Discussion
After stripping the oil pump a few weeks ago to fit new gears, I'm convinced that I'm getting worse pressure now than before!! So I decided to strip the pump again and check the relief valve wasn't jammed.
Now I presume the chrome piston in the centre of the picture is supposed to move back and forth within the bore?? Well mine dosn't, it's jammed all the way to the right or in the bottom of the bore. Does this mean its jammed open or shut?? Also can it be saved or do I need a new base??
Cheers
Andy
>>> Edited by andys2 on Sunday 12th September 21:11
Now I presume the chrome piston in the centre of the picture is supposed to move back and forth within the bore?? Well mine dosn't, it's jammed all the way to the right or in the bottom of the bore. Does this mean its jammed open or shut?? Also can it be saved or do I need a new base??
Cheers
Andy
>>> Edited by andys2 on Sunday 12th September 21:11
As oil pressure rises it should push the piston down the bore overcoming the spring preload behind the piston. This allows the oil to bypass the pump so pressure stops increasing iirc. The spring tension determines the final oil pressure. If it opens and stays open like yours, then no oil pressure.
You need to free the piston and then if you can't afford new parts gently smooth the plunger with 1000 grit. Re-fit it with a new spring as yours will have lost some tension.
I may have a new spring and stock plunger and maybe a tadpole plunger around here if they are of interest.
You need to free the piston and then if you can't afford new parts gently smooth the plunger with 1000 grit. Re-fit it with a new spring as yours will have lost some tension.
I may have a new spring and stock plunger and maybe a tadpole plunger around here if they are of interest.
use the tadpole plunger and polish it on a mop till its highly shiney, works great and never jamms, you can replace the impellas but however having a lot of experiance with pumps of a similar design i chose to to re-furb mine(tollerances permitting) by filling the dammaged impellers flat with a slight radius on the ends so not to dig into the base,i also highly polished them, and using a pice of glass and some emery paper/oil i rubbed the casing flat as not to over do it when assembled, make sure their is very very little end play (dont forget to pack it with vasaline)with totaly no spacers in the relief spring engine hot on tickover reads 14psi a blip on throttle reads 55psi 
Boosted Ls1 said:
As oil pressure rises it should push the piston down the bore overcoming the spring preload behind the piston. This allows the oil to bypass the pump so pressure stops increasing iirc. The spring tension determines the final oil pressure. If it opens and stays open like yours, then no oil pressure.
I think his is jammed closed, not open...
On my rebuild I used the standard piston but with an uprated spring. I put a slight radus (and I mean slight!) on the piston edges and similarly all the exposed edges that the piston passes. Riffler file city...
wedg1e said:
As oil pressure rises it should push the piston down the bore overcoming the spring preload behind the piston. This allows the oil to bypass the pump so pressure stops increasing iirc. The spring tension determines the final oil pressure. If it opens and stays open like yours, then no oil pressure.
I think his is jammed closed, not open...
On my rebuild I used the standard piston but with an uprated spring. I put a slight radus (and I mean slight!) on the piston edges and similarly all the exposed edges that the piston passes. Riffler file city...
Hmm, that's interesting. It's been a long time since I had one apart but if the spring comes out of the housing before the piston then it must be jammed part way down the bore. Wonder why the oil pressure isn't to high? It must be partly open.
Andy, the tadapole is like a small sphere on a stalk. It has minimal contact with the bore and is less likely to jam. I don't know how good they are as I haven't used them. Try penetrating oil to move your plunger and get a screwdriver to wobble it free. Maybe compressed air will do it.
Your valve is stuck shut - this is un-usual. I have also tried putting a small chamfer on the end of the piston. Eventually i just put a new one on it (after i toasted the big-ends)
Speak to Chris @ RPI, he sells new ones - although you may want to try bearmach(sp?) - as that's where he got my "new" one from.
HTH,
ELiot.
Speak to Chris @ RPI, he sells new ones - although you may want to try bearmach(sp?) - as that's where he got my "new" one from.
HTH,
ELiot.
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