I know everybody and their brother says to replace heat shields when the inj. are removed but I want to know why. I understand that copper avaition sparkplug washers can become work hardened after torquing but these heatshields are steel. Anyone know the real true reason they must be replaced without question?
Curious in Seattle (area). :?:
That conical area that contacts the injector near the pintle gets flattened. Compare an old vs new and you will see the old is "mushed" or "squashed" by the injector. Sort of like a lock-washer than gets deformed after you use it, loosing some of it's "springyness".
A friend who really knows his VW Diesels (thinking about it, I should get him up here on this list!) had a little trick of hammering a cone-shaped tool to peen the edge back into place. I have tried it myself and sometimes it peens over to the side. So I guess I might use the ones that have been re-peened and looked still stragiht and not lopsided, but I just try and keep a stock of new ones and use them instead, which I trust more. The peened old ones are more of a last report IMO. I would not use old ones because if they don't do their job and seal, you will get a leak and cabon will build-up in the head behind and in the injector threads.
Thanks Jake! Hey, I enjoyed meeting your dad yesterday, quite a nice guy.
RE: Heat shields.
I took a closer look at them and can see, as you said, the cone is slightly deformed on the used ones by about .020". The new ones have a perfectly straight walled cone. I'm sure this is to seal just around the nozzle. Anyway, I turned a tool on the lathe for my arbor press that reshapes the cone back to straight wall. The metal is quite soft so it doesn't take much. I compared my "rebuilt" ones to new ones and I doubt anyone could tell the difference.
i can get these shields for $1.60, if anyone wants some.
Thanks Jake! Hey, I enjoyed meeting your dad yesterday, quite a nice guy.
RE: Heat shields.
I took a closer look at them and can see, as you said, the cone is slightly deformed on the used ones by about .020". The new ones have a perfectly straight walled cone. I'm sure this is to seal just around the nozzle. Anyway, I turned a tool on the lathe for my arbor press that reshapes the cone back to straight wall. The metal is quite soft so it doesn't take much. I compared my "rebuilt" ones to new ones and I doubt anyone could tell the difference.
Wow - that was quick!!! Cool Larry! Those are some nice tools there.
Oh how I wish I had a lathe or a mill, or - something. Looks like a lot of fun.
When I tried peening my heat shields, it was much more "shadetree mechanic" style, with matching results. :shock: I think I just tried tapping the deformed cone areas with an old hardened tip of a bullet (that had a cone shape, but not the nice shallow angle like the cone press tool you made has) to get that shape restored. It would sometimes give a result I might be willing to try but other times not. That tool you've made looks like it would work beautifully - the wide cone would guarantee that the restored center lip would be centered. Nice work!
Thanks for the compliments Jake.
Anyone want me to reshape a bunch of heatshields for them, just clean em up real good and mail em to me and include return postage. Cleaning them is the hardest part. I might even be coerced into beadblasting them if they are clean. That oily crud makes a mess in the beadblaster :cry: .