Houston, we have a problem

[jlaird]

Drove up and got title today.

First time Miss Agatha got any real driveing at 4K.

The good news is no leaks, the bad news is oil pressure is only 20 lbs when fully warmed up and drops to about 8 at idle.

Yep I checked, oil at the full mark.

Plan:

1. Check oil gage.

2. Change over pressure spring and fitting to an adjustable one.

3. Pull engine and replace oil pump.

Any other good ideas?

 

[tony barnhill]

I was worried about that oil pump!

 

[jlaird]

yea Tony, the one I ordered from Moss that did not fit and they would not take back because I did not have the box any longer. No big deal on cost, oil pumps are hard to get too though. However, when engine is out it will get a new pressure plate and disk as well. Oh yea will also look at second gear detent, seems a bit stiff.

Pump had the correct drive but would not fit under the cover welded on the backing plate. That's what happens when you get in a hurry I guess, you would think at my age I would learn.

 

[Branson]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:] That's what happens when you get in a hurry I guess, you would think at my age I would learn. [/QUOTE]

Excitement at any age will do that!

 

[DrEntropy]

Guilty as well. /bcforum/images/%%GRAEMLIN_URL%%/savewave.gif

Just be prudent about the amount of time you clock, Jack! Don't want to see you having to do the whole engine again!

 

[GB1]

Jack

How many\thick shims do you have behind the valve?

Secondly, the adjustable ones are a bit pricey and may not clear her starter.

Pat

 

[ChrisS]

Jack, you might also try replacing the oil pressure relief plunger with a ball bearing of the same diameter. The plunger can hang up and bypass too much oil. More common in a mini due to the transmission sharing the oil system but worth a shot. You will need to shorten the spring a bit to keep the same overall length (since the spring sits in the plunger).

 

[DrEntropy]

Chris brings up a point. I've seen plungers with an excessive amount of wear on the mating face (likely due to poor PM practices) and not seat completely around. If you do decide to pull the plunger, get a mirror and light to inspect the seat in the block well.

Never thought to mention it when you were putting the engine together, but I've used valve grinding compound and a 'sacrifice' plunger to reface the seat on a number of rebuilds. Too late for that in this instance.

 

[jlaird]

Oil pressure guage checks good with air at 60, 40, and 20 lbs.

Pulled the pop off valve, man that spring is tight. There are no shims in the cap. Have four springs, three long ones same size and one shorter one, it may go with the adjustable cap???????

I do have an adjustable cap for it, but maybe I don't understand how it could be that???????

Is it worth putting the adjustable one on and testing by running? Would change the valve for a different one as well just in case. How do I tell if blow by?

 

[Billm]

You don't. An adjustable one is fun to play with but really not of much other use. You want the valve to release at 60PSI and seal up below that. Your best bet is as Chris and Doc say to replace the plunger and see if that helps (it probably will), THEN play with other things.
Bill

 

[kcbugeye1275]

I've used a 1/4" bolt, the head acting like a spacer to up my oil pressure, but I hope your prob. is not deeper the replacement of the pump.

 

[regularman]

Jack, I hope you don't have the same problem I had with the subaru engine. Oil pump got so low that it started knocking.

 

[regularman]

Here ya go jack [url="https://cgi.ebay.com/ebaymot...ay.com/ebaymotors/MG-Midget...dZViewItem]ebay oil pump[/url]

 

[ncbugeye]

Regularman, your url is bad, you have https: twice

 

[DrEntropy]

he's got th' stutters. /bcforum/images/%%GRAEMLIN_URL%%/devilgrin.gif

 

[jlaird]

Got it shut down in pleanty of time, was at 20 lbs running easly and was only 185 temp. Pressure goes up with increase in engine RPM. Just don't idle as it then is at about 8 lbs. at 2K is just over 20 and that's the top.

Will replace the pop off valve over the weekend with another, although both look the same to the eye and no way they are worn to speek of. Will of course use the longer spring as it is new and seems prudent.

Oil is as clear as it came from the can, and is toped off. Castrol 20-50 GTX.

I am sure in my mind that it is the pump, just wish I knew more about them. How the heck can they wear out like that? How long should they last? Are there raceing ones I should be putting back?

Any and all Pump info appreciated.

Damb I hate pulling that engine. Pump should be on top.

Took a new pump apart a bit ago, yep see how that can wear. It's not really a vane it is a positive pushie kind of thing that actually compresses the oil out. Intresting bit.

 

[Hap Waldrop]

Jack, I've got a new peg drive oil pump for a 948/1098 on Ebay right now, it's not got any bids on it and opening bid is $20.00, item number #220116822617, there's about 8-9 hours left on the auction.


Jack also I got a box full of the hardened ball bearings to replace the oil regulator's cup

 

[DrEntropy]

Go for Hap's balls, Jack. /bcforum/images/%%GRAEMLIN_URL%%/smirk.gif

That would be the first thing to try: Much more positive seat than the cup.


DISCLAIMER: This is not to be interpreted in any manner other than HARDWARE.

ooohh... nevermind.

 

[jlaird]

Go for Hap's balls, Jack. /bcforum/images/%%GRAEMLIN_URL%%/smirk.gif

That would be the first thing to try: Much more positive seat than the cup.


DISCLAIMER: This is not to be interpreted in any manner other than HARDWARE.

ooohh... nevermind.

Thanks Hap, will give you a call monday. Meanwhile will jump on your auction.

 

[Hap Waldrop]

Jack, yes they make supefflowpumps, that increase the volume at high rpms, but I doubt that will help with a pressure problem.
You and Tony mentioned some doubts about the pump in the engine, elaborate please.

As far as making a adjustable regulator, I tell you how to do it, give me a call at the house now 8:17am or at the shop a little later, it's pretty simple, I've made dozens of them.