[shiva]

I decided to get some ARP head bolts and to replace teh HG in my 6m. I think I'm going to stick with a stock type headgasket because I dont want to disassemble my head and get it machined and all that. Should I bite the bullet and get a the redesigned gasket from Toyota? Can I go with the ones that sell on ebay (felpro / beck arnley etc)? Want to hear peoples experiences/suggestions. I plan on one day running near 14psi from time to time.

Thanks,
Shiva

 

[SilverMk2]

14 PSI on any stock HG sounds like a bad idea to me.

 

[trdmkii]

If i were you i would purchase a metal head gasket for the 7m-gte, all the important water jackets are there. A stock headgasket is much weaker, if you planning on running boost that high you should probably get a metal one.

 

[shiva]

Yeha I just kind of shrugged the MHG idea off 'cause I didn't want anyone to recommend it because I don't want to deal with it I guess it would be a good idea. To get a head machined, do I need to remove valves, cams, housings, etc? Is it hard to rebuild a head?

Does anyone have a rebuilt head for sale? Maybe if my parents help me out with the costs I'll just get everything done with at once.

Thanks so much for your suggestions

Shiva

 

[WadeT]

I decided to get some ARP head bolts and to replace teh HG in my 6m. I think I'm going to stick with a stock type headgasket because I dont want to disassemble my head and get it machined and all that.

Why does the head have to be machined with a MHG and stock one does not? C'mon man. People have this image in mind that the head and deck need to be machined for perfection for a MHG and that is not true. The idea behind the machining is to take out the high spots on the head which tends to warp much like the shape of a banana. This machining needs to be done no matter what type of gasket your using. If your head isn't warped outta spec then there is no real need for machining. All that matters is that the surface is clean and flat.

Don't waste all that time and money doing a headgasket job only to endup saving $30 on stock HG over a metal one.

Personaly, I'd do a retorque on the stocker till it blows or if it blows.

 

[shiva]

The idea behind the machining is to take out the high spots on the head which tends to warp much like the shape of a banana. This machining needs to be done no matter what type of gasket your using. matters is that the surface is clean and flat.

Personaly, I'd do a retorque on the stocker till it blows or if it blows.

I will check to see if the head is reasonably flat. I'm just a bit confident that the head won't be warped out of spec-- 60k on it, though who knows its history, so maybe this confidence is unfounded...

I was under the impression that the kicker with a MHG is the smoothness, that stockers work better with a slightly rougher smoothness while MHG need to be machined to get something insanely smooth to seal. So if the head's flat within spec, there's really no need to machine for a MHG??

how do i measure this, btw?? where do i find something flat and as long as my head?

Shiva

 

[CRF_Rider]

Get the head and deck machined if you go wtih a MHG. Also make sure the machine shop can put a smooth finish on both of them.

If you take off your stock HG you will notice it leaves a silver residue behind. THat is put on them to seal any imperfections on the head or block. The MHG's dont have this and can not seal a rough surface.

The stock gasket will most likley blow even at stock boost, it just may take a while. If you are going to run 14psi it will blow the first time you hit boost (ok, maybe the second or third).

You will have to grind a little on the upper, rear timming belt cover to get it on once the MHG is installed.

 

[WadeT]

I will check to see if the head is reasonably flat. I'm just a bit confident that the head won't be warped out of spec-- 60k on it, though who knows its history, so maybe this confidence is unfounded...

I was under the impression that the kicker with a MHG is the smoothness, that stockers work better with a slightly rougher smoothness while MHG need to be machined to get something insanely smooth to seal. So if the head's flat within spec, there's really no need to machine for a MHG??

how do i measure this, btw?? where do i find something flat and as long as my head?

Shiva

I ran my old 7mgte with HKS MHG, ARP studs with no machining and it never leaked. The real key is to get the surface clean.

With the ARP studs and moly, you can torque a MHG down to 90 foot pounds, 130 with motor oil. The idea that the small pits on the block deck will cause a leak with out machining seems to make sense but I have yet to hear/see any evidence that they cause leaks with a MHG and ARP studs. BTW, I've never "decked" any of my blocks and haven't had any leaks.

Not to give you bad advice, but it is always rememended to have the head "kissed" just to take out the old gasket indentation as Aluminum is very soft.
You can get a nice straight edge (large framing square) from home depot.

 

[shiva]

Ok,
I think I've decided to go with ARP bolts and a stock 7m composite gasket. It's the redesigned one with the little copper ring around the bore and what not, and from what I've read on supraforums, it does very well even at high boost, so long as you aren't detonating.

I still can't sort fact from fiction here, and I'm sure it isn't quite as straightforward as I'm trying to make it. But it makes sense to me that if I can't find a shop to give my head a really smooth mirror finish and yank my block over to a shop to get it decked I ought to stick with a composite gasket. Depending on how warped the head and block are, I will see whether to machine them or not-- I've heard that it is really stupid to machine the head and not the block, because they tend to warp in the same pattern. Unless the block's pretty straight and the head's reaallly warped, I think I'm just going to make sure the surfaces are relaly clean.

I appreciate all your guys' advice-- if you think I'm really making a mistake, let me know.

My question now is what other seals/gaskets do I need if I'm doing the head gasket? Should I get a complete head gasket kit for the 5m ($130), and add on the 7m's head gasket for another $45? Or can I get by spending less?

Thanks again guys,
Shiva

 

[jdk_ii]

7MGTE's can run up to 15 psi with stock head gasket and ARP head bolts,
assuming all is good.

As for head/deck surface prep, the first concern is they are "flat".
Better that it's flat before machining, otherwise some issues might arise.

Second, is surface finish. The sufaces need to be a finish level
of RA 30. Blanchard ground heads/decks may have very fine grooves.

The argument it has to be a super mirror finish is over stated.

If one is trying to obtain this, it's really expensive, and a place
that does this also does gasket-less industrial fitting (like high
pressure oil pipes - they don't use gaskets).

For more MHG machining, this article I found is excellent ->
http://www.babcox.com/editorial/ar/eb30320.htm