How do you save the oil driveshaft backslash with cam ?
#1143424
12/24/11 05:13 PM
12/24/11 05:13 PM
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Joined: Aug 2007
Posts: 6,096
Valencia, España
NachoRT74
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Joined: Aug 2007
Posts: 6,096
Valencia, España
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I have seen the BIG backslash play between cam and oil pump driver shaft gear. I think that's the reason why lot of us have a "jumping" spark when setting the timming. I still dunno why it happens this big play.
I'm using a new bushing, new camshaft and an used oil pump driveshaft but really looks allmost new with no signs of wear at all, just regular polish for the use and still get lot backslash. Mounted the dist and I can see how the dist rotor can be moved a lot just SLIGHTLY moving the oil pump driveshaft up and down.
I have seen the garden hose ( or whatever hose ) trick at dist shaft to save this keeping the oil pump driveshaft in place. However I was thinking more on fill the oil pump driveshaft slot to keep the dist making some pressure againts. Dunno yet what kind of material, maybe somekind of felt.
Another way could be to use some shim washer between oil pump driveshaft gear and block brass bushing.
Have you noticed this and how you did save it ?
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: How do you save the oil driveshaft backslash with cam ?
[Re: NachoRT74]
#1143425
12/24/11 05:52 PM
12/24/11 05:52 PM
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Joined: Jan 2003
Posts: 10,731
North Dakota
6PakBee
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,731
North Dakota
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About 30 years ago I bought a setup from Yother Performance that used a Torrington thrust bearing and a shimmed collar that took up the distance from the base of the distributor to the face of the drive gear. I have no idea if they are still in business but it was an elegant solution that worked really well.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: How do you save the oil driveshaft backslash with cam ?
[Re: NachoRT74]
#1143427
12/25/11 02:12 AM
12/25/11 02:12 AM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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If the cam and intermediate shaft gears arent worn then MOST of the "timing jump" is the dist shaft moving up and down... we normally put a 1/2" brass collar on the dist shaft so its just snug and just above the blade on the dist shaft..then install the dist and snug the hold down to make sure the dist is all the way down... pull the dist back out and tighten the set screw on the collar... this will take 95% of the timing jump out of it... we use to use 1/2" rubber hose but that would sometimes swell up and get loose and not hold the shaft up like you need to do 
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Re: How do you save the oil driveshaft backslash with cam ?
[Re: MR_P_BODY]
#1143428
12/25/11 03:13 AM
12/25/11 03:13 AM
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Joined: Aug 2007
Posts: 6,096
Valencia, España
NachoRT74
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OP
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Valencia, España
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I forgott the collar solution!!!
yes, really the play causing the timming issue is up and down due the great clearence between dist shaft and oil shaft, not really the cam/oil shaft gear backslash. any RPM variation causes the gear going up and down and making a jumping timming.
Now, WHY THIS UP AND DOWN PLAY ? did factory consider this when assembling ?
I meant why we have to fix this on original parts ?
Take in mind my dist is MP, but did happen with my stock dist too
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: How do you save the oil driveshaft backslash with cam ?
[Re: NachoRT74]
#1143430
12/25/11 08:11 AM
12/25/11 08:11 AM
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Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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drive out the dist lower shaft roll pin & add flat 1/2 ID washers to get the axial play to .005". No good ans for the rotor rotational play prob tho the above will take care of alot of it. People have (carefully) hit the tang to widen it a bit and a skilled welder could narrow the intergear slot WO warping anything. I agree Nacho the amt of play is not acceptable as is
live every 24 hour block of time like it's your last day on earth
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Re: How do you save the oil driveshaft backslash with cam ?
[Re: MR_P_BODY]
#1143431
12/25/11 12:44 PM
12/25/11 12:44 PM
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Joined: Aug 2007
Posts: 6,096
Valencia, España
NachoRT74
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OP
master
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Valencia, España
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Quote:
Quote:
I forgott the collar solution!!!
yes, really the play causing the timming issue is up and down due the great clearence between dist shaft and oil shaft, not really the cam/oil shaft gear backslash. any RPM variation causes the gear going up and down and making a jumping timming.
Now, WHY THIS UP AND DOWN PLAY ? did factory consider this when assembling ?
I meant why we have to fix this on original parts ?
Take in mind my dist is MP, but did happen with my stock dist too
The dist is jumping from the valve springs... when you turn
the engine over by the crank(with a ratchet) you feel
how it snaps at different points (the crank jumps)
well thats the springs causing that... as it snaps
its loading and unloading the intermediate shaft
which turns and when it turns its trying to lift
the intermediate shaft and when it lifts it turns
and when it turns it turns the dist... if you knock
out the lifting it wont turn... thats the reason
for the collar, so it pushes down on the intermediate
shaft(the dist is up all the way with MINIMAL clearance...
big roller cams and stiff springs show it real easy
without the collar
I understand everything you said the reason and how to fix it, what I don't understand is how to accept this from engine design and engineering
Is it an overlook ? Are just some engines makes this ? some fail in parts involved ?
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: How do you save the oil driveshaft backslash with cam ?
[Re: RapidRobert]
#1143432
12/25/11 12:54 PM
12/25/11 12:54 PM
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Joined: Aug 2007
Posts: 6,096
Valencia, España
NachoRT74
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OP
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Joined: Aug 2007
Posts: 6,096
Valencia, España
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Quote:
drive out the dist lower shaft roll pin & add flat 1/2 ID washers to get the axial play to .005". No good ans for the rotor rotational play prob tho the above will take care of alot of it. People have (carefully) hit the tang to widen it a bit and a skilled welder could narrow the intergear slot WO warping anything. I agree Nacho the amt of play is not acceptable as is
The play is so big than the actual dist shaft collar adjustment will make nothing over the intermediate shaft. The washer will actually necesary underneath the intermediate shaft gear, just right over the brass bushing. What worries me about a washer there is a premature failure of the brass bushing. A perfect smooth and clean edges washer or set of washers for a nice shimming will be required.
I could say the play in there is able to move the rotor up to 10-15 degrees. Of course won't happen running due the rotation inertia, but by hand I think the play makes 10 or 15 degrees change, maybe more
I thought and liked the felt ( or whatever similar material ) inside the intermediate shaft slot idea for cushioning when this happens, and even maybe even being an autoadjustment method, also making an easier and cleaner job than the hose at the shaft.
The collar is THE perfect adjustment method, but maybe a constant hitting over hard surfaces there could make some premature failure around ? ( like dist housing parts or block bushing ? )
With a Charger born in Chrysler assembly plant in Valencia, Venezuela
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Re: How do you save the oil driveshaft backslash with cam ?
[Re: RapidRobert]
#1143435
12/26/11 03:06 PM
12/26/11 03:06 PM
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Joined: Jan 2003
Posts: 1,607
Western Washington
Sixgun
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,607
Western Washington
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Got a super nice setup from Dvorak years ago for BB. The first go-round he wanted the distrib to set it up hisself, when I went to the MSD billett it required a little different tack, so we did it here at the machine shop. My .02 
I'm 55 now, no time to waste. Not a week goes by that I don't hear about someone passing on.Let's get out there,smoke some tires,have a beer with a good friend,do what you have always wanted to do.I am pretty sure no one will ever say on their deathbed "gee I'm glad my life was calm and boring"
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