• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

How bad do Spridgets leak oil from the crankshaft?

Share this page

J

JOeyKnapp

Jedi Hopeful
Offline
I am trying to decide if I need to sell a kidney to get a rear oil seal or not. How much of a leak are we talking. If it sits for a week will all the oil drain out? Does it just leak a little after driving. Does it leak enough that when driven oil will cover the underside of the car? Is there potential for the clutch disk to get oil on it?

Just trying to feel out the importance of this piece and if it is worth financial stress...
 
This is a question that never seems to go away. The "A" series engine uses a "scroll seal" on the crank that in theory will drive the oil back into the pan sump. My engine loses a little but I just pay attention to oil levels and its not too bad. A lot of people say that pay attention to the PCV system and make sure it is working right and it will take care of oil messes at the crank- Last time I did a clutch I replaced the diaphram in the valve and oil leakage is minimal. Oil leakage will not be so severe that it all leaks out. I have heard both good and bad about seal kits for these engines and I just keep a eye on oil levels and oil pressure and so far so good-I have driven 1000's of miles with my 1275 with no catastrophies and a lot of fun-I think the pcv is what controls most leakage issues at the rear of the crank
 
Mine was just a matter of drops, and dampness on the bellhousing.
 
Keep in mind that when it's sitting without being run all the oil is in the pan and thus lower than the rear of the crank. Generally leakage into the bell housing should occur when running and there's pressurized oil flowing to the rear main bearing. The scroll should catch most of it and dump it back into the pan but depending on component wear and setup some amount will leak out. And since it doesn't all drip out instantly there will be drips over time. Unless you end up with a large puddle and the dipstick shows its doown over short run periods, I wouldn't worry too much. Just make a habit of regular checks of oil, and other fluids.
 
Mine still leaks even after the oil seal kit was fitted (Rivergate 5 speed conversion with kit applied). It leaks less now that I have the original style PCV valve/system in place. I experimented with PCV valves from the local auto parts stores. One supplied too much vacuum which sucked oil into the intake and fogged mosquitoes for 5 miles when the engine warmed up. Another supplied vacuum but as soon as the engine was off oil poured out the seal and out the cotter pin hole in the original transmission.
 
jhorton3 said:
I experimented with PCV valves from the local auto parts stores. One supplied too much vacuum which sucked oil into the intake and fogged mosquitoes for 5 miles when the engine warmed up. Another supplied vacuum but as soon as the engine was off oil poured out the seal and out the cotter pin hole in the original transmission.
Click to expand...

As per my recent post/thread on the PCV matter, I had that problem... which initially freaked me out. :yesnod: So, what PCV valve did you use (and is it rigged between the oil separator and the intake manifold - and what sort of carb setup are you using)? Was it just trial and error? I guess I'm wondering if I can fool with restricting the vacuum to the pancake PCV valve (in my dual HS2 carb set-up).
 
This is my 3rd summer with the Sprite and it is the only one I have experienced. It came with a 1974 1275 that was locked up. I bought a 1969 rust bucket for the front brakes and the motor was supposed to be bad. Before I pulled the motor I squirted gas in the frozen carbs and hit the starter and it started right up. It was covered with oil and all the breathers were plugged. I cleaned it off and changed all gaskets painted it and installed it. I had to use the carbs of the 1974 motor and they have a Y at the base and I piped the breather there with no PVC. No smoke and only 2 drops on the floor for this summer. I keep checking the oil and wonder why it doesn’t leak. I think someone put new brakes and a motor in a severely rusted car then gave up. Should there be a PVC before the Y?
 
Someone just posted pics of the proper setup on one of the threads. On my 1098 Pipe/hose goes from timing cover vent to Flying Saucer valve and then into the intake manifold. My spare 1275 has the Y hose, I believe the PCV Valve goes between hose from Timing cover and the Y going to the carbs.

If you are seeing minimal leakage I'd be tempted not to bother. Back to the "Doctor do no harm" school of thought.
 
I have always said (search the forums) that the first line of defense is proper machining/assembly of the half moon seal and of course proper venting is key to making it work as intended. An original engine, that does not have excessive wear can sometimes perform well if the half moon seal has never been disassembled. The reality of the situation is, only a small number of engines today meet that criteria. The half moon seal works correctly when the tolerance between the scroll and have moon seal are maintained at around .002 clearance. In the many years I've been rebuilding these engines, I've only had one that leaked at all after the rebuilt. This is a part of the build that I pay a lot of attention to, but I suspect maybe the machinist did not give this detail enough attention during the line bore.

In the event that venting does not solve the problem or a complete rebuild is "not in the cards", what are your alternatives? Either live with it or find something that works, short of an entire rebuild. I have experienced and also heard from many about the tablespoon to half cup of oil the engine pukes on shutdown. A few have been able to cure it with correctly plumbing the venting. I'd say conservatively more than half are unsuccessful with the various possible fixes, including the "JB Weld fix".

I think most of you know I have been working on an alternative to either of those. Reports are, when properly installed, my solution works... just saying there is another option.

Here's a recent thread on the subject on the MG Experience Forum.

Rear seal kit
 
Mine only drips a few drops when its not running. When you stop the engine and all the oil is draining down the scroll seal is not scrolling. I never give it a second thought, that is just how it works. If its leaking while its running then you don't have enough vacuum on the crank case, or something else is bad wrong.
 
Between bore flex and stuck or broken rings, these engines can develop a lot of blow-by, so sometimes developing enough vacuum just isn't possible to overcome that. That pressure when your driving is certainly escaping where it can, and the rear scroll seal is usually the place of least resistance.
 
Yeah Gerard, it will blow out under the bottom with something like that. That is a good clue if the whole underneath is coated with oil. I have seen that on a mini but found a vacuum line sucking air and it hadn't been idling good either.
 
Gerard said:
Between bore flex and stuck or broken rings, these engines can develop a lot of blow-by, so sometimes developing enough vacuum just isn't possible to overcome that. That pressure when your driving is certainly escaping where it can, and the rear scroll seal is usually the place of least resistance.
Click to expand...

But what if the suction/vacuum is TOO much?
 
Gerard said:
Boink said:
But what if the suction/vacuum is TOO much?
Click to expand...

Blue smoke... :crazyeyes:
Click to expand...

Hehehe. More than that! TONS of smoke with blue mixed in. As all the awful stuff is mostly burned, it switches to a lovely blue... and then it's gone. :shocked:
 
What are your feelings regarding the evac-u-sump systems that use the exhaust to create a vacuum. I wonder if one sized for our engines pulling through an air-oil separator would solve the problem. Higher RPM would create more pressure, but would also create more vacuum, using an inline valve to restrict the vacuum might prevent pulling oil into the exhaust.

Last year I installed one of the Summit Racing kits on my 1380, but since it was sized for one side of big block V8, it pulled oil out of the sump and left a cloud of smoke. The tube for the exhaust pipe was probably twice the size it should be for our size engine. I was pulling it through a remote recovery bottle, but it still would smoke sometimes. I pulled the fitting out and patched the header, but was thinking I might give it another try with a smaller dia vacuum pipe for the header and an adjustable valve in the line to the catch tank.
 
Thanks... though it sounds complicated. :eeek: I guess I was hoping to use the originally designed system (but maybe I've got more blow-by that I should).
 
I've also found a little oil tends to go a long way and can look more then it actually is.
My car when I bought it had the leak at the rear and all we could try was a new main seal, it seems to have have helped a bit but still leaks.
If you looked underneath the car you'd be forgiven for thinking that it was loosing the lot but I found after a 360km trip yesterday the engine had used maybe 200ml of oil and a lot of that may have been use rather then leaks.

My rocker cover box is not vented at all, the only venting my engine gets (1098) is the breather on the side of the block which I have running to atmosphere as my Weber carb and manifold set up do not allow for a vacumm return.
 
Proof that a little bit can go a long way (though it's hard to dispute what you found on the ground), I once had a 1275 (back in about 1975) that a previous owner put ARCO graphite in!!! Remember that stuff? It was BLACK (containing suspended graphite in it)... and in an A-series engine that meant BLACK <span style="text-decoration: underline">everywhere</span>. And, as they say, once black you can never go back. :cooler: It didn't leak a lot, but that little bit made a mess and I'm glad I finally got rid of that car.
 
Back
Top