old greybeard

My 69 Cutlass has the hc 350. Likely 66k on the engine. Runs quiet and smooth.
Have been reading of the timing chain jumping due to the plastic covered teeth wearing down.

Is the general consensus that it should be proactively changed?

The car does not have the correct fan, its a ac car and has a fixed 4 blade fan. Does run cool but was considering putting in the correct fan and clutch, if I can find them.
This would be a good winter project, s it something that a person of moderate technical abilities could do? I have changed water pumps in the past, bit never pulled the cover.
Thanks

Sugar Bear

At 66k miles wear and cracking off of the nylon gear teeth would not be expected but, due to 66K miles AND 50 plus years of age, changing the entire timing set as maintenance is a good idea.

If you have done water pumps you can do a timing set. Read about it, study it and when you understand it move forward. Go slowly, follow a manual and take pictures.

Position the engine on #1 @ TDC on the compression stroke before pulling it apart, remove the front cover then STOP and take pictures of the gear alignment as a reference.

Good luck!!!

RetroRanger

Agree w above! The t chain is basically another 2 steps past the water pump.

don71

I think it's a good idea to change out the timing chain. I think you can do it.

Take note of the fasteners removed and where from, like stud with the spacer for the power steering bracket. Also, those two smaller bolts under the pump: don't over tighten.
Reinstalling the timing cover and aligning it on those two dowels with a new pan seal can be cumbersome for some.

oldcutlass

A timing chain at this point in time is probably a good idea.

acavagnaro

I have a '69 Cutlass S with the low compression 350 and 80k original miles. The car idles and runs as smooth as a sewing machine. I decided to replace the chain last Christmas for the same reason you're considering it. We all know about the nylon timing sprocket coating (it is a coating, the sprocket is not made from it) so I figured why risk it.
I checked with cutlassefi for a quality recommendation and he confirmed the Cloyes I was considering was a good choice. It's a pretty straightforward job but there are some potential pitfalls. You'll need to buy, rent or make a tool to hold the balancer in position as you loosen the large bolt holding it to the crank nose. I actually made a simple tool by cutting/drilling/bending a long aluminum bar. Worked great for disassembly and reassembly. Once you get the bolt off you'll need the proper puller to get the damper off. Lots of YouTube videos on this (DON'T use a puller that pulls on the outer ring - you need one that will attach to the pulley bolt holes in the damper).
Make sure you organize all of your bolts and small parts as there are multiple sizes and each goes in a particular location. Without question, the trickiest part of it is getting clearance on the front of the oil pan to reinstall the front cover with the seal in its proper place. No easy way to do it. I wrestled with it for an hour. Lot's of cursing that day but I finally got it and no leaks.
My timing sprocket actually was in great condition. Looked brand new with no visible cracks. I'm still glad I changed it but there was no real slack in the chain and it would have lasted quite a long time. That may be partly due to the low compression and a relatively easy 80k mile life.
I changed the fuel pump and water pump while I was at it so everything on the front is new. I also sent my balancer to a place called Damper Dudes in California for a rebuild. I'd highly recommend it as the rubber can be in pretty sad shape after 50 years. Cost about $100 and they turned it around in about a day. Nice work.
Good luck. You can do it!

BillK

Don,

The biggest problem trying to do the timing set in the car is getting the front cover back on without lowering the oil pan. I can be done but can be difficult.

That and holding the crankshaft while you loosen the bolt. I ended up making a fixture that bolts to the damper when I did my Wifes car.

joe_padavano

I've found a trick that makes this relatively easy. Remove the two dowel pins in the front of the block. Make two eccentric screws that thread into the bottom two front cover bolt holes. To do this I cut the heads off of two bolts, ground the outer part of the bolt to an eccentric shape, and cut a slot in the end. Thread the two bolts into the lower bolt holes with the eccentric in the up position. Slide the front cover over the eccentrics. Now use the slot to rotate each bolt 180 deg so the eccentric is down. This forces the rubber seal on the front cover against the oil pan lip. Loosely thread the next two bolts into place, then reinsert the dowel pins through the cover into the block. It sounds more difficult than it is. I used this technique on the last front cover I installed. No muss, no fuss, no thrown tools.

BillK

I have done the same thing on Chevy engines but just used two small phillips screwdrivers in the holes to pry the cover down. Takes two people though. Glad that I very, very rarely do this stuff in the car

joe_padavano

Yup. I've used tapered punches on the Olds before, and the "need three hands" problem is why I tried the eccentric bolts. You can turn then one at a time.

old greybeard

Thanks. I ran into a couple hours of local Oldsmobile guys about 1 block from my house this week. They advised me to do this, hopefully I can get help if needed.