Camshaft options

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plmbcrzy
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Camshaft options

Post by plmbcrzy »

I'm rebuilding my engine and I am wondering what cam to run. I'm using a 64 block with 66 140hp heads, 4spd, +.060. Otto valve springs. Heavy duty rods. I will be using the Holley 2300 Sniper EFI. I'm debating over the OT20 or 30. Somewhere I read the OT30 is a better option for std. My concern is that it may be too much umph to be comfortably streetable, yet I'd love to run down some of those piss pot punks in there rice burners. I was thinking about offsetting the crank gear to gain a little low end also.
I drove down to Ft. Meyers FL area from Buffalo NY. I heard of Suncoast club, but couldn't find a # to call. Any info on nearby clubs would be great.
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plmbcrzy
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Re: Camshaft options

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Forgot a pictureImage

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plmbcrzy
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Re: Camshaft options

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I am doing something wrong. First pic doesn't show up for me. Try one more time before I give up.Image

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66vairguy
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Re: Camshaft options

Post by 66vairguy »

You'll get a LOT of opinions. It's really what you want to deal with. With older engine designs it is pretty basic -- HP = torque X RPM. A high lift and longer duration cam will move the torque peak further up the RPM range for more HP, but there is no free lunch as the lower RPM torque will be reduced and with the 0T-30 or Isky 280 cam you're going to have an aggressive looping idle. Some like this. Personally I run a 140HP with an Isky 260 which is actually slightly "hotter" than the original stock cam. Lots of off the line grunt, pulls strong to 5,000 RPM. I have no complaints. That said with higher tension springs and a hotter cam I'd have more pull in the higher RPM range and would be able to go to 5,500RPM (or higher) without valve float. Considering I drive a lot in the city I don't want to deal an engine you have to get above 3,000RPM to "come alive". Just me.

The Corvair 140HP PG crank gear moved the timing of a very mild cam (not the 140HP cam) so that you'd get a little more ooomph at higher RPM with a mild cam. It was a compromise vs. a new cam grind when Chevy found the 140HP cam and the PG resulted in a car with less off the line go than the 110HP PG car. It was done to improve lower RPM torque with a mild cam, but shift the static timing to allow for better breathing at higher RPM - a compromise.

I just enjoy the Corvair for what it is.
Peter
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Re: Camshaft options

Post by Peter »

Dude, you will be awfully disappointed when you find out you cant run down those piss pot punks grandmothers in their 89 corolla. Much less their 240xs turbo four banger ricers. You better stay on the porch.
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terribleted
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Re: Camshaft options

Post by terribleted »

I am with 66vairguy. I like moderate cams. I have installed cams similar to the OT-10, 20 and 30 cams in different engines over the years (some were Otto parts and some were similar Clarks performance cams. I personally have not liked the OT-30 or 270 cams as much as the lesser 260 and OT-10 and 20 grinds. I also like the Gm replacement 304 cam in mild engines particularly in a powerglide car but also in standards. The 270 and OT-30 give a pretty lumpy idle and there is a noticeable decrease in off the line power. It all depends on how you expect to use the car. If most of your use is at moderate to high speeds and you want max power at speed and do not mind the lumpy idle then perhaps the bigger cams are what you want, but, for general all around performance I suggest staying with the slightly smaller grinds like the OT-20 or Clark's 260 for your 60 over 140. I suggest you read the descriptions of the OT-20 and 30 cams on page 7-Otto of Clark's catalog set to help you with your decision.

I personally would not bother with the crank changes you mentioned.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
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66vairguy
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Re: Camshaft options

Post by 66vairguy »

Peter wrote: Mon Dec 18, 2017 3:13 pm Dude, you will be awfully disappointed when you find out you cant run down those piss pot punks grandmothers in their 89 corolla. Much less their 240xs turbo four banger ricers. You better stay on the porch.
There's some truth to what you say. The only way your going to outrun some of today's modern cars is with a twin turbo, fuel injected, multi coil, computer controlled Vair engine. I've done it on paper and to make it all work reliably is about the same cost as a used WRX that will still be faster, handle better, and will most likely be more reliable. Not to mention you can sell the WRX for more than a highly modified Corvair when the time comes.

Just me, but the slower Corvair is more fun than a ticket getting WRX.
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lostboy
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Re: Camshaft options

Post by lostboy »

66vairguy wrote:
Peter wrote: Mon Dec 18, 2017 3:13 pm Dude, you will be awfully disappointed when you find out you cant run down those piss pot punks grandmothers in their 89 corolla. Much less their 240xs turbo four banger ricers. You better stay on the porch.
There's some truth to what you say. The only way your going to outrun some of today's modern cars is with a twin turbo, fuel injected, multi coil, computer controlled Vair engine. I've done it on paper and to make it all work reliably is about the same cost as a used WRX that will still be faster, handle better, and will most likely be more reliable. Not to mention you can sell the WRX for more than a highly modified Corvair when the time comes.

Just me, but the slower Corvair is more fun than a ticket getting WRX.
Agreed.

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1961 Corvair 700 Sedan (80hp 3spd Gasoline Heat)
Bob Helt
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Re: Camshaft options

Post by Bob Helt »

Just an old Geezer here speaking from experience, but making all those planned changes all at once (and some needed but unmentioned changes to go with them) is a recipe for a kludge. You'll be trying to sort out the resulting problems for a long time. In other words, basically make changes one at a time and then evaluate the results.
Bob Helt
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