Unknown camshaft

[Thedeputy]

I'm fine tuning the 440 in my 66 coronet and allready ran into a few issues that make me suspect more is wrong.
The biggest issue is that it won't run faster than 4500 rpm. When it comes to that point it starts running bad (backfire, detonation) and I suspect the ignition system (petronix) is bad but that's of secondary concern. I thought it's best to start with the basics and that's the crankshaft timing mark. It was off by 7 degrees.
I would now like to check what kind of cam is installed and how it is set up. I suspect that the advised centerline of the cam is not correct since the balancer mark was so far off.
I've read some articles about degreeing a cam but they are all about known, new, cam's with the cam card. I have no cam card and so, no way of knowing what is inside. According to the previous owner ,who did not build the engine, it is supposed to be some sort of mopar perfomance purple cam.

Can someone please provide detailed steps on how to obtain the cam specs with the engine in the car and everything installed.

Do I need a solid lifter and adjustable pushrod to check the lobe's specs? If so, can I make a solid lifter out of a used old hydraulic lifter?
On a given duration @0.50 is that 0.50" lift measured at the lifter or at the valve?

Any help is greatly appreciated,

Thanks,

Antoon

 

[oldbee]

You should be able to look on the net for purple cam specs. BUT, I think you have ignition/fuel delivery problems. My 30+ year old Accel BEI ignition took a dump; tried new coil first-no go. So went with a complete Mopar electronic dist. setup. Fired right up. Let us know.

 

[oldbee]

Almost forgot, maybe your harmonic balancer rubber has moved-I.e. the timing marks have moved.

 

[miller]

If so, can I make a solid lifter out of a used old hydraulic lifter?
On a given duration @0.50 is that 0.50" lift measured at the lifter or at the valve?

Yes...that's what I did on my build...used an old lifter, gutted it, and fit a solid piece of steel rod in it. Worked great for dialing in my cam.
Measure the 0.50" lift at the (solid) lifter, to get the correct reading. Are there any numbers on the cam? Otherwise, you could 0 in on the lobe's base circle, getting lift dimensions off it, to at least know total lift on the lobes themselves. Might check both intake, and exhaust.

 

[Thedeputy]

The balancer is an aftermarket piece. Some sort of fluid damper so the turning of the outer ring is not the case.
I'm aware of the fact that there are also fuel/ignition related problems. I allready have a good used original electronic distributor but I thought I'd check the basics first. Thanks for thinking with me.

The block is still all buttoned up and before tearing into it and taking of the waterpump and timing cover I'd like to try and get the cam specs with everything installed. That's why I can't get any visible numbers from the cam.

I will try to gut an old hydraulic lifter and make it solid, and cut an old pushrod to make it adjustable.

If I measure the 0.50" at the retainer of the valve, with which number do I have to multiply it to get the correct lift? I have original shaft mounted non-adjustable stamped rockers. Just 1.5, or is that not accurate enough?

Thanks for the help.

Antoon

 

[miller]

I will try to gut an old hydraulic lifter and make it solid, and cut an old pushrod to make it adjustable.

If I measure the 0.50" at the retainer of the valve, with which number do I have to multiply it to get the correct lift? I have original shaft mounted non-adjustable stamped rockers. Just 1.5, or is that not accurate enough?

On the hydraulic lifter, it's just a wire clip that keeps the 'piston' in place. Pull the clip, then the piston, and spring. I had a good piece of 1/2" bar stock, 3" long, with a good flat end. That's key on something like that, to get good readings via a dial indicator. Pressed the bar stock into the gutted lifter...fit real good, and did what I wanted. (It's now in my toolbox.)
If your going to use a 'solid' lifter, take the readings directly off it, not the valve retainer.
Without knowing what cam (and it's specs), check all your basic crank/cam stuff first, to find all your basic timing, and if the cam is installed right. But, having an idea what the cam lobe lift actually is, you might be able to figure out what cam you have, and get timing specs for it.
That's simply what I would do...a little work, but helps knowing what you have!

 

[Thedeputy]

That sounds like it would work. Did you use anything on your 'converted' hydraulic lifter, like a small spring, to hold the lifter on the lobe?
If I at least can get a total lift value I might be able to determine what kind of cam it is.

Thanks, Antoon

 

[miller]

Only used the 'weight' of the solid bar stock. But, understand all that was while I was building up the motor, doing the cam timing.
Just too many ifs, instead of reading directly off the cam lobe (and the follower), for accuracy. In your case, heads and intake still in place, I used an extended tip on my dial indicator, in line where the pushrod goes, rocker shaft off. Just have to make sure the indicator is mounted solid, and in line with travel.

It does make a mess, when your working with unknown parts.

 

[miller]

The balancer is an aftermarket piece. Some sort of fluid damper so the turning of the outer ring is not the case.

Just thinking out loud on this...fluid damper...any idea of the brand/maker on it? Some of the other guys might chime in on that, who have used them. Just wondering if it might take an offset key, to dial it into 0.

 

[Thedeputy]

Could be. I just scribed a new tdc mark on it.

Antoon

 

[Thedeputy]

 

[Thedeputy]

Well I finally found some time to check the camshaft.
I installed a solid lifter and an old slant six pushrod. The pushrod rests in the corner of the intake port to a bolt that lies in the base of the head. Not super accurate but it was the best I could do. With the heads installed I couldn't use a gutted hydraulic lifter with a piece of round bar because it hits the head.

The numbers are as followed:
Total maximum lift is 8,25 mm, or 0,325"
Installed centerline is now at 107 degrees
Duration at 0,050" lift is 247 degrees

I have the original stamped steel rockers. Are they a 1,5 : 1,0 ratio?

Anyone have a clue what it might be, and whether the installed centerline is correct?
Or do I have to measure the exhaust as well to get a more complete picture?

Thanks,

Antoon

 

[oldbee]

Stock rockers are 1.5...Camshafts and I never really got along all that great,but I would guess one of the "purple shafts"??The smallest of 2 or 3 of the options??? Never tried one myself.

 

[hangn0ut]

Wouldn't it have been better to remark the timing cover instead of the dampner? That way all the marks on the dampner are good not just tdc.

 

[miller]

Don't know if this chart will help...

 

[Thedeputy]

Hi Miller. Yes thanks. It's very helpful.
I think the lift I measured is pretty accurate so that would be a 0,484" lift purple cam (according to the previous owner there was some sort of purple cam installed but he couldn't confirm that)
Only the lift @0,050 does not add up. I measured that at 247.
Or does a solid lifter on a hydraulic cam give a slightly different result?

Thanks for the help,

Antoon

 

[miller]

Only the lift @0,050 does not add up. I measured that at 247.

Right...chart telling 241. So, the way it goes, 241@.050 is the suggested set...could mean it's not degreed in right, with the crank. But, I'm no expert. There are others here that know a heck of alot more than I do, telling you for sure, fitting this new crap gas. (Does sound like it's set wrong to me.)

Or does a solid lifter on a hydraulic cam give a slightly different result?

Assuming you mean the 'solid' tool your using. No effect, gives a more positive #, since hydraulic lifters have 'give'.

That @.050 setting is fairly critical on cam timing. If it was mine, I'd be pulling the chain cover, and start over. Could easily explain why the motor is falling on it's face!!
But, I'll toss in a few thoughts on the 4500 RPM thing. Besides camming, valve float from weak valve springs, bad valve guide clearances, and so on, can ALSO cause that.

At least you have a fair idea what cam your fooling with.

 

[Thedeputy]

The 4500 rpm problem is not an issue anymore. After making a new timing mark on the balancer I was able to adjust the timing and hook up the vacuum advance. I had it up to 5300 a few weeks ago and that went smooth.
Right now I'm just interested in what kind of cam is installed.

About the hydraulic lifter giving some timing, that could explain the slightly higher number of 247 I found. Since the solid lifter is rigid and does not 'give' every degree the cam turns is transferred to my gauge. If a hydraulic lifter 'gives' a little the effect would be a slightly shorter duration.

Since it's now installed at a 107 degree centerline I'm going to leave it alone for now. It might not be super correct, but 107 degrees is not a really strange number. I can now get on with more fine tuning on the ignition and carb.

Thanks,

Antoon

 

[miller]

Yup...all those cam numbers are (suggested) guidelines anyway, something to shoot for. Too many variances between motors, not all built the same. The balancer timing mark being off could have been most of your problems. Good to hear your getting it's act straight!

 

[62 Dart Convertible]

Hey Antoon

How did you originally ascertain that your balancer timing mark was off by 7 degrees?