head gaskets: take two

[SappySE107]

http://foreverpontiac.com/index.php?showtopic=2722&pid=59531&st=20&#entry59531

"I'm am working on fixing the PCV issue today. I can tell you right now it's NOT the piston rings though. He has no clue wtf he is talking about on that one... they are good. I did everything by the book so there's no way they could be bad. Regardless I'll be doing a compression test as soon as I can get a good compression tester, just so he'll shut up about the rings. My compression tester has a bad pressure relief valve and isn't holding pressure like it should."

Yes, I took a guess at what was wrong based on what your engine was doing, and that might not be it. I hope I am wrong, considering you have found 1 source of oil.

[CNCguy]

Aaron... out of curiosity have you had the heads rechecked for flatness since their removal? No one has brought this up but there are two surfaces that need to be in spec for a gasket to seal. Is it possible that the decks aren't flat? With two gasket failures, I wonder if there could be a different issue besides the head flatness. Hopefully, you won't have another gasket failure.

[Mars]

Honeslty, go with a PCV exhaust slashcut on the rear valve cover and keep the front PCV setup stock. Works WONDERS. I had all kinds of oil leaks before doing this cause I was boosting the case. now, the slashcut sucks it all out and my motor stays clean. I just got the thing from summit.

http://www.summitracing.com/parts/SUM-120108/

[geldartb]

http://foreverpontiac.com/index.php?...20&#entry59531

"I'm am working on fixing the PCV issue today. I can tell you right now it's NOT the piston rings though. He has no clue wtf he is talking about on that one... they are good. I did everything by the book so there's no way they could be bad. Regardless I'll be doing a compression test as soon as I can get a good compression tester, just so he'll shut up about the rings. My compression tester has a bad pressure relief valve and isn't holding pressure like it should."

Yes, I took a guess at what was wrong based on what your engine was doing, and that might not be it. I hope I am wrong, considering you have found 1 source of oil.

yeah i kind of went WTF when i read that. hey shit happens every one makes mistakes every now and then.. i think at this point you have nothing to lose since your taking the engine apart every thousand miles anyway. why not just blow it completely apart instead of playing the oh this didn't work must be something else game.

[AaronGTR]

Looks pretty close to them saying to use 15-20 ft lbs more than stock.

I don't see your gaskets listed on the store so I can't update it.

Sorry I moved earlier this year and didn't answer my phone when you needed me most. Its obvious that was the reason you have had all these engine problems.

Sorry you misunderstood what I meant. They asked me what the stock torque specs where and what I torqued them to with the head studs. Basically they wanted to know if I could have severely under or over torqued them. Based on what I told them, they said that 82 ft/lbs with the studs should only equal 15-20 ft/lbs clamping force more than with the bolts. Not a radical difference and not under torqued. That's what I meant... was trying not to write a novel.

Anway, my specific gaskets aren't in the store no... they are similar construction to the Cometic gaskets you do have though, and since you yourself said the same requirements apply for both, it might be helpful to tell that to customers considering the cometic ones don't you think? Sarcasm on the other hand helps no one, and refusing to do something that might help other customers not make the same mistake is just stupid.

And as I said in the other thread, you weren't the only one moving. I also moved AND was dealing with legal issues while in the middle of doing my engine rebuild. I am not and have not blamed all my engine problems on you, but that doesn't change the fact that those gaskets didn't seal up properly because of some information you didn't provide to me. So yes, you could have helped avoid ONE of the problems. I understand you are busy, but you aren't the only one. You are the one though running a store with paying customers who expect some customer support.

[AaronGTR]

Aaron... out of curiosity have you had the heads rechecked for flatness since their removal? No one has brought this up but there are two surfaces that need to be in spec for a gasket to seal. Is it possible that the decks aren't flat? With two gasket failures, I wonder if there could be a different issue besides the head flatness. Hopefully, you won't have another gasket failure.

I dropped the heads off at the machine shop friday last week. They said they where going to go over everything again and would recheck them for flatness. I should hear something back by the end of this week.

As for the block, I had that at the shop for inspection as well after I originally tore the engine down and found the #2 piston wasn't coming up to the correct height above the deck. I had them completely check the block and the crank, all connecting rods, etc. They found the #2 rod was bent. Crank was fine, and they said the surface of the block was flat. The piston bores and pistons where both worn though making my piston to wall clearance too high, which is why I had them bore and hone the block .04" over. That was the only machine work done to the block. They cleaned it, put in new plugs etc, and replaced the cam bearings at my request since the old ones were also worn. That was it though.

[AaronGTR]

i'm just going to throw this out there, that it could be possible that you originally blew your head gasket due to hydro locking with oil from worn valve guides/seals. Regardless of what gaskets you put on the motor the second time, you would have had a similar problem as the oil leaking down the block or blowing out another gasket. now that you have changed the heads, this problem will disapear. End result the gaskets are probably toast now, and heads are a waste of money to fix.

I am no Master Motor Builder, or have a degree in Failure Analysis Engineering, but i could make this assumtion from the pictures i veiwed on that pontiac forum. How ever i cant figure out how you got your surface of the failer heads to be so clean, it almost looked like they were infact machined, but i could tell from the resolution.

I hope we can all come to a conclusion together civily and put this behind us.

Anythings possible I suppose, but I don't think that's it. It didn't show any signs before the orginal gasket failure of excess oil consumption, and there wasn't any sign of oil leaking from the valve guides that time either. Really there was only evidence of oil leaking from one valve guide on the second tear down. I still don't know for sure what caused them to blow the first time, and I may never know. The run that they blew on there was no detonation on my scan, but the run before that showed 2 degrees of KR in 2nd and 3rd gear. The injectors where maxed out and I had seen 2-4 degrees KR on the dyno the week before that. My plan was to run 100 octane unleaded at the track, but they didn't have any when I got there. My best guess is that the gaskets blowing and the bent rod where caused by a sudden detonation, or just from abuse of too much light detonation over too long a period of time.

I'm hoping to have solved that problem with larger injectors, changes to the SC setup, and an alcohol injection kit later if I still need it and can afford it. The MLS head gaskets weren't really needed at my power level. I was just hoping they would be some extra insurance against another blown gasket while I try and get the tuning right. Since I'm back to stock heads and cam and I'm dropping the red line back to stock I'll be at a lower power level and probably won't have to worry about it as much now. Not as likely to have KR.

[onefastV6]

Anway, my specific gaskets aren't in the store no... they are similar construction to the Cometic gaskets you do have though, and since you yourself said the same requirements apply for both, it might be helpful to tell that to customers considering the cometic ones don't you think? Sarcasm on the other hand helps no one, and refusing to do something that might help other customers not make the same mistake is just stupid.

And as I said in the other thread, you weren't the only one moving. I also moved AND was dealing with legal issues while in the middle of doing my engine rebuild. I am not and have not blamed all my engine problems on you, but that doesn't change the fact that those gaskets didn't seal up properly because of some information you didn't provide to me. So yes, you could have helped avoid ONE of the problems. I understand you are busy, but you aren't the only one. You are the one though running a store with paying customers who expect some customer support.

Aaron, if you were to order Cometic Gaskets from Summit Racing for a 3800 or any other engine they have MLS gaskets for.... they would not have told you that you must mill your heads either. http://www.summitracing.com/parts/CGT-C5720-066/ Instead, you must read the instructions that come with the product, which you have clearly indicated the slip that came with the gaskets said that the heads must have 50 RA surface finish. If there is something you are not familiar with it is best to try to research it before hand, I understand that you were in a hurry to get the engine back together and consulted with a shop that you thought was reputable. From what I can tell the machine shop did not do several things right and it is possible that they do not have the proper equipment to do the jobs that many other shops are capable of. Their theory on heads having the best finish from the factory, might be true to some extent when they are brand new. Once the heads have been ran on an engine, that theory goes out the window and they should be milled to ensure flatness..... which I personally though was common practice in the engine building community.

Hopefully you will get it back together and not have any other issues, however I would find a new machine shop in the mean time.

[pocket-rocket]

they should be milled to ensure flatness..... which I personally though was common practice in the engine building community.

I have it done to completely stock engines, especially if they have blown a head gasket and especially if they are aluminum heads. It's cheap insurance and I don't like doing the job twice to get paid for it once.

[AaronGTR]

Aaron, if you were to order Cometic Gaskets from Summit Racing for a 3800 or any other engine they have MLS gaskets for.... they would not have told you that you must mill your heads either. http://www.summitracing.com/parts/CGT-C5720-066/ Instead, you must read the instructions that come with the product, which you have clearly indicated the slip that came with the gaskets said that the heads must have 50 RA surface finish. If there is something you are not familiar with it is best to try to research it before hand, I understand that you were in a hurry to get the engine back together and consulted with a shop that you thought was reputable. From what I can tell the machine shop did not do several things right and it is possible that they do not have the proper equipment to do the jobs that many other shops are capable of. Their theory on heads having the best finish from the factory, might be true to some extent when they are brand new. Once the heads have been ran on an engine, that theory goes out the window and they should be milled to ensure flatness..... which I personally though was common practice in the engine building community.

Hopefully you will get it back together and not have any other issues, however I would find a new machine shop in the mean time.

sorry but I disagree. You can hardly compare WOT-tech to Summit racing. First of all Summit racing is way bigger and does far more volume, and they also aren't specialized to one engine family like WOT is. They deal in everything and can't give recommendations like that because the same recommendations don't apply to every engine type and gasket type. They also don't sell specialized parts like custom hand ported cylinder heads. Since Ben specializes in one engine type and supports a specific automotive community, you would expect those kinds of recommendations. I think I would know, my brother runs a successful shop specializing in one make of car, and he returns tons of phone calls and emails every week. That's what it takes to keep customers happy and loyal, which is how he makes a living. I specifically asked Ben if I could have his number so I could call him if I had questions and he gave it to me. If he never intended to answer it or if that wasn't the best way to get ahold of him, he could have said so from the beginning. And you know what would happen if you called Summit Racing and asked for a recommendation right? They'd probably tell you to consult a machine shop and go by their recommendation... which is exactly what I did, and apparently Ben thinks was the wrong thing to do.

And yes, I did want to get my engine back together as soon as possible because I had to get my car out of my friends drive way, but I didn't rush things as you are implying. I blew the head gaskets on March 24th and I didnt' even pay for the last of the machine work to get started until May 27th. The engine wasn't back together until June. I had two full months of digging for info and ordering parts to get things ready while I waited for the money to come together. I DID research (since I couldn't get ahold of anyone I trusted for info) and I didn't find anything really relevant. The best article I found was here http://www.aa1car.com/library/ic697.htm and not everything in that exactly agrees with what Ben is saying, so I still don't 100% believe him. The article just says they have to be flat. I asked the shop to check... they said they were flat enough. Like I said though... I don't know what common practice is in the engine building community. This is the first major engine work I've done, so the only way I have to get the info is what the shop says and what the so called "experts" tell me.

[AaronGTR]

On the topic of the oil from the PCV system, I checked it today and there was no evidence of oil in the intake after two days of driving. I think that fix did the trick. I'll check it again on Saturday to be sure. Otherwise, all I can do is put more miles on it and keep an eye on the oil level in the pan to make sure it isn't still consuming oil at an abnormal rate.

[Joseph Upson]

GM uses torque to yield bolts with the MLS gaskets. My understanding or what I have read states that torque to yield bolts in the MLS application favors more consistant pressure over the heat cycles, the reason that non torque to yield bolts in some applications require retorquing after a while depending on the gasket in use.

Since the MLS gasket is a superior product generally speaking, to graphite, composite whatever gaskets, they perform well on properly prepared surfaces under higher than usual stresses. I'm not going to break out the physics book to review metallurgy to defend this idea, but most of us are aware of the purpose of torque plates when boring a cylinder.

With that being said it's not so far fetched an idea that studs and MLS gaskets might be a bad idea or at least very strict when it comes to tolerances as any distortion from the increased clamping pressure be it in the block or the softer aluminum head might lead to a leak problem. Copper gaskets are historically problematic in this area, how much less an even harder material if the surface is not up to spec.

The RA spec for GM MLS gaskets is very low so you can pretty much put your money on a 60 degree motor that didn't come with MLS gaskets from the factory not having a deck and head surface up to par for the MLS gasket even if they are perfectly strait.

[AaronGTR]

Now that is some interesting info. Thank you!

I had read in that article that more cars where starting to come with MLS type gaskets from the factory now, and was wondering what they do to make them work. I figure since they have to meet warranty requirements and spend millions on engine research and development, that whatever they are doing is probably going to give the best results.

[Fieroghini]

I just did the gaskets on my 3900 and GM had a very generous layer of a blue colored sealant around every hole and between every layer.

[SappySE107]

Torque to yield bolts are used because they are much more forgiving to the installation process that the factory uses. If you want the best, you have to do it precise, and that takes valuable resources like time and money. GM does not favor towards endless power capability and longevity over initial costs vs desired warranty periods. It is very easy for a stock GM motor to run torque to yield and MLS gaskets. MLS won't save your motor from poor tuning and detonation either, nor will studs.