Paint Blister From Sidepipe at Body Opening

[msinghof]

I have seen one pic of a car with an approx. 1/4" aluminum edge on the body opening for the sidepipe. This trim actually wrapped around from the inside and layed flat on the body. Can't find the pic to ask the author how this was done. If anyone knows what I am talking about and how this can be done on a fiberglass SPF it would be greatly appreciated!

The reason is that I have developed several small paint blisters near the back edge of the opening. Timing has been checked and is at 12 degrees BTC for this 427 at idle. Headers are standard SPF, jet coated and perfectly aligned in the openings. Cooling air was used during the initial start-up on an already hot tested motor. Go figure...?

[Rick Parker]

This was discussed at length about 10 days ago. Do a search for "Trim Ring for Headers".

Rick

[Whaler]

These things tend to get hot alright especial at standstill where air won't dissipate the heat given off by headers and pipes.

I am just wondering why any trim made of metal won't just pick up the heat as well. With the proximity of a heat sink like a trim ring for that opening do you think it may get almost as hot as the source?

I remember many discussing the heat sheilds that can be bolted onto a sidepipe to protect ones legs from burns. They tended to eventually get as hot as well as transfer of heat occured. This is a little more direct,granted, as it is bolted right to the pipes.

The other day when we did our engine break-in, we noticed how hot our hoodstay rod got simply by being above the passenger side header. We had the hood open and one almost couldn't put a hand on that.

So getting back to this trim ring/heat shield, it too would pick up heat. How would it be fixed to the car and how wide of a lip do you give it to "protect paint"..The contour of the openings inside curves makes it difficult to fab I would think.

Tim

[427 S/O]

I've seen one other like this, found he was running to lean.

[msinghof]

Thanks for the responses! Tim, I agree with your logic that there will be heat transfer to another metallic material adjacent to the pipe, but will it also reflect some back? The blisters are already there and more have not appeared with the shake-down road check so the thought was to cover what is there and hope more do not appear further out around a trim ring.

As for the engine running lean that could be. I have not checked idle circuits yet with a vacuum gauge. Southern Automotive built this motor and they were to go through carb, valve lash, and timing twice during a two hour hot run.

[craigayl]

msinghof

I had a similar problem on my 514 SPF after an engine rebuild that included a new distributor. The car had 5000 miles on it prior to the rebuild with no paint problems. This included much slow crusing in very hot weather. The original distributor was set up with 20 degrees total advance and was set to run 12 to 32 degrees.

The new distributor was built with 30 degrees total advance (won't get into why that was), so it was set to run from 6 to 36 degrees. The paint started to blister almost imediately. I modified the weights to 22 degrees total advance and now run 14 to 36 with no problems.

Some thoughts you may want to consider

You may want to give it more initial. 14-16? when you go too far, its pretty obvious due to hard starting and and knocking

Too lean can also contribute to this problem. It may be worth getting the car on a chassis dyno to find out exactly where the air/fuel mixture is.

Good luck...

[CSX 4027]

Your car is running with the timing retarded.
It is in no way too lean. That has little or nothing to do with it.
By running retarded you are actually running too rich. You are igniting the mixture outside the pipes therefore, the pipes are getting excessively hot and possibly are glowing. It is not easily visible. Use a temp gun to the pipes to see.
***Check your total advance. It doesn't make a difference that you see 12 at idle. You don't drive at idle. If you are only advancing to 25 or 28 and your engine builder said "set it at 12 and forget it"....You might be owed a paint job.....By your engine builder.
I have seen many SPF cars and their factory paint is really good. I also have never seen one with the problems you are having. Forget the metal. That won't fix your problem.

[msinghof]

Thanks Steve, appreciate the feedback, and yes I will verify how much advance I have. Unfortunately I won't be able to work on the car until this weekend due to an out of town trip but I still have the same question. This blistering occured during the initial start-up on the car under idle conditions while checking for leaks, cooling fan operation, etc. This did not occur from driving. It never left the hoist.

The builder told me that they verified on their hot run 36 degrees at 2500 rpm. I will make a post this Saturday after I put the light on it again. Many thanks!

[CSX 4027]

You said initial run. Was the motor broken in on a dyno? How long did it idle? At 12 degrees for long period of time, the pipes will get hot? How were your other temps? Water? Oil?

[CJ428CJ]

Msinghof,

Did you ever find out what the problem was? I fired up my 428 for the first time last night. Other than a few water leaks and that sort of thing, everything was going well until my buddy noticed that the header pipe on cylinder number 7 appeared to be glowing hot. That was after about 15 minutes of running at 1500-2200 rpm and only header number 7 seemed to be having the problem. I shut down and pulled all the plugs and they all looked good (although number 5 was a bit darker brown than all the others). Now I need to decide a course of action. Here's what I plan:

1. Verify that my timing marks are correct by finding TDC using a spark plug hole piston stop device. I figured I better do this since I did put a different vibration dampner on the car that is larger in diameter than the original which caused me to have to move the pointer a bit. I thought I had this all set up right but I better double check.

2. To get the car to fire up and run, I had to advance the timing quite a bit more than I would have expected. I had to set it at about 20 degrees initial. Anything less than that and it didn't want to run smoothly or idle. I'm using an MSD billet distributor and I haven't monkeyed with the total advance yet. Whatever springs came with it initially are what are still in it.

3. The firing order of a 428 has cylinders 7 and 8 firing one after the other. Maybe I'm inducing a spark at the wrong time between the two plug wires since the wires are routed close together. I suppose that could cause one of they cylinders to fire way to soon or way too late. I'm going to separate the wires to eliminate the possibility.

4. I plan on double checking that I have the rocker arms adjusted properly and that an exhaust valve isn't staying partially open or something.

I'd appeciate comments or other suggestions that anyone might have.

Chris

[Mr.Fixit]

First fire ups, the motor runs hotter than normal. period. I always put shop fans pointing at the body exits during engine break-in when the motor was in a cobra, it only took cooking one custmer car's paint to learn that one. After engine break-in, you should be fine, so long as the sidepipes aren't really close to the paint, which from the picture, looks like it is not a problem.

[CJ428CJ]

I just did a search of the forum using the term "glowing" and found a long thread on "really hot ceramic headers." That thread had a lot of good suggestions and the general consensus seemed to be not enough distributor advance could cause the headers to get too hot. It seems like that might be the root of my problems. I guess I'll double check my timing marks and then double check the timing. Hopefully that'll solve my problem.

Chris