a 3 inch extension for the magnaflow water pump to clear the blower belt. So I drilled and taped the end of the extension shaft for a 10/32 set screw. Staked the threads and lock tight. Was able to set end play at .008".

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View attachment 1031955

 

[rider68]

After getting the cam endplay set. I set the timing pointer and had to repair the oil pump pick up tube due to a crack in the bracket. So I fabbed a new bracket out if 3/16 flat strap and brazed to the pick up tube.

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[obnoxious001]

Ok so much for winter. I finally started assembly of this engine. It has new race tech pistons, with scat H beam rods that I all ready had. Degreed the cam. Then had to figure out cam end play. After several ideas. I came up with this. I had to buy a 3 inch extension for the magnaflow water pump to clear the blower belt. So I drilled and taped the end of the extension shaft for a 10/32 set screw. Staked the threads and lock tight. Was able to set end play at .008".

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View attachment 1031955

Arg! I could have shown you a couple of other ways of doing that! One requires a milling machine and a torrington thrust bearing, the other simple use of cam lock plates or other shims behind the drive that mounts to the cam. Hopefully that set screw is not able to move.

 

[rider68]

Slowly getting more done. Measured for push rods since they needed a upgrade. Anybody have experience with running e85 with a 8-71 blower. Thinking about converting my Holley's to run on it. Looking at the kits from e85carb.com. Does anybody have experience with this product.
Thanks

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[rider68]

Arg! I could have shown you a couple of other ways of doing that! One requires a milling machine and a torrington thrust bearing, the other simple use of cam lock plates or other shims behind the drive that mounts to the cam. Hopefully that set screw is not able to move.

I don't see that set screw moving. It is bottomed in the hole with red lock tight. I took a lot of time to measure how deep the hole needed to be.

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[rider68]

So I just got done with a Dyno testing. I converted the carbs to run on E85. Engine made 845 hp @ 6100. It ran great and I enjoyed tuning and learning about running with e85. Thank you for everyone that help and gave advice along the way.