Teflon coated piston skirts

[Gary R.]

Re: Teflon coated piston skirts

I used the Teflon Hypers when I built my 350 8-9 years ago. Have 12k miles on the engine now no issues.

[Mike T.]

Re: Teflon coated piston skirts

Just got another question from my rebuilder.
A bearing spun and scored the crank.
I have to let him know if want him to turn it, or just get a new replacement crank.
If it's a 1182 forged steel crank as opposed to a cast 2442, I should probably keep the original 1182 unless it's scored too badly, correct?

[Duke W.]

Re: Teflon coated piston skirts

...depends on how bad it is "scored". Post a photo.

Light scoring might be polished out and you can get .001 oversize bearings to keep clearance in range.

Normally when cranks are "ground" all journals are ground undersized - usually .010" or .020", but if only one journal is damaged to the point were grinding undersized is necessary, I don't see a problem grinding just the one journal.

I don't know if the 1182 crank is Tufftrided, but grinding the journals removes the surface layer of very hard steel, so I don't recommend grinding Tufftrided cranks unless absolutely necessary. Grinding a Tufftrided crank reduces durability, but that may not be important if it's not going to be run up to high revs very often.

You only described the engine as a "69 350", so we really don't know what it was originally or now, and you haven't described how you will us it.

Duke