70's chevy engines

Helping a friend with his hot rod.
It has a late 70's Chevy 350 truck engine.
We cannot get it timed off of the timing indicator that is mounted to the timing chain cover on the drivers side. I can make it run perfect timing it by ear. It seems to me that the pointer should be on the passenger side because that is where the mark is showing up when it is running good. My real question is. Did chevy make an engine in the 70's where the pointer was mounted on the passenger side of the timing chain cover? I could swear that one time I worked on a car or truck that you could set the timing from either side of the vehicle.
I'm wondering if the pointer should be on the left side or does it has the wrong balancer on it.

You need to get the book on that model because some of them you had to set the rpm up to 1500 to set the timing not sure on yours but chevy had some weird ways to set the timing back then.
Walt

I'd be willing to bet that the harmonic balancer spun. The rubber in between the two rings gets worn out and brittle. Go to your local auto parts store and get some timing tape and a piston stop. You need the piston stop to be sure that you are at absolute top dead center, otherwise, when you put the timing tape on the balancer and time it, it will be off. Good luck to ya.

The earlier SBC's used a timing pointer located at the 1:00 to 2:00 position (as viewed from the front).

Later engines used a mark nearer to the 12:00 position, between the 12:00 and 1:00 positions.

You have to look down behind the water pump to see that pointer.

Or, the damper pulley may have been installed without a key, or mangled in place shearing the key.

You can use a TDC finder to locate actual #1 TDC, and make a new mark on the damper.

Oh, yeah, you ARE timing it off of #1 cylinder, RIGHT? (Front-most cylinder on the driver's side.)

Also, the hose vacuum needs to be removed from the vacuum advance unit and plugged.

Here's a TDC finder, $8.99 from Jegs, or, if you are handy, you can make your own out of an old spark plug and a piece of threaded rod.

<img src = "http://www.jegs.com/images/photos/77866792.jpg">
Using a TDC finder

I've found Chev 350 timing pointers at driver's side,straight up behind water pump,and underneath on motorhomes.Depends on the application.I'll agree with Steve and say the outer ring spun on the balancer.

I have two spun harmonic balancers. Time by ear, don't look back.

If the balancer indeed HAS spun (IMHO, RARE, but possible on an SBC) it is a good idea to replace it with a good one that can do it's job of helping the crankshaft to stay in on piece!

It sounds like the balancer has spun the outer ring... I had one do that... and it actually is pretty common. You need to get a new one to replace this one... price isn't too bad.

Got a '77 corvette, 350 tired of replacing harmonic balancers on. Just keep an eye on it so it doesn't go too far forward or back.

Also have a GMC motorhome with Olds 403 and a spun harmonic. Can the balancers be bought by the gross?

Another good reason to replace the balancer if it's spun is that I had one on a 1980 Camaro that spun and slipped back and wore a hole in the timing chain cover....not exactly the place you'd really want a big vent between the crankcase area and open atmospheric conditions....

I agree with the others, that it's probably either slipped or has the wrong timing cover(could possibly have one where the pointer is 12:00 and you have to look down behind the waterpump to time it) or vice-versa it could have the wrong balancer(one that's made to go with the 12:00 timing cover).

For a quick check: Pull the number 1 spark plug and hold your finger over the hole while someone slowly by hand turns the engine over until you start feeeling compression building. Then take a peice of wire and put it through the plug hole into the cylinder so you can feel the piston coming up. Have your helper continue to rotate the engine until the piston is as far up as it'll go, and just before it starts going back down. Then compare the mark on your damper with the timing mark on your timing chain cover. This won't give you dead-on timing but it'll be enough to tell if you have a problem with either wrong parts or a slipped balance ring.

If someone put an aftermarket cam in it the timing will have to be set way off of where any factory timing marks are.

Buy a FUILDDAMPER. NO Rubber ring all internal.

Kent

To time a Chevy you would have to have an original pointer and an original harmonic balancer for that motor for that to work maybe.Then if its moved,which they do,you still cant go by the marks.You can mark it yourself after you find TDC.Once you get TDC marked you can set the timing with a light,just measure how far it is from TDC where the marks are at,then measure from your TDC mark to where the timing mark should be,take a small square or something and draw a line right there,take a hacksaw and cut a little line there,paint it white with whiteout or white paint and you are done unless it moves again.I just set a Chevy where it starts good when its warmed up,usually is not far off.