mk3 supra how to drive after head gasket

[2fast4u]

hello ive got a 1990 toyota supra turbo. it's a manual with a lsd differential. r`154 transmission. with the 7mgte engine. i just replaced my head gasket and the car has 20 miles on it after head gasket has been changed. my question is how should i drive the car. and also how long should i drive it this way. i used toyota head gasket with arp head studs, had the head resurfaced, pressure tested, and cleaned. also the head bolts were torqued to 86 foot pounds. my question is how should i drive the car. should i let the turbo spool over zero. please help.

[Awyman18]

i would definintly baby it for a bit...dont be redlining it anytime soon. go like 500 miles, then get into boost so it will start and kinda "heat seal" the hg, then at about 1000 retorque them and ur good

[2fast4u]

will then should i not make even 1 psi of boost my boost gauge goes up to 8 plus

[cre]

The term is heat cycle. It's more a matter of getting everything with a different expansion rate to nestle in good and cozy not just gaskets. There aren't any thermal setting seals in this vehicle.

Drive the car until it's up do normal operating temperature and keep it there for 5+ minutes. Take it home and let it cool completely. Repeat. After about 5 to 10 full heat cycles you should torque the head fasteners and inspect for any leaks. Then, check torque again after a few hundred up to a thousand miles.

I agree with taking it easy even after the first retorque session simply because if you've done something wrong it'll blow with less of a show than if you were racing. Use the time to make sure everything is perfect.

[2fast4u]

but when i drive it my turbo kicks in is this ok because i heard that i shouldnt let the boost gauge go over zero and if i do this its really slow like cars line up behind me

[cre]

Originally Posted by 2fast4u

but when i drive it my turbo kicks in is this ok because i heard that i shouldnt let the boost gauge go over zero and if i do this its really slow like cars line up behind me

If you've prepped everything properly it's not going make a big difference if you go over a couple psi. Staying at zero is unrealistic. Honestly, IF everything was properly prepped and installed you'll be less susceptible to issues as everything settles than if you had used head bolts.... But I seldom give anyone the benefit of the doubt.... So I'm going to say 'it's going to burn and you'll be driving a Honda in a week'.

If this was just a head gasket job you don't need to worry so much if everything was done "by the book". Just driver it mildly until it has been through a few heat cycles and retorque accordingly. ARP states that it is not necessary to retorque their head studs if they were installed to the specified 90 some ft lbs using molybdenum grease.... I still retorque them, it's cheap insurance.

If you've done something wrong (like not getting the block deck machined and installing a MHG) well, you're screwed anyway... It's just a matter of when it bites you in the ass (it's usually sooner than later).

RECAP: Drive like a SANE inner-city driver for a couple days, retorque, be done but inspect after 1000 miles.

[Awyman18]

yea like i redid my HG, and i was gentle with it, but i ended up not retorque them for like...9,000 miles, and they didnt need any retorquing...lol but i was gentle with it at first

[2fast4u]

How gentle like for example is around how many r p ms should I shift? Also how much boost should I let it make

[cre]

Originally Posted by Awyman18

yea like i redid my HG, and i was gentle with it, but i ended up not retorque them for like...9,000 miles, and they didnt need any retorquing...lol but i was gentle with it at first

I hope you accounted for striction when you tried to retorque, especially after that much time. It'll make a bolt read 140ft lbs of torque when it was only ever torqued to 100ft lbs.... . A bolt which has been through a couple heat cycles will stick and need to be backed out 1/8 to 1/4 turn before being torqued further.

For those not in the know: Striction = Static friction and is VERY important to pay attention to when dealing with fasteners. Fasteners need to go in good and smooth. If you encounter striction while tightening a bolt you'll feel it stuttering or popping... This is B A D and tells you that the fastener isn't lubricated well enough and is going to torque below what you read on the wrench.

Originally Posted by 2fast4u

How gentle like for example is around how many r p ms should I shift? Also how much boost should I let it make

As I said, drive like a sane person. If you don't know any whom you can mimic, try cruising between 2K and 3K and shift by 4500 to 5000RPM. Essentially drive casually but not like my 90 year old neighbor and not like a teenage human male. There's nothing written in stone on the matter and it's less finicky than cutting new rings.

[2fast4u]

so when i shift between 3500 rpm wont the turbo spool and wont this cause damage?