Is new head gasket a must?
 

I have an 89 Supra non-turbo with 125,000 miles on it. The engine runs great. I've had no problems. I see a lot of people recommend changing the hg. Why? This seems like a rather expensive endeavor if you are not having major engine trouble. Isn't the hg rather hard to get to? Whats involved? How about valve cover gaskets? Are there two seperate gaskets or is it one large one? Can this be done by a weekend warrior? Any help would be much appreciated.

Thanks,

James

scruffboy, if you plan to drive your car hard or for a long time, the headgasket is a good investment to put some money into, the factory gaskets are pieces of s**t, trust us on that, it would be a good idea to replace it, its not that hard, but you will need to torque the bolts to the correct amount, i think its somwhere on this forum ive seen it a bunch of times but i dont remember it off the top of my head, you basically need the new gasket and a torque wrench, or any kind of wrench, and this could be easily done in a day...well half a day i say

on a non-turbo, i dont think its as necessary. its a long and fun job(sarcasm) that everyone should enjoy with 100 degree weather.

the reason the hg is a must is because.........

from the factory toyota neglected to torque the headbolts to the correct value
so they only torqued to 58ft lbs where they actually need 72ft lbs

depending on power output you want you can stay with the stock hg or upgrade to a metal head gasket
if you just wanna do the 12psi, exhaust, intake thing you should be fine (on a new hg)
for high boost/power applications a mhg is recommended (hks or cometic)

basically... the original torque setting is the failure on the 7m (it's a very capable motor)

7mges also blow hg's... just take a little longer hehe

related question
 

what appeared to be a metal head gasket ( a thick metal gasket between two thin gaskets, held together by 4 rivets ) came out of my supra. mostly it was the corrosion and overheating, but one of the thin layers was cracked between bores 5 & 6. 3 & 4 loooked like they were just about ta go thru as well. is a mhg really the end-all ?

understanding that my car is about as well taken care of as you'd expect ...

have you put it back together yet?

can you take pics of the block and head surfaces (clean preferably)

me ? yea its together, and the boss might have thrown the gasket out. i was going to frame it and the one i crimped when it went together the first time and hang them both on my wall.

i would say machining was not up to scratch for the mhg

just at a guess

half the gaskets on the manifolds were so old they splintered taking them off. don't know if thats a good thing but when i saw it i smiled.

65 alright as a torque setting ? 58 was recomended, so we went a little higher.

thats a badd thing if they splintered coming off...they musta taken a beating over the years

72 lb ft of torque is what everyone recommends for the head bolts. You DID use new bolts, didn't you !!??!! Hell, only $46 fron dealer. Where did you get your gasket set??? Only $155 online, 2 day mail, no shipping or tax, Ishino Toyota factory oem. You are replacing all the hoses, right??

... hey scruffboy, just don't do it. i spent a totally uncool amount of time doing it ( although it reallllyyy did need to be done ), and then i got into all the cool little gasket replacements that weren't in the head set, then there's the problem of things that just dont want to go back on properly. and still leak ...



paid about $ 300 for a head gasket set.
what is it with the head bolts ? half the people tell me they are torque to yeild and they stretch after the first use so must be replaced. and the other half tell me not to worry but retorque them after 10000 km.

yeps 72 for new stock head bolts & arp head bolts... 82ft lbs for arp head studs :)

normally for stock gaskets etc... i torque bolts to 72 then after 1000km i retorque... but generally i have found they don't move... maybe you could retorque at 5000km but i think ur better off leaving it alone

my 2c worth ;)

i did take it to dunedin after all that whussing i was doing. 1 week and i've almost got that thousand km's on it :D heh cost me a bit tho

took dunedins hills like they were straight roads !! click it outta o/d, only had ta apply more throttle on the really bad ones. was amazed and mind-blown by my car :bow:

few minor things like vaccum and oil leaks, then i can start boosting and such.