Cam Choice

[Scott H]

I have a rebuilt 140 engine that I am going to put into my 65 4 speed Coupe. The motor has an Isky 280 cam, forged pistons (40 over), balanced and polished crank, but other that it's stock. It's only driven on the street. I was recently told the 280 is too radical of a cam and I should switch it for an OT20. Should I opt for the milder cam or will the 280 be ok?

[Stinger Motorsports]

A Isky 280 cam will do just fine on the street. The OT20 that had been suggested to you is almost the same specs as an Isky 280.

I install a cam very similar to the Isky 280 in all of the stock / mild performance engines I build.

I think you will like the way the Isky 280 cam wakes up the 140 engine.

David Clemens

[Scott H]

Thanks Dave.

..wakes it up. I like the sound of that.

[atwistedgrip]

How's an Isky 270 cam in a 110hp/4spd/3.55 for a Rampside?

[mlevair]

anything from a stock 140 cam to a 280 duration is just fine in a stick shift application for street use. I really like the 280 with .125 over sized carbs.
Your rampy should be very peppy .

[Butcher&Vairs]

270, awesome response, I run that in my 64 Powerglide , with 60 over forged pistons, man, I dig it. I drove it from Kali to St George , Utah , and all over the place. I won't use anything else besides Isky. In my friend's car, a 65 4-door Powerglide, we run a 260, 30 over , and some other mods....We drove that baby from Cali to the Heartland, some 1800 miles each way, went to Texas, New Mexico, the boonies, you got the picture..... another awesome cam...........Recently, I just got done with my 140, in that I run a 300 Isky and some mods....nice daily driver,. Believe it or not, with the exhaust that I am running, many people think it's a V8 under the hood, the way it roars........Anyhow, keep them rolling, peace out !

[Butcher&Vairs]

Here's some pix.

[UNSAFE]

I agree with the others.

Unless you are a grandma type of driver that lugs the engine you should be fine with the 280 and a stick.

I think the OT 20 is pretty close but it is a split duration with a little more on the exhaust side.

I surely wouldn't take out a Good Isky just to try an Otto 20.

Crane lists a 292 and it says - Fair idle,good mid range.

I've always used Otto cams and have no experience with others.

I have an OT 30 in my car and it works great from slow idle up to 7000. The fact that I have a bigger bore essentially makes the cam smaller. It might be pretty peaky on a stock bore motor.

One of the biggest hot rodders mistakes is over-camming.

When it comes time to start it - cam break-in is critical !

If you want that 140 to really wake up you should bite the bullet and get the heads massaged including angle tube exhaust.

[CobraJet]

Has anyone played around with non-stock cams for a turbo engine?

[gatorfrey]

Good thread!!
I have a question. The Otto cams... I cannot find the specs for the OT 10-30. Can someone post the lifts,durations,etc?
The above post starts a train of though on turbo motors as well. The Otto TB (TURBO series ) cams. Same question. Specs?
I remember turbos like shorter duration. That would be a good opening consideration.

[Scott H]

Here's some info I found on an OT10 with dyno sheets too.
http://home.hiwaay.net/~langford/corvair/specs.html

[Scott H]

Here's the OT20 cam specs
http://www.corvairkid.com/ot-20.htm

[gatorfrey]

Great links. Got part of it !
Anyone got their OT3O spec sheet laying around? That will give us the specs on Otto asperated cams. And, with turbos popping up on many of the hot rod engines, I would like to see specs for the TB cams also. Especially the TB30, as that would be likely on a radical turbo engine.
Good topic. I like it.

[CobraJet]

Here's some info I found on an OT10 with dyno sheets too.
http://home.hiwaay.net/~langford/corvair/specs.html

That's one hell of a nice torque curve. Power comes in strong starting at 2000 RPM. I like!

[Scott H]

Found the TB30 cam specs.

Grind: TB-30

Rocker ratio: 1.56

Checking at: .005"

Intake Exhaust

Lift: .480" .468"

Open: 32 62

Close: 66 28

Total: 278 270

Dur @ .050" 228 214

Lobe lift: .308 .300

Overlap 7 degrees

[Scott H]

found some speculative data for OT20 and OT30 comparisons with charts.
http://www.rbgault.com/Corvair_36L/Cam/Cam.htm