The engines in the Sprites and Midgets don’t have a rear main seal.
They have like screw threads on the rear of the crankshaft and like a small cup cast into the block on the backside. There is a small flat plate that bolts at the top and the clearance between it and the crankshaft is critical to keep the oil from getting by
It literally screws the oil back into the oil pan.
See item # 35 for the plate I’m talking about.
.That damn Sprite of mine literally used to leave a trail of oil behind it. One drop every 8 imches or so and it would leave a little puddle under it every time I parked it.
Part of that was because I didn’t have the $75 PCV Valve assemnly hooked up.
See Item #30 at right for that contraption.
The bottom slides into a rubber hose that fits on a nipple in the middle of the intake manifold and the other hose goes to a nipple sticking out of the timing chain cover.
When I last tore the engine down and rehoned the cylinders, I took care of both of those issues.
I bought a $250 Billet Aluminum rear main seal conversion kit and “machined” the back side of the lip on the flywheel down that slips over the back of the crankshaft flange for clearance by 1/4 of an inch using a pneumatic die grinder and a bunch of Roto Lok surface preparation discs and then hand polished the flange for the crank where it fits into the flywheel. That’s what the seal rides on and it works like a charm.
I also paid the $75 and got a new PCV valve and hooked it up.
Now I have something as rare as hen’s teeth. A 1275 CC A Series British engine that DOES NOT LEAK OIL!
Like old Harley’s, THEY ALL leaked a little oil. Now mine doesn’t.
It’s nothing short of a miracle, I’m serious.
I’m still having trouble with it popping out of 2nd gear when decelerating so at some point I’m going to have to pull the engine and transmission FOR THE SEVENTH TIME and when I do, I’m going to swap out the tail shaft housing from the last one I had in it that I put a brand new rear seal on because this one is worn and it does drip a little gear oil where the driveline slides in when I park in the driveway because it’s sloped.
But other than that, I am very happy to have cured that oil leaking shit.
about the only good thing I can remember about working on Spitfires was that they where easier than most to work on. and yes, never saw one that DIDN’T leak oil.
here a idea, drive behind a Spitfire and watch the rear end work on tight turns.
it doesn’t. most kind of arch up a bit ? weird as hell first time you see it.
made quite a few bucks under the table working on English sportscars back in the 1980’s. I charged about half or less than the shops off base did.
for a MG clutch job with tune up was 600. drop it off at the craft shop after work
and I have it done by lunch Sunday easy. also did a fair bit of electric trouble shooting on them. one case of beer per hour. and good beer not some cheap shit ! found a short in a 68 XKE in 20 minutes than to a old ford flasher unit and a amp meter. the guy (LTC) was tickled to death by that. gave me a 100 bucks and 2 case of beer ! he was told by some shop in Kansas city that it would cost him
250 or more if they looked at it.
one thing I learned along the way, Majors and LTCs pay more and faster than any other higher officers ever did. seem like the higher in rank they where, the cheaper they became. or you should just do it because I out rank you kind of shit.
A/H could be a nightmare to work on at times, depending on the job
ever see a MG 1100 ? yeah, some kind of hydro suspension in them. you had to pressure the system to 275 PSI to get it to work right. and any engine work would kill you back unless you pulled the damn engine out !
did have to correct the timing on that one, what a pain in the back that job was !
hope your project works out for you. and YES.it a matter of pride to have a English sportscar that doesn’t leak oil and starts every time.
one thing I remember doing was to change the oil in the tranny with new and adding some “Slick 50” to it. might be wrong, but it did seem to shift a lot easier after that. BTW, I found a bottle of carb oil downstairs on my workbench last night
I knew I still had one. but a good ATF oil will work just as well too.
just remember this neat fact. ever see a Daimler sportscar ? kind of a weird one.
had a little V-8 in it. fast as hell but watch where you park it. there was NO front seal on the crankshaft (??) yup, depending on the slope, depends on how much oil you have left in it. only saw one and told the guy I wouldn’t touch it and to take to the bandits off base. and besides. he just rubbed me the wrong way off the bat.
in other words a flaming asshole. which was weird as most officers I did work for where very happy I saved them some bucks and their car ran better than ever.
did a few Weber conversions too. people didn’t like/trust the S.U. or later on the Strombergs (?) I didn’t like them either, most of them just sucked and where a stone cold bitch to get tuned right. where as the Weber was a easy fix that stayed tuned for the most part. unless you fucked with it that is.
Well, you know what they say about British cars:
https://www.getyarn.io/yarn-clip/679b1d59-6399-4ad9-92f4-64bbf3240140
Leigh
Whitehall, NY