head gasket question

[585Soup]

I am looking for some direction to find where I can buy a specific one.. I don't plan to go Metal.. but I heard there is a newer OEM style that has rubber or something incorporated with it, that's suppose to be a fairly good gasket. I've searched and searched, but can't seem to find this one, nor a 83mm gasket. I'm assuming that's what the bore size would be.
I'm not sure on thickness yet. I don't have a bad head gasket, but I'm doing the valve covers and all the intake gaskets, so I might as well spend the extra cash and time to just replace it for security. I have hopes of some decent power out of the car, but have the head and blocked machined is just too much for me. I'm hoping to not even need to have the head done. But i'll be checking that when I get it off.

thanks!

 

[SupraTrbo89]

You will not get a ton of power out of the car without a metal head gasket period. And I wouldn't take the chance of putting in a metal head gasket without the proper block and head resurfacing. If you don't want to do all that get a stock head gasket from driftmotion and a set of arp head studs and torque it to the specs per the included instructions. If the head is in good shape you should be able to run 10psi but wouldn't go much more than that.

Also, it costs about $200 to $300 to have the head resurfaced once removed from the car so you may be able to get away with just having the head done and use a metal head gasket but the block would have to be perfect. There are so many people that try to get away with installing a metal head gasket with out the proper prep work and they end up redoing the work. In closing, if the $200 to $300 is an issue for you financially I wouldn't be adding power to the car.

 

[585Soup]

Understandable. Now, as for getting the block perfect, this means level(which I should be able to determine with feeler gauges and straight edge, my dads a machinest so I can get these) and then, just no residue left over from the prior gasket/corrosion(if the gasket had gone). I think I'll just pull the head and determine where to go. I mean, the stock gasket hasn't gone, so I would have to assume the block is fine. It's crazy how these head gaskets can't take much psi.. when my old subaru pushed 18 with out a problem. lol.

 

[3p141592654]

It means average surface roughness below 90 RA-nm. Actually 25 would be a much better target, but 90 is presumed acceptable. This is a different spec from absolute flatness that you are referring to.

Also, the stock OEM gasket will leave deep grooves around each cylinder in the block from the metal fire rings. These are the primary source of problems when switching to an MLS.

The thermal expansion of the aluminum head and iron block on the 7M results in about a 0.5 mm of difference in length from cold to hot. So each drive cycle you scrape that gasket across the surface of the block, and after many years it leaves deep scars.

To give you some frame of reference, here is the ra associated with different sandpaper grits.

View attachment SIC-newsletter2.PDF

 

[585Soup]

I plan to go with an oem style.. when i search, i find the one by drift motion, i know toyota directly i can get one.. what is the hks bead type? or is that just a metal one.. trying to figure out the differences, and my best option before i buy anything. any clarification would be great. I've done a lot of googling and forum trolling and i can't seem to find a clear answer

 

[suprarx7nut]

I plan to go with an oem style.. when i search, i find the one by drift motion, i know toyota directly i can get one.. what is the hks bead type? or is that just a metal one.. trying to figure out the differences, and my best option before i buy anything. any clarification would be great. I've done a lot of googling and forum trolling and i can't seem to find a clear answer

I'm not sure if Driftmotion is the Toyota OEM or not. If it's below $80 it may be a FelPro brand or other.

I have always used the Toyota OEM HG from a Toyota Dealer. My local dealers are a RIP OFF when compared to the good online dealers. Think mark ups of 50% or more. I use Champion Toyota in Texas and Elmhurst in the midwest (Curt from Supraforums can provide discounted pricing for forum members).

HKS (of any variety) is metal. If you're not removing the block do not use MHG. While it's possible to get the block to seal it's not easy and without some luck you could just have another BHG. If you're going for big power, remove the block and do it right. If you're not going for big power then you can use a regular HG and enjoy the crap out of it.

My OEM HG has lasted a long time (4 years+ and 35k miles and counting) on 10-12 psi on a 50 trim CT-26. It's plenty fast for a fun, sporty car and very reliable.

In my mind there's a pretty big jump going from right around fuel cut (~320-340whp) to much beyond that. More than that power requires a lot of little upgrades that add up. Tuning, Air metering, fuel pump, injectors, intercooler, piping, BOV/BPV, clutches are less friendly, CT-26 turbo's aren't very efficient, etc... I've sat just under that limit and the car has been really enjoyable and reliable. It's still faster than most other cars on the road, I just won't be beating any big time supercars.

Also, this may provide some good reading material for you: http://yotamd.com/toyota/mk3_supra/bhg.html

 

[chevyguyjoe]

The one Driftmotion sells is indeed the OEM Toyota headgsket with the updates. I have a brand new one i didn't use if you are interested. Check your pm's. Personally i did like everyone says dont do, and i used a Cometic mls gasket on an unprepped block. I think the previous owner had it machined, but it was pretty rough. Its held for over a year now, but that has only been 4,000 miles. I had to use an mls due to the large amount that has been machined off of my head. I was told the head had never been off the engine when i bought the car, upon disassembly i discovered otherwise. That's why i have the unused Toyota gasket. But i digress.

 

[585Soup]

I just saw the PM. i ended up actually cutting a deal with a kid that works for toyota, i'm trading him a front lip i never used, for the oem updated one. well i havent traded yet, but he placed the order for the gasket. i ended up ordering ARP head Bolts as well, not studs. i dont plan for huge power until i pay the bills off for everything else i've fixed, plus the cost of the car. i just want a reliable driver for now.

 

[chevyguyjoe]

Cool beans.

 

[SeeUSmile]

http://www.supramania.com/forums/sh...rience-with-AJUSA-gaskets-cams-or-other-parts i believe its this one you're talking