My 2 cents: Try some octane booster. My '69 Toro used to diesel whenever I ran cheap gas, used to ALWAYS need octane boost to prevent it, regardless of timing or idle settings. Shutting off in drive worked too.........until a CV joint blew out.

 

Thanks for the tip

As a matter of fact I just changed gas stations as of today Was going to shell but unhappy with the points

now trying esso gas here in Canada

 

That cam is aggressive, but nowhere near as wild as the factory W-30 cam. If I remember correctly, the W-30 cam was 244* at .050, granted with much less lift.

You have a 4 speed, drop the idle speed a couple hundred rpm. Assuming the oiling and cooling system are correct, you should have no trouble.

If you really want to get it running good, find a shop with a chassis dyno and the desire to dial in the engine tune.

 

There can be a difference between brands and additives. I always got my gas from stations that pumped a lot and refilled their tanks often.

 

Depends what "W-30" cam you are comparing. The 1966-67 (308) cam would be about 244. 1968-70 (328) would be about 260 degrees according to my guessimations.
The advertised duration for his cam is slightly less than a stock 442 (285) cam. It does make a little more power because of .050" more lift and faster opening and closing ramps. It should still idle like a stock 442.
............Just my two cents,

 

I just came back from a road trip across Canada and I noticed several Esso locations in Ontario had 94 octane gas. I looked and they have a store locator for it on their website but for some reason I couldn't manage to link to it. You should check it out.

 

https://classicoldsmobile.com/forums...-specs-158072/
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Fun71, thank you Sir. My "guesstimater" has been recalibrated. I also copy and pasted the Olds cam .050" specs to a safe place.

 

Chevron 94 is the go to fuel for pump gas performance engines in Canada. There are guys racing with this fuel with no additives.

 

Definitely preferred -- I believe it's also ethanol-free. However, I think it's only available here in BC, not across Canada. At least, I didn't see it anywhere once we got east of the Rockies.

 

really? send me a link to any ESSO in Ontario with 94. I want to know where they are

 

Just skimmed through here. In GENERAL there are things that can aggravate run on/dieseling, BUT, there is one thing that the engine absolutely needs to have that happen and that is FUEL. In most cases that fuel is available because the throttle plates are open slightly, exposing the idle & transition slots in the Venturi/throat to intake air.

This often happens because the idle circuits are not calibrated properly for a cam that creates lower vacuum than the carb is set up for. People are suggesting that you lower the idle speed because that will help close the throttle plates, thus not as likely to have moving air drawing fuel out of the idle slots upon shut off.

One other thing to try MIGHT be to add advance at idle through whatever means are available for your distributor and adjusting/limiting advance accordingly. In HEIs I usually run between 18-23* initial advance, as long as the car does not experience hot start problems, though those problems can often be in the starting system. With that much initial advance, the total has to be limited accordingly so that full mechanical brings you up to 34-36*.

You could also try connecting vacuum advance to manifold source if it is presently drawing ported vacuum.

Thats the .02 that I’ll throw in.
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