Nylon timing gears ? still in use ?

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Long ago late 70's I worked as a mechanic. Back then a lot of engines had nylon cam timing gear teeth from the factory (was meant to have less noise). Most all replacement cam gears were steel.
Since a lot of newer engines are going back to timing chains, are the manufactures using the nylon gears ?
The nylon cam gears would loose the teeth, and of course the timing would jump.
 
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It's a cheap alternative when the camshaft is in the block.

Now that pretty much every engine is overhead cam, it's not such a cost effective alternative.
 
Nylon toothed (or even nylon coated metal sprockets) went out of fashion after the 70s, mainly due to reliability and longevity issues.

Pretty much everyone went back to using metal-to-metal configuration RE: cam/crank sprockets and timing chains. No one want to deal with the nylon coated designs anymore.

Q.
 
I haven't seen any since I went to Auto Tech school 12 years ago. The old timers in the engine rebuilding class kept a SBC on a stand to show us whipper snappers what they used to have to deal with.
 
I had an 1988 club wagon with a 300ci 6cyl. It had fiber timing gears as OEM equipment. I had them replaced with metal ones during some maintenance procedure. The metal ones made a singing noise at idle that the fiber ones didn't. at tleast the metal ones didn't self destruct.
 
Its been a LONG time (early 80s) since I've seen a nylon-covered cam gear. The Dodge Magnum engines used solid metal gears, and now the Hemi, Pentastar, and (no longer produced) 4.7/3.7 use metal. I think the same pretty much went for GM and Ford as well- certainly Ford Modulars never had plastic covered gears like the 70s 302 and 351 did. I don't think GM has used them since the days of the carbureted 350 either.

Where "nylon" or some other polymer does still come into play is timing chain guides and tensioners, but those are a lot more forgiving than the cam gears were.
 
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Yeah, no one is using those anymore...thank god. The only worse idea was the fiber gears that Fords had in them way back.
 
I remember seeing some plastic timing gears..GM products. The plastic would break-up and destroyed engines. Not the best engineering and they don't use them anymore except in lawnmowers.
 
I had a Nylon gear on a Ford 351W fail. I had a Phenolic Resin Composite gear in a Pontiac "Iron Duke" fail.

I suspect the trend will be to find some new wonder material to fail next, and not rely on the old, discredited wonder material.
 
Many small engines for OPE still use Nylon cam gears. I know that my Kohler Courage twin cam OHV uses them as well as my Briggs Quantum and Sprint. They almost never cause a problem.

As far as auto engines though, I havent seen them used on anything in the last 20 years at least.
 
I can tell you of two engines that had them at least recently. One was the Ford 5.4 V8, had many problems here with V8 Falcons developing nasty rattles and grinding noises which turned out to be caused by nylon timing gear wearing or breaking at very low mileage. This was around 2003 to some point where Ford replaced them all back to steel.
Another was at least one of the engines used in the Nissan Frontera/Navara. Probably about 2009 a neigbour had a new one and the nylon sprocket broke, yet again at a few thousand miles, and it threw the timing out so bad it chucked a rod through the side of the block. Apparently this was very common on these too
 
My '84 Ford Ranger had fiber timing gears(2.8L)

...and I had to replace them when they decided to "let go"....
 
I have seen a piece of plastic gear get into an oil pump and stop it. The small block Fords would Candy Cane the oil pump driveshaft and if the driver was not paying attention he would burn the engine up.

I have not seen a Plastic gear in many years.
 
Originally Posted By: Chris142
I have seen a piece of plastic gear get into an oil pump and stop it. The small block Fords would Candy Cane the oil pump driveshaft and if the driver was not paying attention he would burn the engine up.

I have not seen a Plastic gear in many years.


I tell any customer that if they are rebuilding a SBF to always used the ARP oil pump shaft, I think the Ford one is disco duck anyway, but the ARP one is the way to go.
 
Back in the early 80s, I had a '71 Chevy Impala with the factory 402 big block. (If you ever looked up parts for this animal, the parts man would ask if it had a 2 barrel or a 4 barrel carb. The 2 barrel carb was the small block 400. The 4 barrel carb was the 402) Driving it to work one day, the oil light came on when it was idling. When you revved it up, the oil light would go out. I limped it to our mechanic shop another half mile away and shut it down as I pulled it to the shop and heard the lifters clacking. I pulled the oil pan and saw the plastic camshaft gear had shredded and had plugged up the oil pump pickup. I replaced the crankshaft gear, the camshaft gear, the timing chain and the oil pump. I made sure the oil filter was filled, started it up and the lifters stopped clacking within 30 seconds. I drove that thing another 100K miles before the tranny went out.
BTW, the factory put nylon gears in those engines, but the you couldn't (IIRC) buy a replacement nylon gear from the factory. They were all steel.
 
Would nylon gears be easier on oil in regards to shearing? Not saying that's why they are/were used, just a random oil related thought.
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