timing chain cadillac 1970 472ci

[Christian]

hello,

is the this only pinion of camshaft which is covered with plastic or both pinion?
(excuse my bad english)

[Tim Pawl CLC#4383]

Both gears as built by the factory were coated with plastic as a means of silencing chain noise. However, over time as the plastic deteriorates it comes off and can clog the oil pickup screen, thereby starving oil supply and usually takes out rod bearings.  The aftermarket/service replacement gears do not have the plastic coating.

[Bruce Reynolds # 18992]

Tim,

I thought it was only the Cam Gear that had the Nylon protective covering.

The chain is a morse type chain, and the Crankshaft Gear was all steel.

Bruce,
The Tassie Devil(le),
60 CDV

[Christian]

Thank you Tim and Bruce, i understand.

[Tim Pawl CLC#4383]

I can only state from personal experience, on an early 1969 (not 1970) body number 1065 (September 1968) build 472, that both gears had nylon silencer coating. This material was found all over oil pickup screen after engine developed serious rod knock, and only partial material remained on gears. Replacement gears were both all steel with no coatings. I think that was why the original message was generated , because if you are putting on new service gears they wont have the coating and you might think you have the wrong gears. You live with a little more noise but much better than rebuilding engine.

[Mike @19861]

 In all my experience that would be the first time I have ever seen both gears coated in nylon. It is very common for all manufacturers to use a nylon coating on the camshft gear, but only the camshft gear.

 In a factory installation, steel gears were usually only used on HD or high performance applications, however there are exceptions. Most replacement aftermarket gears are steel.

 Mike