New addition to the BHG club!

[CPAutobahn]

Yep so I was headin' down 64 going back to Lextown when all of a sudden every MKIII owner's fear... became a realization for me. shit-ton of white smoke... the fresh sent of burnt(ing) ant-freeze (actually not too bad of a smell) and all in the rain. Must say it was an EXCELLENT day "off"!

Anyway... I now have several questions for anyone who'd like to help...

Which MHG to go with? As far as thickness.. does it matter THAT much?

ARP Head Bolts or Studs?

If I decide I really don't feel like turning the wrenches myself on this project....
1) who's the man to see?
2) how many monies?
3) how soon can they have it back to me?

thanks fellas

Cody

[sturbo87]

as far as bolts and studs go, im not sure if either is better, but you can remove the head easier in the future if u get bolts because you dont have to lift the head over the studs. id say HKS 1.2 mm bead type gasket, andrew magee is the man too see...he works at grossman tuning and his name on here is andrew91pgt, PM him sometime and next time i see him ill mention it to him. he usually works for pretty cheap but i wouldnt know an exact price

[supraguru]

the thicknes of the headgasket determines your final compression ratio. big boost get a thicker head gasket. also some guys run a hks 1.3mm gasket then a .1mm gasket on that as a crush plate

[StreetSports]

as far as bolts and studs go, im not sure if either is better, but you can remove the head easier in the future if u get bolts because you dont have to lift the head over the studs. id say HKS 1.2 mm bead type gasket....

Head studs are always preferable over bolts. Also, for the very same reason that you have to lift the head over the studs applies to installing the head. Meaning that you pick the head straight up, or place it on straight down. This way there will be no scraping of the mating surfaces that can cause additional problems.

We have had almost as many HKS head gaskets re-fail as OEM's. About the only ones we have had to survive well are the one's from GReddy.


If I decide I really don't feel like turning the wrenches myself on this project....
1) who's the man to see?
2) how many monies?
3) how soon can they have it back to me?

1) We can perform this work for you, as I am sure there are many capable people out there who can also. However, we have had a bit of experience with these. I believe the first one of these that we did was back in '97 or '98.

2) I am at the house right now and so I do not have access to my labor guides. If you have not chosen by Monday what to do, then just call me at the shop and I can get you an estimate of the costs. However, if the head were measured and needed to go to the cylinder head shop, that machine work would of course be extra. But the job would be complete and correct. And we put a lifetime warrantly on our work.

3) Depends on several factors. Parts availability and machine shop time (if required) are the main factors, as we do not have direct control over these.

Whether you would like to choose to use us either as a source for the parts or the labor or both, we wish you good luck on this project and hope it turns out well.

Shawn @ Street Sports

[supraguru]

street sports is there a reputable machine shop in town becasue i heard there arnt any speed shops that can resurface heads and decks worth a crap in louisville

[sturbo87]

maybe not a speed shop...but bell motorworks downtown does a really really good job with stuff like that from what ive heard.

[CPAutobahn]

thanks for the help fellas...

pretty sure I'm gonna do most of the wrenchin' but I am gonna need a good machine shop. The way I see it...might as well get a vavle job (and possibly a port :D ) while I have the head off.

I'll give you a call later on today StreetSports

[1FKNFST7M]

Keep in mind If you use a MHG then you will have to have the Block & the head milled. As far as I know there isn't any machine shops in the Lou or Lex. area that will mill the block with it in the car & assembled. Everyone I checked with wanted it removed, Not sure why. I know several dosen other owners got theres milled using a hand lapping tool. If you want to save the trouble you can use a Felpro HG. Myself & other Supra owners are running 15-17 psi on stock upgraded CT-26 w/o any problem. Just make sure you have the supporting mods & that your watching whats going on so you don't detonate. That along with a bad mill job will even kill a MHG. Keep an eye on things with a Boost, EGT, A/F or Wideband gauge. As for using ARP studs I'm sure you have to pull the engine to place the head on & take it off later when needed. ARP Bolts tq'ed to 72 ft lbs will work fine. If you plan on running a larger turbo & 18+ psi then pull the motor & install a cometic MHG & ARP studs.

[marcbeatty]

uhhhh, check all of your coolant lines before you dive into this maybe you just busted one. I thought the same once and it turned out to be the line behing my head.

[CPAutobahn]

I appreciate the insight marc, guess I forgot to metion the idle problems I'd been having up to the final day. Thus I'm pretty sure it's the gasket

Something I would like to ask the board though...


Why did the gasket blow?
1) b/c I shimmed the wastegate and was running too much psi for the factory HG.
2) b/c I ran around with the BOV venting to the atm. for about a day and a half.
3) b/c the car had been hot before (judging by both a new radiator & water pump) and it was just it's time to go.
4)???

I don't belive it is #1 b/c I didn't think the amount of boost ran had too much (not saying none) to do with the HG.
I don't think it is #2 b/c this would make a rich mix which would just cause the car to run like crap.

To my understanding the main reason a HG goes down is b/c of lean situation?

So once I replace the gasket am I going to have problems again? Do I need to look for something else that is screwy?

Any input appreciated...
Cody

[Andrew91PGT]

I appreciate the insight marc, guess I forgot to metion the idle problems I'd been having up to the final day. Thus I'm pretty sure it's the gasket

Something I would like to ask the board though...


Why did the gasket blow?
1) b/c I shimmed the wastegate and was running too much psi for the factory HG.
2) b/c I ran around with the BOV venting to the atm. for about a day and a half.
3) b/c the car had been hot before (judging by both a new radiator & water pump) and it was just it's time to go.
4)???

I don't belive it is #1 b/c I didn't think the amount of boost ran had too much (not saying none) to do with the HG.
I don't think it is #2 b/c this would make a rich mix which would just cause the car to run like crap.

To my understanding the main reason a HG goes down is b/c of lean situation?

So once I replace the gasket am I going to have problems again? Do I need to look for something else that is screwy?

Any input appreciated...
Cody

Following found at http://www.supras.org.nz/techinfo/bhg.htm


All cars are vulnerable to BHGs due to various factors - a head gasket is a fallible component like any other part of your engine. The 7MGE & 7MGTE engines in the 3 litre Mk-III Supras are VERY prone to blowing gaskets. The primary cause of this is due to incorrect assembly during manufacture - the specification for the torque applied to the head bolts in the factory was approximately 20-30 lbs-ft too low, meaning normal running of the engine will eventually cause the gasket to fail. Toyota have never admitted this to be a problem, but did retrospectively change the torque specifications after the fault became known.

Another note: If you do even end up getting it fixed have the head milled and check the block deck for warpage with your trusty feeler gauges. Service limit for the 7M is .05mm or .0020in. If you do not know how to do this you may want to have someone who is capable at least help you. You cannot (to my knowledge) have the block deck resurfaced while in the car due to most machines made for that require the main caps to be torqued down around a rod on the machine. This requires no pistons and no crank, and of course engine out of the car.

[CPAutobahn]

Following found at http://www.supras.org.nz/techinfo/bhg.htm


All cars are vulnerable to BHGs due to various factors - a head gasket is a fallible component like any other part of your engine. The 7MGE & 7MGTE engines in the 3 litre Mk-III Supras are VERY prone to blowing gaskets. The primary cause of this is due to incorrect assembly during manufacture - the specification for the torque applied to the head bolts in the factory was approximately 20-30 lbs-ft too low, meaning normal running of the engine will eventually cause the gasket to fail. Toyota have never admitted this to be a problem, but did retrospectively change the torque specifications after the fault became known.

Another note: If you do even end up getting it fixed have the head milled and check the block deck for warpage with your trusty feeler gauges. Service limit for the 7M is .05mm or .0020in. If you do not know how to do this you may want to have someone who is capable at least help you. You cannot (to my knowledge) have the block deck resurfaced while in the car due to most machines made for that require the main caps to be torqued down around a rod on the machine. This requires no pistons and no crank, and of course engine out of the car.

Thank you...

I'm definitly familiar with feeler gauges... One last question (for now at least :) ) The block is cast iron right? so unless something went really crazy there shouldn't be a need to pull the motor right? (as oppsed*sp to an aluminum block that would for sure have to be removed and decked.)

On a side note... I started ripping it apart today... and I have two things to say thus far..
1) gosh damn what a bish (I definitly prefer tearin' apart the LT1)
2) geez I feel sorry for people just wanting to change the spark plugs. (would be quite a hassle for such a simple thing)

[supraguru]

this is off topic but im getting ready to rebuild a NA motor to put in my car. if i just use a standard non metal head gasket and torque it to like 40-60pounds will i be ok to autocross on teh motor

[More_Boost]

OK, so I have to ask this question, since some of you guys know about this. I have heard a lot of debate about whether or not to retorque a stock HG. Mine is fine, stock, about 70K on the motor. If I retorque my head bolts, do I make the risk of BHG worse, or do I decrease it? My 7M is totally stock, not even a shim on the wastegate or anything, but I do plan on getting after it, adding a down pipe, exhaust, and hard pipes before changing my boost at all. Am I just headed straight for bhg no matter what? I'd like to avoid this as long as I can, obviously. I'd appreciate any input.

PS. Sorry for hijacking the thread...

[1FKNFST7M]

If you do the retourque correctly you will decrease the chances of a BHG. 1st make sure you have a good quality TQ wrench & a 10mm allen socket. 2nd Follow the TSRM retourque sequence to the T. 3rd Start out at the original toyota Tq specs of 58 ft/lbs & work in 3+ passes to 72 ft/lbs. Now if the HG is already slightly leaking this may even cure it. You can chek this out with a simple to use block tester from NAPA.
Andrew is correct in above post but there is another factor causing 7M HG failures. That is heat on #5 & #6 cylinders. Anyone that has been around the 7m will note the large % of HG failures on stock engines are on 6, 5 or both. Toyota made another mistake by designing poor coolant flow passeges on the Head. To top that off the heat build up from the stock precat & exhaust side of the turbo further deteroates the HG resulting in failures. So you will greatly reduce the risk of a BHG by adding a Downpipe along with a free flowing exhaust. I just want to point out that everything above & even a MHG wont hold if you detonate the engine. Before you go above 8psi get a good Boost gauge.

HTH

[sturbo87]

speaking of andrew and retorquing heads....think we can set up an appointment for me?........let me know. thanksssss

[Andrew91PGT]

speaking of andrew and retorquing heads....think we can set up an appointment for me?........let me know. thanksssss

I am sure I can find some time in the near future. Like this Sunday perhaps?

[sturbo87]

sounds good, i also just purchased a greddy profec b spec 2 boost controller i have some questions about too....i'll give you a call saturday or something

[db7M]

im gonna pipe in here a little late. head gasket failure is usually due to detonation or not a properly prepared surface or too little torque.
steve is right, heat does have some to do with it as well, a lot of it also because of the stupid egr system on the backside of the head.
streetsports mentioned a high failure rate on hks gaskets. ive NEVER heard of this. doesnt mean it isnt true, but all the supra message boards ive been on ive never heard of one failing except from poor surface prep. the head and the block have to be mint for it to seal properly. oem type gaskets have a lot more squish and more forgiving. your best bet is using a felpro gasket like steve said. all the surfaces cleaned up, proper torque on the bolts and take care of a/f you will be fine.
good luck

dave

[Supraman502]

really? how long have you lived in louisville? Bell did my block/head work and I would recommend them to anybody

street sports is there a reputable machine shop in town becasue i heard there arnt any speed shops that can resurface heads and decks worth a crap in louisville

[1FKNFST7M]

I will be going out of state for any block & head resurfacing. This is based on 3 factors 1)Quaility of work, 2) Down time 3)Appropriate charges. I guess this is based on shops with a understanding of how a 7M should be done. When these shops are only 2-3hr drive thats cheap ins. I have to agree with db7m about the HKS MHG. The only time I have seen them blow was because of bad machine work &/or detonation.