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Re: Bronze dizzy gear faliure in Hemi need help!
[Re: John_Kunkel]
#1399696
03/11/13 06:03 PM
03/11/13 06:03 PM
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Joined: Jun 2004
Posts: 6,780
Alabama
Mopar-Al
master
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master
Joined: Jun 2004
Posts: 6,780
Alabama
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Yeah. I hang around chevy guys, ford guys, pontiac guys, buick guys, so what does that mean? If you spin your roller cam engine in the direct of operation, with the dizzy drive out, and the lifters on the lobes, it will walk the cam up to the front of the block, and you can visually see what will happen with the roller lifters vs the lobe when it does. Oil pumps and drives on a bb mopar are driver front. dizzy gear on drivers side and counter clockwise timing. Dizzy on chevies is in back and clockwise rotating. Mopar sb is counter clockwise to but on the other side right?
You don't wear out the block face on a bb mopar, it is very rare to do, but you will see a bunch of mopars failures or damaged when the cam went forward. If you don't get the lateral travel right, a failure will happen sooner or later.
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Re: Bronze dizzy gear faliure in Hemi need help!
[Re: cudaman1969]
#1399698
03/11/13 06:49 PM
03/11/13 06:49 PM
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Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
Performance Only
top fuel
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top fuel
Joined: Jul 2010
Posts: 2,091
Delray beach, Florida
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Quote:
Do you think Chrysler would design the cam to (walk) out of the block? The front gear is oiled by the front cam journal. Look at a cam and the lifter rides to the back of the lobe therefore pushing the cam in not out. Take the oil pump off put dist.gear in and lock it so as not move then turn the cam, see which way cam moves. There could have many reasons you'rs walked out but who knows ask a chevy guy they know everything.
So i guess a lot of people have wasted a lot of money worrying about putting a cam button on a roller cam in a big block mopar? Ummm, No, I don't think so.
Last edited by Performance Only; 03/11/13 07:22 PM.
machine shop owner and engine builder
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Re: Bronze dizzy gear faliure in Hemi need help!
[Re: cudaman1969]
#1399699
03/11/13 07:07 PM
03/11/13 07:07 PM
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Joined: Jun 2004
Posts: 6,780
Alabama
Mopar-Al
master
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master
Joined: Jun 2004
Posts: 6,780
Alabama
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My roller cams, the lifter rides in the center of the lobes. Not the back. Everything in cars and for that matter everything is engineer'd that doesn't make them perfect. Chrysler didn't engineer the slant six to kick rods out of the #6 cylinder either,taking out the starter, but it will. I am going on what I see, what I experienced and what has been seen as failures. If it was pushed backwards, there would be all kinds of posts over the yrs asking what to do when your mopar keeps eating up the back of the sprocket and the front of the block. Chrysler didn't design the old mopars to run on a roller cam either, they were designed with flat tappets and hydraulics. We all can debate on here, it creates options, but bottom line, like most complaints, the cover was flexing or the cam went north not south, and it isn't the first or last time. If something is not controled, then it will be out of control.
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Re: Bronze dizzy gear faliure in Hemi need help!
[Re: Performance Only]
#1399700
03/11/13 07:28 PM
03/11/13 07:28 PM
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Joined: Jan 2004
Posts: 8,290
fredericksburg,va
cudaman1969
master
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master
Joined: Jan 2004
Posts: 8,290
fredericksburg,va
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Quote:
Quote:
Do you think Chrysler would design the cam to (walk) out of the block? The front gear is oiled by the front cam journal. Look at a cam and the lifter rides to the back of the lobe therefore pushing the cam in not out. Take the oil pump off put dist.gear in and lock it so as not move then turn the cam, see which way cam moves. There could have many reasons you'rs walked out but who knows ask a chevy guy they know everything.
So i guess a lot of people have wasted a lot of money worrying about putting a cam button on a roller cam in a big block mopar?
Roller cams are not flat Tappets, not ground the same. It is good insurance to put a button in a roller app. not in a hdy. We could pi!! all day over this but to the question The guys cam is alignment problem like a rear end gear. 
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Re: Bronze dizzy gear faliure in Hemi need help!
[Re: Mopar-Al]
#1399701
03/11/13 07:28 PM
03/11/13 07:28 PM
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Joined: May 2005
Posts: 6,446
NJ-USA
HPMike
master
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master
Joined: May 2005
Posts: 6,446
NJ-USA
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Quote:
My roller cams, the lifter rides in the center of the lobes. Not the back. Everything in cars and for that matter everything is engineer'd that doesn't make them perfect. Chrysler didn't engineer the slant six to kick rods out of the #6 cylinder either,taking out the starter, but it will. I am going on what I see, what I experienced and what has been seen as failures. If it was pushed backwards, there would be all kinds of posts over the yrs asking what to do when your mopar keeps eating up the back of the sprocket and the front of the block. Chrysler didn't design the old mopars to run on a roller cam either, they were designed with flat tappets and hydraulics. We all can debate on here, it creates options, but bottom line, like most complaints, the cover was flexing or the cam went north not south, and it isn't the first or last time. If something is not controled, then it will be out of control.
Ill post up a pic of a stock cover that was properly "set up" but you can clearly see where there is a circular mark left by the button putting stress on that cover. It wasnt just "kissing" it either...
MB
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Re: Bronze dizzy gear faliure in Hemi need help!
[Re: MR_P_BODY]
#1399703
03/11/13 07:55 PM
03/11/13 07:55 PM
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Joined: Oct 2005
Posts: 8,882
Ontario, Canada
Stanton
Don't question me!
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Don't question me!
Joined: Oct 2005
Posts: 8,882
Ontario, Canada
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Quote:
So i guess a lot of people have wasted a lot of money worrying about putting a cam button on a roller cam in a big block mopar?
Ya mean I spent money on a good cover, bought and farted around with four different buttons, two different gasket thicknesses, assembled, measured, disassembled, then did it all again trying to get just the right endplay ... and I did all that for nothing ?!? Sheeeet!
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Re: Bronze dizzy gear faliure in Hemi need help!
[Re: nz383man]
#1399707
03/25/13 05:00 AM
03/25/13 05:00 AM
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Joined: Jan 2005
Posts: 193
Australia
Teamx
OP
member
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OP
member
Joined: Jan 2005
Posts: 193
Australia
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Update: Std volume oil pump and Milodon gear and drive installed, oil presure has dropped from 65 psi+ at idle to 45 psi and at revs from 90 psi down to 60 psi.Will keep a close eye on the new gear!
Thanks for all the imput Tim
Last edited by Teamx; 03/25/13 05:01 AM.
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Re: Bronze dizzy gear faliure in Hemi need help!
[Re: Teamx]
#1399708
03/25/13 06:23 PM
03/25/13 06:23 PM
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Joined: Nov 2003
Posts: 2,715
closer to Canadian beer!
torkrules
I'm neurotic
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I'm neurotic
Joined: Nov 2003
Posts: 2,715
closer to Canadian beer!
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Quote:
The end play is set at .015thou. I understand the timming cover may flex a little if the button runs against it.
Correct me if I am wrong but dosnt the turning of the dizzy/oil pump drive force the cam to the back of the block, I thought this is what the torrington on the back of the timmig gear set was for?
Tim
.015" end play on the cam is a bit too much. I would drop that down to about .005-.006". Two things force a stock flat tappet cam backwards on a big block Chrysler. One the position of the distributor drive and the helix on the cam/distributor drive gear and the other is the taper on the lobes. Roller cams are ground flat so the only thing driving it back is the first point.
However, acceleration/deceleration will cause the cam to walk. Also, if your lifter bores are not straight or out of alignment, this could cause the cam to walk forward.
I would side on the opinion that thicker oil can wear out the gear prematurely. It takes more force to spin the pump. Also, if there are any burrs or imperfections on the cam drive gear it will wear the gear early. Usually the first gear wears out faster until the cam gear takes a "set".
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Re: Bronze dizzy gear faliure in Hemi need help!
[Re: torkrules]
#1399709
03/25/13 06:46 PM
03/25/13 06:46 PM
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Joined: Oct 2007
Posts: 288
Birmingham, England
Mick70RR
enthusiast
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enthusiast
Joined: Oct 2007
Posts: 288
Birmingham, England
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It doesn't matter whether the engine is accelerating or decelerating, the crank is still turning in the same direction. The crank is still driving the cam in the same direction, and the cam is still driving the oil pump in the same direction. The cam is being forced back towards the back of the block by the resistance of the oil pump drive.
1970 Road Runner
505 cid
MCH CNC ported Stealth heads
MP 528 camshaft
4 speed
GV overdrive
11.98 @ 117 on street treads
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