Mi16 Expected Pressure With 26t Sprocket And Gti6 Spring

[sport1901966 8]

The oil pressure is at the top of the peugeot gauge all the time (i know its inaccurate but I'm looking for a rough idea)

 

I was wondering if anyone can confirm I'm getting the pressure that would be expected with the above pump modifications?

 

I'm trying to chase down an oil leak that even after the third re-sealing of the sump (and believe me it was clinically clean, I even removed the pump pick up to avoid getting oil on the surfaces). It still leaks in the same place, just under the oil filter.

 

I am pretty certain the seal could not be made any better so wondering if its a pressure issue.

 

Cheers, Geoff

[B1ack_Mi16 67]

The oil pressure is at the top of the peugeot gauge all the time (i know its inaccurate but I'm looking for a rough idea)

 

I was wondering if anyone can confirm I'm getting the pressure that would be expected with the above pump modifications?

 

I'm trying to chase down an oil leak that even after the third re-sealing of the sump (and believe me it was clinically clean, I even removed the pump pick up to avoid getting oil on the surfaces). It still leaks in the same place, just under the oil filter.

 

I am pretty certain the seal could not be made any better so wondering if its a pressure issue.

 

Cheers, Geoff

 

Could be.. you might wanna open the oil-pump and make sure the bleed-valve is not jammed in there.

Anyway ain't the GTi6 using a 26t sprocket orginally so the pump spec would be identical to a standard GTi6 one?

 

Once hot pressure shouldn't be any more than the pre-load created by the gti6 spring...

[sport1901966 8]

Could be.. you might wanna open the oil-pump and make sure the bleed-valve is not jammed in there.

Anyway ain't the GTi6 using a 26t sprocket orginally so the pump spec would be identical to a standard GTi6 one?

 

Once hot pressure shouldn't be any more than the pre-load created by the gti6 spring...

 

 

Yep thats what I thought as regards to pump spec.

 

Am I right in thinking the bleed valve is the steel cap that sits over the end of the spring?

 

Thanks for the help so quick

[Tom Fenton 1,526]

Is that the area where the pressurised oil passes from the pump to the block gallery? I can't remember off the top of my head. If so it may be the joint from oil pump to block that is you issue.

[sport1901966 8]

Is that the area where the pressurised oil passes from the pump to the block gallery? I can't remember off the top of my head. If so it may be the joint from oil pump to block that is you issue.

 

Yep thats right, is there meant to be a seal or is it just mated machined surfaces?

 

Thanks, Geoff

[Tom Fenton 1,526]

I must admit I cannot remember. But if you are getting oil forced out of this joint under pressure it will most likely overwhelm whatever you do to try and seal the sump.

[sport1901966 8]

I must admit I cannot remember. But if you are getting oil forced out of this joint under pressure it will most likely overwhelm whatever you do to try and seal the sump.

 

Definately sounds like a potential candiate then, I should get another chance to look early next week so will take some pics. Any thoughts on the full oil pressure, is that to be expected with a newly rebuilt engine with the mentioned pump set up?

[Tom Fenton 1,526]

I've had a problem with high oil pressure caused by fitting a OE Peugeot 6 bar spring into a aftermarket replacement pump. Is your pump the original Peugeot, or a spurious replacement?

[sport1901966 8]

I've had a problem with high oil pressure caused by fitting a OE Peugeot 6 bar spring into a aftermarket replacement pump. Is your pump the original Peugeot, or a spurious replacement?

 

I believe its OE peugeot, can you think of any telltale markings off the top off your head?

 

Thanks again for the help

[matthewm 1]

I fitted an aftermarket pump with the 26t sprocket and 6bar spring few weeks ago - was giving me 95psi at cold tick-over and blowing oil filter seal out. After returning to the standard 5 bar spring it came down to 60psi cold tick-over, 20psi tick-over when hot on event, and all is well.

 

My aftermarket pump had 'autopumps' written on the casing, although otherwise all looked the same - not sure if someone else with a sharper eye will be able to offer you more help.

 

Also no, there is no seal between the pump and block, just the 'L' shape spacer plate.

[sport1901966 8]

I fitted an aftermarket pump with the 26t sprocket and 6bar spring few weeks ago - was giving me 95psi at cold tick-over and blowing oil filter seal out. After returning to the standard 5 bar spring it came down to 60psi cold tick-over, 20psi tick-over when hot on event, and all is well.

 

My aftermarket pump had 'autopumps' written on the casing, although otherwise all looked the same - not sure if someone else with a sharper eye will be able to offer you more help.

 

Also no, there is no seal between the pump and block, just the 'L' shape spacer plate.

 

Interesting, are those figures using an aftermarket gauge? I am pretty certain the pump is oe, where abouts is the marking on your pump? Maybe I'll try putting the 5 bar spring back in.

 

Thanks, Geoff

[Alan_M 66 1 Cars]

Interesting, are those figures using an aftermarket gauge? I am pretty certain the pump is oe, where abouts is the marking on your pump? Maybe I'll try putting the 5 bar spring back in.

 

Thanks, Geoff

 

I've got an 'Autopump' on my Mi16 with the uprated spring. The pressure when cold is 7bar+ when cold and thats on an aftermarket mechanical gauge. Seriously considering going back to standard now, as its now sprung a leak on the crank seal behind the flywheel.

 

I was thinking of fitting a spare GTi6 pump/sprocket etc onto the Mi to try and counteract the surge problem but don't think I'll bother now.

[Anthony 1,000]

I've got an 'Autopump' on my Mi16 with the uprated spring. The pressure when cold is 7bar+ when cold and thats on an aftermarket mechanical gauge. Seriously considering going back to standard now, as its now sprung a leak on the crank seal behind the flywheel.

 

I was thinking of fitting a spare GTi6 pump/sprocket etc onto the Mi to try and counteract the surge problem but don't think I'll bother now.

A leaking crank seal won't be anything to do with oil pressure though, as that's not a pressurised part of the system.

 

It'll either be a worn seal (it was a pattern one fitted I'm guessing, and that engine must have done alot of miles in the 5 years odd since now?) or there's a breather/ring issue causing the crank case to pressurise, forcing the oil out wherever it can.

[Tom Fenton 1,526]

The problem is that the aftermarket pumps do not have the spring seating machined to the same dimension as the OE pump. Therefore when fitting a spring that gives 6 bar in the OE pump, it is more compressed in the aftermarket pump, thus you get oil pressure high enough to cause issues elsewhere.

 

However the crank seal failure isn't due to oil pressure, this seal sees engine breather pressure and no more. The oil that has lost its pressure in a gradient over the bearing width is at no pressure when it exits the side of the main bearing and then drains down to sump via the drillings in the end main cap.

[Alan_M 66 1 Cars]

A leaking crank seal won't be anything to do with oil pressure though, as that's not a pressurised part of the system.

 

It'll either be a worn seal (it was a pattern one fitted I'm guessing, and that engine must have done alot of miles in the 5 years odd since now?) or there's a breather/ring issue causing the crank case to pressurise, forcing the oil out wherever it can.

 

Of course......I have no idea why I wrote that. Think before I post next time!

 

The seal came from a bottom end gasket set from QEP, reputable make but not OE. I gather OE is the way forward for replacement then rather than GSF? Incidentally, it's covered 30k-ish now.

 

The problem is that the aftermarket pumps do not have the spring seating machined to the same dimension as the OE pump. Therefore when fitting a spring that gives 6 bar in the OE pump, it is more compressed in the aftermarket pump, thus you get oil pressure high enough to cause issues elsewhere.

 

May swop to the GTi6 stuff after all then (might just fit the entire 6 bottom end).

[matthewm 1]

Yes, my readings are from an aftermarket electric gauge. From memory the marking is in the middle of the pump body, which you can see when the sumps off.

 

Alan M - tried fitting the spring that came with the pump although found the pressure to be only30psi cold tick-over, so on Tom's advice fitted a standard pug 5bar spring which brought it up to the 60psi I have now.

 

Has anyone had any troubles with these aftermarket pumps, remember a few people slating them on another thread, made by FIA if I remember rightly?

[welshpug 1,627]

gti6's aren't immune to oil surge either.

[Alan_M 66 1 Cars]

gti6's aren't immune to oil surge either.

 

No, but by all accounts better than an XU9J4.

[tony perks 1]

I know everything points to excess pressure here, but have you fitted bolts that are too long around the filter area , and maybe they are bottoming and not pulling the sump up tight?, i have known bolts too long to punch into the oil gallery at this point!!,

 

Indeed at the moment i am having an oil leak after just reshelling my engine and fitting 26 tooth pully and 5 bar oil spring, and guess what its just by the filter housing darn it.

[sport1901966 8]

I know everything points to excess pressure here, but have you fitted bolts that are too long around the filter area , and maybe they are bottoming and not pulling the sump up tight?, i have known bolts too long to punch into the oil gallery at this point!!,

 

Indeed at the moment i am having an oil leak after just reshelling my engine and fitting 26 tooth pully and 5 bar oil spring, and guess what its just by the filter housing darn it.

 

Thats a good suggestion I'll check that, I always use a torque wrench so shouldn't have punching into any oilways... I hope!

 

This will be the 4th time I've re-fitted the sump and its always leaked from by the oil filter. It may also be worth mentioning I'm using 20W-50 oil to run in the engine as recommended by Matt (QEP) after he did the machining on the engine for me, so maybe the extra thickness is creating more pressure.

Edited September 14, 2010 by sport1901966

[sport1901966 8]

I know everything points to excess pressure here, but have you fitted bolts that are too long around the filter area , and maybe they are bottoming and not pulling the sump up tight?, i have known bolts too long to punch into the oil gallery at this point!!,

 

Indeed at the moment i am having an oil leak after just reshelling my engine and fitting 26 tooth pully and 5 bar oil spring, and guess what its just by the filter housing darn it.

 

Just measured the protrusion of the bolts either side of the filter and when tightened there is about 2 mm between the end of the bolt and the bottom of the hole in the block. I may put another washer on each, just to be sure but I think they're ok.

[Alan_M 66 1 Cars]

You have the spacer in for the oil pump, yeah?

[sport1901966 8]

I do yep, although I measured the bolt length next to the oilway passage from the pump into the block and its very close, within a mm of bottoming out so Im putting a 0.9mm washer on to play it safe, I've also made sure all the mating surfaces are as flat as possible. Just refitting the pump at the moment!

 

Edit - Had to forget the washer becasue the bolt hole is chamfered to ensure the head is properly seated meaning the washer just bent.

Edited September 14, 2010 by sport1901966

[tony perks 1]

I run Valvoline 20/50 VR1 racing oil all the time in my engine it is an 8V though, I would have though 20/50 too thick for hydraulic followers!

[sport1901966 8]

Well took it out for a test drive today with the 5 bar spring and still pissin out like no time, the leak is from between the spacer and block around the green circled area. Its definately a sealing issue rather than excess pressure I reckon, which leads me to believe either the pump bolt adjacent to the pump-to-block oilway (circled red in pic) is bottoming out and not clamping the pump to the block tight enough, or the machined faces are not mating well.

 

I cant see where else the oil forcing its way out between the spacer and block could be initiating from other than the area circled in blue....unless anyone else has any suggestions. Thanks again!