common turbo cam centerline

[clemsgn]

What are most of you seeing for intake lobe centerlines on most turbo cams ? I've got a Crane 212/206 billet roller and the tech @ Crane said it has a 104 deg. centerline, but the cam has 5 deg advance ground into it. This doesn't seem right to me ? The 2 or 3 other cam cards I have all say between 108 - 110 C/L ? If I put it in straight up, I think that's a bit too advanced ? norbs, Nick Micale, Russ Merritt, Louis Lopez or anyone...what do you think ?

Thanks everyone

 

[getchasum]

Both times I installed my billet Crane 212/210 it was 4* advance (placing the center line around 100). When degreeing, I retarded cam 4* to have the center line at 104 per specs. Most everyone I’ve spoke to said that all Crane cams come with the 4* advance, why, not sure, unless it’s there for future chain stretch. I’d retarded it to bring my center line numbers up closer to specs if you have an adjustable timing set.

 

[Russ Merritt]

I put that cam in 2002, and didn't degree it. Installed it straight up and it ran great! I loved that cam! Went low 10s on it.

 

[clemsgn]

I put that cam in 2002, and didn't degree it. Installed it straight up and it ran great! I loved that cam! Went low 10s on it.

Thanks Russ

Anyone else ?

 

[turbo6randy]

My ATR 212-206 had a 109 centerline and I installed it at 2* advanced. Spooled my TA-66 Q-trim very easily.
Randy

 

[clemsgn]

Anyone else ? Check those cam cards please .

Thank You

 

[Nick Micale]

We are a Comp dealer so we mainly use their cams. For the Buicks, the centerline spec is between 108 and 110 deg.

The install is almost always straight up. If the car needs more bottom end after track times, we will advance slightly according to the overall combo.

 

[clemsgn]

We are a Comp dealer so we mainly use their cams. For the Buicks, the centerline spec is between 108 and 110 deg.

Thanks Nick !
That's what I thought, up around 108 or so. If I leave it at 104 with this "reletively" small duration cam, the intake and exhaust events would be too early, I think ? (212/206 duration, 109 separation) With a longer duration cam (224/224) and a wider separation, it may be beneficial to advance it a bit more to keep the events early enough.....I would think anyway....Is my thinking right on this ?

Thanks all for the input !!

 

[getchasum]

Thanks Nick !
That's what I thought, up around 108 or so. If I leave it at 104 with this "reletively" small duration cam, the intake and exhaust events would be too early, I think ? (212/206 duration, 109 separation) With a longer duration cam (224/224) and a wider separation, it may be beneficial to advance it a bit more to keep the events early enough.....I would think anyway....Is my thinking right on this ?

Thanks all for the input !!

If your at 104* and advanve cam timing, by way of your timing set, isn't this going to pull your centerline number down??? I was at 100, so I retarded cam timing 4* and that pulled my number up to 104, maybe I did something wrong.

One thing I learned last week from a machinist/engine builder when degreeing my cam is, and you may me doing this, allways use a piston stop and a degree wheel to establish true TDC. I was using a dail gauge. He advised, there can be almost 4* of cam timing to be had or lost when the piston is basicly in limbo at TDC when crank is making it's rotation.

 

[Louie L.]

All of the cams I have owned... several versions of the 210/210, my old 214/214 and the 224 i use now are all on a 110 C/L. All were degreed and checked right straight up.

 

[clemsgn]

If your at 104* and advanve cam timing, by way of your timing set, isn't this going to pull your centerline number down??? I was at 100, so I retarded cam timing 4* and that pulled my number up to 104, maybe I did something wrong.

No, you are right retarding it. What I was saying is 104 may still be too advanced....I would try to advance it even more to say 108. Are you keeping tension on the drivers side of the chain to simulate operating conditions ? Your readings can be off between slop in chain & keyway to balancer.

allways use a piston stop and a degree wheel to establish true TDC.

Not true....dial guage is fine if you pick the same spot (around .100 on dial guage) B-4 and after TDC and check degree wheel at those spots. It should be the same amount of degrees B-4 and after TDC if wheel is set dead on.

 

[clemsgn]

All of the cams I have owned... several versions of the 210/210, my old 214/214 and the 224 i use now are all on a 110 C/L. All were degreed and checked right straight up.

Louie, thanks for confirming again what I thought all along. I don't know why Crane has this 212/206 roller's centerline at 104 ? Mine checked right at 104 straight up also, but I've already retarded it to 108...I think it will perform a bit better there.