Cam question for Duke

[William B.]

Six years ago I purchased a 1966 327 roadster automatic. The previous owner had the engine rebuilt with a Comp (Kit) roller rockers/cam etc., Cam No. 12-408-8. The current cam is a Crane No. 119821 that he had installed later. I believe it idles somewhat rough as the idle characteristics are not as smooth as I would prefer. I can get it to idle at 600 RPM but no lower. Do you have a recommendation for a roller cam that performs as an original or close to original or is this Crane cam the best I can do? I'm not looking to red-line or race the ole gal, just a leisurely Sunday driver. I am not an engine mechanic or anything close, so your advice will be appreciated.

Thanks
Ken Bryant

[Joe L.]

Re: Cam question for Duke

Six years ago I purchased a 1966 327 roadster automatic. The previous owner had the engine rebuilt with a Comp (Kit) roller rockers/cam etc., Cam No. 12-408-8. The current cam is a Crane No. 119821 that he had installed later. I believe it idles somewhat rough as the idle characteristics are not as smooth as I would prefer. I can get it to idle at 600 RPM but no lower. Do you have a recommendation for a roller cam that performs as an original or close to original or is this Crane cam the best I can do? I'm not looking to red-line or race the ole gal, just a leisurely Sunday driver. I am not an engine mechanic or anything close, so your advice will be appreciated.

Thanks
Ken Bryant

Ken------


The Crane 119821 is really not that hot of a cam. In fact, I'd say it would be a good choice if one wanted to get more performance out of a 1966 Corvette with base 327/300 engine. However, if you would like to have an even smoother idle, probably comparable to the original flat tappet cam, you could go with the Crane hydraulic roller 119811. If you'd like something between what you have now and the 119811, you could use the Crane 119561.

Even the Crane 119811, while providing smooth idle, will give you increased performance over the original flat tappet cam. That's because of the increased lift this cam has over the original flat tappet cam. That's one of the major advantages of an hydraulic roller cam over a flat tappet----you can get more lift with approximately the same duration. This can be done because of the lobe following advantage of a roller cam.

[William B.]

Re: Cam question for Duke

Thanks Joe. Your response is what I'm looking for. I don need to burn rubber or impress the cars beside me at a stop light with the rumble. I left all that jazz in the sky's of South East Asia in the sixties.

Thanks again

[Duke W.]

Re: Cam question for Duke

I can't be of any help because I do not follow the hundreds of different cam options in the aftermarket including roller conversions. The idle "problem" is because the installed cam has more overlap than the OE cam, and because most aftermarket roller cams are considered "performance" cams it may be tough to find one with the same effective overlap as the OE cam.

All I can recommend is that you consider going back to the OE replacement cam, but once an engine is converted for a roller cam I don't know if you can go back to a flat tappet type.

Duke

[Joe L.]

Re: Cam question for Duke

I can't be of any help because I do not follow the hundreds of different cam options in the aftermarket including roller conversions. The idle "problem" is because the installed cam has more overlap than the OE cam, and because most aftermarket roller cams are considered "performance" cams it may be tough to find one with the same effective overlap as the OE cam.

All I can recommend is that you consider going back to the OE replacement cam, but once an engine is converted for a roller cam I don't know if you can go back to a flat tappet type.

Duke

Duke------

Not all hydraulic roller cams are wild grinds. The Crane 119811 is quite docile. It has intake duration @ 0.050" of 204 degrees and exhaust duration @ 0.050" of 214 degrees. Lobe separation is 112 degrees. It will have a quite smooth idle but with modest performance benefits over the stock cam.

An engine which has been retrofitted with an hydraulic roller cam can be converted back to flat tappet with no problem, at all. However, I don't recommend it. One of the principal downsides to an hydraulic roller cam retrofit is the cost of the parts, particularly the retrofit roller lifters. He already has those. For another thing and as I've mentioned many times before, I consider flat tappet cams to be obsolete. In this day-and-age, I think hydraulic roller cams are absolutely the way to go. There are grinds available for just about any requirement, from mild to wild.

[John S.]

Re: Cam question for Duke

William,
Thanks for your service patrolling those skies. Can't say that often enough.

[William B.]

Re: Cam question for Duke

Gentlemen,

Thanks a lot. I think I've got my direction.

Service was a pleasure!!!

Ken Bryant