Cam Degreeing/Checking Important

[GOSFAST]

This is another "tip" with respect to degreeing, or at least checking, the cam position BEFORE the final assembly!

It is an item I know few really pay attention to during most rebuilds. I would assume most professional builders would check and correct? We do this on EVERY build that leaves here, regardless of make/model or street/strip!

It isn't that easy to "move" a Flathead cam, just takes a bit of "outside-the-box" thinking!

The two photos below (on the left) show one member's build ready to be be corrected, I have another member's to do today also! The one in the photo below is 4* advanced with the "dots" lined up, the other (we've already checked it a few days ago) is 3* advanced also with the "dots" aligned.

Thanks, Gary in N.Y.

P.S. Here's a shot of one I'm working on at this moment, this is for an 8BA "blown" build. It will be moved to the correct spot later today. There's two ways to accomplish this, one is by a "quick-pin" method, the other uses a timing "pill" (pictured also) the same as a SBC and can be "moved" (advanced/retarded) easily at any later time if necessary.

[cadillac512]

That's a very important tip,Gary. I've seen cams ground as far off as 11 degrees and if not checked would have run like....you know what!

By the way, how far "out of the hole" are the pistons in that block? I like the way you think.


Terry

[A bones]

Thank you for taking the time for us,,, and them. I've had experience with off timed cams. Several in fact. It is the entire ball game.

[Bored&Stroked]

One thing to note is that it is really common to install a cam with it advanced 2 - 4 degrees. Some cam grinders will put the advance in the profile, while many others will ask that you install it advanced (given an adjustable timing chain, etc). It would not surprise me that given that it is not easy to change the advance on a flathead (and most do not have the skills/tools to do so), that the advance is pre-ground into the profile.

[Ronnieroadster]

Cam degreeing nothing to it! So far every aftermarket Flathead cam I have installed for initial checking has been consistent per the cam timing card all of them have been way off. Any Flathead being built with any brand cam needs to be checked. Not a simple task for most.
Also on every engine I build when correcting the cam timing all four bolts holes in the cam gear transfer the torque each one is the correct 5/16 diameter. Ford and all replacement cam gears have only two 5/16 holes the other two are oversize. Beware of limited ways to transfer torque on your cam gear mounting.
Ronnieroadster

[GOSFAST]

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Originally Posted by Ronnieroadster

Cam degreeing nothing to it! So far every aftermarket Flathead cam I have installed for initial checking has been consistent per the cam timing card all of them have been way off. Any Flathead being built with any brand cam needs to be checked. Not a simple task for most.
Also on every engine I build when correcting the cam timing all four bolts holes in the cam gear transfer the torque each one is the correct 5/16 diameter. Ford and all replacement cam gears have only two 5/16 holes the other two are oversize. Beware of limited ways to transfer torque on your cam gear mounting.
Ronnieroadster

Hi Ronnie, no different than decreeing a Chev, or any other brand.

On these Flatheads we start by slotting (elongating) all 4 cam gear holes, when we get the cam where we want it installed we tighten the bolts (we never use the OEM bolts).

We then slide the cam out of the block with the gear still attached and set it up in a fixture I made to install a SBC type pin (1/4"). The pin ends up getting pressed into in the cam and being a "slip-fit" fit for the gear.

Once the cam is in the fixture it's a 10 minute pinning job! I'll have a shot of this maybe sometime tomorrow! It takes about another extra 5 minutes if we want the "timing-pill" in the program. In this case the pin hole (only) in the cam gear gets drilled to accept the "pill" diameter after removing it from the cam. The other 4 now slotted bolt holes allow for the movement needed to locate the cam depending on the "pill" offset, 2*, 4*, 6*, or 8*.

We check every single build we do, always have. We drill the Chevy cam gears even before we start working with them, all 4 holes.

Thanks, Gary in N.Y.

P.S. Dale, these cams need to be moved, there is no "recommendations" on any of the cam cards where they want the cams, we wouldn't care anyway, we always put them where we know they'll work best, depending on the application!

[RalphM]

I’ve built plenty of engines, and as you say, I have never degreed a cam. So for us cam dummies, does the dial indicator on #1 cyl check for TDC? And how do you set your front needle point?

[frnkeore]

The general way of finding TDC, is to rotate the crank, only clockwise, while picking up locations.

Set the dial indicator on the piston and find the approx top of the stroke. Rotate again, set the degree wheel at 0, when the indicator gets to .100 BTDC, then rotate until it's at .100 ATDC. Divide the number of degrees by 2 and that is TDC. Next rev, stop the crank at that number and reset the degree wheel to 0.

You can use any number on the dial indicator but, .100 is covenant.

If you use a bump stop, you'll be close but, you won't be at TDC, because of the back lash, between the crank gear and the cam gear and that's why you only turn the crank CW.

You don't have to turn only CW but, if you don't, you have to go well past your locations and start turning CW again, to be sure you've taken the back lash out.

[Ol' Ron]

hen running the stock car,I would put star washers under the bolts on the cam.I found thet they never slipped. I often wondered how much of a difference, 3 or 4 degrees would make in any engine stock, street or race. Checked a few L-100's Most ee\were close enough to pass on, lazy I guess.

[Ronnieroadster]

Originally Posted by GOSFAST

Hi Ronnie, no different than decreeing a Chev, or any other brand.

On these Flatheads we start by slotting (elongating) all 4 cam gear holes, when we get the cam where we want it installed we tighten the bolts (we never use the OEM bolts).

We then slide the cam out of the block with the gear still attached and set it up in a fixture I made to install a SBC type pin (1/4"). The pin ends up getting pressed into in the cam and being a "slip-fit" fit for the gear.

Once the cam is in the fixture it's a 10 minute pinning job! I'll have a shot of this maybe sometime tomorrow! It takes about another extra 5 minutes if we want the "timing-pill" in the program. In this case the pin hole (only) in the cam gear gets drilled to accept the "pill" diameter after removing it from the cam. The other 4 now slotted bolt holes allow for the movement needed to locate the cam depending on the "pill" offset, 2*, 4*, 6*, or 8*.

We check every single build we do, always have. We drill the Chevy cam gears even before we start working with them, all 4 holes.

Thanks, Gary in N.Y.

P.S. Dale, these cams need to be moved, there is no "recommendations" on any of the cam cards where they want the cams, we wouldn't care anyway, we always put them where we know they'll work best, depending on the application!

Gary I stay focused and specialized i never do Chevy engines or as I call them agent orange engines. My specialty is and always has been Ford Flathead's. But i have and will do any HEMI type engines of course including ARDUN's daily driving a 426 HEMI is also fun.
Ronnieroadster

[Pete]

Here is how I do the cam timing adjust thing on a Ford flathead engine.
I use an early press on timing gear core, usually steel.
I put the crank gear on ONLY far enough to match the cam gear which I only press on about 1/16 inch at the factory marks.
I degree the cam per standard procedure.
If I need to move the gear, I pry it off, move it and knock it back on at the new location, then recheck it. It only has to be on far enough to not slip. 1/16 or LESS.

As far as knowing how far to move it requires some math.
The drive hub is 2.624 dia. so is 8.23 circumference. Moving the gear one way or the other 1/16 inch from the factory mark will give you 3 degrees. (Eyeball resolution)

After I determine the final location I drill and tap for a 1/4-20 set screw on the parting line of
the gear/cam.

[frnkeore]

I like the buttons and make my own.

Here are some of my spares. I keep them on a 1/4" dowel and use both 3/8 and 1/2" sizes. The black one is store bought.

If the 3/8 hole is not a press fit or, I need more advance/retard than the 3/8 bushing will yield, I ream the timing gear or sprocket, to .499 and drill and ream a new .500 dia bushing to position. In this way I can get any degree movement I want and not just +- 2*.

[frnkeore]

For the actual valve timing, you do it the same way. Put the indicator on the valve, as in GosFast picture.

Rotate until you get .100 (or what ever you want it to be), mark the degree wheel, rotate until your on the down side, at the same indicator number. 1/2 that is your center line, for that lobe, same on the other one. Then you count the number of degrees, between those CL's and you have the lobe center.

You count the degrees between piston TDC and valve TDC and that gives you the installed lobe center.

You can then, get your valve timing. Reset you indicator at 0 on the valve, rotate to .006 lift and then to .050, mark those and do the same on valve closing and you have your cam timing.

A lot of time and effort but, you will KNOW what you have and if the cam is what it is suppose to be and set as it should be.

You don't put the degree wheel on the cam, because the timing is all in crank degrees.

[frnkeore]

I know that it's a lot of info to take in, in one shot. It's the same for everyone!

Do it a few times and you'll always remember it. My first time at doing this was with a twin cam engine, in 1974, you have to set one cam, decreed properly, then set the other cam, to that cam.

Very, very frustrating for someone that had never done it and I think that's why I've remembered it, all these years.

[Pete]

Originally Posted by frnkeore

I know that it's a lot of info to take in, in one shot. It's the same for everyone!

Do it a few times and you'll always remember it. My first time at doing this was with a twin cam engine, in 1974, you have to set one cam, decreed properly, then set the other cam, to that cam.

Very, very frustrating for someone that had never done it and I think that's why I've remembered it, all these years.

Was the first time an Offy or a NOVI?

[frnkeore]

No, even though my dad worked for the owner of the Novi, I was a little young, at that time

My first time was with a Cosworth Twin Cam.

[Pete]

Originally Posted by frnkeore

No, even though my dad worked for the owner of the Novi, I was a little young, at that time

My first time was with a Cosworth Twin Cam.

A fine go fast engine.

[Tim Ayers]

As I've mentioned before, I have learned quite a bit having Ronnie build my engine. I was quite surprised to hear that the Potvin cam, as marked, would have been at 119 degrees v. 110.

Just stabbing a cam in and leaving it at 119 would created a horrible performing engine.

Being meticulous with what he does, Ronnie got it timed to be exactly 110 degree. He plugged and re-drilled the timing gear so it is dead nuts right.

The reason I mention this is I was left wondering how many cams are actually installed without being degreed and then a owner is disappointed and blames the cam.

Sometimes it is a poor cam choice, but I've wondered how many times it was just an incorrectly timed school that performed poorly.

[Pete]

Originally Posted by Tim Ayers

As I've mentioned before, I have learned quite a bit having Ronnie build my engine. I was quite surprised to hear that the Potvin cam, as marked, would have been at 119 degrees v. 110 as stated.

Just stabbing a cam in and leaving it at 119 would created a horrible performing engine.

Being meticulous with what he does, Ronnie got it timed to exactly 110 degrees and plugged and re-drilled the timing gear so it is dead nuts right.

The reason I mention this is I was left wondering how many cams are actually installed without being degreed and then a owner is disappointed and blames the cam.

Sometimes it is a poor cam choice, but I've wondered how many times it was just an incorrectly timed school that performed poorly.

I presume you are talking about lobe centerline. This can be diddled around.
The lobe separation angle can NOT be moved after the cam is rough ground.
The tag will indicate lobe separation angle MOST of the time.
The lobe center line is usually determined by the application of the engine.

A Potvin 425 has a lobe separation angle of 110.

[GOSFAST]

I brought this back (maybe for the last time?) to show the finished products.

You can see in the photo below the (.247") pin pressed into the cam and the corresponding hole in the cam gear (.248"/.249") to line it all up. If you look (very) closely you can also see the cam bolt holes are now "slotted" slightly to move the gear where it's needed. These particular pieces are for the "blown" unit, cam is now "in" where we want it when installed as seen.

At this point for this build we are done.

(Add) Not trying to say this entire procedure a "must-do" in order for the unit to run, if all is installed correctly (timing marks aligned) it will run, but when chasing HP (especially on the Flatheads) it's really the only way! And ALL builds should at least be "cam-degree" checked, this is "mandatory" here. It isn't all that difficult to just check where the cam's at.

Thanks, Gary in N.Y.

P.S. I'm adding this to show that when we've reached this stage it is really simple to go a step further and still move the cam more by simply drilling ALL 5 cam gear holes 13/32" and installing a "pill" (photo below also), same ones (most times) we use for the Chevy's we build, simple! No nonsense deal!