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My 79 L-82 when we changed cams a few months ago had a single roller sprockets and chain.. I've known the car since new and nobody ever changed it. . But it has a good cloyes now.
Smokey was no dummy I know a couple pro stock guys years ago that experimented with nylon gears to see if it helped with spark control and even frictional loss before belt drives came about. Obviously not 100k mile engines.
I use Morse chain sets here in my engine builds and ZERO issues now dating back over 40 years.
The few times I deviated from that deal and went to a "double roller" variety they stretched out quickly and got loose enough to require replacement.
Case in point. Back in 2000 when I built the first 455 for my Ventura I was supplied a complete "kit" from a big Pontiac speed shop. In the kit was a Rollmaster double roller timing set with billet sprockets, high end chain, and 9 keyways to move the cam around. I questioned them about it and they said that ALL their builds get them and they last forever. 4 years later mine failed at the track in the semi-finals of a big race. Not happy at all about that and it was replaced by a 3/4" wide NOS set which lasted for many years after that deal. I even had to go in once and replace the timing cover gasket due to a coolant leak (Pontiac 455) and the timing chain was tight and only very light "witness" marks on the gears.
The nylon top sprocket is an EXCELLENT set up. The Morse chain provides constant tooth contact and the nylon teeth absorb harmonics between the crank and camshaft. Using those was an old racers trick before crank triggers and belt drive set-ups became more popular and the 3/4" wide nylon sets became difficult to obtain.
Folks thinking that "double roller" timing sets are some sort of "upgrade" over the Morse design simply comes from the fact that the nylon variety eventually started to chunk off some teeth and they ended up in the sump. The Morse design is at least 3-4 times stronger than a roller variety, if you don't think so take a look in a 4 x 4 transfer case and see what kind of chain and gears are used there. It's just one of those things that get passed down thru the generations like the bottom plugs leaking on a Quadrajet carburetor when the factory corrected that issue in 1969 when they quit using pressed in brass cup plugs and smashed out front lead plugs. RARE to see a leaker after 1968 but ALL Q-jets I work on here have a ton of "monkey chit" dabbed over the plugs so much so that it often holds the main casting so far away from the baseplate the gasket isn't sealing!
Anyhow, we do NOT get accurate feedback from these double roller sets because most folks don't drive these cars daily nor do they put a lot of miles on them. Since I build engines for a living I get to see a LOT of them, and any that got a "low" end double roller variety timing set installed at any point it will have a BUTT LOAD of slop in it. I wouldn't put any of that junk of my granddaughters bicycle let alone an engine that I cared about!
The good news is that these double roller timing sets will last long enough most of the folks reading this woln't have to worry about it even if you used a high volume/high pressure oil pump you didn't need and 40-50lbs too much spring load for the "fast ramp" cam someone talked you into........FWIW.
I use Morse chain sets here in my engine builds and ZERO issues now dating back over 40 years.
The few times I deviated from that deal and went to a "double roller" variety they stretched out quickly and got loose enough to require replacement.
Case in point. Back in 2000 when I built the first 455 for my Ventura I was supplied a complete "kit" from a big Pontiac speed shop. In the kit was a Rollmaster double roller timing set with billet sprockets, high end chain, and 9 keyways to move the cam around. I questioned them about it and they said that ALL their builds get them and they last forever. 4 years later mine failed at the track in the semi-finals of a big race. Not happy at all about that and it was replaced by a 3/4" wide NOS set which lasted for many years after that deal. I even had to go in once and replace the timing cover gasket due to a coolant leak (Pontiac 455) and the timing chain was tight and only very light "witness" marks on the gears.
The nylon top sprocket is an EXCELLENT set up. The Morse chain provides constant tooth contact and the nylon teeth absorb harmonics between the crank and camshaft. Using those was an old racers trick before crank triggers and belt drive set-ups became more popular and the 3/4" wide nylon sets became difficult to obtain.
Folks thinking that "double roller" timing sets are some sort of "upgrade" over the Morse design simply comes from the fact that the nylon variety eventually started to chunk off some teeth and they ended up in the sump. The Morse design is at least 3-4 times stronger than a roller variety, if you don't think so take a look in a 4 x 4 transfer case and see what kind of chain and gears are used there. It's just one of those things that get passed down thru the generations like the bottom plugs leaking on a Quadrajet carburetor when the factory corrected that issue in 1969 when they quit using pressed in brass cup plugs and smashed out front lead plugs. RARE to see a leaker after 1968 but ALL Q-jets I work on here have a ton of "monkey chit" dabbed over the plugs so much so that it often holds the main casting so far away from the baseplate the gasket isn't sealing!
Anyhow, we do NOT get accurate feedback from these double roller sets because most folks don't drive these cars daily nor do they put a lot of miles on them. Since I build engines for a living I get to see a LOT of them, and any that got a "low" end double roller variety timing set installed at any point it will have a BUTT LOAD of slop in it. I wouldn't put any of that junk of my granddaughters bicycle let alone an engine that I cared about!
The good news is that these double roller timing sets will last long enough most of the folks reading this woln't have to worry about it even if you used a high volume/high pressure oil pump you didn't need and 40-50lbs too much spring load for the "fast ramp" cam someone talked you into........FWIW.
Well, I'm sure it isn't a scientific test but in 1988 I took my brand new trans am to John lingenfelter to have one of his 383 conversions done to it and I put 320k miles on it and the timing was fine. Now that engine had a Callie's cranks Oliver rods etc and I'm sure it was well balanced so that may have helped.
I do know that cloyes have different quality timing sets but I've never used bottom shelf stuff and I always thoroughly clean engine parts
. A timing set is no different.
Interesting thread. FWIW my 79 had about 190,000 miles on it when I bought it 25 years ago. Engine ran like crap and leaked like the Exxon Valdez. I put a gasket set in it (not including head gaskets) freed up the frozen distributor advance mechanism and replace the timing set. The cam gear was worn but there were no broken teeth and the chain had not jumped. After that the engine ran like a Swiss watch. I offer this not to argue for or against nylon gears, (I personally wouldn’t use one) but simply to add a little more data to the discussion...
I just swapped the original in my 46k mile LT1 survivor for a Cloyes double roller last week... and not a moment too soon!
In addition I figured out my balancer had slipped by approx 30 degrees. (the timing mark should be just slightly counterclock wise of the key way.)
Slipped damper's hub appears to be stamped " A T P " ... is that an aftermarket replacement damper ? (atp does market low$ replacement dampers)
Originally Posted by firstgenaddict
I just swapped the original in my 46k mile LT1 survivor for a Cloyes double roller last week... and not a moment too soon!
In addition I figured out my balancer had slipped by approx 30 degrees. (the timing mark should be just slightly counterclock wise of the key way)
NEVER a good idea to re-use a factory harmonic balancer. The rubber is decades old and at the end of it's life cycle. All my builds here get new ones, usually the SFI variety since many of my engines end up at the track and many of those cars run quick enough they may require those parts during inspection........
Yep. New balancer in every car I restore. Fluid damper where I can. It's amazing how much difference a balancer makes btw. On my dad's 67 *whispers* mustang *whispers* the idle quality improved. That balancer was very shot though. Saw it moving around.
Probably has as much to do with time and non-use as much as anything. What I mean is, regular use as a daily driver, constant heat cycles, always bathed in oil, etc, and the nylon sprockets provide fine service. Now take that same thing and park it for months or years, with the nylon exposed to the air, and the plastic changes and gets brittle.
