Oil pump studs

Hello,

at the moment I am resurfacing my oil pump. When I demounted it I recognized that the nuts were tight but studs relatively loose.
The reason is that the thread of the studs are short (about 9mm) and they do not bottom out in the holes. The holes are about 12mm.
It has the factory helicoils in the holes. The studs can be tightened but not much. Is that normal ?
I decided to fix the studs with blue loctite.

Thanks,

Ralf

I ma surprised the the factory did any hell-coils. When I find them during a tear down/inspection, I have always assumed that the engine/gearbox had been worked on. I always replace the standard thread of the oil drain with a hell-coil just for good measure Good luck with your oil pump rebuild.
Mike

No heli coils from Norton factory. I'd go with Red Loctite as once studs fixed well there is little to no reason to remove again. Do note there are 3 things vital to get proper oil seal on pump nipple, its base gasket or not and the nipple seal matched to the TS cover gasket. Vendors know this so sell matched sets for 750 or 850's. IIRC I used 850 set on my 2 Combats and left out the pump gasket, which was so thin appeared as just a stain w/o any height by time I got to see them. Took parts book for me to realize what hard to remove stain was.

hobot said:

No heli coils from Norton factory.

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As I know the later models have helicoils from the factory.

hobot said:

Do note there are 3 things vital to get proper oil seal on pump nipple, its base gasket or not and the nipple seal matched to the TS cover gasket.

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The nipple rubber was well compressed (not to much) when I took it apart, with the paper gasket in place. So I think assembling it in the same way would be ok.

Ralf

I have a later model timingside casting in hand ,yup ,oil pump holes are definately helicoiled.

Ok I'm corrected > Norton helicoiled later versions, cool, hope not to need em in my Combat. Its suggested as good practice to replace the oil snout nipple about each time but should work regardless. Just alerting to be alert to the clearance factors.

Noted. The oil pump output crush nipple is rubber and will harden up what-with all the hot oil pressure and timeage. Matter of course replacement. Have seen a couple of riders replace those studs with steel bolts to locktight into place. So I did the same too. :|

Torontonian said:

I have a later model timingside casting in hand ,yup ,oil pump holes are definately helicoiled.

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Great, can you tell how deep the holes are ?

IIRC you can also shim behind the conical seal. Not sure what the part # for them is.

Towner I cannot measure such depth with my tools (what calibrated tool would do this ?)- but understand where you are going to on this. I would say get the correct thread sized bolts first then determine depth for them to land home with error factor so nothing bottoms out. Alot of water has flowed under the bridge as we did this many years back. :|

Conical seal shimming as standard practice in between tea breaks. English Breakfast ? :?

Torontonian said:

Towner I cannot measure such depth with my tools (what calibrated tool would do this ?)- but understand where you are going to on this.

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The point is the studs have such short threads and the hole is much deeper. As I know studs should bottom out to get the best fit. So I am wondering whether I have the original situation on mine.
I don't need to know the exact depth, only if is nearly the same as mine. You can stick a nail in the hole and measure it with a ruler. It's for my peace of mind to know that's normal .

Ralf

Studs should be shorter than the hole in alloy or they break out the back of the hole, use loctite to fix them.

kommando said:

Studs should be shorter than the hole in alloy or they break out the back of the hole, use loctite to fix them.

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Thanks, that would be an explanation. Maybe the back wall is thin. I already fixed it with blue Loctite. The pump was tight when I took it
apart, so it will after assembling. I only was wondering why they left about 3mm unused in the hole though the thread is very short. The thread
has only 5 turns. So you think this is factory-made ?

Ralf

Hello,

now I finished the oil pump job. It was successfully - wet sumping has decreased a lot, more as half less than before.

But now after all I am not sure if I took the correct torque for the studs. Before assembling I read the manual and I didn't recognize that there were different
torque setting stated in the technical data and the description of the procedure. I considered the technical data to be correct (15 ft.lb). Then I read in this forum,
that the torque has been reduced on the later models from 15 to 10/12 ft.lb. I was not sure, what figure is correct and decided 13.3 ft.lb (18NM) to be a good medium.
But now I recognized that in all workshop manuals in the description of the reassembling procedure is stated 10/12 ft.lb and in the technical date 15 ft.lb.
So 10/12 ft.lb seems to be the correct setting related to the short threads of the studs.

Now I am worring that 13.3 ft.lb is too much. I have loctited it well and everything could be tightened smoothly. How high is the risk to get a damage ?

Are there any experiences with overtightened oil pump studs with 15ft.lb ?

Edit: I mean 15 ft.lb for the nuts not the studs. The stud have been tightened in the case with a much lower torque (lower than 10).

Thanks,
Ralf

The books say 10 to 12 ft lb's (120 to 144 in lb). I might think 15 is too much.

pete.v said:

The books say 10 to 12 ft lb's (120 to 144 in lb). I might think 15 is too much.

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Woudl you take it apart again, because it is tightened to 13.3 ?

No, leave it be.

kommando said:

No, leave it be.

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Thanks ! :wink:

I agree, leave em as proper torque for the oil pump nuts on studs, that is - above the too low manual listed levels. Lots of others including me go as high as you no problemo and less chane of working loose.
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