Degreeing the cam

62Ranchero200

62Ranchero200

Famous Member
Just sharing some of my recent experiences on degreeing a cam on a small six:

Doing this accurately is one of the most difficult things I have ever done.

Head on or head off - from what I've seen, it's essentially no difference: at least with high lift cams, for me it was not possible to get an accurate reading on the valve stem, retainer, rocker arm or adjusting nut, so if I wanted to degree with the head on I would pull the rocker shaft and degree with a pushrod on the lifter. However, degreeing seems more accurate with a solid lifter (unless you stack a hydraulic lifter with washers or otherwise immobilize it), so if you'll be running hydraulic lifters you'll need to pull the head to temporarily insert solid lifters. If you're already running with a solid cam and lifters, and you just want to degree to check the specs on a cam you plan to continue running (as if, for example, you purchased the car or engine and wanted to verify the specs), you could certainly do that with the head on, pushrod on a solid lifter.

Pushrod on a lifter is also how I would degree with the head off. Some, including my machinist, suggested dial indicator extension on a lifter; but I definitely had more repeatable results with the dial indicator on a ball and cup pushrod, which was on the lifter. This could be because the dial indicator extension is smaller and moves around in the top of the lifter; or maybe because the lifter rotates and is affecting the dial indicator somehow as it rotates, whereas perhaps the ball and cup pushrod doesn't rotate, or doesn't rotate as much.

The commonly available cam degreeing kits are not all that suitable to precise measurements: every tiny change you make in the dial indicator's mounting throws off the zero on the indicator drastically. Someone "should" make a dial indicator mount with rack-and-pinion type adjustments in at least two dimensions, rather than having to loosen clamps to make adjustments.

If I ever perform another cam upgrade, I'll get a "cam indicator", which fits into the lifter bore and includes a very large cam follower, such as the following:



Thanks
Bob
 
Hi Bob, that's a really nice tool you posted. I made lots of my own tools and equipment when I started racing FE and SBF V8 Fords back in the 1960's. For degreeing cams I took a used Hydraulic lifter and gutted it out then I welded a hex head bolt into it to extend it and so there wasn't any movement. I have a semular magnetic base and dial indacator togeather with that simple home made part it gave me accurate and repeatable results on cam degree measurements. I have another dial indacator mounted to a home made aluminum fixture that's slotted so it can bolt on to the block deck to measure piston TDC, also made couple of piston stops for use with head on (out of a gutted spark plug) or with head off (simple drilled flat bar with rounded tip bolt) for checking the Crankshaft Dampner TDC marks. One of my friends machined an aluminum Rod the cam lobe end kind of looked like that tool that he used in place of a lifter when degreeing cams in his SBC race motors. Good luck (y) :nod:
 
Its tricky sometimes because the lifter bore isn't always perpendicular to the deck, so you have to make sure your indicator follows the path of the lifter, and have it as straight as possible or that can skew your readings on the dial indicator. Using a hydraulic lifter isn't a problem if you have the head off, or even the rocker shaft because the tension on the dial indicator wont compress the plunger. Finding TDC is a little more tedious with the head on. You'll need to use a piston stop of some type to insert into the spark plug hole. With the degree wheel installed, you will have to rotate the crank in both forward and reverse to observe the reading on your degree wheel when the piston hits the stop both times, and then the center point of these readings will be your "true TDC" reading. But its pretty straight forward, if you know the basics you shouldn't have any problems.
 
62Ranchero200":xtb67mt2 said:
Just sharing some of my recent experiences on degreeing a cam on a small six:

Doing this accurately is one of the most difficult things I have ever done.

Head on or head off - from what I've seen, it's essentially no difference: at least with high lift cams, for me it was not possible to get an accurate reading on the valve stem, retainer, rocker arm or adjusting nut, so if I wanted to degree with the head on I would pull the rocker shaft and degree with a push-rod on the lifter. However, degreeing seems more accurate with a solid lifter (unless you stack a hydraulic lifter with washers or otherwise immobilize it), so if you'll be running hydraulic lifters you'll need to pull the head to temporarily insert solid lifters. If you're already running with a solid cam and lifters, and you just want to degree to check the specs on a cam you plan to continue running (as if, for example, you purchased the car or engine and wanted to verify the specs), you could certainly do that with the head on, push-rod on a solid lifter.

Push-rod on a lifter is also how I would degree with the head off. Some, including my machinist, suggested dial indicator extension on a lifter; but I definitely had more repeatable results with the dial indicator on a ball and cup push-rod, which was on the lifter. This could be because the dial indicator extension is smaller and moves around in the top of the lifter; or maybe because the lifter rotates and is affecting the dial indicator somehow as it rotates, whereas perhaps the ball and cup push-rod doesn't rotate, or doesn't rotate as much.

The commonly available cam degreeing kits are not all that suitable to precise measurements: every tiny change you make in the dial indicator's mounting throws off the zero on the indicator drastically. Someone "should" make a dial indicator mount with rack-and-pinion type adjustments in at least two dimensions, rather than having to loosen clamps to make adjustments.

If I ever perform another cam upgrade, I'll get a "cam indicator", which fits into the lifter bore and includes a very large cam follower, such as the following:

HPA_ENGINEBUILD_tool.jpg


Thanks
Bob
Click to expand...


That's a nice part. (y)

At the lab, we do many measurements for pavement tests, and Engineers get really particular about repeatability. For plate bearing tests, Benkelman beaming, California bearing ratios, the bigger the diameter, the better. I like Smiths push-rods. I make carbon fiber push-rods, which come from stock ex LA.

The specs on carbon fiber are impressive, its dimensionally stable and much stronger, and its cheep; a great thing for measurement.


wmtc_003-jpg.632691


wmtc_002-jpg.632692



The timing chain is the Achilles heal of your engine. Timing scatter is huge with just a few thousand miles. The crank just needs 50 thou taken off the nose, and you then follow Mike1157 and Does10's methods to put a 302 timing gear set on.

Believe me, I understand cost, but having worked on Toyota's and Nissan's with 4 and five valve per cylinder mash ups, with some really stupid engineering in the belt drives and cost cutting on the cylinder blocks that defies good reason, our Ford engines are just grey slurry, and they love better components from other engines.

The work your doing is all first rate, but don't loose site of fixing the standard Ford compromises on cost. Quality price trade offs are the life blood of doing stuff well.

Any time Ford makes something, someone races it, and Ford devises an improvement.

Those Fairlane ball joints on later 62-1/2s.
The 2V head and its Classic Inlines Replacement.
The SBF bell-housing on the 250.
The Ford designed and developed T5 gearbox based on the humble Mustang II SR-4 gearbox, the one everyone said was a turkey.
The great 8" axles Ford imported from Brazil

Already, FE engines are using carbon fiber push-rods, and your 250 has the exact same push-rod length as the FE 427.

Keep your eye on the cost, but don't miss the grand goal. Going the Distance and being able to administer Hot, Nasty Speed.

Signed

The Lab Tool


lab_tool.jpg
 
"...to measure piston TDC, also made couple of piston stops for use with head on..."
eather way (on/off) the piston wrks best in my simple minded world (like it off tho)
 
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