cam gear destroyed - dont want to repeat

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cam gear destroyed - dont want to repeat

Post  swoodman23 on July 5th 2016, 10:31 am

hi All,

this is my first post here, been lurking for a while and just joined. Im currently building a big tire 66 fairlane and have a 460 going in it. chassisworks suspension front and rear. This is my first 460 build, Ive done other ford engines, and I will readily say that Im constantly learning and still have TONS to learn about engine building.

So, I got this 460 together with the following:
bottom end stock (D1 block), ported c9ve heads, comp cams flat tappet .560 lift 292H, with correct springs. 3/8 chromoly pushrods, guidepplates, scorpion 1.83 roller rockers, edelbrock performer intake. Also have HV oil pump, and did not do any oiling mods to the block.

I took all the assembly precautions, lots of lube, removed inner valve springs, primed oil system, etc... and I fired the engine and broke in cam. All seemed to go ok. When I reassembled engine to run with correct springs and test drive, the engine wouldnt start. long story short is the cam gear for the distributor was destroyed after 25 minutes of running.

So I paid some "tuition" here to learn about cam and dizzy gear materials, and I figured out that my dizzy had a steel gear, which is apparently a no-no with a cast flat tappet cam. I also see now that HV pumps can wreak havoc on these gears as well.

I've ordered new parts to fix my screw up, including a standard volume oil pump, and an iron dizzy gear.

I wanted to ask here if there is anything else I need to consider before I do a "take2" so this doesnt happen again.

Also, I notice on the new pushrods that there is some scraping happening on the guideplates- it only appears to happen on the "higher" pushrods, and it seems light. before I bought pushrods and assembled, I did measure pushrod length using the "center mark on top of the valve" method, and I turned the engine over by hand after getting valvetrain together and it seemed ok. Is there any reason I cant grind a teeny bit out of the guideplate at the bottom of the guide hole - should not affect side to side guide, which I think is the purpose of the guideplate (could be wrong here thats why Im asking)?

any info is appreciated.

thanks!
Scott


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Re: cam gear destroyed - dont want to repeat

Post  Paul Kane on July 5th 2016, 12:53 pm

There is no way a cast iron cam core "destroyed" a "steel" distributor gear.  If anything it would be the other way around.  Incidentally, you should closely inspect the distributor drive gear on your camshaft as well.  In order to minimize gears getting chewed up, you really need to set your distributor thrust clearance.

HV pumps in-and-of-themselves do not "wreak havoc" on distributor drive gears and anyone who thinks that is not really thinking at all, they are more likely just regurgitating internet rhetoric.

Centering the roller wheel of a rocker arm atop the valve stem is not practicing valve train geometry and more likely is affecting geometry negatively.  Again, contrary to all the internet rhetoric by the masses focusing on the roller wheel/stem tip, take a closer look at the pushrod side instead.  Also, go here and subscribe/read/read/read: http://mid-lift.com/MID-LIFT-TECH.htm

(If you still need to clearance guide plates after geometry is optimized then that's okay.)
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Re: cam gear destroyed - dont want to repeat

Post  swoodman23 on July 5th 2016, 1:01 pm

thanks Paul - Ive seen your name lots on here and I trust your opinion.

first, yes it IS the other way around, I probably wasnt clear. my cam was destroyed, not the dizzy gear.

so on the HV oil pump, Ive seen lots of opinions both ways on this, and yeah, this is my first BBF build so IM going on what Ive read (they cant put anything on the internet that isnt true - right? Very Happy ). I was going to go back to standard volume to be safe, but in your opinion, should I need to?

Ill check out that link you sent.

thanks again!




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Re: cam gear destroyed - dont want to repeat

Post  jasonf on July 7th 2016, 1:39 am

Make sure and tear it down so you can clean all those oil gallery's. Those little filings will be everywhere.
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Re: cam gear destroyed - dont want to repeat

Post  swoodman23 on July 7th 2016, 12:36 pm

good call on teardown - I plan on doing that this weekend. thanks!...

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Re: cam gear destroyed - dont want to repeat

Post  dfree383 on July 7th 2016, 1:01 pm

Make sure the distrubutor gear is install properly and it has proper clearance to the block
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Re: cam gear destroyed - dont want to repeat

Post  wayney on July 7th 2016, 9:58 pm

dfree383 wrote:Make sure the distrubutor gear is install properly and it has proper clearance to the block


if you are not sure how to do this ..... at least install the distrubutor with the gear already on it in the block without the cam and oil pump installed and tighten the hold down. then make sure the distributor rotor turns freely.

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Re: cam gear destroyed - dont want to repeat

Post  ChrisH on July 8th 2016, 12:24 am

Paul Kane wrote:  Also, go here and subscribe/read/read/read: http://mid-lift.com/MID-LIFT-TECH.htm

man that is a great read. it also lends you to understand how one could advance or retard the cams action to the cranks rotation if one were so incline. basically speeding up or slowing down when valve events occur in relation to the crank degree.

I now have something else to check when I pull my 501 in a few weeks since I did the 1/3 2/3 set up.

thanks paul

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Re: cam gear destroyed - dont want to repeat

Post  Straubtech on July 8th 2016, 9:48 am

Morel made MSD's gears for 35 years. They don't anymore as of 2 years ago. Morels are 100% USA made.

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Re: cam gear destroyed - dont want to repeat

Post  TommyK on July 8th 2016, 5:10 pm

dfree383 wrote:Make sure the distrubutor gear is install properly and it has proper clearance to the block

To wit:


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Re: cam gear destroyed - dont want to repeat

Post  Lem Evans on July 8th 2016, 7:44 pm

I like the MSD method, but it's ~ the same.


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reassembly question

Post  swoodman23 on August 6th 2016, 5:35 pm

hi all,

Im finally getting back to this. While engine was apart I took care of some other to-do's on the car, now reassembling engine.

I have a question... Im putting the new cam in and the endplay is zero. If I tighten the camgear and check endplay, its tight - doesnt move.

Im using this cam kit: (comp cams K34-336-4) that included the timing set... stock thrust plate... Again, Im relatively new at this and still learning, I looked around for shims or something, didnt see anything, or are there thinner thrust plates or something like that? or am I just doing something wrong?

any thoughts or insight is appreciated.

thanks!
scott

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Re: cam gear destroyed - dont want to repeat

Post  69F100 on August 6th 2016, 7:01 pm

When the cam gear is tighten down does the cam turn freely if not make sure someone has not drove the exspanion plug on rear of the block for the cam in to deep.
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Re: cam gear destroyed - dont want to repeat

Post  swoodman23 on August 6th 2016, 7:10 pm

thanks for the reply.

if I tighten the cam gear, the cam turns but it feels like theres some drag. I dont think its the expansion plug in rear though, with the cam in and the thrust plate on but no gear, I can move the cam in and out maybe 1/8 inch or so. when I put the gear on and tighten it pulls the cam forward against the gear, but I can see the gear tightens right up against the thrust plate.

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Re: cam gear destroyed - dont want to repeat

Post  Super Snake Steve on August 6th 2016, 9:06 pm

Did you have new cam bearing installed sometime block shift will make the cam hard to turn over they have a method of bearing scraping I've never done it. I chuck the cam up in the lath and polish the cam with emery cloth till it spins free by hand I measure before and take half to 1 thousands off at a time mine has never been so bad that this method Didn't work

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Re: cam gear destroyed - dont want to repeat

Post  swoodman23 on August 6th 2016, 9:15 pm

if the timing gear isnt on, the cam spins freely with no problems at all. when I tighten the timing gear thats when I feel a little drag, and it *looks* like the timing gear is tightening up against the thrust plate.

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Re: cam gear destroyed - dont want to repeat

Post  rmcomprandy on August 6th 2016, 11:03 pm

swoodman23 wrote:hi All,

Also, I notice on the new pushrods that there is some scraping happening on the guideplates- it only appears to happen on the "higher" pushrods, and it seems light.  before I bought pushrods and assembled, I did measure pushrod length using the "center mark on top of the valve" method, and I turned the engine over by hand after getting valvetrain together and it seemed ok.  Is there any reason I cant grind a teeny bit out of the guideplate at the bottom of the guide hole - should not affect side to side guide, which I think is the purpose of the guideplate (could be wrong here thats why Im asking)?

any info is appreciated.

thanks!
Scott


I will presume that you have HARDENED pushrods.

The pushrod side of the fulcrum with roller tip rocker geometry is the most important part of that geometry.
With a ROLLER tip rocker arm ... the roller simply needs to be ON the valve tip and not going near either edge.

If the pushrod is rubbing the back of the guideplate near maximum valve lift, then the pushrod is usually to long and conversely if the pushrod is rubbing the back of the guideplate with the valve closed, the pushrod is usually to short.
The intake and exhaust sides WILL exhibit different geometry if the same rocker arm is used.
Getting the best compromise with the geometry on both intake and exhaust is the target.

Only SOMETIMES the guide plate is at fault but, not very often.

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Re: cam gear destroyed - dont want to repeat

Post  swoodman23 on August 7th 2016, 9:41 am

yes, pushrods are hardened.

I read the link that Paul gave early in this thread about geometry - make sense, Im going to revisit that once i get this endplay issue figured out - thanks!...

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Re: cam gear destroyed - dont want to repeat

Post  rmcomprandy on August 7th 2016, 11:31 am

swoodman23 wrote:yes, pushrods are hardened.

I read the link that Paul gave early in this thread about geometry - make sense, Im going to revisit that once i get this endplay issue figured out - thanks!...

The link Paul gave is mandated to using "Mid-Lift" DESIGNED rocker arms. Most rocker arms in the marketplace are not this design.

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Re: cam gear destroyed - dont want to repeat

Post  swoodman23 on August 8th 2016, 5:30 pm

I just wanted to do a quick follow-up here so if someone searches this in the future, it might help them.

I shaved .005 off the thrust plate and its good now. cam endplay is now .002. I believe specs are .001-.006.

if someone knows why I shouldnt proceed this way or if Im using incorrect specs, feel free to let me know.

thanks!

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