Had the car over at Speed Inc. today to get dyno tuned after the ATI install, and the new cam install, they did an excellent job by the way...

Car blew a head gasket 3rd run into dyno session (well thats at least what we think) there was no coolant in the crankcase, dipstick looked normal, but it was pouring out of the exhaust, and you sure could smell it......

We are not sure as to why this happened, there are a few issues at hand....

#1 The person who sold me the MTI Stage 2 heads (2.055/1.60) valves informed me that they were stock compression 10.3:1, that should be fine under boost, then dan over at speed told me he wasn't sure if he remembered seeing welds on the combustion chambers, that means some work was being done....they are going to pull them off and let me know what the situation is on that...

#2 My car has had some oil comsumption problems from day 1 when I had it, got the usual 500 miles to a quart of oil, recently it got as bad as 100-200 miles to a quart, no noticeable smoke on start up...from the oil entering the combustion chamber mixed with the 93 octane will lower the octane level about 7-8 points, which is NO good..I'm thinking this might of been the problem...not totally sure if its a ring or PCV, there is going to be a leak down done on it, but this event probably lead to some detonation, I was glad to see no coolant on the dipstick, thats a good sign that the piston held together...

#3 The car has an 8psi pully on it, made 6psi tops...12:1 AFR for all runs, 19 degrees of total timing

I put down 470rwhp and 540rwtq, through a TH400 with a nonlocking 3500 converter, through a 12-bolt, closed cutout, yada yada yada, I think thats pretty good for only seeing 6psi...

Speed is in the process of taking things apart to see what happened...I don't know what I'm doing from this point on, but what looks to be like a blown head gasket off of 6psi is defiently a warning sign...

Any ideas folks?

 

Most MTI heads are milled from what I was told. I would call MTI and ask them to check the records of the customer who purchased the heads originally..

 

Then the stock ones might be milled as well, to get that 10.3:1 compression...

 

I was told my ARE heads were stock compression (these are an OLD set of ARE heads).

After pulling the suckers we measured .030 milling and 63 CC combustion chambers <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" />

I had to order dish pistons to compensate for the compression increase of the heads.

Either way, Stage II heads it is standard practice (or at least it was) to cut them down .030.

Good Luck.

 

I thought stock compression was 10.1:1 <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

 

Pull the heads and measure the size of the chambers...

 

I will be over at speed saturday for our MFBA meeting, I'm sure I will find out more details when I get there...

Ryan I was told that the stock compression on MTI heads was 10.3:1 compression.... <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />


TTT on this folks...


BLUE HAWK DOWN <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" />

 

Don't take this the wrong way, but what possesed you to put a blower on a motor that burnt a quart of oil every 100-200 miles?

 

Yeah and ask how long the motor would last??

 

It was one occurance where I saw that happen.....I should of logged it better...but most LS1's have the normal 500 miles to a quart oil problems...I have a few friends who have similar problems...

 

500 miles to a QUART!!!!!!!!! HOLY COW!!!! Mine isn't that bad but I drive 100 miles a day that would be a quart every week. Something is definately wrong besides the head gasket with that amount of oil consumption.

 

The car is going to get torn down this afternoon so I will find out...

 

I wouldn't say most. Just because you know of other LS1's that do the same thing doesn't mean that they don't have issues also and it's "normal" for an LS1 to do it.

No biggie. I was just trying to figure out, in my own head, why anyone would run a motor NA that burned that much oil let alone put a blower on it. Thus the question above...

I figured subconciously you really wanted to blow it up as an excuse to go bigger and more power. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

Thanks for the replies, keep them coming...

I'm getting price quotes for the cheapest possible 346 build up possible, but that will last...

<img border="0" alt="[gruffy cottonball]" title="" src="graemlins/gr_gruffy.gif" />

 

What was the programming setup, specifically the timing tables? Was the programming stock?
Also, measure the cc's of the chambers while they are off so you know your true C/R. Do a leak-down test also. Hopefully it's just a gasket. Replace your gasket with an MLS style & head studs.

 

I hate to sound negative, but it sounds like you're going to need a rebuild of that motor (those heads sound kind of suspect to me too). It might be a godsent though...you can just put all forged internals in now!

As for only seeing 6psi, I'm not suprised at all. The 8 pound kit is designed for stock heads. You had S2, and therefore they should flow allot better (thus the lower psi reading).

Let us know what you find out. Good luck.

 

Heres whats happened so far...

--programming was done with LS1edit, Jim over at speed inc was doing it, hes damn good at what he does, so I have complete trust in him, the AFR was a solid 12:1 through all runs with 19 degrees of total timing--


#7 cylinder head gasket showed up as being the problem, all other cylinders checked out fine leak down wise....but I'm not sure what to do...

Replacing the Head gaskets with cometics and new head studs is not saying that this same problem isn't going to happen again....

But they can't tell if the rings on #7 no good or not until I give them the green light on what to do, because they would need to replace the head gasket, put the head back on, and do a compression test to see if it holds all the way..

I need your opinions on what you would do in this situation...

 

What did the monitored detonation/KR look like? What spark plugs are you running? Injectors? Pump?

 

I didn't ask about the KR...

I'm running 42.5 injectors...255 intank pump, 255 inline pump...

It had enough fuel

 

Definitely enough pump. Do you have a Fuel Pressure Gauge?

I'd find a way to monitor the KR.
LS1 Scanmaster, AutoTap, etc.

Spark Plug type?