OIL PUMP MAINT

Just read an article in the Feb issue of Roadholder about oil pump refurbishment.
A comment in the text got me thinking about a noise that has started from my bike when under load.
The author had been talking about wear in the pump allowing the oil pressure to be ok for the crank but not enough for pushing enough oil through the conrod bleed holes for cylinder lubrication, and the wear allowing oil just to circulate round the pump.
The comment was " How often do we hear of a re-bore that has failed and the replacement pistons or re-borer getting the blame"
The sound from the engine under load sounds the same as it did before having a +20 rebore 3000 miles ago, so although the pump was refurbed at rebuild I decided to have it apart and have another look, it did show signs of wear on the end plates which were ground flat as per the script in Roadholder.
It all went back together and I've run the bike up with a pressure gauge fitted into the rocker feed, I've run the bike on Castrol GP50 since it was run in and the results from the run up is as follows.

Initial start up from cold @ 2000RPM = 80 Psi

As the oil warmed up the pressure dropped off as expected, when finally hot

Idle (1200) = 18 Psi
3000 = 32 Psi
4000 = 34 Psi
5000 = 36 Psi

So the question to all those people who have gone down this road already is, Are these figures respectable? I would be really interested to hear from your exploits.

If the noise continues I'll need to have it apart and have a wee look to see if I can see the cause, just hope it's not another re-bore.

Mac.

The subject of conrod bleed holes has been discussed before, the general consensus is that the oil holes are basically unnecessary.

con-rods-oil-hole-t8374.html

Your oil pressure figures seem healthy enough.

Thanks LAB, hadn't seen that thread before, learn something new every day

Mac.

the main and about only issue of worn leaky oil pump is how you handle wet stump before start ups as once runing crank sling feed big ends so only need enough pressure to feed head. Rod oil holes were attempt to solve early models piston seizures thought to be poor pin oiling but turned out to be a bad batch of pistons but the rod holes still supplied though about universally blocked off by racers switching rod shells to block em. Most other engines like to see 10 PSI per 1000 rpm but Nortons are very happy a long time on just 5 PSI or less per 1000 rpm to point Norton quit offering a oil gauge in few months after all the freaked out complaints it showed no oil pressure at hyw speeds. There is a service manual spec on this deletion from late Mr. Hudson.

Oil pressure looks fine. Keep in mind that oil pressure is also a function of wear on the rod journals.

On to the noise you are hearing. Can you further describe the noise and under what specific conditions you hear it?

willy mac said:

Initial start up from cold @ 2000RPM = 80 Psi
As the oil warmed up the pressure dropped off as expected, when finally hot
Idle (1200) = 18 Psi
3000 = 32 Psi
4000 = 34 Psi
5000 = 36 Psi
So the question to all those people who have gone down this road already is, Are these figures respectable? I would be really interested to hear from your exploits.
If the noise continues I'll need to have it apart and have a wee look to see if I can see the cause, just hope it's not another re-bore. Mac.

Click to expand...

You don’t state whether your oil pump has a 3 start or 6 start worm drive, no matter, the oil pressures you have are all within acceptable limits. Incidentally, if you are taking the oil pressure from the rocker oil pipe, you are taking it from the return oil pump side, not the feed pump.
There is quite a lot of noise that comes from the timing cover, as the chain to the camshaft and the earlier magneto wizz round, so pinpointing where nose is coming from is v. difficult :shock:

you might want, or not want to look at this;

https://www.youtube.com/watch?v=X3p5uU0rdXE#t=127

willy mac said:

Just read an article in the Feb issue of Roadholder about oil pump refurbishment.
A comment in the text got me thinking about a noise that has started from my bike when under load.
The author had been talking about wear in the pump allowing the oil pressure to be ok for the crank but not enough for pushing enough oil through the conrod bleed holes for cylinder lubrication, and the wear allowing oil just to circulate round the pump.
The comment was " How often do we hear of a re-bore that has failed and the replacement pistons or re-borer getting the blame"
The sound from the engine under load sounds the same as it did before having a +20 rebore 3000 miles ago, so although the pump was refurbed at rebuild I decided to have it apart and have another look, it did show signs of wear on the end plates which were ground flat as per the script in Roadholder.
It all went back together and I've run the bike up with a pressure gauge fitted into the rocker feed, I've run the bike on Castrol GP50 since it was run in and the results from the run up is as follows.

Initial start up from cold @ 2000RPM = 80 Psi

As the oil warmed up the pressure dropped off as expected, when finally hot

Idle (1200) = 18 Psi
3000 = 32 Psi
4000 = 34 Psi
5000 = 36 Psi

So the question to all those people who have gone down this road already is, Are these figures respectable? I would be really interested to hear from your exploits.

If the noise continues I'll need to have it apart and have a wee look to see if I can see the cause, just hope it's not another re-bore.

Mac.

Click to expand...

I also saw the NOC article by Phil and technically was not all that impressed. Very entertaining though.
The apparent lack of actual "critical" examination of the gear faces, as I have done to several dozen pumps, fails to define the pump defects beyond the end wear. That is only one wear point that was addressed. Granted the "factory" recommended refurbishment only addresses one of the 4 wear points. I continue to develop test procedures for my test machines/fixtures. So I don't have every answer, but I believe I can define all the problem areas in the pump. A new pump is the only total cure. A "factory" recommended refurbishment can possibly improve a fading pump but there is no guarantee. I have been given several failed pumps that could NOT be salvaged to a useable condition.
I have done oil pump testing for norton bike shops and rebuilders on both 3 and 6 start pumps. I have a NEW pump from AN (BSA regal) as a reference/sample...as well as many earlier pumps back to the zinc bodied skinny gear pumps 1949.

copied from a previous forum entry:
I will retype this since it does not come up on "search"....in less than 3 years past. I KNOW I have done this before but the older files have been purged to clear up forum hard drive space.

There are four (4) paths for wetsumping.

1. (feed side) Clearance between the sides of the gears and the brass plate...The most commonly discussed since it can be addressed by fettling out some of the wear using the "factory" rehab procedure.


2. The clearance between the tips of the gear teeth and the body.

3. Clearance between the two sets of gear teeth themselves

1 & 2 & 3 are addressed by the MKIII style pump output spring valve or the Nortech-AMR mod. this is supposed to prevent passing oil through to the rod bearings/crank interface then out into the sump. No question that reliability of this mod is spotty(refering to the MKIII MOD not Nortech's). The theory is good.

4. Cross cavity through the PAIR of shafts drive and idler from feed into the scavenge back down to the sump.

5. putting the crank "up" is a joke.
I have some supporting data done during the oil pump research project that is now on hold until after I finish moving into my new (to me) shop....

I know it is foolish but a posting on the commando forum "should" mean we are discussing a 6 start pump.

"Incidentally, if you are taking the oil pressure from the rocker oil pipe, you are taking it from the return oil pump side, not the feed pump."
not true for commando

I agree with the oil pressure numbers as good, particularly the idle numbers.

I feel that the point of an oil pressure guage is not to determine how much oil pressure, but to simply show that you have some oil pressure.

Hi Bernhard

The statement you made

"if you are taking the oil pressure from the rocker oil pipe, you are taking it from the return oil pump side, not the feed pump".

Does not ring true for a Commando have another look at the oil system, the rockers are fed from the same gallery as the crank.

Mac.

Dances with Shrapnel said:

Oil pressure looks fine. Keep in mind that oil pressure is also a function of wear on the rod journals.

On to the noise you are hearing. Can you further describe the noise and under what specific conditions you hear it?

Click to expand...

The noise is almost like "Pinking" and occurs when accelerating, the timing has been checked with a strobe to 5k and is around the 28-30 deg mark,(Boyer Ign) plugs are quite light though but I think thats due to the fuel rather than a weak mixture.
It's a similar noise to what I had before but the rebore seemed to have cured that, when cruising along it sounds fine but as you open the throttle you can hear it.
Bit of a bugger really and I can't think of anything else to look at before I pull the barrels off.

Mac.

If the pump cover plate is worn,it's possible the pump inner face is worn? Did you use a straight edge and feeler gauge on the gear/face?
If you like to see more pressure you can fit a 4 start worm..this up's the flow,and slightly increase's the pressure.

willy mac said:

Just read an article in the Feb issue of Roadholder about oil pump refurbishment.
A comment in the text got me thinking about a noise that has started from my bike when under load.
The author had been talking about wear in the pump allowing the oil pressure to be ok for the crank but not enough for pushing enough oil through the conrod bleed holes for cylinder lubrication, and the wear allowing oil just to circulate round the pump.
The comment was " How often do we hear of a re-bore that has failed and the replacement pistons or re-borer getting the blame"
The sound from the engine under load sounds the same as it did before having a +20 rebore 3000 miles ago, so although the pump was refurbed at rebuild I decided to have it apart and have another look, it did show signs of wear on the end plates which were ground flat as per the script in Roadholder.
It all went back together and I've run the bike up with a pressure gauge fitted into the rocker feed, I've run the bike on Castrol GP50 since it was run in and the results from the run up is as follows.

Initial start up from cold @ 2000RPM = 80 Psi

As the oil warmed up the pressure dropped off as expected, when finally hot

Idle (1200) = 18 Psi
3000 = 32 Psi
4000 = 34 Psi
5000 = 36 Psi

So the question to all those people who have gone down this road already is, Are these figures respectable? I would be really interested to hear from your exploits.

If the noise continues I'll need to have it apart and have a wee look to see if I can see the cause, just hope it's not another re-bore.

Mac.

Click to expand...

If the pump cover plate is worn,it's possible the pump inner face is worn? Did you use a straight edge and feeler gauge on the gear/face?

Hi John

Both end plates and main body were ground on a surface table till all witness marks were removed, gears were ground while installed in the body to make sure they were flush. Are you talking about fitting a 4 start worm drive onto the pump to be driven by the 6 start on the crank? I've not heard of that before, where would you get one of those from RGM don't have them in their catalogue.

Is there a post on here showing multi start worms?

willy mac said:

Dances with Shrapnel said:

Oil pressure looks fine. Keep in mind that oil pressure is also a function of wear on the rod journals.

On to the noise you are hearing. Can you further describe the noise and under what specific conditions you hear it?

Click to expand...

The noise is almost like "Pinking" and occurs when accelerating, the timing has been checked with a strobe to 5k and is around the 28-30 deg mark,(Boyer Ign) plugs are quite light though but I think thats due to the fuel rather than a weak mixture.
It's a similar noise to what I had before but the rebore seemed to have cured that, when cruising along it sounds fine but as you open the throttle you can hear it.
Bit of a bugger really and I can't think of anything else to look at before I pull the barrels off.

Mac.

Click to expand...

To me, a pinking sound while opening the throttle would indicate detonation. Have you increased the compression ratio? You might have another look at your actual ignition setting and confirm timing marks in primary cover are accurate. Also try a fresh tank of higher octane fuel as a bit of test.
Do you get the pinking sound while open throttle under moderate steady load. Is it worse when the engine is hotter?

Bernhard said:

willy mac said:

Initial start up from cold @ 2000RPM = 80 Psi
As the oil warmed up the pressure dropped off as expected, when finally hot
Idle (1200) = 18 Psi
3000 = 32 Psi
4000 = 34 Psi
5000 = 36 Psi
So the question to all those people who have gone down this road already is, Are these figures respectable? I would be really interested to hear from your exploits.
If the noise continues I'll need to have it apart and have a wee look to see if I can see the cause, just hope it's not another re-bore. Mac.

Click to expand...

You don’t state whether your oil pump has a 3 start or 6 start worm drive, no matter, the oil pressures you have are all within acceptable limits. Incidentally, if you are taking the oil pressure from the rocker oil pipe, you are taking it from the return oil pump side, not the feed pump.
There is quite a lot of noise that comes from the timing cover, as the chain to the camshaft and the earlier magneto wizz round, so pinpointing where nose is coming from is v. difficult :shock:

you might want, or not want to look at this;

https://www.youtube.com/watch?v=X3p5uU0rdXE#t=127

Click to expand...

On a Triumph.....

To me, a pinking sound while opening the throttle would indicate detonation. Have you increased the compression ratio? You might have another look at your actual ignition setting and confirm timing marks in primary cover are accurate. Also try a fresh tank of higher octane fuel as a bit of test.
Do you get the pinking sound while open throttle under moderate steady load. Is it worse when the engine is hotter?

Click to expand...

I don't use the timing marks on the outer chain case as I know they can be wide of the mark. I set the engine to TDC then used a dial gauge to set the engine to 30 BTDC and then put a mark on the alternator stator, so I think I'm ok with the timing.
Compression ratio is something that I've not even measured but no modifications have been done by myself to alter it, I'll maybe try going for a higher Octane rated fuel and see how that goes.
Once the bike is cruising along the sound goes, it's only on accel cold and hot.