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Oil pump

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healeyboz

healeyboz

Jedi Knight
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Is there anything that is supposed to go in between the oil pump and the cam shaft besides the rear plate and the gasket on a pin drive pump?
 
Not a thing cam hooks direct.
 
So back of the motor gasket, rear plate, gasket, oil pump? Vb shows some kind of round piece in the description. I almost looks like a seal of some sort. The pin drive pump doesn't have an attachment like the star?
 
VB may be using a generic A-series engine picture. Over the years there was/were pin-drive, star-drive, and slot-drive pumps and cams. The star-drive has an intermediate piece (a spider or star) that goes between the cam and pump. Slot and pin drives don't have any intermediate items.
 
I took the star drive out with the star pump and put in the new cam that has a slot drive. The picture that I saw looked like some sort of seal?? I don't know maybe nothing. I am waiting on the new pump to arrive. Is there supposed to be much play in the cam (forwards and backwards) before the oil pump goes in?
 
After you put the cam keeper on the front there will be none.
 
I got the camp keeper on the front but the oil pump is not. All kinds of play back and forth!!!
 
Is the front engine plate and cam gear on?
 
How can this be, well cam will slide if oil pump is not on as well. keeper on front pump on rear should not slide but a tiny bit.
 
the front plate is on. the cam gear is not on. the oil pump is not on. Does the oil pump hold the camp from sliding?
 
What? From memory, on both pin and slot drives I remember there was tons of axial travel available at the pump end. I remember the end float control being a function of the clearance between the front retaining plate, pulley, and cam boss. Again from memory, aren't you supposed to replace the front retaining plate if the endfloat isn't between 0.003/0.006 ?
 
I think that part on the VB drawing that is causing the confusion is that light-weight, dish-shaped oil pump cover. In the picture it is between the block and the oil pump but actually it is slotted into the rear plate and covers over the oil pump. To my eye, the parts as they are shown in the VB pic are NOT in order.

JACK
 
That is my recollection as well Doug. I haven't seen an oil pump with wear marks from the cam; the wear has always been on that retainer between the cam gear and the front plate, but I've only worked on 1275's, are the 948's and 1098's different?
 
Not really, the wear is always on the front.
 
""""""Does the oil pump hold the camp from sliding? """"

NO.

Install the cam. Then the front thrust plate. So now the forward thrust of the cam is limited by the plate.

now install the cam gear. Now the rearward trust is limited.

The total end play of the cam should be .004" - .006"

Installing the oil pump .......GM brown sealer or Aviation Form-A-Gasket on the gasket and position it properly in the case so the 3 holes line up. I like to use drilled head bolts and safety wire but on a street motor it's not necessary. On a pin drive pump there is no intermediate gear or shaft. That "thing..or seal" is actually the dust cover that slides inside the hole on the backplate b4 that gets screwed on the case.

ALL "A" motors are the same but some use star drive.

Someone mentioned a plate. some of the oil pumps have a screw on plate thats part of the pump. The Concentric brand pumps (no longer made) also have a plate and a retaining screw. But thats all part of the pump. The replacement pumps that are still availiable and are made in a country of un-dertermined origin, are not the best design...but are ok for a street car.
 
They are pretty much the same except for the rear plate. I have never built a 1275 before this one. I got one on the way!! Along with an entire set of rings when all I need is one compression ring.. /bcforum/images/%%GRAEMLIN_URL%%/frown.gif
 
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