metal headgasket.

[hottscennessey]

ok, i have a 7m motor with anywhere from 20-40k miles on it. i want to put more power on this but i dont want to blow my stock head gasket and crack the head or the block. do i have to get my head AND my block resurfaced? is there any way that i can just leave my block in the car and try to surface it really well myself. I've heard of other people doing this, even with metal gaskets. I'd have no problem taking the head to a shop to get it re-surfaced, and some tell me thats the only part i should need resurfaced since i've never had a blown head gasket. any thoughts? are these people crazy? thanks

 

[supradan22]

No matter what you do with the 7m the chances are the headgasket will break either way stock or modded the headgaskets are faulty. Havent really heard much about having the block resurfaced the 7m blocks are strong but im not the right guy too answer that question.

 

[empera]

http://www.supramania.com/forums/showthread.php?t=1643

this thread might help.

 

[shaeff]

No matter what you do with the 7m the chances are the headgasket will break either way stock or modded the headgaskets are faulty.

this is a common misconception. it is not the headgasket that is to blame. the problem is the low torqe figure of the stock headbolts. factory specs call for 52 ft. lbs. which is entirely too low a figure to hold the head tight enough to the block. the bolts loosen up and back out a little over time, and thats what causes blown headgaskets for the most part. (aside from reasons such as detonation/running lean etc...)

Havent really heard much about having the block resurfaced the 7m blocks are strong but im not the right guy too answer that question.

the blocks being strong doesnt really have anything to do with resurfacing. having a good solid block doesnt mean that the RA (roughness average) will be correct for sealing a headgasket well. over time things warp, and/or get pitted. it happens, unfortunately. we deck the block to make sure its not warped, pitted, and to make sure the RA is proper for the type of headgasket we use. we machine the head because it's aluminum, and it warps much more easily than iron. (our block) and to make sure it's also the proper RA.

-shaeff

 

[hottscennessey]

yea, well i've already re-torqued, but i want to run higher HP than just like 330 or so.. so i want something that can handle the power. Has there been anyone on this forum that has put a metal headgasket on their unblown motor without getting the block professionally re-surfaced? I would like to, if i could just clean the block really well by myself (i dont wnat to take the block out of the engine bay) and get the head professionally re-surfaced since its alluminum. anyone think this is an ok/good/bad idea????

 

[Idealsupra]

search: cometic

 

[hottscennessey]

wow, that came up with alot of information...

so idea.. you still stand strong with this statement made in a previous post?

Quote:
Originally Posted by TurboWarrior
Thats not the issue for me. I was going to buy the arps and get a cometic HG but I was told that if you don't deck the block it will blow. I can't afford it time wise and money wise to pull the block.



WOW...BIG misconception...you DO NOT need to deck the block for a COMETIC hg. thats what makes them so much better then the hks or greddy ones...

for a cometic you simple need to resurface the head and check the block for warpage...if there is none... which more then likely there isnt....simple clean the surface with a razor blade and brake cleaner so its nice and smooth...and youre good to go with the cometic.

the RA on the cometic is a lot more forgiving then the hks or greddy mhg which DO need the block resurfaced.

 

[Idealsupra]

yes i stand by that...AS LONG AS THE FOLLOWING APPLY: there is no warpage on the block, there is no pitting on the block, and there are no lumps or dips or anything...

basically meaning if its visually straight and a straightedge says no warpage...and yuo can clean it nicely with brake lceaner and razor...YES what i said is true.

 

[mk3forme]

ok so is that the consensus of this forum? That cometic is better than the HKS or Greddy. And of course im looking for facts based on personal experiences and not opinions. Thanks in advance

 

[boost PSSH boost]

I am running the grex (greddy) without a problem.

 

[hottscennessey]

i'm sure that the greddy and HKS gaskets hold up great with the specified RA, but if i can possibly run the cometic gasket without professionally resurfacing the block, then thats what i'll go with. thanks a lot everyone!

 

[Idealsupra]

i cant stress enough to MAKE SURE the block is in good shape....

 

[hottscennessey]

oh trust me, i will, I'm pretty anal about that sort of thing, i'm going to have a compression test and everything before i even think about taking the head off.

 

[xride63]

this is a common misconception. it is not the headgasket that is to blame. the problem is the low torqe figure of the stock headbolts. factory specs call for 52 ft. lbs. which is entirely too low a figure to hold the head tight enough to the block...

this is true. the stock HG is fine the problem is that toyota didn't torqued them enough. its been said they come torqued from 52-54 ft lbs. they should in reality be torqued anywhere from 70-80 ft lbs. of course don't try and retorque it just yet. get ARPs first so you don't break a bolt while torqueing because you have no idea the tolerance on the stock bolts or how many times they have been touched.. not to mention they can be anywhere from 20-13 years old.

 

[Justin727]

greddy and HKS mhg's are great if the block and head are prepped right. Now for the cometic still a little weary of that mhg even tho many have used it no problem except i plan on pushing some power.. Wish more people would use the cometic and give good feedback!

 

[GrimJack]

Do you know what kind of power you want to run?

The option that nobody has mentioned is putting in a new stock gasket. They are on a whole new level of forgiving when it comes to the RA, and they are more than sufficient to 400+ hp.

 

[shaeff]

...of course don't try and retorque it just yet. get ARPs first so you don't break a bolt while torqueing because you have no idea the tolerance on the stock bolts or how many times they have been touched...

eh, i re-torqued with my JDM motor. the stock bolts were never stretched fully, and wont break when re-torquing to 72ft lbs. many, many people have done it. i personally havent heard of a single time when one broke. the tolerance was discussed once before, i dont remember the exact figures, but i do know that you're not going to snap one if torqued to 72ft lbs.

-shaeff

 

[Idealsupra]

greddy and HKS mhg's are great if the block and head are prepped right. Now for the cometic still a little weary of that mhg even tho many have used it no problem except i plan on pushing some power.. Wish more people would use the cometic and give good feedback!

err bryan (slow66 on SF) uses one and has one of the fastest mk3s in the comunity...hes had ZERO problems...

mine held up to MAJOR detonation ....i got VERY lucky that it did...my timing got advanced a LOT somehow...... mines still holding fine.

theyve been being used in bikes for years...no problems there....its not like they just came out of nowhere to make the gasket for our car

 

[tkvtec]

I believe the Cometic and Titan are the same. Have a cometic in my car, no problems. Not much for boost yet, but no problems nonetheless.

 

[hottscennessey]

wow, this is an old thread