Mark21

Has anyone replaced the gears and timing chain with the engine in the car?
I've had more than one person tell me that since my 350 has 130K+ miles, I should start thinking about changing the timing gears and chain since it probably has the good old GM nylon cam gear. I've changed a few on small block Chevy's so doesn't seem like a big deal for a winter project. What concerns me is that everything I've read says "jack up the engine and remove the oil pan". Seriously, that seems pretty extreme! Has anyone ever done it without ripping everything apart? If that's the case, I need to invest in a few more garage tools.

VI Cutty

The short story is "yes", you can do it with the engine in the car. But it sucks. Getting the timing cover back on properly is a challenge due to how it sits into the oil pan, etc. Search the forum and you'll find multiple threads discussing ways to overcome the difficulties.

When I did mine, getting the timing cover on slowed the job immensely and resulted in a long litany of profanity. If I have to do it again, I WILL lift the engine!

Fun71

I've changed the camshaft a few times without removing the oil pan. Installing the timing cover is a bit tricky with the oil pan in place. I have trimmed the lower portion of the timing cover seal and used silicone to lubricate it to help it slide into place and also seal up. I had to pry the cover into place and it was not easy. Joe P has posted a way to lever the cover into place using modified bolts and that seems a LOT easier.

Sugar Bear

Absolutely can be done. If the cam gear is missing nylon teeth the oil pan should be removed and the oil pump intake cleaned of debris. Put the engine on TDC on the compression stroke before pulling it apart. Once the cover is off take a picture of the gear position. Before reinstalling the cover take another picture of the new gear position in order to prevent second guessing yourself.

Whoever is advising you to replace the chain and gears at 130k is correct.

Good luck!!!

oldcutlass

You might want to measure the slop in the chain before just jumping in there and doing it. Chances are if you're not the original owner it may have been done already based on your current mileage.

Sugar Bear

X2 ^^^ Good point...

otto72

Good Point
Can this be done without removing the cover? Also are the tolerances listed in the Chassis Manual (I know lazy on me for asking without looking first)

oldcutlass

This can be done by removing the distributor cap and rotating the engine by hand and seeing how far the crank turns until you see movement of the rotor from one direction to the other.

otto72

Oh ok I get it. Just kinda see if it it sloppy or not so sloppy not a calibrated measurement with a feeler gauge or other unit measure. Thanks

Sugar Bear

Another check would be to remove the fuel pump and look into the cavity with a borescope. If you see a nylon cam gear replace the chain and gears. If the cam gear is not nylon toothed you are fine.

Good luck!!?

66SportCoupe

In the car is not the most opportune place to replace the timing chain and gears. The biggest hurtle is the oil pan lip.

JohnnyBs68S

I loosened the first few front bolts in the oil pan to help make room to get the timing cover back on.

Kensey

Can the oil pan be removed while the engine is in place? Seems like dropping the oil pan ins't that big of a deal, what am I missing?

oldcutlass

While it can be done, dropping the pan with the engine in the car is a pain. I don't recommend that at all.

Sugar Bear

What year, model, trans, exhaust system etc. do you have?

Dynoking

To check slack in the timing chain, rotate the engine clockwise by hand to aline the timing mark on the damper with 0* on the timing tab. Remove the distributor cap. (you usually can unfasten and pull up and move the cap to the side with the ignition wires still connected) While watching the rotor carefully rotate the engine counter clock wise, stop rotating as soon as the rotor starts to turn. Now look at the scribe on the damper. Measure in inches the difference between 0* and where the scribe mark is now. I have never seen a factory spec for this measurement, but an experienced tech would accept about 1 1/2 to 1 3/4 inches (tops) of movement. Anything more may indicate worn cam timing components.

Mark21

So I tried this method of slop measurement and came up with about an inch and a quarter. Basically the length of the timing mark bracket give or take a sixteenth or so. I'm guessing I should start thinking about replacing the timing chain and gears this winter.

Mr Shifty Sidney

I replaced the timing chain on my 70 Cutlass with the engine in the car. I loosend all the oil pan bolts to the point of just a few threads holding. I then took a small screwdriver and carefully worked my way around the oil pan prying it away from the engine. You do not want to be aggressive on this part. With the pan loose and resting on bolts you can then install the front cover. Apply some gasket sealer at each end of rubber gasket on front cover. I also went around the oil pan and dabbed a small amount of gasket sealer before I tighten the bolts. I have not had any issues.
The main issue with the timing chain swap is getting the front cover on. The oil pan fits OVER the rubber seal on the bottom of the front cover. With the oil pan still on the engine and tight, you are trying to force the rubber seal on the front cover in place.
If you decide to remove the engine to do the job you are probably going to run into issues with exhaust bolts breaking. I hate dealing with that, so that is the reason I did not pull engine. There are more than 1 way to skin a cat. Good luck with the method you choose.
Don W

Dynoking

I would give 1 1/4" a pass. That can be considered normal for a V8 timing chain that has been in service.

Rocketguy

What is the easiest way to get the pins out of the block without scoring them?

joe_padavano

The easiest way is with . The collets grab the dowel pin without damage. I didn't pay anywhere near this much for mine, however.