First off I am aware that Fel-Pro is a advertiser here at GRM. And I have sung there praises in the past. How ever this time I have run in to a problem with there product. And I need to vent a little bit

I am replacing the head gaskets on a 97 3.8 Mustang Motor. The head gaskets are seperatly wrapped in the top end gasket kit with big labels on them saying not to open unitll you are going to use. So I open one and it has a marking on it that said TOP. I say ok this is the top of the gasket. I put it on the head to make sure that all the steam holes and the oil return holes are alighted and all looks good so I proceed to install the left head. I then go around to the right side of the motor and open the other gasket and guess what it has stamped on the gasket?.. . . . TOP LEFT!!!!

I am so pissed off at the moment with my self for actually following the directions and not opening both at once. I took the gasket marked "Top Left" put it on the block and checked to see that all the holes lined up and everything looks good. I put it on the head and it also looks good. So now what? Do I go ahead and install it and hope for the best?

I guess I have to call Fel-Pro Monday and find out if they are interchangeable. If they are not I am going to have to purchase another head gasket set AND another set of head bolts AND I had the heads decked so now that I have torqued it down I am betting that I am going to have to have it decked again. I am looking at least a couple hundred $$$$$ if these gaskets are not interchangeable. If I have to pay for all this again my head gasket change job is going to cost me more than a used motor.

So If you are doing head gaskets on a V motor always open both head gaskets even if the labeling on them said to open them only when you are about to use them.

The head gaskets definitely are side-specific. Good luck. I see no reason for you to redeck your head, though.

Also related, i don't understand why Felpro will label the gaskets on a "V" motor "Left," and "Right."

On a motor that was never available in RWD configuration.

92CelicaHalfTrac wrote: Also related, i don't understand why Felpro will label the gaskets on a "V" motor "Left," and "Right." On a motor that was never available in RWD configuration.

This is in a RWD config. Mustangs, thunderbirds had them. I am working on a mustang.

Kramer wrote: The head gaskets definitely are side-specific. Good luck. I see no reason for you to redeck your head, though.

The torque on these is quite high (torque to yeald bolts) and these are aluminum heads and I am woried that when I take it off it will be warped again.

dean1484 wrote:

92CelicaHalfTrac wrote: Also related, i don't understand why Felpro will label the gaskets on a "V" motor "Left," and "Right." On a motor that was never available in RWD configuration.

This is in a RWD config. Mustangs, thunderbirds had them. I am working on a mustang.

Sorry, i'm tired...

Just showing my experiences with Felpro head gaskets last night. "Left" and "Right" were really confusing on a FWD-only motor.

dean1484 wrote:

Kramer wrote: The head gaskets definitely are side-specific. Good luck. I see no reason for you to redeck your head, though.

The torque on these is quite high (torque to yeald bolts) and these are aluminum heads and I am woried that when I take it off it will be warped again.

I would have exactly NO concern about that. Really.

I put two oil pan gaskets into a bmw m20 recently. One was German made, the other fel- pro. The fit on the felpro was terrible.

Streetwiseguy wrote:

dean1484 wrote:

Kramer wrote: The head gaskets definitely are side-specific. Good luck. I see no reason for you to redeck your head, though.

The torque on these is quite high (torque to yeald bolts) and these are aluminum heads and I am woried that when I take it off it will be warped again.

I would have exactly NO concern about that. Really.

I hope you are rite. I am going to ask my machienest what he things. Since it has not been run I am hoping your rite but from my past experence with alu heads is if you look at them wrong they warp.

kreb wrote: I put two oil pan gaskets into a bmw m20 recently. One was German made, the other fel- pro. The fit on the felpro was terrible.

That is surprising. I have used Fel-Pro for years and never had a fitment problem.

92CelicaHalfTrac wrote:

dean1484 wrote:

92CelicaHalfTrac wrote: Also related, i don't understand why Felpro will label the gaskets on a "V" motor "Left," and "Right." On a motor that was never available in RWD configuration.

This is in a RWD config. Mustangs, thunderbirds had them. I am working on a mustang.

Sorry, i'm tired... Just showing my experiences with Felpro head gaskets last night. "Left" and "Right" were really confusing on a FWD-only motor.

Why? FWD motors still have L and R. The 3.3L in my wife's old Caravan had head gaskets marked L and R.

In reply to curtis73:

It's front and rear dammit!!!

I couldnt tell you which head was left and which was right on a standard fwd v6.

92CelicaHalfTrac wrote: Also related, i don't understand why Felpro will label the gaskets on a "V" motor "Left," and "Right." On a motor that was never available in RWD configuration.

Left and Right are the correct way to refer to the heads on a transverse, too. The reference is made as if from standing behind the flywheel.

What gets confusing is when you are trying to order motor mounts. SOME people refer to the chassis and SOME refer to the engine, so you need to be extra special sure when you order a "front" motor mount, or a "left" or "right".

A possibly more legitimate gripe is cylinder numbering. 90% of the time, you can look at the connecting rods in a V engine and run down the list from front to back, so the forwardmost cylinder is #1, the front cylinder on the other bank is #2, evens and odds all the way back. 9.9% of the time it's not evens and odds, but #1 is still the frontmost cylinder.

Except for Pontiac. Pontiac has reversed cylinders compared to other GMs - they are passenger bank forward. But the driver's side still has #1. Going from front to back down the crank, the numbering is 21-43-65-87.

fords run 1234 on left bank and 5678 on right bank normally.

I just got off the phone with Federal Mogal (AKA Fel-Pro)

There is a difference with the two gaskets and I do have to take it apart.

HOWEVER the tech from Fel-Pro said I don't have to replace the gasket's If I have not started / run the car then it is ok to re use them. The key is the heat cycling with the new multi ply composite gaskets. Since I have not run the vehicle then I can just go ahead and take it apart and swap the gaskets side to side.

I will have to replace the head bolts but those are cheep compared to the gaskets. So although this is a bit of a PITA as I have to take it apart again it is not as bad as I thought it was going to be. So off to order new head bolts and it is coming apart again.

BTW the Tech line at Federal Mogul was excellent. Very knowledgeable person on the other end of the line.

I was told that they are going to look in to the labeling of the parts in the kit and see if they need to make some changes as they can see how it would happen.

the tech from Fel-Pro said I don't have to replace the gasket's If I have not started / run the car then it is ok to re use them.

He beat me to it. There is no reason not to reuse it.

I've even reused Felpro head gaskets that have been used several weeks on a race motor. As long as they came off clean I reused them, and never had a problem.

KATYB wrote: fords run 1234 on left bank and 5678 on right bank normally.

1 is on the right bank.

I timed a Ford off of the front cylinder on the left bank, once. That didn't end well.

well i suppose your right labeling from rear of engine but my duratec and all 3 modulars ive owned if you look at it from the front of engine(harmonic baqlancer the number 1 has been on the left.

If you're looking at the front of the engine, the bank on your left is on the engine's right.

I learned something new again about this project. I was going to just go replace the head bolts but I figured I would call Federal Mogul about it as the car has not been started and I wondered if they were like the gaskets in that if they were not heat cycled you can re use them. So I called and in fact you can re use the head bolts even though they are torque to yield. There are two thing.

1. I have not started the car so the bolts have never been that cycled. If you ehat cycle the bolts they take a set and can not be re used.

2. I have to inspect the bolts and check them with a strait edge. If they are strait I can re use them if they have a curve to them I have to replace them.

The tech person said that they will only bend / curve if they were over torqued during installation. Since I followed the instruction to the letter there is a very good chance that I will not have to replace the head bolts either. I am going to purchase a set as backup to have if I need them but I may actually be able to remove the heads swap the gaskets and it will not cost me a dime. I am very happy about this.

If the bolts are truly torque-to-yield (TTY) then I'm skeptical that they can be reused. TTY bolts exhibit plastic deformation if you actually torque them properly -- meaning they ain't springing back after you release the tension by unbolting them. If the manufacturer is telling you to re-use them, methinks they're not actually TTY and they just want you to buy a new set of their bolts every time :) They're telling you to re-use them now because they know it's okay and they don't want you ticked off at them.

But that's totally my conspiracy theory at work. I would assume that they really are TTY and just buy new bolts.

I've reused TTY bolts with success. You just need to measure them against each other to see if there are sections of stretched threads.

Knurled wrote: I've reused TTY bolts with success. You just need to measure them against each other to see if there are sections of stretched threads.

I think it's going to be based on the wrench. A typical click style torque wrench is only about +/- 15% from the studies I have read. If you're on the low end of 'yield', great! if you're not, not great!

You'd have to measure very carefully. I would probably replace, and I can't see how it has anything to do with heat cycles.

Winston wrote: If the bolts are truly torque-to-yield (TTY) then I'm skeptical that they can be reused. TTY bolts exhibit plastic deformation if you actually torque them properly -- meaning they ain't springing back after you release the tension by unbolting them. If the manufacturer is telling you to re-use them, methinks they're not actually TTY and they just want you to buy a new set of their bolts every time :) They're telling you to re-use them now because they know it's okay and they don't want you ticked off at them. But that's totally my conspiracy theory at work. I would assume that they really are TTY and just buy new bolts.

One good way to check is to measure the length on the used bolts and compare them to the unused bolts. Use a micrometer for this or ask your machinist to do it for you. If the used bolts are longer than the unused ones, replace them.

After listening to you all. I am going to get two sets on my way home and just replace them for the $40 it is cheep insurance