Does any one know if all the 305's and 350's put in third gens have nylon teeth on the timing gears or is it just certain years? I'm hoping GM might have smartened up in the later years and put in completely steel gears.

 

Many factory timing chain sets have nylon teeth gears. It makes them very quiet.

 

all the original '86 and earlier thirdgen engines i have
had apart did have the nylon teeth as did the '84 vette
350 i put in my car-however an original 350 i took
from an '83 cop car had iron gear,so possibly certain
H/D fleet apps had the iron.
i have not checked '87 up roller cam 3rd gen engines,
but all other original roller cam engines i have had
apart all had iron gears-the roller engines use a slighty
different design gear in order to accomodate the
thrust plate

 

My early 86 iron head 350 Vette engine (flat tappet L98 model) had all steel gears.

4-bolt main, one piece rear main seal block, but no roller cam mounting provision. Sort of a hybrid.

Jake

 

I never noticed solid timing sets making very much noise. I think they put the nylon teeth in to engineer an expiration date into the engines so people would have to buy new cars I was thinkin maybe the 87' and newer L98's would have solid gears since chevy used em' in the vette's.

 

there were installed in the early 80's
I believe they installed steel gears again 85....
I have yet to see them.. 86 - current

 

thats good to know

 

I never heard of such a thing in a SBC - sounds like Jap Junk to me - I'd only want steel.

 

chevy started using the nylon teeth somewhere around
1965-they actually wear pretty decent,problem is as
the plastic teeth age they shrink a little and crack loose
from the aluminum hub plate.
The original set on my '74 nova lasted exactly 140,000
mi...(this was back in '86)

 

I was coming home from the beach when I was in high school and out 84 T/A just quit with no indication of a problem. $250 tow bill. Sure enough the crank gear lost all its teeth.

 

My '82 T/A had a nylon cam gear, as did the '75 SBC in my wife's Camaro, both were replaced with true double roller timing chains. Don't ask me if the new chains are quiet though, can't hear 'em over the exhaust.