headgasket question

7mturbo

New Member
Mar 16, 2010
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The sticks.
could i just get a cosmetic head gasket and arp studs/bolts? i don't plan to pass 400hp ever. i know metal would be smarter, but my friend can only machine the head for free...
 

hvyman

Dang Dude! No Way Man.
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Apr 17, 2007
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Whats cosmetic? Or do you mean cometic which are mhg's.

It may hold for a little while or it may not. Imo 400 is about the very limit of composite head gaskets.
 

grimreaper

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Jul 2, 2008
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I dont think a good quality composite hg is the limiting factor. The tune is. A metal one will give you more leg room if your not on top of air/fuel/timing/boost.

Where do these HP to HG numbers come from? Last year it was 350whp, the year before that 300whp.. Is there any data to back these?
 

hvyman

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Apr 17, 2007
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Ill back 300 thats where i am. How long will it last i have no idea.

But the millions of bhg threads with stock hg's is not proof enough? They blow its a fact and always has been.
 

89supra7mgte

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Sep 20, 2009
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colorado
these numbers are "swags". I do believe as well that it is in the tune. you can have an mhg blow out at 300 and a composite not? it all depends in my opinion. proper install and preparations will be the limiting factor.
 

hvyman

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Apr 17, 2007
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I dont disagree with the tune part but even n/a's blow stock hg's.

Edit: I wouldnt go over 400 because the money your going to spend on mods to get you there is not worth it to just to blow a hg.
 
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grimreaper

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Jul 2, 2008
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just keep in mind that the weak point was not the hg per say, it was the material it was made out of + the TQ specs used. Kind of a system weakness all around. I guess i should ad the biggest weak link as well, up keep from the owner.
 

IJ.

Grumpy Old Man
Mar 30, 2005
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89supra7mgte;1562317 said:
But an upgraded composite type with correct or updated torque spec should be good correct?

Installed correctly and kept out of detonation yes, but keep in mind 1 dud tank of fuel and a rattle will ruin your day!

A bit like the Cast V's Forged piston debate, yes stock pistons can cope will with very high outputs but can't cope with a rattle.
 

WillWorkFoBoost

that guy
Sep 1, 2009
130
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Maine
Okay so I had a similar question. first of all I installed a hks mhg and arps and had the head planed, not the block. I know I should have done this now but didnt at the time. it held for a few months but seems to be leaking now... so which option would be more legitimate, throw a composite hg on it along with the arps, clean the viton off the mhg and copper spray it and see if it seals, or has anyone had good luck with the hks stopper as ive heard it has a layer of sealant so that stock block finish is fine? or obviously last resort would be remove block and machine it. same situation, not going for ridiculous power, just a good seal.
 

I6Boost

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Apr 14, 2010
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My Supra
WillWorkFoBoost;1562788 said:
Okay so I had a similar question. first of all I installed a hks mhg and arps and had the head planed, not the block. I know I should have done this now but didnt at the time. it held for a few months but seems to be leaking now... so which option would be more legitimate, throw a composite hg on it along with the arps, clean the viton off the mhg and copper spray it and see if it seals, or has anyone had good luck with the hks stopper as ive heard it has a layer of sealant so that stock block finish is fine? or obviously last resort would be remove block and machine it. same situation, not going for ridiculous power, just a good seal.

Perfect example...

This guy skimped out on the MHG installation process and is now paying for it...

And he can only do the head for free? most machine shops only charge about $50-$60 to machine the block...
If you cant afford $50-$60 then sell your damn car and get another job...


WHY do you wanna skimp out on things? i dont understand...
you wil pay for it later i can almost promise....


Everyone here is arguing about how this hg will hold to this with a right tune
and this HG will hold to this with this tune etc.

Machine the head and block, get a MHG and be worry free.
Why drive your car and mod it while the whole time in the back of your head
thinking "Well i hope my HG holds" "I hope my tune is good" etc etc.

I see a future "My HG is leaking" "Compression is low" "Losing coolant" "Knocking inside engine?!"etc thread.

If your the kind of person to skimp out on things, then get a honda.
Supras are not the car to skimp out on things, Ask anyone here with senority with supras.

Do it right, do it once.
Nice things arent cheap, and cheap things arent nice.

Remember those 2 things and you will be set for life.
 

WillWorkFoBoost

that guy
Sep 1, 2009
130
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Maine
yea so once again I was asking what would be the best option as stated above. I dont skimp on things though it is my fault because I never heard that I should machine the block until it was back together or else I would have. my fault for not researching. so, "which option would be more legitimate, throw a composite hg on it along with the arps, clean the viton off the mhg and copper spray it and see if it seals, or has anyone had good luck with the hks stopper as ive heard it has a layer of sealant so that stock block finish is fine? or obviously last resort would be remove block and machine it. same situation, not going for ridiculous power, just a good seal." not asking for someone to tell me what I did wrong.
 

I6Boost

New Member
Apr 14, 2010
182
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My Supra
WillWorkFoBoost;1563014 said:
yea so once again I was asking what would be the best option as stated above. I dont skimp on things though it is my fault because I never heard that I should machine the block until it was back together or else I would have. my fault for not researching. so, "which option would be more legitimate, throw a composite hg on it along with the arps, clean the viton off the mhg and copper spray it and see if it seals, or has anyone had good luck with the hks stopper as ive heard it has a layer of sealant so that stock block finish is fine? or obviously last resort would be remove block and machine it. same situation, not going for ridiculous power, just a good seal." not asking for someone to tell me what I did wrong.

Read this about the copper spray sealent etc on mhg's.

http://www.supramania.com/forums/sh...ay-Sealer-on-a-MHG-...Might-Want-to-Read-This

If your not going for rediculous power then no need to get the hks stopper...

HKS stopper is around $300~ (Dont get me wrong, it is in my opinion the very best HG you can ever have, Design is perfect)

Typical MHG (Titan, SIP, etc) $110-$150

Cost to machine the block is around $50-$60.

So your willing to lose around $150~ just to not remove the block and have it milled?
Not to mention still having the possibility of your HG leaking?
 

kotu100

Active Member
Nov 23, 2006
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Guys I dunno where you're gettin ur numbers from but the cheapest I could find was $250 just to machine the block and head. No assembly or dissasembly included.
 

CyFi6

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Oct 11, 2007
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Theres a lot of factors... Keep in mind if your head has been machined and you use a stock head gasket, it better not have been machined much otherwise you are increasing your compression, increasing the chance of blowing it again.
And just because machining of the block deck costs $50-60 doesn't mean that is what you are paying to get it done. Not to mention, if you are paying $50 for a deck machine it will probably worse of a finish than it was to begin with. Its very hard to find a place that can machine it smooth enough. Then add the cost of a full bottom end rebuild with parts machine work gaskets seals etc and you have a huge project on your hand. If you machine a block it has to come apart, and you are just stupid if you put it all back together with the same parts. If pistons come out you need a hone and new rings minimum, but you will likely find your bores out of round or tapered which require you to go oversize, which requires all that machine work plus new pistons and rings. You need all new bearings (which btw cost about $15-$20 EACH from Toyota, that's x6 for rods and x7 for mains), if you use std bearings from a kit you will likely have clearances all over the place unless you are lucky. If you go with STD bearings you need everything machined (line hone/rods re-sized) to fit those bearings which are a different thickness than stock(even though they call them std). Once you have this all done, you need new gaskets and seals, probably a new timing belt, and money to pay for misc broken or worn out parts, not to mention you will need to get your block tanked or cleaned, and if its tanked any brass freeze plugs and oil pump shaft bearings need to be replaced.

As you can see its not as simple as getting the block machined for $50-$60 and having peace of mind of having it done right, because if you put it back together without touching a thing you are not doing it right.
 

IJ.

Grumpy Old Man
Mar 30, 2005
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WillWorkFoBoost;1563014 said:
yea so once again I was asking what would be the best option as stated above. I dont skimp on things though it is my fault because I never heard that I should machine the block until it was back together or else I would have. my fault for not researching. so, "which option would be more legitimate, throw a composite hg on it along with the arps, clean the viton off the mhg and copper spray it and see if it seals, or has anyone had good luck with the hks stopper as ive heard it has a layer of sealant so that stock block finish is fine? or obviously last resort would be remove block and machine it. same situation, not going for ridiculous power, just a good seal." not asking for someone to tell me what I did wrong.

Should be the first resort....
 

I6Boost

New Member
Apr 14, 2010
182
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My Supra
CyFi6;1563098 said:
Theres a lot of factors... Keep in mind if your head has been machined and you use a stock head gasket, it better not have been machined much otherwise you are increasing your compression, increasing the chance of blowing it again.
And just because machining of the block deck costs $50-60 doesn't mean that is what you are paying to get it done. Not to mention, if you are paying $50 for a deck machine it will probably worse of a finish than it was to begin with. Its very hard to find a place that can machine it smooth enough. Then add the cost of a full bottom end rebuild with parts machine work gaskets seals etc and you have a huge project on your hand. If you machine a block it has to come apart, and you are just stupid if you put it all back together with the same parts. If pistons come out you need a hone and new rings minimum, but you will likely find your bores out of round or tapered which require you to go oversize, which requires all that machine work plus new pistons and rings. You need all new bearings (which btw cost about $15-$20 EACH from Toyota, that's x6 for rods and x7 for mains), if you use std bearings from a kit you will likely have clearances all over the place unless you are lucky. If you go with STD bearings you need everything machined (line hone/rods re-sized) to fit those bearings which are a different thickness than stock(even though they call them std). Once you have this all done, you need new gaskets and seals, probably a new timing belt, and money to pay for misc broken or worn out parts, not to mention you will need to get your block tanked or cleaned, and if its tanked any brass freeze plugs and oil pump shaft bearings need to be replaced.

As you can see its not as simple as getting the block machined for $50-$60 and having peace of mind of having it done right, because if you put it back together without touching a thing you are not doing it right.


And i agree completely, and actually i just got done doing ALL of that within the last 3 weeks.

But this was just the aspect of HG's, nothing more...
I didnt really think me explaining everything else was needed
since he should already know this.

&& So your saying my 20 RA machined block is worse than what i started? I think not.

Only reason i could think that my Machine shop prices are lower than yours is because we have alot of them
around here, and i mean alot... In turn now that i think of it i've never seen anyone or heard anyone talk about machine shop
prices that are out of state/town etc. So my appologies if i gave a wrong estimate.
 

CyFi6

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Im willing to bet most machine shops that people have access to are going to charge more for the same job and will probably have older machines that wont get the proper finish like yours did. The OP seems fairly new to the head gasket thing, i just don't want him thinking its simpler than it is before ripping into it.