Yeah,
I had a long discussion with Mike Kerr on the subject. He suggested that
the lower guide does help keep the lower chain controlled. I left it out
when I first rebuilt my 2L. When I pulled it apart - 7 years but less than
20,000 miles later - I found that the weird noise I'd mistaken for valve
train was infact the lower chain coming apart. I'll post a picture of it
this week as I'm way over due to update my web site. Long and short was
that the two outer links at one point on the chain had come off so that only
the middle link was holding the chain together at that point and the link
pin could be easily pushed out with a finger. I was much closer to and FJ20
/ SR20 swap than I had realized! I don't know for sure that leaving the
lower guide out caused the problem, it could have been a bad chain. I whish
I'd paid closer attention but I had stored the car for 3 years while I was
in Maryland without a garage. The mileage was way low for a chain failure.
This time, after Mike and I talked for a while, I decided to reinstall the
guide. The failure rate seems to be very exaggerated, much like the
infamous jackshaft failures which occur occasionally in racing engines but
rarely on the street. Mike also said that most of the lower guide failures
he's seen caused no damage to the engine. The guide was laying harmlessly in
the bottom of chain cover.
Again, my problem may have been a bad lower chain. I can't remember where I
got it and I don't feel like looking through the decade old stack or
receipts that one of the family cats peed on right now. I may break them
out when I post the picture I took of the lower chain. Man is that a SCARY
picture.
Brian '69 2000
Tampa, FL
http://web.tampabay.rr.com/oilleak/
-----Original Message-----
Subject: Re: Timing chains
Don't bother. You're better off not replacing it. They are notorious for
breaking off, and there is a chance it could get caught in the gear and
cause $$ damage. Besides, AFAIK there has been no evidence that it's
needed. Anyone else heard otherwise?
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