Anonymous HG Poll

[thedave925]

You should have a "Not blown No prep OEM HG" option

I am doing a HG job now.
I will use a felpro composite to unmachined surfaces for stock boost.

My headgasket never blew. It started seeping very slowly last year, and was held off by a retorque at the time until a few weeks ago when the supe began noticably leaving its mark.

Another telltale sign I noticed was that my oil pressure gauge wasn't reading accurately even after installing a new one. The gauge would read high and take a long time to settle down. Nothing showed in the oil during changes though the cap smelled sharp. The leak was so minute that a simple compression test would've probably been wrong.

When I pulled the head, I found that this was the original headgasket, and there was no sign of contamination, obvious corrosion, build up or what not. There was hardly any pitting around the coolant holes. Due to time and head, the headgasket had aged harder on the exhaust side. No head warpage. Very discreet.

I've calmly cleaned my surfaces with a brass wire brush and plan to brake quiet the felpro and decks, and torque to 85ft lbs with moly and studs.

This is preventative maintainance with coincidentally good timing.
-Dave

 

[dugums]

I thought I had that option???

Composite (factory or felpro, etc.) + No machining

 

[Junior]

should also add an option for "misdiagnosed" meaning... it wasn't actually a headgasket.

There's people that immediatly change the head gasket 'cause they think that's what the problem is when infact it's something completely different, but they bandwagon just 'cause everyone tell them that it must be a headgasket.

as far as all the guys saying "do it right" and "anyone who doesn't do this or that is getting kicked in the nuts" you need to shut the fuck up. This is about gathering data, not pimping the size of your e-peen 'cause you can overzealously follow "cover my ass" walkthru's, when you don't actually know shit about your car or working on an engine.

 

[dugums]

Even if it was misdiagnosed, it doesn't change the preparation method. This poll is to measure the success rate of different options, not just the rate of head gasket failure. If you opened up the engine and found the head gasket was not blown, you either put in a new one, or not. The answer as to prep still applies, you either did some, or you did not. Hopefully we can get a large data set to offset the importance of highly modified cars, etc.

 

[Shytheed Dumas]

I know you're getting a lot of shoulda, coulda suggestions, but it might be helpful for people to state how many miles since the change along with maybe estimated HP. I think the ultimate goal here is to determine the expected lifespan of the headgasket and those numbers would definitely be a part of the model along with the degree of machine work. I love this kind of thing!

Edit: It's been just over one year and 13,500 miles on a composite HG with head machining only, and ARP bolts at 81 ft-lbs. Stock boost on basic supporting mods until last week, and now running 11 psi and 213 whp (SAFC will fix that!). NO PROBLEMS!

 

[rumptis]

i swear to god if i see ANY number other then ZERO next to any of the "no machine work" options someone is getting kicked in the nuts.

Start kicking......

I just cleaned everything really well and used an Composite HG and ARP studs over a year ago.

I ran 12-14 PSI just off Fuel cut for about 8 months of that till my stock CT started using more oil and now have cut it back to 8 psi and boost creep to 10 psi.

Still running strong.

 

[dugums]

Start kicking......

I just cleaned everything really well and used ARP studs over a year ago.

I ran 12-14 PSI just off Fuel cut for about 8 months of that till my stock CT started using more oil and now have cut it back to 8 psi and boost creep to 10 psi.

Still running strong.

Composite or Metal HG?

 

[rumptis]

Composite.

Add that to my post

 

[Junior]

Even if it was misdiagnosed, it doesn't change the preparation method. This poll is to measure the success rate of different options, not just the rate of head gasket failure. If you opened up the engine and found the head gasket was not blown, you either put in a new one, or not. The answer as to prep still applies, you either did some, or you did not. Hopefully we can get a large data set to offset the importance of highly modified cars, etc.

fair point ya. I just figured that if it wasn't warped in the first place, the importance of machining is gonna go down ALOT.

 

[Sawbladz]

I didn't have the block machined but it was checked and re-checked for 20+ min by a Toyota mechanic who has done TONS of 7M's with MHG. The head was a fresh head from the machine shop. We also used MHG spray from Chrysler. No problems.

Might want to add the spray option...thats another topic of great debate.

 

[billspreston01]

huh. nice thread
104,000 mile motor.
Toyota gasket with arp studs @ 85ft-lbs (whatever spec was) and moly lube. Scraped the head and block clean with some light sanding.
Running 9psi winter and 12-13psi summer for 2 years.
Currently have over 140,000 miles on the clock and over 40 drag passes.
0 problems.
266hp 292 tq @ 10psi stock turbo.

 

[starscream5000]

Yes, a copper spray or Permatex brake quiet for both composite and MHG options should be in there as it's a hot debate around here at times.

 

[bigaaron]

Trying to figure out what "right" is. It seems there are different opinions. The article I linked should explain why the question came up. I trust Reg's opinion quite a bit more than most.

I am also weighing risk/reward based on my options.

I am currently planning on doing a composite with the head machined, which technically is "right", but I am trying to see how risky it would be to step up to a MHG.

Since it seems (according to the write up) that getting the block machined to the correct tolerances is going to be tough, I don't know that I want to try.

Anyway, this isn't an argument about HG, rather just trying to gather honest, empirical data to evaluate my decision.

The right way to do it is to surface the head and block properly for a new metal headgasket. The poll really has no value. If you made a poll on the internet and asked if 2+2=3 or 2+2=5, would that make the outcome right? We can sit here all day saying what is the right way to do something, and at least 50% of people will still do the cheapest option. What they don't consider is that the cheapeast option is the most expensive option, after doing the job twice.

 

[Jaguar_5]

I'm willing to bet that the 2 people who check MHG, Head and block machined, still having problems, forget to deck the front plate with the block!

 

[starscream5000]

Lol, yep, don't forget that piece when doing it!

 

[dugums]

The right way to do it is to surface the head and block properly for a new metal headgasket. The poll really has no value. If you made a poll on the internet and asked if 2+2=3 or 2+2=5, would that make the outcome right? We can sit here all day saying what is the right way to do something, and at least 50% of people will still do the cheapest option. What they don't consider is that the cheapeast option is the most expensive option, after doing the job twice.

I don't believe it's as cut and dry as that. Many people end up using a machine/race shop to do their machine work, not knowing if it is to the proper spec. According to Reg, it seems this will be worse than leaving it alone (provided that it is flat).

As far as the poll having no value, I think that is completely wrong. While agree that having both the block and head machined to the exact proper specs is clearly the "right" way to go, it is not an option for some people.

Anyway, I think it is nice to see what people have actually done, and how it worked.

I am VERY HAPPY you think this way though (about the "right" way to do things) as my turbo and exhaust manifold are on their way to you as of this morning!:icon_razz :biglaugh: :icon_razz

 

[dugums]

Aaron,

While I am at it, let me direct a question to you, as from everything I see I am inclined to listen to your advice over many others:

If you had ONLY the following two choices which would it be:

Keep in mind boost will be kept in check (albeit from your 57 trim upgrade). Shooting for 350 HP at the most:

1. Head Machined + Composite Gasket + ARP studs.

2. Head Machined + Metal Gasket + ARP studs. Block is not machined but in excellent, flat condition. Maybe the possibility of having it lapped in the car.

My thought is that there doesn't really seem to be much upside to using a MHG in this scenario and a big downside if it doesn't seal properly.

I have pretty much decided that I will NOT be doing a MHG unless I go ahead and rebuild the bottom end (and have all the requisite machining).

 

[bountykilla0118]

sounds like you need to get the stock h/g with arp hardware.

 

[Idealsupra]

wow there are 7 VERY brave or VERY dumb and/or VERY lucky people on these boards right now...AND there are frankly 2 VERY STUPID AND LUCKY people on these boards....

im shocked! shocked i say!

 

[steven89]

wow there are 7 VERY brave or VERY dumb and/or VERY lucky people on these boards right now...AND there are frankly 2 VERY STUPID AND LUCKY people on these boards....

im shocked! shocked i say!

most of the people that are running composite/stock HG just dont run that much boost.

I have a composite in mine with ARP studs and im gonna be running 10psi and a max of 12. A composite will hold that no problem.