Timing chain replacement
Timing chain replacement
First post here.
I'm in my late 60"s and have owned 2 1969 442's many years ago.
A wild hair inspired by nostalgia caused me to purchase a 1971 convertible 442 with documented 69k miles and I'm considering replacing the timing chain and gear set just because of age. The car runs beautifully but because the owner used it at his summer home it apparently sat 9 months of the year all it's life.
I recall a nylon gear in my 69 and when I replaced that chain set, the engine performance improved dramatically.
Any advice from others with experience would be appreciated.
thanks
I'm in my late 60"s and have owned 2 1969 442's many years ago.
A wild hair inspired by nostalgia caused me to purchase a 1971 convertible 442 with documented 69k miles and I'm considering replacing the timing chain and gear set just because of age. The car runs beautifully but because the owner used it at his summer home it apparently sat 9 months of the year all it's life.
I recall a nylon gear in my 69 and when I replaced that chain set, the engine performance improved dramatically.
Any advice from others with experience would be appreciated.
thanks
If it's the original timing set it has the nylon covered cam sprocket.
I've seen them worn out at 50k miles and running fine at 150k. No rhyme or reason. But since this engine sat idle a lot, with age and miles probably not a bad idea to change it. The worst part will be getting the replacement oil pan seal to seat and not leak.
Last couple I've done I took a page from Chevy playbook. Use a die grinder or other tool that can do it to cut a bit off the oil pan side of the timing cover seal trough. Makes it a little easier to rotate the timing cover into place without fighting the oil pan.
Not responsible for any MAW jobs you find while you're in there!🙂
I've seen them worn out at 50k miles and running fine at 150k. No rhyme or reason. But since this engine sat idle a lot, with age and miles probably not a bad idea to change it. The worst part will be getting the replacement oil pan seal to seat and not leak.
Last couple I've done I took a page from Chevy playbook. Use a die grinder or other tool that can do it to cut a bit off the oil pan side of the timing cover seal trough. Makes it a little easier to rotate the timing cover into place without fighting the oil pan.
Not responsible for any MAW jobs you find while you're in there!🙂
Even with that low mileage you should be prepared for the MAW rabbithole RR mentions above. Same thing happened with my '69 400G -- one thing led to another and by the time we popped the heads off we noticed significant cylinder ridges, even though the car only had a documented 71K on it. Ended up doing a complete rebuild.
So supposedly the engine threw a rod around 35k miles in the 80's according to what I've been told and the owner took it to the dealer and it was rebuilt.
I drove it an hour at 70 mph on the highway to a friend who has a lift and it's dry underneath and idles smooth with it rebuilt quadrajet. I just hate to tear into it.
I drove it an hour at 70 mph on the highway to a friend who has a lift and it's dry underneath and idles smooth with it rebuilt quadrajet. I just hate to tear into it.
Well, if it ain't broke ... it likely got a new timing set when it was rebuilt, but nylon teeth? Who knows?
All I know is, I tore into mine even though it ran well and found out things I didn't want to know. As they say on the internet, YMMV.
All I know is, I tore into mine even though it ran well and found out things I didn't want to know. As they say on the internet, YMMV.

BTW, you really need to post some pictures!
[img alt="All new interior and top but body is a little rough.
Then again it is 54 years old"]https://cimg5.ibsrv.net/gimg/classicoldsmobile.com-vbulletin/2000x1504/20241115_105214_9253f83a150989daa773cfab52e349e548 f95046.jpg[/img]
All new interior and top but body is a little rough. Then again it is 54 years old
Then again it is 54 years old"]https://cimg5.ibsrv.net/gimg/classicoldsmobile.com-vbulletin/2000x1504/20241115_105214_9253f83a150989daa773cfab52e349e548 f95046.jpg[/img]
All new interior and top but body is a little rough. Then again it is 54 years old
[img alt="All new interior and top but body is a little rough.
Then again it is 54 years old"]https://cimg5.ibsrv.net/gimg/classicoldsmobile.com-vbulletin/2000x1504/20241115_105214_9253f83a150989daa773cfab52e349e548 f95046.jpg[/img]
All new interior and top but body is a little rough. Then again it is 54 years old
Then again it is 54 years old"]https://cimg5.ibsrv.net/gimg/classicoldsmobile.com-vbulletin/2000x1504/20241115_105214_9253f83a150989daa773cfab52e349e548 f95046.jpg[/img]
All new interior and top but body is a little rough. Then again it is 54 years old
Some say you should be able to see the timing chain cam gear through the fuel pump hole...pump removed and with a bore scope. Some say you can look down the fill tube with a small diameter bore scope, doubt it, but I'd like to see that. I've always just yanked the cover off so I can examine the chain and sprockets.
If you have receipts proving the rebuild rest assured the cam gear is all steel.
Do you have the service history? If not I recommend servicing everything that has fluid down to the power steering and brakes. Those soft brake hoses have an expiration date just like tires. Safety items,
Love that color. So refreshing to see a regular 442 hood with the regular 442 stripes and no W35 trunk wing.
If you have receipts proving the rebuild rest assured the cam gear is all steel.
Do you have the service history? If not I recommend servicing everything that has fluid down to the power steering and brakes. Those soft brake hoses have an expiration date just like tires. Safety items,
Love that color. So refreshing to see a regular 442 hood with the regular 442 stripes and no W35 trunk wing.
^^ +1. I'd try to take a peek before pulling the timing cover off, that's a lot more invasive. I'd hate to go through all that coolant draining and disassembly to find a metal timing set. It would be downright negligent for even a dealer to replace the timing set with a nylon sprocket-ed replacement.
Another way I've relied on is to check how stable the timing is. If its fluttering around and its not the distributor, its the timing set.
Another way I've relied on is to check how stable the timing is. If its fluttering around and its not the distributor, its the timing set.
Last edited by JohnnyBs68S; Nov 18, 2024 at 12:16 PM.
best and cleanest way to check it has already been suggested…pull the fuel pump and check with a mini camera.
they are dirt cheap now and adapt to most phones..some young kid can scope it for you to see if a plastic gear got put back in when rebuilt.
another simple way to check for a loose worn timing set is to remove the belts and put a bar on the crank bolt,, with all the spark plugs removed .. try rotating the crank back and forth slightly to feel for when the chain slack is taken up in each direction . this is more of a feel thing if you’ve done it before.
they are dirt cheap now and adapt to most phones..some young kid can scope it for you to see if a plastic gear got put back in when rebuilt.
another simple way to check for a loose worn timing set is to remove the belts and put a bar on the crank bolt,, with all the spark plugs removed .. try rotating the crank back and forth slightly to feel for when the chain slack is taken up in each direction . this is more of a feel thing if you’ve done it before.
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