Eating distributor gears - Page 6 - Vintage Mustang Forums
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post #76 of 105 (permalink) Old 06-06-2019, 07:48 PM Thread Starter
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.13

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post #77 of 105 (permalink) Old 06-06-2019, 07:57 PM
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It is a waste of time and a pain in the butt. Just like rechecking the crank bearing clearances on a short block that just came out of the machine shop. Except for that one time when they assembled one with the wrong bearings in and it wasn't. Degreeing a cam is also a pain in the butt waste of time. Except for that one time when the Summit Racing timing chain set was manufactured and marked WAY advanced and that wasn't. I have more but those two zingers that personally happened to me jumped right to mind.
FoMoco and Tom Monroe say to check the endplay. Two pretty good references there. I take it you did NOT read the directions I posted from Competition Cams or you would know they were not for a different camshaft and were actually pretty Ford small block specific.

If your spec is where you want it to be, at least you will KNOW. And can then slam everybody here by saying "THAT'S not the problem, I checked it myself."

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post #78 of 105 (permalink) Old 06-06-2019, 08:01 PM
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OK. 0.005" then. Right in spec.

You seem to have had an issue with your timing cover gasket. It appears you might have had to take that back off anyway.
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post #79 of 105 (permalink) Old 06-06-2019, 08:02 PM Thread Starter
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Looking for spec to see if .13 is out for a flat tappet hydraulic and find this:

End play only applies to Roller Camshafts. Flat tappet cams have tapered lobes that force the camshaft toward the back of the engine block. When installed correctly, flat tappet cams will not walk.

So now that I have done this, please provide a documented measurement for the end play for a flat tappet hydraulic SBF cam. I could continue to search, but I just added another hour to putting my engine back together.

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post #80 of 105 (permalink) Old 06-06-2019, 08:04 PM Thread Starter
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Originally Posted by GypsyR View Post
OK. 0.005" then. Right in spec.

You seem to have had an issue with your timing cover gasket. It appears you might have had to take that back off anyway.
Please show me "flat tappet hydraulic" spec. Roller is different.

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post #81 of 105 (permalink) Old 06-06-2019, 08:26 PM
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Wow. OK. I did. That info I linked to from your buddies at Comp Cams that you are determined to ignore does not mention roller cams at all. If you looked at it you would see it lists engines the instructions apply to and most of them are decidedly non-roller.

Another reference might be the well-respected book by Tom Monroe, "How To Rebuild Small Block Ford Engines". On page 71 in particular. Worth noting that Mr. Monroes's book rather predates roller cams and thus all info in it about cams applies solely to flat tappets.

Someone here probably has a reference to a factory manual too but I believe I shall be stepping out of this discussion myself. Y'all go ahead.
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post #82 of 105 (permalink) Old 06-06-2019, 08:37 PM
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Quote:
Originally Posted by 69GT350H View Post
Please show me "flat tappet hydraulic" spec. Roller is different.
I can tell you what my original Ford Mustang Shop manual says in its detail engine specs:

Camshaft End play All Motors: .001-.007"
Wear Limit: .012"

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post #83 of 105 (permalink) Old 06-06-2019, 09:09 PM Thread Starter
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Quote:
Originally Posted by dennis111 View Post
I can tell you what my original Ford Mustang Shop manual says in its detail engine specs:

Camshaft End play All Motors: .001-.007"
Wear Limit: .012"
What does the Ford Shop manual say about Gear Drives?

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post #84 of 105 (permalink) Old 06-06-2019, 09:18 PM Thread Starter
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Yet another:

"The end play doesn't usually matter with a flat tappet cam, since the lobes are ground at an angle, and the lifter faces are convex, it pulls the cam back into the block as it runs. "

On hold with Comp Cams for 55 min, and now its after 8pm Central time. Guessing I'm not going to get to talk to them tonight.

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post #85 of 105 (permalink) Old 06-06-2019, 09:24 PM
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Since the engine didn’t originally come with a gear drive the manual wouldn’t say.
Gear or chain shouldn’t matter. That is if the gear thickness and chain sprocket thickness are both the same. If they are different then who knows.

So...
Is the thrust plate worn?
Does it have a machined recess for something like a Torrington bearing?
If you put a chain drive on, does that change the thrust clearance?
That’s all I can think of.

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post #86 of 105 (permalink) Old 06-06-2019, 09:25 PM
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Originally Posted by 69GT350H View Post
On hold with Comp Cams for 55 min, and now its after 8pm Central time. Guessing I'm not going to get to talk to them tonight.
Now you have time to degree the cam

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post #87 of 105 (permalink) Old 06-06-2019, 09:30 PM Thread Starter
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post #88 of 105 (permalink) Old 06-07-2019, 07:15 AM
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In your internet searches have you noticed that the vast majority of such distributor gear discussions are SBF specific? I wonder why that is?

If the flat tappet cam is always self centering why would Ford have manufactured and installed a retainer plate on a SBF decades before rollers were ever introduced? I'm pretty sure that eliminating 2 bolts and the machined retainer across millions of motors would have resulted in a significant manufacturing savings.

Also, why would they even bother publishing an end play specification in the first place?
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post #89 of 105 (permalink) Old 06-07-2019, 11:22 AM Thread Starter
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Originally Posted by dennis111 View Post
In your internet searches have you noticed that the vast majority of such distributor gear discussions are SBF specific? I wonder why that is?
Cant tell you that, but it is more than just one manufacture's settings that are being mentiond, as well as the instructions that were included in my cam box.

Quote:
Originally Posted by dennis111 View Post
If the flat tappet cam is always self centering why would Ford have manufactured and installed a retainer plate on a SBF decades before rollers were ever introduced? I'm pretty sure that eliminating 2 bolts and the machined retainer across millions of motors would have resulted in a significant manufacturing savings.

Also, why would they even bother publishing an end play specification in the first place?
Because the cam thrust plate is still required as the cam moves forward it needs something to go up against. Now if I had left it out altogether that would be a problem. You might also notice that Ford included an oiling passage in the thrust plate, so there is a 2nd need for having one.

With all this talk, before I spoke to Comp Cams Tech support I want to gather as much info as possible. I took the gear and thrust plate off. measured the thrust plate at .2525 then noticed a nick on the cam dowel pin. The eccentric bolt washer is contacting the pin and not going on fully. I inspected the previous pin and there is no interference, so this is a new problem. the pin is now pressed hard into the cam, so I am going to cover everything up and use my Dremel to take a little metal off the pin so the gear can fully seat.

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post #90 of 105 (permalink) Old 06-07-2019, 12:35 PM Thread Starter
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I resolving the dowl issue, I got it down to .13"

I finally got through to Comp Cam Tech Support. Gave him all the info and, it's a bit of a toss-up.

End play is not an issue with flat tappet hydraulic cams, even less so with the gear drive as it does not have the chain dragging on it. The cam will be pushed forward by the tapered lobes into the thrust plate where it stops at the proper location, and the gear will simply step out the .1" and ride on the idler gears with no issue. He said he would be a lot happier if it were only .10" and not .13"

But, he thinks the .13" end play is a bit excessive none the less, he would like my setup to be at the most .1". He left for a bit to consult something or someone and came back suggesting I put another upper gear on and see what readings I get. He did suggest that it may be an issue of the gear not fully seating on the cam, I am going to have to order another timing gear/chain set so I can install it and make a measurement. It is possible the Pete Jackson upper gear with shim might not be seating correctly on the cam snout.

He would not say if that is or is not a reason for the distributor gear issue. And, it seems the gear Summit sold me was the Melonized gear. That was the one that was destroyed in less than 30 min.



If this resolves the end play issue, I still say I am good with what I have using the gear drive as the tech stated.

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Last edited by 69GT350H; 06-07-2019 at 12:39 PM.
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