1969 sidepipe question

[Roger G.]

Why were the rear fender wells cut to expose the back of the frame rail? It doesn't look like it is required for the mounting.

[Dick W.]

Re: 1969 sidepipe question

Look in the AIM, complete instructions on how to mount.

[Roger G.]

Re: 1969 sidepipe question

Look in the AIM, complete instructions on how to mount.

Thanks Dick, I have the AIM, and also an original 1969 sidepipe car. On cars without sidepipes, there is a small flap of fiberglass that comes down and covers the top of the back frame rail. On my car this has been removed, but its not obvious why, it doesn't seem to be needed for the mounting. The AIM shows a Z bracket between the frame and the exhaust cover, and my car doesn't have this, and there is not a hole drilled in the frame for the bracket. I have seen other posts of original cars without this bracket in the NCRS archives. Interestingly,my car has a tab welded onto the sidepipe and a tab on the cover that line up , apparently to attach the cover directly to the pipe near the rear. I don't see this in the AIM and wonder if this was replaced with the Z bracket later. The AIM shows that a revision was made, as I recall in mid December, but don't have it in front of me now. FWIW my car is 3/11/69

[Mark D.]

Re: 1969 sidepipe question

I do not know why the flap was cut to expose the end of the frame rail but, I've never seen an original N14 equipped 69 Corvette that didn't have the same cut. Most, however, are missing the foam insulation in that cut area.

With regard to the aft attaching method, the 'Z' bracket was the third of three configurations.

[Terry M.]

Re: 1969 sidepipe question

Although I have no evidence to support it, I always thought the cut was to keep the fiberglass from melting because of the heat from the exhaust gasses.

[Bill C.]

Re: 1969 sidepipe question

I don't think that hard attaching the cover to the tab on the muffler would be a good idea.

the cover is fixed to the car and the side pipe muffler to the engine. It will be moving about some as the engine/rpm's increase/decrease.
seems it might be prone to over stressing the cover.

Maybe that is why they created the Z bar .....

Bill

[Roger G.]

Re: 1969 sidepipe question

Although I have no evidence to support it, I always thought the cut was to keep the fiberglass from melting because of the heat from the exhaust gasses.

Terry, that makes sense, and I'll bet it is the reason too. The frame rail gets very hot with the pipe running under it. The AIM shows an L shaped piece of insulation that fits into the cut.... Mine doesn't have it.... May have fallen out over the years. However, on my car the cut is very close, .... It would be hard to get insulation between the rail and the fiberglass. I've seen some pics of the cut on later 69s, and there is a fairly substantial gap between the rail and the fiberglass... That the L shaped insulation would fit into perfectly.....so I'm not sure if it was decided sometime in the production if the close trim was not enough for the heat, and they started cutting it wider and adding the insulation.

[Roger G.]

Re: 1969 sidepipe question

I don't think that hard attaching the cover to the tab on the muffler would be a good idea.

the cover is fixed to the car and the side pipe muffler to the engine. It will be moving about some as the engine/rpm's increase/decrease.
seems it might be prone to over stressing the cover.

Maybe that is why they created the Z bar .....

Bill

Hello Bill, ....That may very well be, pipe movement would definitely put stress on the cover attachment points