i have about 20K miles on a 1987 hydraulic roller block. it has been sitting for awhile and i'm redo-ing the top end, cam and heads.
assuming they look good, is it unwise to use the existing 20K mile cam bearings with a new cam ?
thanks for any thoughts on this.....

kip

It really depends on the engine and it's past care. As a general rule, cam bearings with only 20K should still be 'servicable' (within factory limits for internal dia. and no marks or visible wear patterns). I have torn down SBC's from light truck duty that had over 300,000 miles, but were serviced regularly - and the cam bearings still looked and measured good! But, if the engine has been subjected to long oil/filter change intervals or the wrong grades of oil were used or the cam was allowed to scratch the surfaces being removed or ??????.
You need to take a good light and a mirror and inspect every journal to see if it looks good. Then use an inside mic. to measure each bearing and compare to stock service spec.s. Pay very close attention to the front and rear journals.
In the long run - Cam bearings are dirt cheap, so if you're planning on keeping this engine in the new confiquration for a long period of time - I would recommend you change them so you have a known good starting point.

wow, fast reply... thanks!
i have not inspected them yet, the engine is still together. the engine was taken care of and has been stored well. i usually stay on the cautious side, so i most likely will replace, depending on what condition i find them in.
300K miles and they still were within spec? thats impressive!
thanks again

kip

I was always too afraid to replace them!

so milan,

i take it you've switched cams without changing the cam bearings before? and have had good luck ?
i've previously changed cams only when doing a total rebuild, so this route is new to me.

kip

Kip sorry so long to respond been out of town and swamped. My last cam experience was a nightmare but not for any bearing reasons. I have installed dozens of cams and NEVER done cam bearings.

thanks for the responses, its good to hear other's experiences. i pulled the old heads this weekend and found a deck height of 0.022". it needs to be decked. i built it so long ago i forgot if it was decked or not!(lost paperwork on it) so i've decided on tearing the engine back down and starting over. then i'll have a good,known starting point.

kip