Finishing Rebuild, need help.

[hammerhead]

Hey guys, I am currently putting the final touches on a rebuild that has been sitting in the garage for over two months. I have replaced the following:

Main and Rod Bearings
Piston Rings
All gaskets including valve seals
HKS 1.2mm Bead Head Gasket
ARP Head Bolts

It is a 7MG-TE egine, and I got the HKS EVC to control boost. Daily drive will be at stock boost but for race I have been told I should be safe at 14 psi.
I have a few questions to help me complete everything.

1. To what specs would you torque the head bolts with the ARP bolts, if I plan to run max boost?
2. How should I set the timing, if I plan to run at stock boost most of the time, but I want to be prepared for 14 psi?
3. If there is anything that I am overlooking, please enlighten me..

I really appreciate your input.
Thanks.
Delmer.

 

[IJ.]

Were the Block and Head surfaced for the HKS?

 

[hammerhead]

The block was checked to make sure it was straight, and the head was shaved. just enough to straighten it, which was quite a lot.

 

[IJ.]

The Block needs to be very smooth for the HKS gasket to work I believe it's one of the more fussy MHG's.

 

[GrimJack]

IJ is correct on this.

I'd leave the timing at stock levels, and I'd torque the head to 100ft lbs.

 

[hammerhead]

Ok, I'll talk to the mechanic about the block.

So it would be safe to run a race now and then at 14psi without the time retarded?

One more thing, should I re-torque the head bolts after break-in, or is that just a myth I heard.

 

[IJ.]

I probably would have gone for a 2mm gasket if I wanted to run 14 but if you put some good gas in it you should be safe (always assuming everything else is right)

 

[lagged]

before raising the boost to 10 or above 10psi i would do the fuel system. cars are old, fuel pumps fail! replace the fuel pump, upgrade fuel injectors, add an adjustable FPR.

 

[shaeff]

before raising the boost to 10 or above 10psi i would do the fuel system. cars are old, fuel pumps fail! replace the fuel pump, upgrade fuel injectors, add an adjustable FPR.

good preventative maintenance!

-shaeff

 

[TONY!]

...and the head was shaved. just enough to straighten it, which was quite a lot.

If I haven't misinterpreted the TSRM and the machinists that I know, you can't just mill a head to make it straight. You mill a head to make it smooth.
The max a head can be warped is only .0039" http://www.cygnusx1.net/supra/library/TSRM/em/EM_42.html
When a head is warped more than that, it needs to be straightened by a different service where they straighten the whole head rather than just cut one side to make that side straight.
If you just cut/mill a side of a head to make that smooth the cam tunnels will still not be straight.
This has a bad effect on the cams as they will have to create a new bore which would lead to greater oil clearances.

Also keep in mind that to some extent the middle valves in the head will be opened more, before and after in their cycle as compared to the valves in the front, and probably more so, the valves in the rear.

Maybe the machinist took off a lot because you had pit marks rather than a warped head, or maybe you went to one that is not too bright or experienced.

 

[hammerhead]

yeah, it was mostly just pit marks. Mostly cuz part of the head gasket had actually dissappeared.

 

[hammerhead]

Thanks a lot for the input guys. I'll have to take it easy until I can upgrade the fuel system I guess.

Oh, and about re-torqueing the head bolts, any input on that?

 

[GrimJack]

I have never retorqued mine. I've torn the engine down several times, and they have always been on there DAMN tight when I do, so I don't worry about it.

YMMV, of course.

 

[IJ.]

Oh, and about re-torqueing the head bolts, any input on that?

I do it but then I'm a bit old school

 

[GrimJack]

How about this - it certainly cannot hurt as long as you are running a metal head gasket. There are theories that it might damage a composite gasket, but we don't have to debate those one way or another here.

 

[hammerhead]

Ok, you guys probably figured out by now that I am new to mechanix, especially with turbo'd vehicles (I used to drive a civic).
Does the stock turbo setup for a 88 supra have an internal or external wastegate? I think it's external, but I want to be sure.

thanks.

 

[GrimJack]

Internal.

 

[hammerhead]

damn i suck. heh. thanks.

 

[IJ.]

Hammer: LOL not at all at least you're learning !

 

[hammerhead]

Thanks, I'm trying to learn as i go along. Sometime in the future I want to take some official education in automotive technology. Ok, back on topic, i'll let you all know how the supra will turn out. It should be ready early next week.