Cam spec help

[deyan]

Nevermind!

[GTS Dean]

Did you figure it out? I thought you went with a low compression, stock shortblock after your oil starvation issues, or am I off base here?

[goggles Pizano]

That was i good post/question, why delete it and replace it with 'nevermind'?

Should just posted another reply stating nevermind.

[deyan]

Haha, sorry, I didn't find a way to delete it and didn't want to waste peoples time. I think I need to understand few things a bit better before I ask the question.

Eitherway, long story, I don't have a cam card for my cam, and exotic who built the previous engine don't have any history as they changed ownership at some point.

My new engine that I rebuilt myself has been running reliable for two years of racing but low on power, and I am pretty sure it's a cam timing issue. So I am trying to figure out if I should buy a new cam or chase the unknown I have. I measured the cam myself, but I realized I measured it with the crankshaft sprocket set to the retard position, so that probably didn't help my cause lol. Ideally I would love to keep it

The only information I have on the cam is a stamping of AO 234 and what I measured for specs

Dean, the engine was a stock bottom end with the built heads and cam from the previous engine. But it's visibly lower on power, and my data system shows about 100hp less calculated. I just can't image that's all in the bottom end.

[GTS Dean]

If I remember right, retarded cam timing should make a bit more HP at the expense of torque. Have you done a leakdown test to see if you have sealing problems? I can only assume you have plenty of fuel for the engine to make power with since you didn't change any of that.

[goggles Pizano]

234 Duration is all i can guess even from your first post.
Too bad you didn't measure it when it was out of the engine or within the engine but engine partial apart for easier measurements.

[deyan]

The only thing I did for fuel is I put brand new injectors in there when I had it all apart. I am sure a tune will help, and maybe it's still worth it bringing it to Prefix before I tear into it! Engine doesn't smoke or burn any oil, compression was very consistent when I checked it last year, 160-165 across the board.

Pizano, you might be right, that's very close to what I measured. I did do all the measurements with the engine out, and with a solid lifter, I just didn't realize the crank was set to retard at the time!


The old engine was set at advance on the crankshaft and 6 degree retard on the camshaft sprocket.

New engine is on the retard keyway at the crank and 2 retard at the camshaft sprocket.

So really, that should be both of them retarded 4

[Ramtuff]

As long as the degrees all refer to crank degrees. How may degrees does the cam turn when the crank turns 10?
Did you check center with a degree wheel when you installed?

[deyan]

As long as the degrees all refer to crank degrees. How may degrees does the cam turn when the crank turns 10?
Did you check center with a degree wheel when you installed?

Yep, it was all done with a degree wheel.

It's a hex a just crank sprocket and cam sprocket. The crank sprocket has 4 degree retard, straight up and 4 advanced. The cam sprocket can go up to 6 eitherway.

From my understanding 4 degree at the crank is 2 degree at the cam?

Really I probably just need to put the degree wheel on there and recheck

[Ramtuff]

Yep, it was all done with a degree wheel.

From my understanding 4 degree at the crank is 2 degree at the cam?

Really I probably just need to put the degree wheel on there and recheck

That’s probably where you need to start, the problem is, unless you checked before you took it apart you don’t know what the installed center is supposed to be, and if the degree markings on the cam gear are for the physical cam degrees ( which I know would not make sense since it’s checked with the wheel on the crank) and the degrees on the crank gear are for physical crank degrees your math could be off.
Is there some reason you just didn’t put it back the way it was originally installed?

[deyan]

Yah that's a good question, I probably just over complicated it!
But yah that makes sense, it might be better to just spec a new cam at this point and re time it to the correct specs