TR250 oil pump - no pressure

[Richard Holland]

Has anyone experienced this before?: I have fitted the Moss 217488 aluminium bodied oil pump to my 250, replacing the cast iron version, hoping the increased flow would be a benefit.

However, having filled the sump, taken out the plugs and spun the engine for a while, the pressure guage refuses to shift off the zero mark.

I have dropped the sump again and taken the pump off to make sure everything lines up correctly and it is seated properly, but still no joy!.

I lathered the pump internals with oil before assembly, but can see no way of primimng it.

Any ideas?

[jonlar]

Hi Richard, I've never tried it personally, but filling the oil pump up with Vaseline has been recommended, I'd keep on cranking in bursts with no plugs in, I know on one occasion, it took about 2 minutes (in 15secs. bursts) to get some pressure showing. Just noticed you joined the Forum yesterday - a very warm welcome to you! Best Forum on the 'net.

Edited June 8, 2007 by jonlar

[Andy Moltu]

I guess you haven't primed the pump - vaseline has already been suggested. However if the sump is back on try removing the oil PRV assembly and squirting a 1/2 pit of oil down it - usually sufficient will back flow into the pump to prime it.

[Richard Holland]

Hi Richard, I've never tried it personally, but filling the oil pump up with Vasline has been recommended, I'd keep on cranking in bursts with no plugs in, I know on one occasion, it took about 2 minutes (in 15secs. bursts) to get some pressure showing. Just noticed you joined the Forum yesterday - a very warm welcome to you! Best Forum on the 'net.

 

Thanks for the welcome, Jontar.

I have a day off on Thursday this week and hope to get the thing sorted then. If not, the old cast pump is going back in - it was not too bad anyway.

As a matter of interest my wife, Chris, and I are back down in Penzance for a week in late September. I'm driving the TR down from Castle Donington, Derby, but Chris is going on the train -she swears its a comfort thing and nothing to do with my driving. Will there be any social thing on between September 22nd and 29th? It would be good to met any of the other register members in Cornwall.

[Richard Holland]

I guess you haven't primed the pump - vaseline has already been suggested. However if the sump is back on try removing the oil PRV assembly and squirting a 1/2 pit of oil down it - usually sufficient will back flow into the pump to prime it.

 

Thanks Andy - Ive taken the valve out to give the pump zero head to work on:- still no go, but I guess the squirt of oil into the plv orifice may do the trick. I shall try that on Thursday, and let you know.

[john.r.davies]

Another dodge is to make up a dummy oil pump drive shaft, remove the dizzie and MU, and drive the pump with an electric drill until it picks up oil.

You need a drill that reverses, as the pump goes anticlockwise, as seen from above!

John

[Andy Moltu]

Another dodge is to make up a dummy oil pump drive shaft, remove the dizzie and MU, and drive the pump with an electric drill until it picks up oil.

You need a drill that reverses, as the pump goes anticlockwise, as seen from above!

John

 

& Preferably a torque setting or it'll snag when you do get oil pressure!

[jonlar]

Hi Richard, the Cornwall local group meets at the Plume of Feathers, Mitchell (just off the A30) near Summercourt, so there should be a meet on 25th Sept., you can email <trcornwall@btinternet.com> Last Tues. of month at the Plume of Feathers, Mitchell, from 8.30 pm. Contact Pete Rugg, Tel: 07990 762950

[IanR]

Richard,

Have been thinking about your problem and I am not sure it is to do with the lack of priming, though the vaseline is a good idea, personally I prefer STP neat in the pump but each to their own. What I was thinking is that, if you have turned it over with the plugs out for several minutes (not continuously of course, but in total ) and still no pressure then I suspect you have a pump that is well outside the proper spec even though it is new. I measured several, perhaps 8 pumps at my supplier (all Moss supplied) just recently and there was not one that was within tolerance for rotor clearance or clearance to the body which was way too high. ALL of the ones I measured were worse than the old unit off the car that had done 68K. All these pumps were new. Look at the WM and measure it yourself its not difficult.

 

There are 3 possible solutions to this if it turns out to be your problem as I have never had to prime a pump. Regrettably none is likely to cost you less than the arm but one will cost you the leg as well!

1. Buy a tolerenced pump from Darryl at Racetorations

2. Decide that option 1 is too expensive and do some selective assembly from several new Moss pumps with the coperation of a friendly supplier.

3. Look for a stanpart item on ebay !!

 

Cheers

[Tom Fremont]

I'm with Ian about the tolerances on available new pumps ( I got several NOS rotor/vane kits on ebay years back and sorted the lot to get a close tolerance one ) but I'm dubious that any would be so bad as not to work at all, especially with priming. The difference in hot pressure is not that much really - I would say 5-7 psi max. Certainly not something most restorers/ show car people would notice.

 

Again, as Ian recommends, if you want quality go to the performance specialists for parts - they care if the stuff delivers

[Richard Holland]

Thanks, everyone, it works!

I have some glycol fluid grease, so I took the pum out again (The third time!, filled it with fluid grease and gave it a turn by hand to make sure it did pull through. I popped the sump on with two screws , refiled the oil and gave her a spin - off the zero straight away. Having looked at the tolerances of the pump, they do look pretty good - I can't get a .002" feeler gauge in.

Thanks for all your advice.