One step forward ...two steps back!

[Hooper11772]

WHERE TO BEGIN...
So after Chris graciously stopped by earlier this week to give me hand getting the midget running i've been anxiously awaiting working all the kinks out of it that we discovered upon startup. I got to it this weekend making some good progress....

The first thing that needed to be addressed was a small freeze plug leak. I remedied this temporarily with some JB weld that seems to be holding up quite well. I also needed to fix a small coolant leak from the shut off valve on the head. Made up a new gasket for that and that no longer leaks. Bled the clutch and breaks everything worked well no leaks and plenty of pedal with both.

Sooo onto adjusting the carbs so the engine would run smoothly upon startup. Turned the key engine fired and was revving high so I started making the adjustments from a carb tuning book Chris recommended. That's when progress came to a screachin halt...
I noticed a significant drop in oil pressure. By significant I mean I was running somewhere around 40 PSI and the pressure dropped to 10 PSI. I stopped the engine immediately and took a look under the car to see a good size puddle of oil that had accumulated. Took out the dipstick and was 1/2 quart down. It looks like the leak is coming from between the rear plate and the tranny bellhousing. I checked the oil pressure sending line, oil filter feed line, and oil pressure relief valve and the leak was definitely not coming from any of those. The only thing on the engine that I did not replace new was the oil pump. Although Chris and I did take a look at it prior to installing and it appeared to be in good shape. Could this be anything other than the pump or the scroll seal? The leak is pretty significant and starts immediately after startup. I'm hoping that an engine pull isn't necessary but i'm starting to feel like it is. Any suggestions?

 

[Gray_Cat]

Hi Roger:
Is the engine properly "vented"? By that I mean do you have a hose running from the canister on the front of the timing cover to a PCV valve or other device? DOesn't take much back pressure in the crankcase to push oil through the scroll or even the rear pan gasket. Just doesn't seem like it would be the oil pump or scroll causing that type of leakage, just speculating.
Hope you can find the problem without pulling the engine....
Roy

 

[Glen_B]

If the leak starts immediately with the engine and poured out a half quart in a short tuning session, its not the scroll seal. You also said the drop came on suddenly, also ruling out the scroll seal. Most likely is the oil pump cannister gasket, then the cracked backplate. Either needing an engine pull. sorry.

Glen

 

[Hooper11772]

Hey Roy,
The engine has the vent in the front of the timing cover. It's not blocked however I dont have a PVC so thre is no hose connecting the two. I would think that that should be sufficient for venting do you think. It's posible its leaking out of the rear of the pan i'm defintely going to check that before I do any pulling of the engine.

When I put the plate in there were no cracks and I was sure to replace all gaskets with new as well as use plenty of liquid gasket to assure a tight seal. If the pump went would it leak like that?

When I restarted the other day after discovering the leak the oil pressure was good somewhere around 35 or so and then it gradually dropped. As it dropped the leak got worse. It took about 5 minutes for the oil pressure to drop back down to 10 PSI or so. Thanks for the advice i'll see about a possible pan leak when I get home. I sure hope it's as easy as that.

 

[jhorton3]

If you've got the can on the timing cover wide open, then that's probably the problem. There needs to be a hose connected from it to a PCV valve, then to a large port that's probably on your intake manifold. You've got to maintain some negative pressure for the oil to stay in. Last year mine would pour big puddles of oil out the back when I didn't have a PCV system fitted.

Here's something else to keep in mind with the PCV system. If there's too much vacuum it'll suck atomized oil into the intake and you'll be able to fog mosquitos for a few miles. I even fitted an oil catch can to the system I rigged, and still getting fog. I'm about to trash my entire PCV system and break down to buy the original flat disk style.

 

[Hooper11772]

That's intresting. I was under the impression that the timing cover vent could be left open. I do have a large port on the top of the intake. Do you suggest that I run a hose from the timing cover to the intake port and see if the leak disappears? Do I need the PCV valve first for this? Also I cant find a documehnt that gives the oil capacity for a 1275. I want to make sure I didn't add to much oil. Thanks!

 

[jvandyke]

On my 1098 (a bit different) I ran a line from the valve cover (no timing chain cover vent in the system yet) directly to the intake manifold. Prior to that it was going to the air filter and I had leaks. After I switched it over to the intake, most leaks are gone. So, I'm believer that you need some suction on the vent system.
I'd put it back the way it was meant to be, then see what happens.

 

[Hooper11772]

I'll pick up a hose and give it a try. Anyone have the oil capacity on a 1275 handy?

 

[jhorton3]

You can connect a hose from the can to the intake port as a test to see if most of the leaks stop, but you're going to have oil fog coming out the exhaust pipe. Just make sure you're in a ventilated area.

 

[Gray_Cat]

Roger:
I agree with Jim Horton's statement. The crankcase needs some negative pressure to actually cause oil to reenter the rear of the crankcase by sucking it back into the engine. The way it is set up now, the pressure is forcing the oil out past the scroll and it goes out REAL fast! I believe that would explain the lower oil pressure as well. If the oil is escaping through the scroll it's like having a relief valve there so the oil pressure cannot keep up with the loss of oil.
As Jim pointed out, just connecting a hose from the cannister to the intake (be it the manifold or air cleaner) will cause too much suction and you end up killing mosqitios as the oil will flow through to combust in the engine. Maybe you could hook it up that way temporaily just to see if the leak stops before you invest in any more parts.
If you have a Moss catalog, check it for the capacity - I already did: it's 7.8 pints but need to add for the oil filter so I believe the correct capacity is 4 quarts - if I am wrong on this guys, PLEASE say so!
Keep at it Roger, you are almost there!
Roy

 

[Glen_B]

The absence of suction on a 1275 puts you in the same place as the average 948, losing a tablespoon or two per shutdown unless you have tons of blowby. The oil pressure won't respond to a change in where the oil that leaves the rear main bearing ends up. Whether the oil is pulled by suction into the drain groove and back to the pan or it is pushed out the other way to end up on the floor, the oil pressure gauge won't know the difference. Oil pressure like blood pressure, goes to 0 where the pressurized system meets the outside atmosphere. For the engine, thats at the edge of the bearing/throw interface. The fact that the gauge has recently shown a big drop suggests that there is a newly enlarged exit for the oil leaving the pump. The puddle hints at the location.

I'm running a turbocharged 1275(~1300cc) with a gulp valve to a block vent, so I've had some fun with the block pressure issue.

Glen

 

[jvandyke]

Roger:

As Jim pointed out, just connecting a hose from the cannister to the intake (be it the manifold or air cleaner) will cause too much suction and you end up killing mosqitios as the oil will flow through to combust in the engine. Maybe you could hook it up that way temporaily just to see if the leak stops before you invest in any more parts.

But isn't there really only much vacuum at idle? What I did, and I'm very much a newbie so take if for what it's worth, is I restricted the orifice on the fitting coming out of the intake to about 1/16", thus a "metered" orifice which is(was) common instead of a PVC valve I guess. I was worried about sucking oil into the combustion too but I can't see evidence of it in the exhaust or anything, I guess whatever works I guess.

 

[jhorton3]

Even at idle if there's not enough negative pressure oil will get pushed out the scroll seal in the back and start pouring out the cotter pin hole in the bottom of the transmission. How much or how little depends on the engine, especially after this many years of wear and tear, and what's been rebuild/replaced.

 

[Hooper11772]

I'm checking this evening to get a better idea of exactly where the oil is coming from before I do anything. Where is the cotter pin hole that the oil may come out of? The oil seems to be leaking from the lowest point on the bellhousing where the engine plate meets. Also important to note while my tach is currently not working I do know that my idle is very high. This could be why the leak is so much greater as the engine is revving pretty good on sartup. I need to make the adjustments for lower idle but want to take care of this leak before I run the car for any extent for tuning.

 

[jlaird]

Back about 2 inchs from the front of the tranny on the bottom is a hole it by rights is supose to have a cotter pin in it. No big deal.

 

[Hooper11772]

Update!

Last night I was dead set on trying to figure out where the oil leak was coming from exactly before I got anymore frustrated. So I jacked the midget up high enough for me to see the area the leak generated from. I then cleaned the whole area so I would have a clear picture of the location when the leak began after startup. Started the engine and no leak for about a good 5 minutes not even a drip. Oil pressure was good around 35 or so. After about five minutes the drip began but MUCH slower than before. just a slight drip that was trickling from the rear of the oil pan where that cheap half round cork seal is.

Phewwwww! After fifteen minutes of idling the drip stayed relatively the same oil pressure around 10 PSI towards the end with a temp of 160 degrees. I never did try the hose technique but Chris made a good point. I think the oil leak was so bad as a result of the front end being on jack stands resulting in the oil flowing to the back of the pan and probably pushing out the cork seal faster then the norm MG leak. With the budget engine rebuild I Chris and I did (used oil pump) i'm happy with the pressure and small leak. I'll replace that cork seal with a better gasket but i'm just going to keep a close eye on it for now.

So thanks for all the help everyone. If nothing else I definitely learned allot including stepping back and breathing. I feel much better now. I'll be driving in no time!

 

[jvandyke]

The last oil pan I did (not an A series) I was talked into ditching the rubber and cork in favor of The Right Stuff . FWIW

 

[Nelson]

How do you work with the "Right Stuff"? Do you lay a bead on all the surfaces and then have to torque the pieces together in a given amount of time? Did you use the "Import" version?

Nelson
62 Mk2 Sprite

 

[jvandyke]

Lay a heavy bead without any gaskets (on the pan flange), bolt it up. Some say to wait a while (a day) before final tightening, instructions say to tighten up right away. It worked well on that pan but it was the only time I used it. At $13 a can it isn't any cheaper than gaskets really but don't have to try to keep gaskets lined up during install either, I don't know. Just thought I'd mention it. Absence of the gasket "might" change the clearance between the pan and other parts too so that's a consideration.
I did have to do it twice on that motor, I was too conservative with it the first time. I didn't fill the "sump seal" grooves (the rubber bits). Pans on that engine are pretty notorious for leaking where the rubber and cork meet. Looks like A series pans are the same 1500 just cork all the way around? On that Opel, removing the oil pan included removing the engine crossmember first, it was quite a bit of work. A series looks like a 30 minute job!
I believe the import stuff is formulated for a bit more heat is the only difference. Can't imagine it'd matter.
PS I used the stuff on my aluminum valve cover this past spring too since it refused to not leak. A bead of Right Stuff and it hasn't leaked since, of course, now I need to check valve lash and that cover is essentially "glued" to the head and I'm loath to disturb it so it has its drawbacks too.