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Oil Pump and End Plate clearance issues

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62Migit

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Hi all,

I'm having trouble fitting a new Moss oil pump (435-630) to my 948. It mounts in the engine fine, but unfortunately doesn't let me put the end plate back on. The end plate runs into the upper left corner of the pump and it is not by a small margin (I would guess 0.25"). Anyone see a reason for this (besides the pump obviously being very different on the back side)? Did they make a parts blunder?

In the pic, the new pump is on the left, old is installed in the engine. I threaded the bolts just to locate it correctly.
5863-IMG_4087-small.jpg


Thanks for the help,

Mark
 

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Jack has this same issue.
 
As far as I can work out from the pics in the Moss on line catalogue, 1275s had 4 screws and 948/1098 had 3.

Your new pump looks like it is intended to fit either and they drill either 3 or 4 holes as required, but they haven't realised it doesn't fit a 948, and my guess is that supplies of 3 screw ones have run out and they are using/having made 4 screw ones and adapting them.

So I think there are 3 options
- send it back and ask Moss to supply one that fits - I suspect they won't be able to
- buy one from someone who knows what they are doing
- is it possible to cut off the (undrilled) boss that clashes with the back plate? I would think that it is, although I can afford to be confident as I'm 6000 miles away and it's not my pump that will be wrecked if I'm wrong!!
You can certainly cut tangential to the inner edge of where the drilled hole would be, is that enough?
 
"""""""but unfortunately doesn't let me put the end plate back on. """""""

R u talking about the engine back plate OR the pump dust cover?


U sure you have the pump slid in all the way and engaged properly in the cam?
 
Yes to all the above, it does not fit.

Read my lips, it does not fit.

Might beat the can out or use a different something.
 
"""""Read my lips, it does not fit.""""


But I was talking to/asking MARK....who I'm sure would appreciate the help and not b so snide. (insert the Deevil icon here)


"""""Might beat the can out or use a different something. """"

Sure.....rearranging parts with a hammer and tongs might make it fit......."something"...isnt that what holds in the muffler bearing ?
 
Just makeing a point. I have two of those pumps.

Lots of discussion with Hap on the phone about this problem. He commented that they seal the race car pump covers on with with sealer of some sort, so you could indeed make it fit.

I supose I will have to do something like that when I get to that point, and I will.

I expect this is not just a Moss problem. However, this is only the second person I have heard with it.

Comments Hap, Peter C? Are there other pumps out there?
 
No other pumps that I know of. Pumps are either slotted aka pin drive as the cam has a roll pin at its end, or "star" drive which means the cam has a e eared indentation in it to accept the star adapter that goes onto the splines that are actually on the pump. 948 through 1275 cams interchange with the corresponding pumps. The early pumps, pin drive or slotted, have recently had a change made to them by the manufacturer resulting in them being a tad large in the 948 can. I've seen the pump housing ground off a bit(it's just a corner of the casting and no big deal) and I've the the cans "altered". Both methods with great success and no problems. It is not Moss' fault.
Like many parts on our cars, the pumps likely fit something very popular in Indonesia and the differences that make a problem for us, isn't a problem for them.

Peter
 
Hmm, how about a cover made from a coffee can, they are just sealed/soddered on. Or a small kitchen pot or such.
 
Jerry, I'm sure the pump was installed correctly. The 3-hole mounting pattern forces the correct oil pump orientation. There is no way that pump was to fit under this end plate (when I say end plate, I mean the entire "engine back plate"). It was not even close. After fidgeting with the end plate I noticed there were wear marks on the oil pump where the two were connecting. The wear marks went over halfway into the top left (in my picture) blank mounting hole (and that's how I estimated at least 1/4" of interference). I took the new pump off the engine and dry fitted it into the end plate's oil pump cover and it fits. The problem comes when trying to fit the end plate. The oil pump cover (or whatever it is called) is not centered on the oil pump's location. Maybe they did this because the end plate is a structural member and needed a larger rim on the corner -- who knows. This new pump might work with other 948 engines, but just won't fit the end plate in the Spridget 948.

And as far as modification goes, I'm not comfortable modifying a fairly expensive and critical internal engine part that should fit the first time.

Since I really didn't require a new pump and was only doing it as a precaution while the engine was out, I reinstalled my old oil pump and will return this new one. Unfortunately I am on a schedule to move in a few weeks and couldn't wait for a part's supplier to figure out a solution. The engine is back in the car already, old oil pump installed.

Mark
 
LOL and you have the source for all the parts in Europe. sigh.
 
Mark:

Thanks for more concise information.


"""""" pump cover (or whatever it is called) is not centered on the oil pump's location. """"""

I would call it (the can) a dust cover because it just protects the pump.

Your exercise in refitting would be anticlimatical now, as your using the old pump.

There seem to be a couple of physically different castings both in pin and star drive floating around.

APT would be a better source for a pump in that Dave has actually used the parts he sells.

That being said, then in fitting the pump, the backplate can be modified as all it does in the immediate pump
vicinity (near the big hole for the pump) is locate the dust cover. Material can be removed as necessary and unless its a huge amount, the dust cover will still locate due to its flange on the front side of the backplate. Be sure and check the clearance from the back (flat side) of the dust cover to the front side of the flywheel...especially if you have pinned the ring gear.

BTW..there are two different diameter dust covers.....the 1275 lump is different from the others.
 
Mark,

I had the same problem about 6 months ago. I am using a slot drive pump and believe most vendors carried the same one. I spoke with Dave at APT who as always was most helpful.

What I ended up doing was removing the pump cover from the backplate and then removing some material off the top of the pump, and some material off the rear plate. Once the backplate was seating properly against the block, I epoxied the pump cover to the back side of the backplate. I am running an aluminum flywheel, so this may not work with the stock flywheel due to clearance.

I am pretty sure I ended up using the small bore pump cover and did not use a 1275 pump cover. I think the 1275 pump cover may of interfered with the flywheel, but again this was attaching it the back of the plate and not pushing it thru. APT did have 1275 pump covers a few months ago.
 
That is preaty much what Hap told me over the phone.

Guess I was haveing a hard time typing it.

He further said that this is the racers solution. Epoxy the cover on.
 
I'm putting together a 1275 with a 5 speed conversion and converted my oil pump from a start to a slot type to match the SW5 cam I've installed. Guess what - - the oil pump cover doesn't fit.

Rivergate instructions say to purchase a Rover #AEG553 oil pump cover and that will fit.

However it's $35 from Minimania!!!
 
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