Please bear with me on this. I have never claimed to be an engine guy. I am more of a body, brake and interior person. I can handle the basics. Carburetor rebuild, alternators, water and fuel pumps...you know, things that bolt onto the engine. But when when it comes to valve jobs, changing piston rings, basically the inner workings of the engine, I'm more of a functioning idiot.

The reason that I mentioned this is because, even though my engine is purring now, she does have 145K on her, and I have no idea if she has ever been rebuilt. I was getting ready to start my search for local guys that rebuild/refresh older engines, when at a local show I got to talking with a guy who says that he knows Olds engines.

He claims that you have to be careful rebuilding an Olds engine, because they are very different than your normal GM power plants. He said that when the engine is running, the valves do not just go up and down. When they re-seat, he says that they actually twist a little and this is why Olds engines did not lose compression as regularly as other GM motors.

Have any of you guys ever heard this before? On the surface, it sounds like he was talking out of his a$$ but I do not no enough to be sure. I've heard of the rumored "higher zinc" content of Olds engines to make the blocks last longer, but this was a new one.

 

If it's got 145k on it & you're not sure if it's been apart I'd definitely replace the timing chain. As far as the valves "twisting" starting in the '70s Olds did use valve rotators at the top of the valve springs. Depending on the year some had them on all the valves, some on just the exhaust. It was done for the "new" low-lead & unleaded gas that was coming out at the time. They weren't unique to Olds engines other makes used them too. As far as the "rumored higher zinc content of the blocks" I've never heard that one before??. Olds supposedly used a higher nickel content in their earlier blocks (mid 60s-early '70s) but there's been a lot of debate about that. If it's not huffing or leaking oil, I'd do a compression check & replace the timing chain( a bit of a hassle with the engine in the car, but it can be done) & drive it!! I've had well maintained Olds motors in the past that went over 200k with nothing but a timing chain replaced!

 

I do remember seeing old adverts stating that valve rotators were added to all Olds engines, in '69 IIRC, that do exactly that. I always assumed that this was something GM did across the lines, not just Olds. Not sure how effective those things are, or what they consist of (something different in the valve spring retainer?).

 

Brain-fart on my end. I meant to say nickel, not zinc. Thanks for the info. That makes sense now that you mention about the unleaded gas switch over.

 

^^^THIS^^^

You might consider replacing your valve guide seals as well if the engine has good compression. White smoke at start up is a classic sign of worn valve guide seals. They can be replaced easily enough with the heads on the block.

 

My 71 Cutlass had valve rotators on it but I was advised to take them off when I broke a valve spring about 10 years ago. I overhauled my engine when I got car in 94 and had a valve job done then and installed a Mondello cam which I hated. Anyway I thought I had replaced the valve springs but after looking at the receipts I found I still had the original 1971 springs in it until about 2010 when I broke a valve spring. So when heads were off I went back to a stock type cam. At that time the guy who redid the heads recommended to remove the rotators' which was done. I also had hardened seats installed the second time. I have also heard that Olds engines of a certain year had more Nickle content but I think I've heard on here (maybe Joe P?) that was a myth. I would just run it, if it runs good, maybe it was rebuilt before you got it?

 

Valve rotators were first used by Olds in the 1971 model year as a way to reduce valve wear due to the newly-mandated low-lead gasoline required by the Feds for that model year. Olds was far from the only automaker to use valve rotators. Rotators add a lot of mass to the valvetrain, which contributes to valvetrain loads and valve float at high RPMs. They are typically thrown away for any performance engine build. Steel valve seat inserts are a better choice.

The nickel content thing is a myth that won't die.

The "extra care" needed in building an Olds motor is because Chevy-centric machine shops ***-U-ME that they can just use the same methods and tolerances they use every day on Chebby motors. This typically results in incorrectly set valve height, which plays havoc with Oldsmobile's non-adjustable valvetrain. Internal clearances also need to be correctly set. There's nothing magic about an Olds motor that care and common sense won't take care of. Unfortunately, both of those items are severely lacking today.

 

Exactly what joe said. I would have no problem with any competent machine shop work on my Olds engine, but only if they are willing to machine it correctly. There is nothing inherently difficult about Olds engines, they just don’t like the same machining tolerances that Chevy/ford/etc use. The old rule of thumb “.001 per inch of journal diameter” won’t last on a Olds. Most machine shops argue or just tell you what you want to hear and do it their own way.


if your engine is built too loose, only your machinist will know. Build it too tight, EVERYONE will know!

 

I'm having no smoke or valve tap at all. After start-up, I'll let her idle for about 5 minutes to warm up, and then she purrs all the live long day (knock on wood). I'm just worried because when I bought her 7 years ago, she had been sitting for many years. The original owner had passed, and his son was selling it. He unfortunately, had no info on what (if any) work had been done on the engine. So, in the absence of any real info, I'm going with the worst case scenario and assume that the engine has never been torn apart and checked out.

 

Here is a quick method to check your timing chain without dismantling the engine ;
Get a breaker bar and a large socket and turn the engine over by hand with the bolt in the middle of the harmonic balancer .
Remove the distributor cap .
Turn the engine over until the timing marks align at zero .
Watch the distributor rotor for movement as you slowly turn the engine backwards .
Stop when you first see movement . Observe the number of degrees on the timing scale .
Do this several times to assure you get the same reading .
If you have more than four degrees of slack in the chain I would recommend replacement .
As others have mentioned , check your compression
If there a ten percent or less variance between the highest and lowest cylinders leave it alone .

 

Olds put heavy-*** valve rotators on the top of the valve springs, built into the retainer. Heavy rotator bounces up 'n' down with the valve tip.

Chevy had enough sense to put the rotator UNDER the valve spring, against the spring seat, where it's weight is of no consequence.

They still get scrapped on engines I build.

There's nothing in the Olds design that makes it harder to machine properly. In fact, compared to Chevy with the distributor in the intake manifold, they're easier--you don't have to dick with distributor-to-cam or distributor-to-oil pump driveshaft engagement when decking the block or planing the heads.

 

I had those pesky valve rotators on my 1970 W-30. They were heavy and everyone who raced got rid of them because of the weight. I am sure that the valve spring pockets in the head, required shims to get the proper valve spring pressure back when changing to "non rotators".
I think the rotator was supposed to rotate the valve 1/4 to 1/2 degree at a time.

 

Thanks guys. At least now I have some info when I start making my calls.

 

Chip
you could also take the fuel pump off and see if you can get a boroscope inside to see is the plastic cam gear is still installed
just a thought
I think someone on the forum has a machine shop down your way in Waldorf sorry I cant remember his call sign

 

Bill Koustenis

Advanced Automotive Machine
Waldorf Md
Billk is his call sign

 

If it purrs all day, not blowing smoke-or leaking badly..leave it alone.. you can do a compression check just to see where its at, give you some peace of mind. Unless you plan on beating on it or taking it to the strip, drive it, let it purr and enjoy it. Put a set of guages on it to see where temp and oil pressure are..if curious pull valve covers, if its been rebuilt chances are the valve rotators are gone.

 

Thanks. I'll check them out.