7m Blown head gasket Cylinder #1 #6

IJ.

Grumpy Old Man
Mar 30, 2005
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Ok I'm really NOT trying to be an arse here but this is why your attitude when you joined rubbed so many the wrong way....

You told us you only work on 7M's so therefore "might know more than you" I think was the statement.

It's clear from reading the last couple of pages that you only have a very basic grasp of the 7M and really need to spend some time reading the FAQ's as most of what we're covering here is really newbie basic stuff.

There's NOTHING wrong with admitting you don't know something as there's always something to learn and this situation highlights why some of my explanations are so Gumby and step by step as I have to assume the question asker knows very little, I apologise to anyone that's been offended in the past but I prefer to actually teach someone the correct way instead of assuming they grasp the concept then a few weeks and a dead engine later finding out they didn't.
 

AllStreet

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Feb 3, 2008
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jdub;933575 said:
Here's the FAQ for a Cometic MHG (like I said, the Titan is a rebranded Cometic):
http://www.cometic.com/faq.aspx
Note that Cometic also recommends no additional sealer (like copper spray) be used.

Something else I just thought of since your MHG did not seal from the beginning (High RA usually takes a little longer). Did you remove the rivets holding the MHG together that touched (any where on it) the block deck surface?

Were those suppose to be taken off lol?
 

jdub

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Any rivet that touches the block deck? You bet it needs to be removed or what happened to you will occur...it prevents the seal.

Hope you learned something about relating to the more experienced guys around here...or am I still "a flipping insane idiot...."

Gotta remember attitude goes a long way in getting the help you need ;)
 

AllStreet

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jdub;933806 said:
Any rivet that touches the block deck? You bet it needs to be removed or what happened to you will occur...it prevents the seal.

Hope you learned something about relating to the more experienced guys around here...or am I still "a flipping insane idiot...."

Gotta remember attitude goes a long way in getting the help you need ;)

I guess I still have a lot to learn, this engine has been a hassle and I may not know as much as I should to be do what I am doing,:icon_mad: So I do appreciate your help. I thought everything I did was right which i didn't know the RA used, so they may have hurt me some, I do not think any of the rivets were touching the deck, but as of right now I am just going to remove this engine, I may have to sell this wonderful car, my funds are depleted pretty much now, it's such a great car, but lets hope everything works out, this is my 3rd supra, and 2nd supra turbo, cars are great.

Btw: When the deck gets resurfaced do I have to remove the pistons and crank?

Thanks, man I am defiantly learning, the most expensive way.. :|
 

AllStreet

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jdub;933551 said:
When looking at RA smaller number = smoother...in this case, 50 RA or less is what you want.

You used 75 ft/lbs w/ moly for the ARP bolts...that is what ARP calls for on the spec for an aluminum head. It should not be your problem unless your torque wrench is way out of calibration.

IJ pointed out the front timing cover shown in the TSRM has to machined with the block or the top can keep a MHG from sealing by preventing the head from seating flat. Since you did not re-surface the block, this is not likely.

Did you:
- Torque the head bolts in the TSRM sequence using multiple passes in ~15 ft/lb increments?
- When the head was re-surfaced, how much material was taken off and was the deck perfectly flat?

- Went and bought new Craftsman Torque Wrench did 15-15-15-20-10 Increments on the head.

-Check the timing cover, it is fine with more then .024 clearance, probably three times that of clearence I am fine there.

- As of right now I am going to put the engine back together- valve cover- throttle lines - spark plugs- things of those sorts, and [ pull the motor ] I am just going to get the deck resurfaced, the head checked, and do it out of the car i feel more comfortable, that way, I only use to work on Dsms, a lot easier lol to pull a head by yourself.

Thanks guys.
 
Oct 11, 2005
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Thousand Oaks, CA
With apologies to whomever took these photos (if someone knows please post their name), but the rivet in question is illustrated below.
 

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jdub

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Before you yank the motor, consider using an OEM composite HG w/ your ARP bolts. Much more forgiving on RA, good to ~15 psi all day, and a lot less expense over all. A lot of guys on here run the stock HG at the 350-400 HP level with NP and it will last clamped down with ARP bolts. Just give it a good coat of copper spray when you install it.

It will give you time to gather $$$ for when you do pull the motor and go for the bottom end re-build.


3P - Excellent pics!
 

AllStreet

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Feb 3, 2008
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jdub;934226 said:
Before you yank the motor, consider using an OEM composite HG w/ your ARP bolts. Much more forgiving on RA, good to ~15 psi all day, and a lot less expense over all. A lot of guys on here run the stock HG at the 350-400 HP level with NP and it will last clamped down with ARP bolts. Just give it a good coat of copper spray when you install it.

It will give you time to gather $$$ for when you do pull the motor and go for the bottom end re-build.


3P - Excellent pics!

Hey man. Well see the motor was rebuilt with 4K miles when I bought it, had stock head gasket on it I gave the car about 3/4 throttle, about 7 psi on the turbo and bam it just went, I think I now need to pull the motor and have it check something is terribly wrong here, I can't believe it blew I even asked the guy what torque he used with the stock head gasket , which he is trying to help me right now, he said he used 75 ft-lbs which you can do with the Stock HG anything over that by a lot can crush the gasket and will not work properly, I am going to pull the motor, get ARP head Studs and a new Hg HKS this time, also I was wondering, what head gasket should I get now, the head has been resurfaced twice, and the block will be decked. Also I just want this car to run correctly it's not that bad to pull this motor, I already have the wiring harness off of the car along with the upper manifold it's only taking hour and a half, sad b/c Iv don't this before b/c of other problems, a/c lines are disconnected, might of got that in my system a little >,<! I just want this car is have a good reliable engine lol.... damn so hard to ask fro sometimes.

Thanks.:nono:
 

jdub

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75 ft/lbs on a stock HG *should* be plenty. Keep something in mind (no offense to your friend), don't assume the previous HG was installed correctly.

When you pull it, check the block deck for flatness (head too). Check the head thickness as well...uncut stock is 116mm from deck to cam cover surface...that head could have been cut more than twice from a previous life ;)
 

IJ.

Grumpy Old Man
Mar 30, 2005
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NEVER seen a used 7M with a block surface that I'd plop a MHG on and expect it to seal.

While it may be smooth and clean they're rarely flat and true esp the early light blocks.
 

AllStreet

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Feb 3, 2008
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Question, I am going to do arp head studs now, i want a 500 HP motor, where should i start, I mean Do can i do the bottom end like it is? It's rebuilt to stock with shot peened rods, port and polished head, I will have the motor out so let me have it, I need to get everything ready and build up this motor.
 

AllStreet

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Alright guys, I just pulled the motor, shit that thing isn't light :) But, I removed all the part off of the engine, besides the internals and oil pan, I am going to have it look at and decked, along with the head being checked, I may do a rebuild not sure. Now do you think i should go metal HG or stock one I want to reach about 400 WHP~ out of this car, and I will be happy, do you have any suggestions, I really want this done right, Thanks guys for all your help, it has made things " a lot " easier