Moss Motors, Ltd

Hey to all. long story short i inherited a 1974 midget from my father-in-law. unfortunately he passed away before i started dating his daughter so i never got to talk to him about the car. i found recipts in the car so i know the motor is freshly rebuilt. he didnt have the stock airbox on the carbs just velocity stacks. the car is leaking oil out of the rear main and i figured i would have to do the rear main conversion on it. unfortunately the kit is 300 and my wife and i are broke. last night i read a few posts about adding a PCV valve and running it to the intake. i was hoping since i could afford a pcv valve this would either work or slow the leak down enought to where i could drive it until i get the 300 together to fix it properly.

thanks in advance and you guys have an awsome forum set up here

How bad is the leak?  The "A series" engine is famous for "marking its spot".

A PCV valve will not slow it down and the 74 is not equiped with one. Due to the design of the crankcase scavanging system, its not needed.

I went through this years ago and managed to slow the leak down, but never eliminated it completely until I installed a seal kit., which was a pain. The best oil consumption I got was about 1/8 qt per 100 miles of highway, the worst was 1/2 qt per 100.

If the engine was rebuilt by a general garage, they may not have known about the need to apply sealant between the rear main bearing cap and the block, but even if this was done and a pan gasket was made using high quality silicone such as "The right stuff" (vs the stock 4 piece cork and paper affair), it will still burp small amounts of oil out the back when driven. 

The cheapest thing to do is to put a big flat metal pan under it where its parked to catch the drips (yes, they make and sell pans just for this purpose) and just add oil when its low.

Here are some links for further reading.

http://www.mossmotors.com/forum/forums/thread/4431.aspx

http://www.mossmotors.com/forum/forums/thread/10737.aspx

http://www.mossmotors.com/forum/forums/post/18845.aspx

---

-Michael

thanks for the links. i did a search but somehow could only find one topic. i showed my wife your post and she wanted me to ask if you were channeling her dad. he used to always tell her its supposed to leak and thats what they make drain pans for ect. ect. ect. He was very involved with the local british car club and the motor was rebuilt by him and a bunch of his buddies from the club. I am going to my first meeting of his old club this weekend and will hopefully meet some of his old friends and maybe get some more details on the rebuild ect.

the first few times i fired it up after getting it out of storage it was a pretty contsantant drip...just short of a steady stream. we are getting ready to move and need the garage space for packing so i drove it to my parents house which is approx. 11 miles and when i pulled in the driveway there i noticed a few drops down the block. yesterday i had to fire it up and move it quickly to make room for an ambulance (whole other story). I drove it around the block and when i backed into the other side of the driveway i only noticed about 2 drips down the block. i dont know if the oil level (kept my eye on the gauge the whole time and had excelent pressure)was low or if maybe the pan gasket swole up or what. I will be going there saturday and will investigate more.

Possible leaks down the back of the motor can be from ...

-the rear of the valve cover gasket

-the rear main cap/slinger

-the oil pan gasket

-the oil pump itself (on the back of the motor, but not likely)

- there oil unions  on the RH side rear if the block above the starter motor that might be leaking down the RH side /rear

 

A leak that drips oil on the ground while idling in the drive needs attention, A leak that leaves a puddle about 2" in diameter under the rear main after a hard run, could be condsidered livable, but smaller is better.  Under no condition should you see a steady stream of drips at any time. 

Be aware that to address any oil leak at the back of this motor, except the pan gasket, requires pulling the engine and its easier and safer to do the pan gasket out of the car.  I leaking slinger will likely not leak in the driveway, only when you actually drive it, thus adding to the frustration of tracking down the leak.  If you cant tell where its coming from, clean the areas well with an aerosol brake cleaner and throw a good amount of baby powder into the area.  Run the motor and see where its damp.

I don't know how skillful or knowledgeable the peeps where who did the rebuild but they may have not known to seal the rear bearing cap, or may have trimmed the pan gasket corks to short, or ... you may have another issue.  Don't forget to check the valve cover gasket at the back of the head, it may have split and oil could be running down the back of the motor.

---

-Michael

You might try this potion. I've used it and it does work under certain circumstances (ie dried or shrunken seals).

 "Bar's Rear Main Seal Repair" it's an oil like substance that you add to the oil. It freshens and plumps up seals. It will not replace seal material that has worn away. I've used it in ZS carb dampers to plump up the O-ring seal around the needle and to slow down if not completely stop the leak on my rear main seal.

 Similar additives, but less concentrated, are found in oils specified for older engines for the same reason.

 Don't expect overnight results, but with a little regular driving, if it's going to work, by the next oil change you might notice a difference.

 Walmart, Autozone, etc etc.

So here's the update. The car is leaking pretty much everywhere it can. the main culprits are on the drivers side of the block twords the front there is a pipe comming out of the side of the block and pointing down. this was leaking pretty bad. i did some resarch and i think it belongs to the emissions system which has long since gone bye-bye. anyways i tried to plug that with a piece of hose with a bolt in the end and that made the rear main start puking oil. I am thinking i am going to try and get one of those small breather air cleaners which would allow the pressure to escape but keep most of the oil in the engine. The other option i was kicking around i my head was to run a piece of hose to the intake manifold to create a vaccuume situation to relieve the pressure in the crankcase. so much for getting it drivable for next week

 p.s. for doing the rear main conversion kit does the motor have to come out of the car or can i just pull the tranny and do it that way?

First, I don't believe there is any way you're gonna pull that gearbox with the engine still in. Even if you could, you probably stil could not get to the rear seal area. The approach is to get a little vacuum on the crankcase. There were various methods used over the years. Someone with a '74 will probably be along soon to give better advice. You definately want to do that before going the more extreme route.

 

---

Bayless
Never express yourself more clearly than you can think
'48 Prefect
'67 Sprite (project)

I jst re-read my original post and since then i found out it is a '72 not a 74...dont know how much if a difference it weill make though.

Really, how bad is the leak?  Drive around, park it for 10 minutes, then take a look.  If it's a 12" wide pool, yeah, that's a serious leak.  If it's 1-3" in diameter, it's British!  Brit motors from the Druid era to the 90's all leak.  Some say it's a built-in self-preservation system to keep the bottomside from rusting, others say Brit motors in general are incapable of retaining their vital fluids, period.

We are all so spoiled by the wonderful reliability and leak-free nature of today's modern automobile.  We've forgotten what was considered "normal" several decades ago.  Michael503 has the right idea.  Buy an industrial-sized drip pan for your garage floor, and enjoy the "character" of your Brit car.  20W50 motor oil is dirt cheap compared to what's needed to retrofit proper modern seals into the motor.

Enjoy the car!

The car may not have the original engine in it.  There are 3 sizes of "A series" engine  948, 1098 and 1275.  The 67 - 74 is supposed to have a 1275, but they will swap and bolt up no problem.  If it has a pipe coming out of a cover on the side of the block under the manifolds, then that's the crankcase breather and you have a 948 or a 1098 engine installed.  See the diagrams on "engine external" in the Moss online catalog to ID your motor.  I don't think its possible to swap heads from a 1274 to a 1098, but someone may have tried and actually got it to run

If it has a breather on the side facing down, then the most likely culprit is too much oil, or oil with a lot of gas in it causing the crankcase to be overfull.

They only hold about 4 quarts.  If the oil smells of gas, change it!  Others here have warned of the need for a zddp additive to the oil due to modern oil chemistry  being changed.  Do a search if you don't know about it already.

As to dropping the tranny, forget it, the tail end sits on top of the frame and you'll never get it out.  You can however, remove the engine and leave the tranny in place, but you may not need to.  If its overfull with oil and you plug the breather, it'll blow out the back. There is no rear seal.  Seal softeners and oil additives will not stop the rear from leaking because there's nothing there to soften.

Hope this helps.

 

---

-Michael

I got the engine code off of the block and it is "12V(either 7or/)5872-L5361. From what I can tell from this website http://www.mgcars.org.uk/mgccz/technic/codeseng.pdf on the second page the engine is a 1275cc. Any info would be great, I found out we had a few extra bucks so I am going to buy the coversion kit to fix it right.

also on page 6 of that website it says 12V is the prefix code for a morris marina 1300 which is also a 1275cc motor.

Well, ya got me stumped.  have you looked at the schematic diagrams on Moss's site?

The 1275 does not have a cover on the LH side of the engine with a pipe facing down.  The breather is on the timing cover and faces up.

---

-Michael

I think this I did this right..... http://viewmorepics.myspace.com/index.cfm?fuseaction=user.viewPicture&friendID=34512354&albumId=2854886 here are the pics i took this morning. its kinda hard to tell but the drain/vent pipe is on the drivers side under the front carb.

Well, thats a 1275 all right, but that almost looks like something someone made.  Thats a blanking plate to cover the hole for a mechanical fuel pump. I've never seen anything like it. Without an oil separator, it will spew quite a bit of oil out that pipe

Look at the schematics on Moss's site for the 1275 and look at the timing cover.  There should be a cylinder about 4" long and 2" in diameter attached to the front.  That's the breather. It should have a 1/2" hose going to a Y connector and then to the carbs.  If its not there, then did someone fit a timing cover without one and try to add one somewhere else?  I've never seen a gray block, but they could have painted it when they had it down.  Can you post some more picks a little farther back so we can see the rest of the the motor, particularly the timing cover and carb setup.  It should have a spin on filter, not a replaceable cartridge type.

You should note the residue on the heat shield and on the steering shaft.  That looks like a heavy accumulation of old gas from a leaking carb, maybe from the flexible line going from the jet to the bowl, under the carbs.  If that's leaking, fix it or carry a fire extinguisher, since a leaking exhaust gasket can ignite it.  Fixing it is of course preferable.

Hows the oil level? Its not overfull is it?

---

-Michael