951 Header Removal and Reinstallation

[Dave951M]

Finally finished. The procedure went-

Liberally apply PB penetrating oil often..
1)Unbolt headers from collector.
2)Remove PS resevoir (unclamp and set aside)
3)Remove heater pipe
4)Unbolt headers
5)Remove top two bolts from pass motor mount
6)Remove header studs
7)Remove 2/3 header
8)With wood plate under oilpan, jack engine slightly to get clearance
9)Remove 1/4 header

Reinstallation is reverse of above. Several tips that will help here. Clean the threads of the screws with a fine wire brush and use an antiseize compound for reassembly. Get new studs. Get a tap to chase the stud holes. Tap is a M8 1.25 pitch for a blind hole. If you get the pointed tap, you cannot clean the threads to the bottom of the hole. Be very careful with the tap, don't cross thread or force it. In my case, a cracked header (2/3) and a broken stud prompted this expedition. To remove the broken stud, you will have to have some form of right angle drill. We have a large hardware store chain (Lowe's) with an ok tool selection. In the drill bit section, there is a right angle attachment ($20) made by Vermont American that will adapt any drill. In my case, the stud on #4 closest to the firewall was broken. I happened to have a very narrow 3/8 Sears battery powered drill that would fit with this attachment. The drill bit used was shortened to allow perpendicular drilling on the hole. Once the hole was drilled all the way through the bolt, I applied PB again and used a small pipe to flow it into the back of the bolt through the hole. From there it was a matter of using the old EZ out screw extractor. Advice from past bad experience, use a size larger than recommended. The size recommended for the M8 bolt is a #2, drill 9/64 and use the next size up from a #2.

I'm off the jackstands now and back on the road. I just thought I would post the procedure for anyone else who has to do it.

Dave951M

[asidrave]

Dave, thanx for the tip. im sure someone will (hopefully not) experience the same problem.

[T86951]

hey Dave glad your all fixed up! I am going to have to do that to my 951, leaking between cast flange and pipe on # 4.
Are the cast flanges welded to the header pipes?
Would going back with good hex bolts work OK in your opinion?
thanks
dan

[Dave951M]

Dan-

The header pipe is inserted into the cast flange and seems to rest on a step inside of the flange. The pipe is welded to the flange internally at this place. The weld is very smooth and was almost impossible to accurately duplicate, so mine are welded on the outside, all the way around to prevent creating a restriction. I went back with new studs for a couple of reasons.

1) The studs make it easier to locate the flanges on the ports.
2) There is a clearance problem with the head of a normal hex head cap screw.
3) The clearance on #2 will dictate the use of a stud on the firewall side.
4) If you break a bolt off, it's way harder to drill and use an ez out. The only bolts you should consider will be Grade 8 or better, socket head cap screws 8mm x 1.25 pitch.

One thing I left out was that to get to the two screws on the top of the motor mount, you'll have to remove the heat shield. It's held on by two screws and are very difficult to deal with when reassembling. This part took longer than bolting the headers back together. This heat shield also must come out to be able to manuever the 1/4 header around to get it out. I also had the starter heat shield off while I was under the car and rewelded it as well. While I had several heat shields off, I cleaned, rewelded and repainted them. It makes the job look a lot better when it goes back together.

Dave951M

[T86951]

Dave

I am going to start on mine next week. Other than the broken stud, did you have any trouble getting the other studs out? I am in fear one will break getting them out! Did yours come out ok?

thanks
dan

[951carter]

you do not need to mess with the motor mount or jack the engine. they will come out.

[Lawrence Coppari]

Header 1,4 can be removed and installed without moving the engine. You just have to rotate it at a pecular angle. I did it but do not recall the angle it was at. Should have taken a picture of it.

But it can be done. Patience is a virtue when you do it.

[Dave951M]

Carter- I wish I knew the secret to getting them out without unbolting the motor and jacking the engine, every way I could think of wound up interfering by about 1/8 inch. It went much easier after jacking the engine.

Dan- my studs came out ok, I just hosed them with PB the night before and again about two hours before starting. I used the old fashioned jam nut method even though I have a stud remover. I would highly recommend that if you take them out, replace them with new ones. They are cheap, about $1.10 each I think, at the dealer no less. The real sticker shock comes in if you want to buy new nuts, they come in at $4.15 each, yes, each. I just cleaned mine up and even used a couple left over from the exhaust of a Fiat. You might also want to chase the threads with tap as well. Mine cleaned up nicely but if you have never tapped metal before, be VERY careful. If the tap gets cross-threaded, you will ruin your threads.

It's not a hard thing to do, just time consuming and perhaps a bit vocabulary expanding.

Dave951M

PS- Had dinner tonight with the service rep from the local dealer. He recommends cutting off the factory heatshielding and leaving it off. It will make welding them when they break again much easier. In its place, he recommended header wrap. As opposed to this as I have been in the past, I think I'll try it, but I'll save the heat shields just in case it doesn't work out.