Zero Camshaft Endplay

[KenG]

howdy, long time listener 1st time caller. Hoping someone can help me identify what I'm doing wrong on my engine build.

I'm putting together a 360 based 408 stroker and am installing my timing set and am noticing an issue with my camshaft endplay, specifically my lack of it.

I've got a Howards Hydraulic Roller Cam (long nose), i'm running the magnum retainer/tensioner plate, double roller timing gear (from MRE), fuel eccentric and then cup washer (i have 3 different versions Hughes on the right).

When I stack everything on the cam nose and tighten it down it runs far enough to pinch the cam and timing gear tightly to the retainer leaving zero endplay. When I put the gear and eccentric on and tighten with a flat washer I measure about .080" clearance between the timing gear and retainer plate (see below). The depth of all the cup washers are in excess of .200" so tightening it to the spec'd torque would very much drive it into the retainer plate.

I'm hoping this is something simple that I'm missing but right now I'm stumped. Appreciate any insight you all can provide!

 

[Professor Fate]

There are 3 different depth cup washers that I am aware of:
The more or less "flat" washer that was used on Magnums; short nose cam, no eccentric.
A shallow cup washer; used on LAs (both roller and flat tappet) with a long nose cam and the fuel pump eccentric.
A "deep" cup washer; used on factory LA roller motors with a long nose cam and no fuel pump eccentric. May also apply to some aftermarket cup washer designed for guys not running an eccentric (electric fuel pump) on a standard cam.
I don't have the depth dimensions handy, but the difference between the std. cup and the deep cup washers is obviously the same as the thickness of the eccentric. It looks to me like all your cupped washers are all the same depth.
Try bolting up your timing gear with your cupped washer and no eccentric, and see if it falls within spec.
If so, then what you have are cupped washers for long nose cams without an eccentric. Try to find one of the shallower cup washers from a standard LA.
If not, measure up the thickness of your chain tensioner plate and compare it to a stock cam plate- I'm very wary of replacement part dimensions lately... If the tensioner plate is thinner than the stock cam plate, you may have to run a thin spacer between the plate and the gear, or have one of the deep cup washers cut down slightly to the depth you need.
Just how I'm seeing it, maybe someone else has a better idea.

 

[RustyRatRod]

Nice footwear.

 

[TT5.9mag]

Either the retaining plate is the wrong thickness or the cam sprocket is the wrong thickness.

 

[Newbomb Turk]

Either the retaining plate is the wrong thickness or the cam sprocket is the wrong thickness.

This^^^

The thinner the cam gear the less cam end play you have.

If you have other cam gears laying around, measure them and find out the difference in them if any.

 

[KenG]

thanks guys! I'll measure some stuff tonight and try assembling without the eccentric.
Unfortunately I don't have extra timing gears to try but I'll measure what I have and share.

and yes, thank you Rusty. perk of living in the desert year round sandal weather.

 

[PRH]

Seems to me that the issue is that the step on the cam is shorter than the thickness of the thrust plate.

Which one is “incorrect” is yet to be determined.

Taking a quick measurement on a used Hyd cam I have here has the step at real close to .160”

 

[mygasser]

i don't see the eccentric causing an issue. if the gear is pinching the retainer plate between it and the camshaft then as above the retainer's too thick or the step on the camshaft isn't tall enough. without going to my garage i can't remember if the backside of the camshaft sprocket has a step so part of it recesses into the retainer plate? a quick look online says no. so the simplest fix would be a shim steel washer/spacer between the camshaft and gear to give the required clearance.
neil.

 

[Newbomb Turk]

thanks guys! I'll measure some stuff tonight and try assembling without the eccentric.
Unfortunately I don't have extra timing gears to try but I'll measure what I have and share.

and yes, thank you Rusty. perk of living in the desert year round sandal weather.

Measure what you have and post it here. I have a couple of gears laying around here I can measure and I’m betting many guys have one or two they can measure.

I always check camshaft end play. So good on you for making the check.

It is rare to see too little free play. I find that the gears are too thick so the free play is too much.

Since I run a gear drive and it has a thrust bearing I set the end play at .003-.004.

For what you are doing .006 is plenty.

 

[Max1196]

Just measured a factory roller cam, step on cam is .165, measured an LA cam, step is .165. Measured 3 thrust plates, .1565, .1570 and .1570. See what Your stuff measures.

 

[KenG]

ok, sorry for the delay in getting these measurements posted.

The Tensioner/Thrust Plate is .160
Cam Step is .160
Timing Gear depth is .717

I tried installing the timing gear without the eccentric and the Hughes washer and its close. .002 endplay between the gear and thrust plate. I can turn the timing gear by hand but feel a significant amount of drag.

Tried calling Hughes yesterday but their tech support guy was out. The product description says it works with or without the eccentric so I'm confused how it works with the eccentric.

I also tried with the more factory style cupped washer and same result.

The weird shorter/angled cup washer (on the left) is too shallow to work without the eccentric but too big to work with. Tightening the cam bolt down sandwiches the thrust plate so tight you cant spin the cam by hand.

 

[MOPAROFFICIAL]

You don't need anything between the cam and the thrust plate, and if you have a long nose cam you don't need that extension piece either

 

[Professor Fate]

Extension piece?
All I see are cup washers. If you mean the machined piece, that's a Hughes cup washer. They sell machined ones instead of hydroformed ones.

 

[Max1196]

The Tensioner/Thrust Plate is .160
Cam Step is .160

If this is your math, then You have ZERO for an endplay. What tools did you use to measure this with?

 

[George Jets]

Your aftermarket cam retainer plate is too thick.

Use one from an LA engine. You know > Ma Mopar stuff.


☆☆☆☆☆

 

[Dicer]

Take that junk *** tensioner off.

 

[MOPAROFFICIAL]

Its either the cam and how the nose was machined or the timing gear. The tensioner is the same as stock as far as I know, I've run 2 and never had this issue.
Get a .005 shim or use a beer can and cut a donut with scissors. LoL

I've never heard of this issue, 1st time.

I use the macini billet timing set and a cloyes tensioner for what its worth..

 

[KenG]

thanks for the input everybody, I've got a set of digital calipers I'm pulling these measurements with. I've got a call into Howards to talk through it with them. hopefully they can provide some info, or at least confirm the critical dimensions to eliminate it as problem child.

I've also ordered an LA style retainer just in case that's the issue.

 

[George Jets]

Pretty much knew at first glance back on Tuesday that the cam retainer plate was too thick.

Don't need a bunch of fancy tools to figure that out, when the cam won't turn when things are tightened up.

☆☆☆☆☆

 

[PRH]

It’s pretty basic really.
The cam sprocket butts up against the forward edge of the step on the cam.
The remaining space between the back of the gear and the rear step on the cam needs to be greater than the thickness of the plate.
If it’s not, then the plate is getting squeezed by the sprocket as the bolt is tightened up.

This can be test fit on the bench before the cam is even slid into the block.
Slip the sprocket on the cam, and using an appropriate combo of washers/eccentric, etc, snug the bolt up.
You should be able to slip the thrust plate between the cam and the sprocket.
If you can’t, it’s not going to work.

A few minutes on a surface grinder with a magnetic clamp, and grinding on the front side of the thrust plate in an area slightly larger than where the sprocket rides, to have about .005-.007” removed, and you’d be all set.

 

[KenG]

ok guys, sorry for the delay in wrapping this thread up. i was able to spend some time with it today and after measuring the thrust plate more closely it looked like the manufacturing process they used to create the hole for the cam nose created a raised edge that increased its "thickness" to a point that exceeded the depth of the cam shoulder.

after a little file work to flatten out the raised edge and dressing it up with some 600grit sandpaper it assembled and left me with the correct camshaft endplay.

appreciate the insight and help along the way!