7m Blown head gasket Cylinder #1 #6

[AllStreet]

Well I m back now, but I have a problem with my motor, if you read my forum in 7m-bulletins, that would be greatly appreciated. This problem has never been presented in front of me, the torque i did use was 75 Ft-lbs on a 1.4 Titan Motor Sports Metal head gasket. I was going to run with that for about two weeks, using the motor lightly of course, but My Cylinder pressure in #1 Cylinder is 45 and Cylinder #6 is 75 I have exhaust when the engine has load put on it in the back of the motor, and I head " Hissing " [ Vacuum ] near the intake but it is not the intake, already checked, so right now this is not too good. Only thing I can do before tearing it down is check the torque didn't work it's way out, if it did I will re toque it, that is all I can do right now thanks.

Alright I was wondering I just did my head gasket and i did a compression test and cylinder #1 came up 45 psi and cylinder #6 75 I have exhaust when the engine is rev-ed in the back of the motors , and a HUGE vacuum around cylinder #1? Can I have a vacuum problem, and what the hell went wrong, I did what I should have, but anyhow, Im well I hope I can get this running it's my only car :[ kind of hard to do many things.

Thanks guys for your input

 

[jetjock]

Maybe the head bolts were torqued to the wrong spec?

 

[AllStreet]

Well, man i am not going to say no to any errors I possibly made this time, so I am looking into all possibilities, thanks man.:icon_surp

 

[jdub]

Ok...I see you're back

It's a Titan 1.4mm MHG...ARP head bolts and what lube was used on them?

Was the block/head decked?


BTW - added your info from the other thread for clarity/additional info.

 

[jetjock]

Exhaust at the rear could be the EGR cooler but it sounds like the HG. Were the locating dowels for the head in place on the block? What kind of gasket, how was the head and blocked prepped, and what was it torqued to?

Edit: beaten by the Dubster

 

[IJ.]

#1 I'd guess the rear timing case wasn't installed when it was decked.

#6 could just be in need of a retorque but that's irrelevant now.

 

[AllStreet]

Exhaust at the rear could be the EGR cooler but it sounds like the HG. Were the locating dowels for the head in place on the block? What kind of gasket, how was the head and blocked prepped, and what was it torqued to?

Edit: beaten by the Dubster

I torqued them to 75 ft.-lbs I been reading many forums, but I was going to run it for a little bit go back and check the torque and re-torque to 80 Ft-lbs, I used the moly lube, Maybe i should look at the box I think it said some like 105 or 125, that sure seems like a lot, and I do not think it is the EGR, I just installed a new gasket and the proper torque to it, I also preped the deck of the block and cleaned it, i just don't know...

Also the dowles were in place to put the head on.

 

[jetjock]

D'oh...me thinks IJ nailed it. Was the timing case machined to match?

 

[IJ.]

JJ: The above sounds like the Block wasn't surfaced at all.....:nono:

 

[jetjock]

You're reading my mind. I was just wondering about that myself...

 

[AllStreet]

The whole head was resurfaced lol, for sure it was only like 30.00 I think i paid, the case was not I had that taken off I think the case would easyly be my problem. I will check that.

 

[IJ.]

Was the BLOCK surfaced?

 

[AllStreet]

Was the BLOCK surfaced?

No it was not, Preped but not resurfaced, car gasket blew and car ran for exactly 10 secs after blown head gasket, also can I take off that head gasket or is it ruined to re use along with the arp head bolts have they been stretched?

 

[IJ.]

Studs and Gasket are fine to reuse I posted a thread on reusing MHG's awhile back.

 

[jdub]

As are ARP head bolts. The block AND head deck surfaces have to meet a minimum 50 RA smoothness for a Titan MHG (it's actually a Cometic). If not, you risk it not sealing properly.

 

[AllStreet]

As are ARP head bolts. The block AND head deck surfaces have to meet a minimum 50 RA smoothness for a Titan MHG (it's actually a Cometic). If not, you risk it not sealing properly.

The timign cover #1 the " top " one i checked with a feeler gauge has more then .024 clearance it has more like .9 mm it was surfaced, I guess before when the motor was rebuilt, I just check all 14 head bolts they all didn't lose any torque so, now I am again waiting to see what i Should do, I think I should is find out the size of the head bolt i used, " If any knows, I can " check the torque on the ARP head bolt box, I really need to see if I under torqued it.

Thanks guys !

 

[AllStreet]

As are ARP head bolts. The block AND head deck surfaces have to meet a minimum 50 RA smoothness for a Titan MHG (it's actually a Cometic). If not, you risk it not sealing properly.

So anything above 50 Ra is good? Anything below that will not properly seal?

 

[jdub]

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?

 

[AllStreet]

The timign cover #1 the " top " one i checked with a feeler gauge has more then .024 clearance it has more like .9 mm it was surfaced, I guess before when the motor was rebuilt, I just check all 14 head bolts they all didn't lose any torque so, now I am again waiting to see what i Should do, I think I should is find out the size of the head bolt i used, " If any knows, I can " check the torque on the ARP head bolt box, I really need to see if I under torqued it.

Thanks guys !

The information where did you get it Id like to have it so I can refer to it, the titan motor sports MHG specs or information thanks!

 

[jdub]

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?