Magnetic base dial indicator-checking endplay

Mugsy · Post by **Mugsy** » Tue Feb 10, 2004 7:30 pm

I got my magnetic base in today so I wanted to get started on setting the endplay first. I put the base on the flywheel and set up the dial indicator so it was perpindicular to the flywheel(both axes) and then tightened down all the screws. The damned dial indicator still moves around throwing my readings off...even when I rotate it to zero it in, I can see it moving around; of course when I push the flywheel back and forth it moves about a thou from one move to the next(I'll do one trial measurement and get the measurement, then when I start the next trial measurement its not on zero anymore). So are these things worthless or what?

Thanks,
Andy

mharney · Post by **mharney** » Tue Feb 10, 2004 7:39 pm

I recommend making a stand for it out of punch metal and bracing it from at least two points.

Mugsy · Post by **Mugsy** » Tue Feb 10, 2004 7:48 pm

Yeah, I know Bob Hoover doesn't recommend magnetic bases for clocking cams, but the "How to Rebuild ACVW Engines" shows someone doing it with a magnetic base. I still have to clock my cam, and I guess I was being stubborn, but I'm still kinda hoping somebody knows a trick. Hoover recommends making various base pieces out of spare stock(which I definetely don't have).

Thanks,
Andy

mharney · Post by **mharney** » Tue Feb 10, 2004 7:53 pm

Punch metal is pretty cheap, strong, and easy to work with - the stuff I am talking about is basically angle iron with holes in it. Fairly soft, drillable, and works fairly well provided you are a little creative with it.

Max Welton · Post by **Max Welton** » Tue Feb 10, 2004 8:48 pm

But for measuring end-play, just use the right tool.

http://63.230.74.177/ghia/MVC-396F.JPG

http://63.230.74.177/ghia/MVC-395F.JPG

http://63.230.74.177/ghia/MVC-393F.JPG

http://63.230.74.177/ghia/MVC-394F.JPG

4ghias · Post by **4ghias** » Tue Feb 10, 2004 8:57 pm

So right Max the right tools and give me a picture it?s worth that thousand words they talk about.

4ghias

Post by **sparkmaster1** » Tue Feb 10, 2004 9:06 pm

I've got a tool simalar to that but the dial indicator mounts in the tool and rides on the flywheel. A little more accurate than the feeler gauge method. Another way to do it is to make a jig that mounts the indicator at the pulley end. That way you don't get any flywheel flex. Tim

mharney · Post by **mharney** » Tue Feb 10, 2004 9:58 pm

The advantage to the dial indicator on the flywheel is that you can also measure the runout, and see if you have anything bent. This *can* be done with the screw tool (I actually do have one), but the dial indicator lets you make some dynamic measurements.

Max Welton · Post by **Max Welton** » Wed Feb 11, 2004 6:38 am

Good point Mark.

Hey sparkmaster1. Flywheel flex? How does that happen?

Muffler Mike · Post by **Muffler Mike** » Wed Feb 11, 2004 8:56 am

when i check my end play, i use an old cast iron oil pump cover and bolt that to the case and get my readings off the nose of the crank so i dont measure any flex that might come off the flywheel. this gives me good solid repeatable measurements. i use this same pump cover (actually i ahve a couple of them) to measure all kinds of things, flywheel run out, top dead center of a piston, valve lift, bla bla bla.

Post by **sparkmaster1** » Wed Feb 11, 2004 9:55 am

Looks like MM finally got some good help. My kids (2+5 yr boys) are so handy finding tools that they hid earlier. With a dial indicator on the edge of the flywheel, take a screwdriver and lightly "pry" the flywheel back. You'll be amazed how much it flexes. Tim

Max Welton · Post by **Max Welton** » Wed Feb 11, 2004 11:20 am

I would be surprised if the flywheel flexes at all unless pressure is applied to it.

When I check crankshaft end play, I do it without moving the flywheel except to shift the crank forward and backward. I don't even have to touch the flywheel to do this. What am I missing?

RoWaMe · Post by **RoWaMe** » Wed Feb 11, 2004 1:50 pm

Max, first of all, great photos- clear and close!

I guess that some people (me included) call flywheel flex when you pry the flywheel frontwards (away from case), let go, and the reading slips back a bit. If you have the cylinders and heads already bolted down, I'd guess that the "springing" action is from the rods resisting the motion by the wrist pins. If end play is checked on the shortblock (best), such "flexing" is not possible. Another possibility is that if the crank you're using is not factory-based (like a cast stroker I'm assembling now) and has too large of a radius at the #1 main thrust surface, the radius will not allow the crank's thrust surface to cleanly touch the thrust bearing's surface inside the case. That was the problem I thought I had (based on a recent STF thread on cast cranks) but I checked the clearance and mine is actually OK.

Max Welton · Post by **Max Welton** » Wed Feb 11, 2004 3:07 pm

Thanks Roland. It makes sense to me now.

(A cast stroker? :shivers:

)

Mugsy · Post by **Mugsy** » Wed Feb 11, 2004 5:18 pm

Muffler Mike, thats f'in brilliant. I was going to use a similar idea by using the deck height tool(a la Lo' Cash Racing....hey, did I just plug a product?) and then putting the base on top of that and then putting the dial indicator over the dummy lifters/p-rods for clocking the cam...but that didn't answer the endplay question. I'll try bolting it down in different places to find a good enplay spot(looks like the generator stand looks good).

Thanks again,
Andy