Issue with Expansion Tank

tgitchel · #1 (**permalink**) 11-03-2009, 12:06 PM

Am I missing some sort of spacer, or is the expansion tank supposed to butt up against the distributor cap?

rustyBob · #2 (**permalink**) 11-03-2009, 12:50 PM

no it does not sit against the dist. there should be a thick flange that the thermastat sits in and that helps space it out from the dist.

tgitchel · #3 (**permalink**) 11-03-2009, 12:53 PM

Thanks, Bob.

I figured as much.

Does anyone have a part number?

rustyBob · #4 (**permalink**) 11-03-2009, 01:09 PM

thats not a seperate part that i know of it should be made to the tube that the tank sits on.

Jim Holden · #5 (**permalink**) 11-03-2009, 01:11 PM

Which distributor do you have?

Jim

patrickt · #6 (**permalink**) 11-03-2009, 01:20 PM

Does your tank look like this one from the Gessford site? I'm pretty sure that the ERA ones are not only shortened but spaced out a bit. I think Bob told me that the tanks they have now are made from scratch for them.

lineslinger · #7 (**permalink**) 11-03-2009, 02:05 PM

I had the same problem, expansion tank knocking against the MSD dizzy. Ended up making my own.

Dwight · #8 (**permalink**) 11-03-2009, 02:15 PM

I had to make one for Lainhart 427 s.o.

Dwight

tgitchel · #9 (**permalink**) 11-04-2009, 09:27 AM

Thanks for all the replies.

I got the tank from ERA. The distributor is an MSD (I got the model number off the Keith Craft web site). I would have hoped, for the price, that it would work without having to fabricate additional parts.

Jim Holden · #10 (**permalink**) 11-04-2009, 09:32 AM

It depends on which distributor (ie; narrow or wide) that you got from MSD.

Again, which one do you have?

lineslinger · #11 (**permalink**) 11-04-2009, 09:33 AM

Although components are reasonably interchangeable you sometimes have to be flexible when performing a build...part of the deal I think. The spacer is relatively easy to fabricate.

Gunner · #12 (**permalink**) 11-04-2009, 09:50 AM

My car has the narrow MSD distributor and the ERA-supplied expansion tank, which has a spacer of about 3/8 thickness where it bolts to the intake port. There is about a quarter inch between the lip of the tank and the nearest spark plug wire boot.

The only reason you should need more space is if you're using the wide MSD distributor, or if your intake has an unusually deep inset on the thermostat port.

If it's the former, my 'umble suggestion is ditching the fat-top for a standard configuration disto - the look will be more era-correct and the only real advantage to the wide distributors is reduced crossfire at very high RPMs. As FEs top out at about 6k, you're unlikely to have crossfire problems in any case.

tgitchel · #13 (**permalink**) 11-04-2009, 12:12 PM

Is the narrow distributor taller? I think I will have trouble with my oval air filter bottom plate hitting it as it is. I wonder if short/wide caps with the plugs on the side would fit and solve both problems.

patrickt · #14 (**permalink**) 11-04-2009, 01:36 PM

tgitchel · #15 (**permalink**) 11-04-2009, 01:45 PM

Patrick,

Thanks for the pictures. It looks like you have the same distributor that I have, but your expansion tank appears to have a spacer that mine didn't come with. When I get home I will look through the box again to see if it's in there and take some more pitures. My air cleaner is the long, oval one with Cobra on it that you see a lot. I will need to test fit that next to see how close it comes to the distributor.

patrickt · #16 (**permalink**) 11-04-2009, 01:49 PM

That would be the MSD Pro Billet 8594. I'll take some shots up close and see if that doesn't help -- maybe with a ruler or something.

Gunner · #17 (**permalink**) 11-04-2009, 02:09 PM

Patrick's setup is identical to mine and I have fit the turkey pan and a long-oval with no problem. EDIT: I had to do considerable work to the bottom plate of the long oval to get the AC assembly to clear the trailing edge of the hood, but no problems with engine component interference.

It sounds as if your tank does not have that integrated 3/8 inch spacer - if you got it from ERA, it should have had it in place. If not, you'll need to fab or find one.

patrickt · #18 (**permalink**) 11-04-2009, 02:53 PM

Here are two more shots. I honestly can not tell whether that additional piece is part of the tank or a separate spacer, but I think it's part of the tank. I don't see any gasket/sealer material anywhere around the tank side of where it would be if it was a spacer. If your tank doesn't look like this, I think you need to give Bob P. your credit card number and tell him you want what I have. Tell him "price is no object."

lineslinger · #19 (**permalink**) 11-04-2009, 03:05 PM

Without the spacer the edge of the E tank was just barely resting against one of the electrodes on the dizzy. It wouldn't take a much time for engine vibration to allow scoring of the rubber boot from the seam on the tank. As well I use the same oval air cleaner without problem.

This is the distance I accomplished

Jim Holden · #20 (**permalink**) 11-04-2009, 03:08 PM

The "spacer" is a part of every expansion tank assembly. It is silver soldered to the tube to the tank when it is constructed.

Without seeing what is causing the interference it is hard to say what the problem is. Sometimes the distributer needs to be rotated because a holddown clip or other obstruction on one side or the other of the distributer is hitting the tank. It is a snug fit under the best of circumstances.
Jim