HP500 valve job questions.

[bocco]

OK, it's finally time to do a valve job on my 1997 Gen VI HP500. At 400 hours most people would say I'm past do. The last time I R & Rd a set heads was 1974 so I have a few questions since I plan to do that part my self.

First off my compression reads between 165 and 172. Book says 175 so I think I'm OK there. Spark plugs look good also. I have never had to add a quart of oil to this motor. One oil change per season. About 100 hours on these plugs.

I have a local machinist to do the heads. Of course the first ting to replace is the valve springs. He recommends that we pick the springs based on the cam specs. Probably from Comp Cams.

My first real question is which gasket set. Summit has a Fel-Pro Marine head gasket set which is way way cheaper than the Mercruiser deal. It looks like Mercruiser only sells the full engine kit but it's around $1175.00 which is just outragious. Is there anything wrong with the Fel-Pro set?

Next I want to replace the head bolts with a stud set. Seems like cheap insurance. Am I correct correct that this block has blind holes so I don't need to worry about thread sealant? Do I need 12 point nuts? Looks like that's all ARP makes. Milodon makes a hex nut set. Not sure about the quality difference. Price difference is minimal.

Finally, Lifters. I think I should replace these also. I could just go with what ever is recommended with the valve springs. It looks like the OEM style only comes as stock replacement so the tie bar style seems like the way to go. Any opinions on which is best?

Thanks in advance.

 

[Hydroman55]

OK, it's finally time to do a valve job on my 1997 Gen VI HP500. At 400 hours most people would say I'm past do. The last time I R & Rd a set heads was 1974 so I have a few questions since I plan to do that part my self.

First off my compression reads between 165 and 172. Book says 175 so I think I'm OK there. Spark plugs look good also. I have never had to add a quart of oil to this motor. One oil change per season. About 100 hours on these plugs.
View attachment 1068519 View attachment 1068520

I have a local machinist to do the heads. Of course the first ting to replace is the valve springs. He recommends that we pick the springs based on the cam specs. Probably from Comp Cams.

My first real question is which gasket set. Summit has a Fel-Pro Marine head gasket set which is way way cheaper than the Mercruiser deal. It looks like Mercruiser only sells the full engine kit but it's around $1175.00 which is just outragious. Is there anything wrong with the Fel-Pro set?

Next I want to replace the head bolts with a stud set. Seems like cheap insurance. Am I correct correct that this block has blind holes so I don't need to worry about thread sealant? Do I need 12 point nuts? Looks like that's all ARP makes. Milodon makes a hex nut set. Not sure about the quality difference. Price difference is minimal.

Finally, Lifters. I think I should replace these also. I could just go with what ever is recommended with the valve springs. It looks like the OEM style only comes as stock replacement so the tie bar style seems like the way to go. Any opinions on which is best?

Thanks in advance.

Mercury knows what their doing, replace with same springs and lifters if changed. The valve train works together and switching thing up is a bad idea.

 

[obnoxious001]

Since the Gen 6 block is set up for factory roller lifters, they are not a bad way to go. Are you pulling the heads, or just having springs changed out? Comp makes replacement factory style roller lifters, as well as a couple of other brands.

Springs... I have all my cams custom ground, and know what springs to run based on history. Using what the shop says is probably not a bad idea, but he should be able to test the ones that come off your heads as well. I assemble all heads here myself so have a spring tester to put the spring pressure where I want it.

There is no reason to change over to head studs, head bolts work fine. Clean the threads with a wire brush or wire wheel, and torque properly in 3 steps following the correct pattern.

Rather than buying sets of gaskets, I would normally use Fel Pro marine head gaskets, and I personally prefer Mr Gasket intake gaskets, so you probably end up with about $120 in gaskets. Gen 6 valve covers have a rubber o-ring type gasket that generally will not leak in all of my experience.

 

[Dalton]

If it has those gold rockers 99% of the time you can find a bad one if you look hard enough

 

[mjc]

Price wise last hp500 I had I just changed the heads to aluminum.

 

[bocco]

Since the Gen 6 block is set up for factory roller lifters, they are not a bad way to go. Are you pulling the heads, or just having springs changed out? Comp makes replacement factory style roller lifters, as well as a couple of other brands.

Springs... I have all my cams custom ground, and know what springs to run based on history. Using what the shop says is probably not a bad idea, but he should be able to test the ones that come off your heads as well. I assemble all heads here myself so have a spring tester to put the spring pressure where I want it.

There is no reason to change over to head studs, head bolts work fine. Clean the threads with a wire brush or wire wheel, and torque properly in 3 steps following the correct pattern.

Rather than buying sets of gaskets, I would normally use Fel Pro marine head gaskets, and I personally prefer Mr Gasket intake gaskets, so you probably end up with about $120 in gaskets. Gen 6 valve covers have a rubber o-ring type gasket that generally will not leak in all of my experience.

Yes the heads are coming off and going to the machine shop for everything.

The OEM style lifters are attractive from a price point. I guess if the stock ones made it this far they will be good enough.

He did suggest checking the springs but I would prefer to replace them for peace of mind. The manual shows the lift at .576 intake and .598 exhaust. I'm assuming the fact that it's a roller cam comes into play also because of ramp speed?

Would you actually re use the head bolts or replace? A stud kit is not that expensive. I do want to use something that does not require re torqing because I would have to remove the exhaust manifolds to do it. I would appreciate a recommendation.

Thanks for the tip on the gaskets. I will follow that.

 

[bocco]

If it has those gold rockers 99% of the time you can find a bad one if you look hard enough

I do plan to look at them very closely. Might have the machinist look them over also.

 

[bocco]

Price wise last hp500 I had I just changed the heads to aluminum.

I have considered this also. Not sure about doing that with open cooling. It would be nice to be able to pick a little compression and maybe smaller intake ports.

 

[bocco]

So any opinions on just buying aluminum heads? Edelbrock marine heads look good but the website is not clear if the price ($1430) is for one head or both.

 

[Eliminator21vdrive]

Each on the Edelbrock , I have a set and the hard anodizing is holding up well.
If you are concerned with the integrity of the OE head bolts ARP has replacement bolt sets as well and without the side effects of studs.

 

[obnoxious001]

Would you actually re use the head bolts or replace? A stud kit is not that expensive. I do want to use something that does not require re torqing because I would have to remove the exhaust manifolds to do it. I would appreciate a recommendation.

Since the head bolts go into blind holes, I see no problem using them again as there should be no damaged threads. I ran GM head bolts on my turbo engine in my ski race Schiada when people were telling me that I needed head studs for the application, no problems with that engine. None of the engines that I have built or rebuilt in all my years have had a head bolt fail to my knowledge, although now days I am inclined to use head studs on higher horsepower applications (mostly boosted).

 

[bocco]

OK next question. When I put this back together how do I torque these intake bolts? There's no way the ratchet head of my torque wrench will fit in there with a hex bit. Can I use a universal joint? Will that effect my torque reading.

 

[hman442]

OK next question. When I put this back together how do I torque these intake bolts? There's no way the ratchet head of my torque wrench will fit in there with a hex bit. Can I use a universal joint? Will that effect my torque reading.

View attachment 1069661

Reuse the head bolts, like mentioned above, when was the last time a BBC head bolt failed, and as far as torquing the intake, just tighten them in a pattern, inner, go to other side inner, then back and forth to the outer bolts, do them snug the first time, then a pretty good tension on your end wrench the second time, it'll be fine. If you really want to fool it, go "click" just before you release tension on your end wrench.

 

[rivermobster]

Price wise last hp500 I had I just changed the heads to aluminum.

What heads? Did you have to modify your exhaust system at all?

I've heard the exh ports are different heights/position on some aluminum heads.

Thanks.

 

[obnoxious001]

What heads? Did you have to modify your exhaust system at all?

I've heard the exh ports are different heights/position on some aluminum heads.

Thanks.

Yes, many of the aftermarket ones will have raised ports which might create problems. Brodix is making a line of heads called "Race Rite" that are reasonable, and have exhaust ports in the stock location. I put a set on a "pro street" type engine for a guy, they looked pretty decent.

 

[rivermobster]

Yes, many of the aftermarket ones will have raised ports which might create problems. Brodix is making a line of heads called "Race Rite" that are reasonable, and have exhaust ports in the stock location. I put a set on a "pro street" type engine for a guy, they looked pretty decent.

We are considering this for Steve's Stoker. Maybe a 540 kit too.

 

[guest hs]

No need for head studs definitely replace the roller lifters not a bad idea to replace the roller rockers too if they are gold crane type.

 

[bocco]

Well the heads came off today. The first thing that surprised me is the tie bar style lifters. I was expecting OEM style lifters that don't use tie bars. Assuming that these are not GM lifters.

 

[bocco]

The next item of concern is the valve stems. About half of them look like this. Is this caused by valve float?

 

[28Eliminator]

Well the heads came off today. The first thing that surprised me is the tie bar style lifters. I was expecting OEM style lifters that don't use tie bars. Assuming that these are not GM lifters. View attachment 1071965 View attachment 1071966

If its a 97, it's a Gen V, not gen VI and they use the tie bar lifters.

 

[28Eliminator]

The next item of concern is the valve stems. About half of them look like this. Is this caused by valve float?

View attachment 1071967 View attachment 1071968

That appears to be normal roller/valve tip marks.

 

[bocco]

If its a 97, it's a Gen V, not gen VI and they use the tie bar lifters.

Pretty sure it's Gen VI. It has a cast timing cover. Also the serial number (OK0000503) indicates that it's a Canadian Gen VI. I don't get the Canadian part but it shows up when my local shop looks up parts also. So I'm guessing that the OEM Gen VI lifters weren't adequate for the cam lift so Mercury put Crane lifters in. They appear to be in perfect shape. All of the rollers are smooth with no play or wiggle. I'll see what the machinist thinks before I shell out bucks for a new set of lifters.

 

[bocco]

That appears to be normal roller/valve tip marks.

Thanks. I did some research and came to the same conclusion.

 

[bocco]

So the rocker arms are Cranes and like the lifters they appear to be perfect with no signs of cracking at all. At least not that I can see with the naked eye? Non of the shafts feel like they have any play and they roll smoothly. Is there anything on particular I should look for to indicate a problem?

Also the push rods look like one piece deals. I don't see any indication of a separate tip.

 

[rivermobster]

The next item of concern is the valve stems. About half of them look like this. Is this caused by valve float?

View attachment 1071967 View attachment 1071968

In these two pics, it looks like the rocker arm studs are loose??

 

[Outdrive1]

What heads? Did you have to modify your exhaust system at all?

I've heard the exh ports are different heights/position on some aluminum heads.

Thanks.

Edelbrock sells the aluminum heads that go on a 525. They aren’t super expensive. Direct bolt on, everything will work the same.

He would make a few extra ponies with them and wake that motor up a little.

 

[rivermobster]

Edelbrock sells the aluminum heads that go on a 525. They aren’t super expensive. Direct bolt on, everything will work the same.

He would make a few extra ponies with them and wake that motor up a little.

It's a 502, and I Think the Edelbrock heads have different exhaust port locations?

I think the ones Barry mentioned are the only way to go?

 

[bocco]

In these two pics, it looks like the rocker arm studs are loose??

They are. We needed to move the pushrod guides to get at the head bolts because the only 6 point socket I had was an impact socket.
Probably could have used a twelve point just fine.

 

[Outdrive1]

It's a 502, and I Think the Edelbrock heads have different exhaust port locations?

I think the ones Barry mentioned are the only way to go?

They are direct bolt on. Lol. No changes to the exhaust. Made specifically for Mercury. Call Teague. They stock them.

 

[rivermobster]

They are. We needed to move the pushrod guides to get at the head bolts because the only 6 point socket I had was an impact socket.
Probably could have used a twelve point just fine.

A chrome twelve point would have probably cracked. Sounds like you made the right "move".

 

[rivermobster]

They are direct bolt on. Lol. No changes to the exhaust. Made specifically for Mercury. Call Teague. They stock them.

Interesting. If that part number exists, I'll find it. No need to pay any mark ups.

 

[28Eliminator]

Pretty sure it's Gen VI. It has a cast timing cover. Also the serial number (OK0000503) indicates that it's a Canadian Gen VI. I don't get the Canadian part but it shows up when my local shop looks up parts also. So I'm guessing that the OEM Gen VI lifters weren't adequate for the cam lift so Mercury put Crane lifters in. They appear to be in perfect shape. All of the rollers are smooth with no play or wiggle. I'll see what the machinist thinks before I shell out bucks for a new set of lifters.

View attachment 1072994

Hmm, well I guess it is.. does the valley have the bolt pedestals for the piece that retains the stock dog bones? I thought the Gen VI stuff didn't start until after that... lear n something every day

 

[Teague_JR]

Those look a lot like older gen crane lifters (which were very reliable) I can tell you have babied the motor by the fact the valves have not floated or rotated AT ALL...

I would also suggest the edelbrock hard ano aluminum assemblies that TCM specs rather than putting money into the iron heads. If you are going to reuse the heads, install bronze guides... Reusing valves is a bad idea. I would also suggest a 525efi spec cam, TCM also stocks at reasonable pricing.

Felpro marine head gaskets would work fine. Cometic would be an upgrade. If its a gen 6 you need to use a gen 6 spec gasket regardless of which heads are on it. Use the value priced ARP head bolts. Forgot if that motor has them already or stock chevy's...

dont forget to have fun!

 

[bocco]

Hmm, well I guess it is.. does the valley have the bolt pedestals for the piece that retains the stock dog bones? I thought the Gen VI stuff didn't start until after that... lear n something every day

Yes it has the bosses for the lifter guide plate. Just nothing in the holes. It also has a sheet metal pan across the lifter valley.

 

[bocco]

Well I got the word from the machine shop yesterday. I did in fact have several broken valve springs. Also some bad valves. Stem ware and tuliping. So all new springs and valves. He said the guides looked great so no issues there. They also were nice enough to inspect my lifters and rockers and they all look good to go.

Now we wait to see how long it will take to get parts.

 

[xlint89]

Pretty sure it's Gen VI. It has a cast timing cover. Also the serial number (OK0000503) indicates that it's a Canadian Gen VI. I don't get the Canadian part but it shows up when my local shop looks up parts also. So I'm guessing that the OEM Gen VI lifters weren't adequate for the cam lift so Mercury put Crane lifters in. They appear to be in perfect shape. All of the rollers are smooth with no play or wiggle. I'll see what the machinist thinks before I shell out bucks for a new set of lifters.

View attachment 1072994

Thanks for making this post bocco.

It appears I have the same generation as you. 0559 serial #

Ironically mine is at the builder now. Looking like mine will be full rebuild. Including a NEW block. (bought the engine used from a guy last year) Metal was thin between the cyls and the thermostat was missing because the manifold was corroded so badly, it couldn't support one.

Waiting for builder to complete inspection of existing parts and work up a quote from there.

It's nice to read all the responses and see what I should be paying close attention too.

Was hoping to buy alu heads, but looks like that $$ went to the new block instead.

 

[LOBOATOMY]

Ferrea gives a 40/45% discount to military/veterans. They provide an excellent quality valve train components. FYI

 

[bocco]

Looks like my heads are ready. I don't have the final number but I think I'm at around $1200 with new valves and springs.

Thanks to all for all of the advice.

So next question. On the subject of valve adjustment. I have always heard 1/2 to 3/4 turn past zero. The mercruiser manual says 1 full turn. Is that to much? The valve train has always been a little noisy so maybe that's right.

Opinions?

 

[obnoxious001]

Looks like my heads are ready. I don't have the final number but I think I'm at around $1200 with new valves and springs.

Thanks to all for all of the advice.

So next question. On the subject of valve adjustment. I have always heard 1/2 to 3/4 turn past zero. The mercruiser manual says 1 full turn. Is that to much? The valve train has always been a little noisy so maybe that's right.

Opinions?

Sort of depends what brand lifters you are using. You should be ok at a full turn, but I normally go 5/8 to 3/4. Best to adjust with intake still off the engine so you can rotate pushrods as you adjust to zero lash.

 

[hman442]

I've always tightened them to 1/2, as said, while turning the pushrod

 

[farmo83]

Looks like my heads are ready. I don't have the final number but I think I'm at around $1200 with new valves and springs.

Thanks to all for all of the advice.

So next question. On the subject of valve adjustment. I have always heard 1/2 to 3/4 turn past zero. The mercruiser manual says 1 full turn. Is that to much? The valve train has always been a little noisy so maybe that's right.

Opinions?

I redid mine a few years ago. I think we did 1 turn as everything went back stock. Ran like a top with no issues.

 

[mash on it]

For what it's worth-
The spec for an SBC hydraulic roller lifter preload is .030", which equates to ½ a turn beyond zero lash.
I've used this same method on roller and non roller big blocks. (Measuring at least one cylinder, of course)

Dan'l

 

[Mcchevy69ss]

Price wise last hp500 I had I just changed the heads to aluminum.

This^^^^^. There are a lot of aluminum head options that will out perform the factory heads and remove 75 lbs off the back of your boat. Some are priced pretty competitive to cost of R&R your existing heads (Edelbrock).

 

[bocco]

This^^^^^. There are a lot of aluminum head options that will out perform the factory heads and remove 75 lbs off the back of your boat. Some are priced pretty competitive to cost of R&R your existing heads (Edelbrock).

So my heads are done and I'm going to stick with them. The Edelbrock website says $1430.00 each and out of stock. So I think I'm saving about $1800.00. I didn't do research to see if someplace else had a set. That being said if I ever have whole motor done I would probably that route. And closed cooling to boot.

 

[bocco]

So I read that there could be issues using a stud kit with CMI exhaust manifolds which I'm pretty sure I have even though they say Mercruiser on the manifold. I did a test fit and the four nuts below the exhaust ports are to close for comfort. So the stud kit is out. Went to Summit and ordered ARP-135-3601. My concern is that these bolts come with washers and the stock bolts did not. I did a test fit with the washers from the stud kit and the stock head bolts. Again to close for comfort. If I have clearance problems with the new bolts can I use them without washers? If the supplied washers are thinner than the ones from the stud kit I may be OK but no way of knowing until I get the bolts on Tuesday.

 

[obnoxious001]

So I read that there could be issues using a stud kit with CMI exhaust manifolds which I'm pretty sure I have even though they say Mercruiser on the manifold. I did a test fit and the four nuts below the exhaust ports are to close for comfort. So the stud kit is out. Went to Summit and ordered ARP-135-3601. My concern is that these bolts come with washers and the stock bolts did not. I did a test fit with the washers from the stud kit and the stock head bolts. Again to close for comfort. If I have clearance problems with the new bolts can I use them without washers? If the supplied washers are thinner than the ones from the stud kit I may be OK but no way of knowing until I get the bolts on Tuesday.

Way back in post #3 I told you to clean and reuse the stock bolts. Since they don't go into water jackets on a Gen 6 block there should be no damage to them.

 

[bocco]

Way back in post #3 I told you to clean and reuse the stock bolts. Since they don't go into water jackets on a Gen 6 block there should be no damage to them.

I do appreciate your advice and I'm sure you are correct. I am just being a little over cautious. I guess I've read one to many stories about the head gasket issues with these motors.

 

[bocco]

Well, she's back together and it runs. My cousin came out for the weekend and two Italians managed to put the whole thing back together with just a little ball busting and some family bonding.

Always fun getting the timing right after pulling the distributor. Runs and sounds good on the hose in front of house. Next step is a test run on the water.

Thanks to Barry and Teague and all others for input and advice.

 

[HST4ME]

0 new items by riverdragon marine service

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Final floor test before going back in. For you guys going through these motors I highly recommend you find someone who can straighten out and sleeve the lifter bores especially on a gen 6 block.

 

[bocco]

Well I finally got the boat out on the water for a real test drive. We adjusted the floats and checked the timing and off we went. Ran perfect. Ran around on Sac Delta. Stopped for lunch. then ran for a while longer. Probably put an hour and a half on it total. The conditions were pretty windy so I couldn't run it to hard but it felt and sounded good.

Thanks again for all of the advice.