Some of the pre-cups on the TD head that I'm planning to use have one or two very slight hairline cracks radiating out from the flame hole, how bad is this? They don't look too bad, and none of the cracks is anymore than about 5 or 6 mm long.
I asked my machine shop guy the same thing the other day.. To quote "I guess it wouldn't hurt as long as they don;t get worse, but I generally replaced them to be sure" He's generally pretty fussy about things such as questionable cracks so I was kinda surpirsed that he even left the option open to reuse them..
I'll appreciate any other input as well, but I think I'll replace mine as Murphy and his band of law officers find me frequently...
If you where tearing it all down and planning on dumping a bunch of cash into the engine to turn it into a daily high boost, high (for a diesel) rpm machine I would say do it. If you are just going to run slightly higher boost and fuel I would say just run em. I have seen lots of very small cracks in the precups. Do you have any pictures?
Mine will be a daily driver NA, but I'm replacing damn near everything else in the thing... What's a few more bucks...
No pics yet but I'll try tomorrow or wed. the engine is at my shop and I can't get there much during the week. But I also figured that they would be good enough for a few thou while I rebuild the TD motor for my Syncro, then I will get a rebuild for that one and use that head on the caddy...delayed gratification!