Mr. King

I have a '66 Cutlass with a 330, 4 speed and a 10 bolt posi with 3.23 gears. The motor is a '67 bored .30 over with #4 heads, a Performer RPM intake, Eldelbrock 600 or 650 carb, original distributor with a Pytronix HEI kit on it, cast exhaust manifolds, and dual exhaust.

Here’s the problem. The guy who built it did a good job, except he put the W31 cam in it. It’s huge for this motor. The advertised duration is 308!

This car is a DOG under about 3000RPM’s and it really doesn’t seem to have a ton of power unless it’s floored. Manifold vacuum runs pretty steady at 8 to 9. I’m not sure the vacuum advance on the distributor is working…I tried to “create” a vacuum buy sucking on the vacuum advance line while the car was running and I couldn’t get the rpm’s to change at all….I know that’s bad, but will that cause big problems?

Also, it’s hard to start after it’s been sitting for any length of time….you really have to crank it and pump the gas to get it started. Obviously the idle is very choppy and it surges when you drive it under about 30 MPH….I’m assuming it’s because of the cam.

Ok I know that’s a lot of background, but maybe it will help.

I think I really have 2 options. I can put Rhoads lifters on the current cam and see it that brings back the lower end…..or I have a stock cam and lifter set for the ’67 330. Obviously, either choice is a big job…..but replacing the entire cam is a commitment!

Is there anything else I should check before I rip into the motor?

Oldsguy

I know that Rhoads advertises that they bleeed down at lower rpm's effectively shortening the duration of a cam and the heighth of the lift but I have had no experience with them so I can't vouch for their effectiveness. However, I have stabbed a few cams before and it seems to me if you are going to tear down the engine far enough to change the lifters a few more hours of time to r/r the cam would be worth it. Drain coolant, remove radiator, water pump, front cover and that's about it, oh and the accessories and brackets as applicable. But still, I would go with a full cam/lifter change myself.

Oh, you should see if you can find any vacumm leaks and see if you can verify that you also have distributor vacumm advance, there is a vacumm pump you can attach that "sucks" better than you can (did that sound right???). This may be the cause of the car being doggy but you are right, that cam does sound pretty big with that much duration. Maybe someone can double check the advertised duration for a W31 cam. I think I have some stuff at home that might help.

Mr. King

I don't think I have a vacuum leak becuase I did the old propane/carb cleaner tricks to find a leak and I didn't catch one. Also, the vacuum is really steady although it is low.

Like I said I have a "factory" cam for a 1967 330 low compression engine that I could put in it to bring back the lower end.....

I was hoping that the Rhodes lifters would give me the best of both worlds.

soocutlass

First of all what is low compression because everything before 1971 was a high compression 9.5:1 or better? Second 8 or 9 inch pound of vacuum is low you should be above 15 for the power brake to function. The timing could be too far retarded and this would cause low botton end power, low vacuum and sometime engine surge. What i was told to do is advance the ignition to achieve the highest steady vacuum and the motor does not ping under heavy acceleration. To check to see if the advance is working on the distributer or not put a timing light on the timing mark and remove vacuum from distributer you should see to timing change. You were also saying the vacuum advance when removed does not change the rpm of the motor this is because sometimes the vacuum is on ported vacuum on the carb not manifold vacuum.

Mr. King

SooCutlass thanks for your reply. There were 2 versions of the 330. A low compression and a high compression. Mine is a 1967 9.0:1 that might be slightly less because it's bored .30 over and it's using a modern/thicker head gasket.

So what you are saying about the timing is that I should forget about looking at the timing tab with a timing light and hook my vacuum guage up and advance the timing for the highest vacuum reading without any pinginig? I have heard of using a vacuum guage to set the lean/rich mix, but not timing. At this point if it keeps me from ripping into the motor I will try it.

As far as the vacuum advance...I have used a manifold vacuum source and all of the carb vacuum ports with no difference. Also, I don't have power brakes.

Any other way to check the vacuum advance on the distributor?

Huron

Mr. King,

Yes, with a higher duration cam you will find that the stock timing specs are irrelevant. For a test, disconnect and plug the vacuum line going to the distributor. Using a timing light with the dial, or **** to adjust for advance, verify that you have ~36 degrees timing at 3000 rpm. At this point, don't worry about where your base timing is. If it runs fine there, you found the problem - not enough initial timing. Use the same timing light to verify the vacuum advance. With the advance connected and the engine brought up to a decent idle, you should have about 10 more degrees advance than when it is disconnected. If not, look into getting a different vacuum advance unit. Your's may be defective, or not appropriate for the cam that you are running.

Huron

Mr. King

Huron, thanks for the reply.

I have an older timing light without the dial. Is there a way to do this without a newer timing light or is it time to invest in some new tools.....boy that would be a shame ;-)

I'm pretty sure the vacuum advance isn't working....or I have so little manifold vacuum it's not doing anything. I have three other original distributors laying around the garage so maybe I will swap one out and see if that makes a difference.

I will try it today and let you know the results.

By the way....right now I have the timing set, with the vacuum advance disconected and plugged, at the very top of the timing tab....almost off the "scale". So I figure it's set around 10 degrees....I think stock is 7.

Huron

You could get some timing tape, or mark where 36degrees would be on the balancer, and line up with that mark.

If the vacuum can holds vacuum, and if you can apply vacuum to it from another source and it changes the timing, then it's working. You could run a vacuum line from another running engine to provide the vacuum that you need.

Try 12-16 degrees of initial timing.

Best Regards,

Huron

Eightupman

Change the cam back. That cam grind is for for a big block. Good intentions, however too small a motor.

Do a search on www.oldspower.com for 350 Engine buildups and that will get you back in the ballpark.

John

Mr. King

I tried to tweek the timing today....no luck. It didn't seem to make a difference where the timing was. It still is a dog under 3000 rpms and it surges and almost sounds like it is missing when you try to drive it under 30 mph.

Oh yea....I did figure out the vacuum advance does work.

I think I'm going to pull the cam out and replace it. My Cutlass is in the World of Wheels show this weekend so I guess I will get started on it next week.

I'm still not sure if I will use the new "stock" cam that I have or if I should try to find a mild street performance cam from Crane or Edelbrock.

I remember reading somewhere that the small block Olds like a "single" profile cam....any truth to that? This is my first Oldmobile and I'm still learning.

Anyone have a reccomendation?

THANKS FOR EVERYONES HELP!

By the way here's a pic of my baby:

Eightupman

Yep, mild street performance would be OK. Just a tick or two over the stock cam will give you decent results.

I love your 66. My dad has a 66 442 that I hope to possibly inherit one day.

Are you staying with the non-stock SSII rims or are you searching for some SSI's?? And just for asthetics...you should consider loosing the white walls!!

John

Mr. King

John,

Thanks for the advice. The car came to me with the SSII rims....they are OK...I have the original steel wheels and the hubcaps, but I would really like some SSI's down the road sometime.

By the way, I'm not a big fan of the whitewalls either. Believe it or not, the guy who had the car before me put it in storage for almost 10 years before he sold it to me. Those tires were put on the car in 1988 and they have less than 500 miles on them. They are old bias ply tires and somehow they survived storage (the car was up on jack stands) and they actually are pretty nice. Although it rides like a freakin' truck with those tires.

I'm going to get the motor stuff straightened out....do some REALLY smokey burnouts on the bias plys and then ditch them for a nice wheel and tire combo.

Eightupman

WOW, good call on the stands.. The tires would have flat spotted for sure. I have a set of SS1's with trim rings. They need restored. I have all the centers but you can still get new ones (repops).

John

Huron

Nice looking car!

Not sure about the single/dual pattern on the cams. I've noticed that many Olds cams are dual pattern.

Best Regards,

Huron

Oldsguy

I have a cam in the 455 for my '48 that is a single pattern design by UDHarold, he used to own Ultradyne Cams. I like it. About those bias ply tires, don't burn em up, sell them to somoeone over at H.A.M.B. They kill for "old skool" stuff like those, too bad they aren't wide whites!

Mr. King

I found the specs on the "stock" cam that I got with the car.

It's a NAPA cam (made by Dana)

Can someone translate this for me????? Is this an OK cam or not.

Attributes:
Advertised Duration (Exhaust):264 Deg
Advertised Duration (Intake):250 Deg
Cam Lift (Exhaust):.251"
Cam Lift (Intake):.250"
Cam Timing at .050" Lobe Lift (Exhaust Close):14 Deg Before Top Center
Cam Timing at .050" Lobe Lift (Exhaust Open):34 Deg Before Bottom Center
Cam Timing at .050" Lobe Lift (Intake Close):20 Deg After Bottom Center
Cam Timing at .050" Lobe Lift (Intake Open):13 Deg After Top Center
Degrees Overlap:36 Deg
Duration at .050" Lobe Lift (Exhaust):200 Deg
Duration at .050" Lobe Lift (Intake):187 Deg
Lobe Centerline (Exhaust):112 Deg
Lobe Centerline (Intake):106 Deg
Valve Lash (Exhaust):Hydraulic
Valve Lash (Intake):Hydraulic
Valve Lift (Exhaust):.402"
Valve Lift (Intake):.400"

Thanks!

Eightupman

Yep, that Cam is fine, however...see your other post about Cam question..

John