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Engine Specific Info and Questions => IDI Engine => Topic started by: turbosyncrobus on March 07, 2009, 07:29:06 am

Title: Pre-cup cracks
Post by: turbosyncrobus on March 07, 2009, 07:29:06 am

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.

Title: Pre-cup cracks
Post by: maxfax on March 07, 2009, 11:21:37 am

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...

Title: Pre-cup cracks
Post by: subsonic on March 07, 2009, 02:25:11 pm

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?

Title: Pre-cup cracks
Post by: maxfax on March 07, 2009, 05:00:13 pm

Mine will be a daily driver NA, but I'm replacing damn near everything else in the thing... What's a few more bucks...

Title: Pre-cup cracks
Post by: turbosyncrobus on March 09, 2009, 04:26:01 pm

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!