New Supra, noob questions

dugums

Better, Faster, Stronger
Apr 10, 2007
699
0
16
Chicago, IL
Let me first say that I really appreciate all of the great info on this forum. I am not exactly new to the supra world, but it has been about 8 years since my last mk3. Anyway, I have never had a problem with a HG before thanks to the fact that my previous Supras were already outfitted by their previous owners.

That said, I picked up an 89 Turbo today with 83k on the clock. As far as I could gather, it is running the original HG. The previous owner installed a boost controller and it looks like the motor was run (at least occasionally) at 12psi.

My main question is what to do about the unknown status of the headgasket. I won't have the time to do a complete rebuild down the road and have about 3 weeks to get this car dialed in before my other vehicle has to be turned in.

My only goals for this car is to be a reliable daily driver (well, as reliable as possible, I guess) I don't plan on doing any further power upgrades and, in fact, I will be removing the performance exhaust the previous owner had installed in favor of something a little quieter.

I will most likely use a skilled mechanic to perform the repairs for me, as I am not very confident in this area.

We are going to do compression tests tomorrow and go over the car in general. Is there anything I can have him do to help keep the car going? Or do I just wait for the HG to go bad later? Would putting in a new HG as preventative maintenance be worth it (or possible).

Sorry for the long post, I did use search to try to find my answers, but I didn't find anything that made me confident I was taking the right steps.
 

dugums

Better, Faster, Stronger
Apr 10, 2007
699
0
16
Chicago, IL
super.secret.supra.club said:
change it to a MHG if you can, even if running stock. after that you never have to worry about it again.

Would this involve getting the head/block machined? Or is this only necessary if the HG has already been compromised?
 

Mrbaboon

New Member
Jul 13, 2006
277
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0
Victoria, BC
If unsure about the condition, replace it.

If you only go back to a factory gasket and aftermarket fastening hardware, it will likely stand up to what you plan on throwing at it.

If you decide to do a MHG, do it properly and pull the motor.
 

socc924

Member
Mar 31, 2005
396
0
16
40
CT and Philly
Retourqing the head bolts is taking a risk. It may cause the headgasket to let go imediately, it may seal it better and last forever, or it might just go down the road sometime. I would personally suggest taking the time and replacing it with an oem head gasket and arp hardware. It wont cost much and if your mechanic is as good as you believe it wont be a problem down the road.
 

dugums

Better, Faster, Stronger
Apr 10, 2007
699
0
16
Chicago, IL
So, is the OEM headgasket a suggestion because it will seal properly without milling, etc.? Any idea on how many hours it should take?

I am not entirely opposed to doing work myself, but the degree of difficulty would be the main issue. I can follow instructions without a problem, but would rather not take something apart only to not be able to put it back together properly.

As far as my mechanic goes - he's not a supra specialist, but he does do excellent, precise work.
 

TurboWarrior

New Member
Apr 1, 2005
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Canada
^yes you always have to have the head machined. Its a long head it will warp. Buy a headgasket kit too. It comes with the hg and every seal, gasket, and o-ring you need. Give the machinist the kit when he does the head and he will use what he needs. then use the rest to put the motor back together.
 

rumptis

나는 제프가 당신을 사랑
Aug 16, 2005
814
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0
48
North Vernon, IN
Replace with stock style HG and us ARP studs. Torque down to 75 to 81 ft/lbs and never worry about it again. Unless you go crazy with boost.

If you use stock style HG then you don't have to get everything machined down perfect. Unless something is wrong you wont need to get any machining done at all. They are pretty forgiving.