head bolts
- Thread starter suprakid3
- Start date
There is this, but I didn't write it of course, and of course am not responsible for your engine.
http://cygnusx1.net/supra/TechTips/head_retorque.aspx
http://cygnusx1.net/supra/TechTips/head_retorque.aspx
^thats a good write up.
if you re-torque the stock head bolts on stock hg break each one loose and re-torque to 75lbs one at a time in the torque sequence.
if you re-torque the stock head bolts on stock hg break each one loose and re-torque to 75lbs one at a time in the torque sequence.
suprakid3;1278538 said:
A blown headgasket can sneek up on u. u should check the radiator for carbon monoxide or drive till u lose coolant frequently or bust your hoses then when it gets bad u can only drive for like 30 to 45min.
Dont ask how i know took me a year to fix
7mgte1988;1278641 said:
Man, no engine is the same. The op allready said its not blown, let it be.
Yes re-torque. See this thread. I had the same questions. Its a crap shoot but so far so good for me.
I believe the answer to your second question is No! There is a thread somewhere about someone wanting to replace just the head bolts and the consensus was that it would cause the head gasket to fail for sure.
I believe the answer to your second question is No! There is a thread somewhere about someone wanting to replace just the head bolts and the consensus was that it would cause the head gasket to fail for sure.
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suprakid3;1278538 said:
come again?
Why would it blow?
Headgaskets don't blow because the magical gnomes living inside your engine sprinkle pixie dust and boom, insta-bhg. :icon_evil
for the rest of you folks, you better come in here with better information than
7mgte1988 said:
because unfortunatly it can not. Now you start dicking with the motor and THEN it can and not really as cranking the "boost" up will result in the likely probability of detonation. Do one of the genius mods like EGR removal and you are GUARANTEED a BHG if using the OEM one.
Again, magic does not exist in the universe. blow headgasket are like everything else, CAUSE/EFFECT relation.
dumbo;1278003 said:
That article is missing one very critical piece of information... it is absalutely critical to follow the TSRM's headbolt torque order. There's a diagram in there for a reason:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EM&P=39
I think replacing the stock bolts with ARP studs is a much better solution than retorqing stock bolts. The process is similair, but you remove bolt #1, replace it with an ARP stud (lubricated and prepped properly), torque that stud to 65ft/lbs or so, and then do bolt 2, 3, ect. Then in the proper sequence of order, finish the torque to ARP spec. As long as the engine is stone cold (sat for atleast 2 days), there's no reason that the gasket should seperate if done carefully.
No, you can't do that as the holes need to be properly cleaned.
Only half of the hole is used by the stock bolts, the entire hole MUST be used on studs for them to function properly.
Only half of the hole is used by the stock bolts, the entire hole MUST be used on studs for them to function properly.
figgie;1279312 said:
and one of the causes can be shitty torque specs from the factory and general beating your stock/mildly modded engine
you should probably come with some better information next time :nono:
tErbo b00st;1279461 said:
OOoooohhhhhhhh.....
lookkkkyyyyy what we have-y here... Ohhh shit, we are gonna work hard today!!
Now on to you.
Seeing as your are new here. Time for this post to be an education lesson and what facts are and what bullshit that was propagated by the internet is.
That rhetoric you posted, is nothing more that bullshit propagated by the internet.
Bolt stretching has nothing to do with BHG as that is caused by.... get ready for this
DETONATION.
That is right, the bolt's torque value has a correlation with BHG as the sun coming up each morning has a correlation with the GDP of the United States. incase you don't get it. There is no correlation.
56 lbs/ft is plenty for the OEM value. Start dicking around with the engine and the issue is not the torque value (as it never was), it is with such brilliant owners such as yourself thinking that removing the EGR system is a "good" idea for performance when the EGR system has no inherit detractions in overall performance
Read my signature, learn from it, next time, try to bring a bigger gun to the party.
Welcome to Supramania.
figgie;1279489 said:
just because I don't post on here regulary does not mean that I am new to internal combustion engines you fuck
Yes, detonation can cause a bhg. So can too much boost coupled with too high compression ratio.
Improperly torqued studs can also cause this situation. Whether it is not following the torqueing sequence or too low of torque, this can cause and WILL cause a bhg.
Shitty studs can cause this too...which directly corrolates to stud stretching. Get better studs, get less stretch, get more head gasket life.
Just because your tunes are shit and you experience detonation, doesn't mean that's the only thing that can cause a bhg
k thx bi
fyi, if your greatest claim to faim is dispelling the egr myth...you need to learn more
tErbo b00st;1279503 said:
You could have fooled me with the nonesense you posted, twice now.
tErbo b00st;1279503 said:
the ignorance is strong with you, younglin. So is the lack of English fundamentals!
I honestly don't care if you are Dr. Robert Bosch himself. If you come in here spouting bullshit like you are currently doing. Be prepared to get curbed stomp by yours truely.
I do not take kindly to arrogance but one pet peeve of mine is, blantant ignorance as you are showing. Throw in a dash of mis-spelling FAME for faim... and you have a very long climb up a very slippery slope.
On to your improperly torqued bolts crap.
If you assumption is in fact correct. Then EVERY SINGLE ENGINE (yes not even specific to toyota but every single engine) that is not torquing the bolts to thier yield rating WILL suffer BHG. Of course we know better as even with the stock values, 7m's (both N/A and Turbo) with OEM HG have lasted 225k miles without EVER being opened. That means, the head never ever coming off for anything to include the crap which you believe is tied to the torque yield that Toyota did use and that is, blown head gasket. So that alone makes your assertation, simply put. Complete CRAP!
As for my claim to "faim", I have more than EGR under my belt. I usually start with correct useage of the english language. Then, proper sentence structure. Throw in some physics, blend together and TADA....
you have me.
Welcome to Internal engine design 101.
Class dismissed.
figgie;1279489 said:
figgie;1279517 said:
Well thank you for backing up your knowledge of engines by nitpicking my english (which really isn't too bad).
I'm an engineer, not an english major
tErbo b00st;1279528 said:
If you are infact an Engineer, then English was one of the requirements for your curriculum as you need to convey your engineering diagrams/designs, in ENGLISH, to the project sponsors, be it internal or external. All those physics calculation mean nothing to management, they want to know if it will fail/standup to x hours at y stress, what the FEA says etc, and you will not be doing that in Engineering terms.
But since you did bring it up, what field of Engineering?
just because there is a problem does not mean that EVERY single engine will have that same problem. Varying manufacturing tolerances, driving style, engine mainteance, and modifcations will change the outcome. As we all know, just because a recall is issued on a car, does not mean ALL of the cars will encounter this problem. Only many of them. I can't believe you are willing to make the assumption that because some cars have, that means all cars will.
HG bolts are not suppose to be torqued to their yeild. If you knew anything about material properties and fatigue crack propogation, in tandem with cycling cylinder pressures, you would know this. If you tighten something to it's yield torque that means as soon as any pressure is exerted on it, it will experience plastic deformation. This is bad if you weren't sure. Deformation coupled with cyclic fatigue is also bad.
HG bolts are not suppose to be torqued to their yeild. If you knew anything about material properties and fatigue crack propogation, in tandem with cycling cylinder pressures, you would know this. If you tighten something to it's yield torque that means as soon as any pressure is exerted on it, it will experience plastic deformation. This is bad if you weren't sure. Deformation coupled with cyclic fatigue is also bad.
figgie;1279531 said:
I agree with you. However, the requirement for many schools is VERY few English classes. I took one (as I had prerequisites to not have to take more)
Mechanical engineering from the University of Iowa
tErbo b00st;1279536 said:
According to you there is.
Since their will be a standard deviation on everything to include the torque specs, the failure rates should be even higher with your "hypothesis". Facts are, that the 56 lb/ft is more than enough to make the HG survive 225k miles and that was beating the crap out of that motor. I should know as I am the owner of that engine.That was through the mountain climbs of Georgia (Atlanta to Chattanooga 5 miles worth), Miami heat and humidity, South Dakota snow dumps and Minnesota freezer temps. Never once, a HG issue. Even with the A/C cranking.
The other thing that helped, I also was one of those few owners that did not do the "EGR removal" mod.
Again, Toyota is not as ignorant as the internet portrays them.
tErbo b00st;1279536 said:
I do!
HG studs are in fact torqued to yield. They have to be. As that is where their preload will be maximized, leveraging the studs tensile strength without failure. You can not Torque to yield bolts as you have the rotating force interfering with a proper torque reading.
and just to make sure we are all on the same page.
I am talking about OEM HG on an OEM setup (440cc/min injectors, CT26, perhaps a minor increase in boost etc)! Not OEM HG on a CT26 blowing 12 psi of hotair on 550cc/min injectors etc.
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