PDA

View Full Version : Head Gasket Advise



35ttbirdsc
06-28-2011, 02:45 PM
So I have a 1990 35th with a 4.2L stroker with an MPII ported blower with port matched intake and exhaust manifolds. I blew a the driver side head gasket at the strip and almost blew the passenger side as well with the permatorque head gaskets. I would rather not have to do the head gaskets again after this time. I am soon to be getting headers to relieve some of the back pressure, but was wondering about switching to MLS or what might be recommended for this situation. Also if I should go with MLS, what fits the supercoupes since I am aware that FEL-PRO stop making supercoupe specific MLS gaskets to my knowledge and not all the 3.8's have the same cooling passages.

Thanks,

Jon

bigpoppa822
06-28-2011, 02:49 PM
The gaskets you want are Fel-Pro 9263PT and 9262PT I believe.
I'd probably also upgrade to ARP head studs, part number 233-4003 for the Chevrolet 2.8L.

Keep in mind the deck surface for an MLS gasket should be smoother than for a typical gasket.

CMac89
06-28-2011, 02:52 PM
The head gaskets blew most likely because you were detonating, not because of the head gaskets. Do you have head studs? What did you torque them to, if so?

If you were detonating, nothing you do will solve the problem unless you have it properly tuned. You can go with MLS gaskets, but you need to have a finely resurfaced block and heads to allow them to seal properly. The composite gaskets are plenty sufficient for your motor.

fturner
06-28-2011, 05:44 PM
I'm running the regular permatorque gaskets on my car with an MPX making 17psi of boost with no issues, and have been for quite some time. As Casey said... you're getting detonation which a tune and some alky injection will help cut down on.

Going MLS requires a really good finish on the block which you have to pull out of the car to get done.

Fraser

decipha
06-28-2011, 05:58 PM
its unlikely that you twisted the deck as the heads are much softer and more prone to twisting

i have mls gaskets on all 9 of my supercoupes, never had a sealing issue with any of them even with the stock finish

TbirdSC35
06-30-2011, 03:31 PM
Sorry for the late reply since my account has issues right now. To answer the questions previously asked. This is the 2nd time the head gaskets have gone, but the first with the heavily modified set-up. Before the gasket went there hd not been any detonation for 3 years and 2000 miles after several tunes with the help of Dr. Fred. I have been using ARP head studs torqued to ARP's recommended torque specs and ARP lube. The issue that caused the head gasket to blow in my opinion was high RPM with a dented down tube and the fact I am still using ported exhaust manifolds with 1 15/16" collector as it were at the end of the manifold. I wanted some opinions on switching to MLS gaskets as well as what part numbered gaskets to use since there are 3 sets I have found for Ford 3.8 V6's. So I will restate and ask a new question.

Could the exhaust restriction and backpressure have been the issue for blowing the head gasket?

Since the other head gasket looked like it would have blown if driven longer would it be worth it to try to use MLS gaskets or should composite gaskets be fine if I rework my exhaust?

I am looking to buy headers in a couple of months hopefully so I hoe this answers some of those questions.

Thanks,

Jon

scskydivin
07-01-2011, 12:43 AM
If your dumping massive amounts of air in your motor and not opening up the exaust side..... Head gasket failure for sure, and possibly warped heads are almost always in your future.

As far as the type of gasket to use, I've used the same regular Fel-Pro set on mine for 50,000 or so miles w/o a problem.

If you open up the exaust all the way through to the (aftermarket) resonator at the least, and still have the same issue, then of course, something else is going on.

fturner
07-01-2011, 09:23 AM
Sorry for the late reply since my account has issues right now. To answer the questions previously asked. This is the 2nd time the head gaskets have gone, but the first with the heavily modified set-up. Before the gasket went there hd not been any detonation for 3 years and 2000 miles after several tunes with the help of Dr. Fred. I have been using ARP head studs torqued to ARP's recommended torque specs and ARP lube. The issue that caused the head gasket to blow in my opinion was high RPM with a dented down tube and the fact I am still using ported exhaust manifolds with 1 15/16" collector as it were at the end of the manifold. I wanted some opinions on switching to MLS gaskets as well as what part numbered gaskets to use since there are 3 sets I have found for Ford 3.8 V6's. So I will restate and ask a new question.

Could the exhaust restriction and backpressure have been the issue for blowing the head gasket?

Since the other head gasket looked like it would have blown if driven longer would it be worth it to try to use MLS gaskets or should composite gaskets be fine if I rework my exhaust?

I am looking to buy headers in a couple of months hopefully so I hoe this answers some of those questions.

Thanks,

Jon

I'm also going to restate that it is detonation that is killing the gaskets even first time round. You say you didn't have detonation, but you did... its a known fact with these motors... you get detonation no matter what, you just have to manage it. MLS gaskets can survive longer with detonation, but they too can fail if detonation gets out of hand.

Dr Fred did not have access to the tuning tools we have now-a-days and tuning back then was a crap shoot compared to today. Forget about everything you did a while back and listen to what is going on today...... A LOT has changed AND improved since Dr. Fred. If you are still running with one of his tunes, I'd HIGHLY recommend getting that updated because I can guarantee he did not have access to half the stuff we use today on a regular bases for tuning. Either myself or Dave Dalke (XR7Dave) can help you out in this department if you so desire.

Manage your detonation problem, and the composite's will be fine for your setup. As for headers, unless your making 400+ rwhp, ported manifolds are fine. I put a set of mid-lengths on mine and notice'd zero difference as I did not even pick up more air flow over the ported stock manifolds at my power level (330 rwhp or so) going all the way to 6200rpm. Use your money else where that will make a difference.

At the very least, get rid of the stock resonator and put in a Y pipe setup with the rest of the system stock. I ran that way when I first got the car and it did fine. The back pressure produced by the stock resonator will cause detonation which will wear out the hg's.

Fraser

Mike8675309
07-01-2011, 10:55 AM
For MLS head gaskets the SC owner would want:
Felpro Permatorque MLS gasket for the 98 Mustang 3.8. Part Numbers: PN 9262PT and 9263PT. 9262PT is the Left Hand Side, 9263PT is the Right hand side.

For Composite head gaskets the SC owner would want:
Felpro Permatorque gasket for Thunderbird 3.8 Part Number: 9642PT1 or a complete upper set (permadry) numbered HS9642PT