So, I have my 3500 gm v6 in my rx7 champcar. The engine was fairly fresh, but I put my ported heads on it. Therefore, I had to put new head gaskets on it.
I put the super duty SD 541 gaskets from fel pro.
It pushed water into the at least 1 cylinder after 22 hours of racing...
What the he'll is going on. Here are pictures of both gaskets. It looks like the fire rings are destroyed. Why? Too high of compression ratio?
Basically, cylinders 1, 5 and 2, 4 all have fire rings distorted. Cylinder 4 also has the fire ring burnt towards the oil or water passage.
Any ideas here? I don't want this failure again which means I need to understand it.
My gut feeling is to lose the studs and either go back to OE bolts or undercut studs.
Fasteners can be thought of as springs, OE bolts are designed with a fairly low "spring rate" (as these things go) so the head can expand and contract with heat. Straight sided studs have a fairly high "spring rate" and can crush the gasket and/or the head itself when the head expands, and when it cools off again things loosen up, and you can burn the gasket.
They might work fine with a retorque, I dunno.
Block has been bored and pistons replaced?
Head skimmed and not getting proper clamping on fire ring?
The hardware is arp and torqued to the proper value. It lasted 3 plus years on the 3400 without a gasket failure. This is fresh arp hardware on this build. Everything was proper tight when removed.
Heads have been skimmed.
In reply to dean1484 :
Pistons and rings are stock with 40k on them.
wvumtnbkr said:
I put the super duty SD 541 gaskets from fel pro.
Are those the same thickness as the prior gaskets?
The only other thing that is curious is that the gaskets did not seem to have stuck to the decks after what I assume should have been a thorough heat cycling. Any time I have had an engine run up to temp and back, the gasket material has bonded to the decks and a lot of the gasket stays stuck to the head and block. Those gaskets look intact.
I always give everything a wipe with acetone or brake cleaner and as lint-free a paper towel as I can manage, so the gasket "sticks".
I'm not saying you didn't, I'm just noting that the used gaskets as presented seem a little odd.
Being that it happened to the whole motor, I'd be looking at something causing it to run incorrectly or an improper assembly.
Bad batch of fuel with lower than expected octane causing higher cylinder temps? Wrong heat range spark plugs? Clogged cooling (water and or oil) system allowing engine to run hotter than before?
You said fresh ARP hardware? Do you still have the old so you can compare them side by side? Did you use oil on the threads? Same torque wrench and/or when was the last calibration? How much was skimmed off of each head and should that have changed anything about your assembly procedure?
wvumtnbkr said:
Did you know that your index toe is longer than your big toe?
Stampie said:
wvumtnbkr said:
Did you know that your index toe is longer than your big toe?
Those aren't his real feet; they are safety-toe slip-on flip-flops.
I wasn't expecting that many hyphens.
In reply to Pete. (l33t FS) :
Sprayed with the copper gasket stuff. They were stuck. They just came off without transfer.
Real time. Right now. Size 13.
NOHOME
MegaDork
8/18/23 8:52 p.m.
Heads have been skimmed
Any chance you ran out of thread on the studs before you hit the torque setting?
Skimmed head and new studs a tad bit longer?
What do the plugs look like?
NOHOME said:
Heads have been skimmed
Any chance you ran out of thread on the studs before you hit the torque setting?
Skimmed head and new studs a tad bit longer?
That happened to us with a lightened flywheel and ARP bolts holding it down. SUPRISE!
Besides the "ran out of thread" which I too have seen.....How is the deck of the block. They can warp, and I have seen the top of the stud holes grow up a few thousandths at the start of the thread. Some soft iron blocks I countersink the stud holes .020" with a 45* counter sink to prevent it.
I can't really tell from the picture, but there's a couple of spots that almost look like the fire ring was hanging inside the bore a wee bit. Am I seeing things?
In reply to Streetwiseguy :
Your words made something click. There are two different 3500 engines, one with a small bore, and one with a 3900 block and a short stroke.
The gasket has a 95mm bore. The second of the two 3.5ls has a 99mm bore.
Which engine is it?
That was my thought as well. Bore size of the gasket is pretty critical.
How's the tune? I've seen detonation take out fire rings in short order.
Also, Fel Pro (I think) strongly forbids the use of any sealant on those gaskets. Every SD, printoseal, and redline gasket I've ever bought from Fel Pro say ixnay on the ealantsay.
In reply to Stampie :
Well, according to Xavier Hollander ....
wvumtnbkr:
How does the underside of the head look? Any obvious anomalies?