c3:71 LT1 motor rebuild inquiry

[Peter M.]

Have a 71 Lt1 with M21 and 411. Numbers match but car didn't seem to go like I remember a 411 lt1 should. Thouhg Motor ran smooth with no blue smoke, I guessed motor seemed tired and when compression test was performed was about 90lbs across the board. Don't know if this is typical of a tired motor(down in lbs uniformly) but looking to have it rebuilt. Would like to have it rebuilt stock but include a performance valve job-in other words make it a solid running Lt1.

Original transitor ignition pieces also gone-wondering whether I should reinstall or are these troublesome pieces(This is my first corvette).

Finally, looking for good engine rebuilder who knows LT1 well. Thought I read this message board where a Terry McMannmon was an LT1 whiz and was wondering if he had suggestions-I live in New Jersey. Thanks

[Joe L.]

Re: c3:71 LT1 motor rebuild inquiry

Peter-----

90 lbs compression "across the board" is very low and unusual if the test was performed correctly. I would look first for a cam timing problem, such as one caused by an incorrectly installed timing chain or one that has slipped one or more teeth. The original cam timing sprockets for these engines were aluminum with nylon teeth and are notorious for wear and "shedding of teeth".

[Terry M.]

Re: c3:71 LT1 motor rebuild inquiry *TL*

Peter,

You did prop the throttle open when you did the compression test, right? Otherwise what Joe said. I would do some more checking before I threw down on an engine rebuild.
Sorry, I am not familiar with any engine shop in New Jersey. This is the kind of information an NCRS Chapter can help you with. There is a very friendly group in Central NJ - see the contacts page for an address.

[Clem Z.]

Re: c3:71 LT1 motor rebuild inquiry

a leak down check would give a better look into the engine condition.