Oil pump gaskets… who needs ‘em…?

Fast Eddie

Fast Eddie

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Am I right in thinking that early bikes didn’t have them?

I striped a race motor a while back that didn’t have one (built by a highly regarded engine builder].

Just got me wundrin’ …
 
Sadly, you need a thick one when you get this from a reputable builder!
Oil pump gaskets… who needs ‘em…?
 
Adjusting gaskets and / or gasket thickness to get a good oil pump seal fit sounds very logical gents.

Next question, if using no oil pump gasket, what’s the recommended MO… some form of sealant on the pump face, or just dry?
 
You sure you want to try this? Methinks the gasket mitigates bleed off, I once thought of machining the back of the pump for orings around the scavenge and feed holes but too little surface between them to make it feasible.
 
Fast Eddie said:
Adjusting gaskets and / or gasket thickness to get a good oil pump seal fit sounds very logical gents.

Next question, if using no oil pump gasket, what’s the recommended MO… some form of sealant on the pump face, or just dry?
Click to expand...
If I were going to do it, thin Permatex #3 on both surfaces, let dry a few minutes and assemble. A little Permatex #3 in the passageway is unlikely to hurt anything. Most of the favorite sealers on the forum certainly could.

Then I suppose one or more of the shims that AN sells would be needed - haven't measured - don't know.
 
acadian said:
You sure you want to try this? Methinks the gasket mitigates bleed off, I once thought of machining the back of the pump for orings around the scavenge and feed holes but too little surface between them to make it feasible.
Click to expand...
Not planning on trying it per se. I’ve always thought a gasket was a no brainer in this context, so I’m just intrigued by the fact that Norton didn’t always fit one and neither did this particular engine builder. Just wundrin what’s what.
 
jseng1 said:
Better off without it. Your oil PSI is fine without it. They can blow and then you have a serious problem.
Click to expand...
Interesting .
Never had a gasket blow ever , on a Norton , and I've owned 4 . Leaked yes . But not the oil pump ,
Bigger factor is fitting it backwards , way bigger attention to detail .
 
I’m very appreciative of the feedback from y’all on this topic. It made me look far more closely at this situation than I perhaps might have otherwise done.

I have now concluded that this engine was missing its oil pump gasket by design. I’ve played around with 2 timing covers, 3 types of gasket, and 2 different types of pump oil seal.

There is no space for a gasket !

It will be going back together with a thin application of Wellseal around the oil holes and no pump gasket.
 
Not sure if this is the right thread to post this, but here goes:

Situation: I need to rebuild my 1970 750 oil pump, but have a good 850 oil pump on hand that I´d like to use instead.
Question: Will an 850 oil pump work here provided it has the correct seal?

850 seal: Will the 850 pump, with its corresponding seal (06-6190) and bush (06-6191), fit correctly into the machined opening in the 750 timing cover (sans anti-sump valve)?
750 seal on 850 pump body: Or should I remove the 850 bush from the pump body (I believe it just pulls out), and install the 750 bush (NM15515) from the old pump with a new 750 conical seal (NMT272 or 06-7510)?

I´m inclined to use a pump gasket to compensate for the newer timing cover gasket.

Thanks for your advice!
timson
 
timson4 said:
Situation: I need to rebuild my 1970 750 oil pump, but have a good 850 oil pump on hand that I´d like to use instead.
Question: Will an 850 oil pump work here provided it has the correct seal?
Click to expand...
There is one type of pump for all years 1966--74 and capacities, 06.3037 / NM25368. The spigot detail change for the Mk3 is just a minor alteration and the latter is also usable in earlier engines.

- Knut
 
timson4 said:
850 seal: Will the 850 pump, with its corresponding seal (06-6190) and bush (06-6191), fit correctly into the machined opening in the 750 timing cover (sans anti-sump valve)?
Click to expand...

Sounds like an 850 Mk3 pump in which case as mdt-son says you can use the spigot but use the pre-Mk3 06.7510 seal. Only use the Mk3 seal with a Mk3 timing cover.
andover-norton.co.uk

Andover Norton - OIL PUMP SEAL (NMT272) - 06.7510

OIL PUMP SEAL (NMT272)
andover-norton.co.uk
 
Fast Eddie said:
I’m very appreciative of the feedback from y’all on this topic. It made me look far more closely at this situation than I perhaps might have otherwise done.

I have now concluded that this engine was missing its oil pump gasket by design. I’ve played around with 2 timing covers, 3 types of gasket, and 2 different types of pump oil seal.

There is no space for a gasket !

It will be going back together with a thin application of Wellseal around the oil holes and no pump gasket.
Click to expand...
I've built several engines without using a pump gasket, just used a thin film of Wellseal. No problems.
 

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