Guy at work has a '74 2.0. He bought stainless heat exchangers about 2 years ago and we put them on. In the process, one of his exhaust studs pulled out of the head. So he had the typical tstststststststststststst leak at the head. He pretty much just parked if for over a year. This weekend, we pulled them back off, I tapped the head for a 8/9 stud and loctite it in. We let that cure up while we remove the front bumper to add a top pad, fix the passenger door handle, fuel leak, etc.

Soooooooooo... new gaskets, new nuts, etc. Put the exchanger back on, everything is snugged up... start it... TSTTSTSTSTSTSTSTSTSTST... leaks. Loosen it up, tap it with weighted hammer to get it to seat up in there and resnug the nuts... with the muffler end loose, it doesn't move.. it's for all intensive purposes, SEATED... tightly. Snug up the muffler end.. start it tstststststststst...

What gives? Could he have some wrong exchangers? the depth of the opening from the mounting tabs different? mounting tabs and surfaces are all flush/square and flat.

I told him to flip the car on it's roof and we'll fill the head ports around the exchangers with JB weld and duct tape... those fix EVERYthing!!!

you can mount any '4' heat exchangers to any 914-4 motor

could there be a crack in the exchangers?

with the car on ramps, you can start the car and put your hand up near where they bolt up. You can feel the exhaust blasting out. Exchangers aren't cracked. Didn't get into the heads at all though... Hope that's not it!

I'm no expert but this has come up several times on the board. The mounting flange on many of the exchangers is not flat. The experts recommend getting a very large file and making sure the two mounting faces are flat in relation to each other by filing across both at the same time. do a search this just came up about a month ago.

Also, many recommend annealling the copper gaskets to soften them prior to installation. The exchangers should be installed first individually then the muffler attached, it sounds like you did this.

hope this helps,

Jim

Thanks for the info. Next time he decides to work on the car, I'll try the file idea. I talked to him today and he mentioned that it got quieter on the way home. Perhaps that was the gaskets heating up and softening up to mold to the exchanger flanges. He said he had a couple of other running issues on the way home. He made a noise and said, it sounds like that... lol. well, from the noise he made, I'm guessing he's got plug wires shorting or a spark jumping the gap in the cap.

use a black sharpie to mark the piping edges. BIG file, light passes. the first pass usually reveals the irregularities. don't remove anymore than you need to. push up on the HE and tighten in progressive stages and in X pattern.