MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - BIG oil leak!

Help! I've just completed the rebuild of my 59 1500 engine and have a problem with an oil leak. I know a small one is to be expected, but this is a major puddle! As part of the rebuild, I switched from the cannister filter to the spin-on adapter from Moss. When I purchased the adapter, I also bought a filter (Fram PH-3600) from them to make sure I had one that is compatible. The car runs for 15-20 seconds, then the gasket around the top of the filter gets pushed out and oil sprays everywhere. I've checked the gasket and it isn't damaged. What would cause such a build up of pressure?

Thanks
SJ Jackson

SJ

When I did the canister conversion I omitted to remove the solidified original gasket (it was so hard I thought it was metal and part of the groove). The new gasket was therefore sitting too high in the groove and blew out much as you describe. I was on a motorway at the time and lost the entire contents in about 1/4 mile. Just made an escape road. Underside of the car was covered in oil.

Steve
Steve Gyles

Steve,
As this was a compete rebuild, I made sure that the old gasket was completely removed. The gasket on the oil filter itself, not the adapter, is the one that is blowing out. I've scoured Barney's website on this as well as lurked around here during my rebuild to hopefully catch issues like this before they happened to me.

There is a bright side to the undercarriage soaked in oil, no rusting! My car is acting like a puppy on hardwood floors, puddles, puddles, puddles.

Steve
SJ Jackson

Did you notice the pressure indication on the oil pressure gauge? If the engine shop put a brass plug in the wrong hole in the bottom of the engine block, it could have no path to return oil to the sump from the oil pressure relief valve. In that case oil pressure can go sky high as engine speed increases, going high enough to blow out a rubber gasket or even to burst a tin canister.
Barney Gaylord

Steve, is your pressure relieve valve ok (right hand side of the engine at the back when looking from the front). This releases pressure at about 75 lb psi but if it didn't you would get a pressure build up. Just a thought, Lindsay.
Lindsay Sampford

The problem is with the design of the spin on adapter (Moss?) The filter thread bottoms out on the brass retaining nut of the adapter. Only certain filters are acceptable and do have the right clearance. See my thread of April 1 on this subject - lots of options that fit OK.
Art Pearse

Steve,
Since you put on a spin-on adapter you might want to check the fit-up of the filter to the housing. If the filter is bottoming on the screw and not the housing it could cause this symptom. I had a bad leak when I first install my adapter. But I think it was between the adapter and the block. Still, I'd check the fit-up.
Good luck,
Gerry
G T Foster

Barney,
Yes I was looking at the pressure gauge and it went to ~80 psi, then max'd out on the first start, was reading 80 psi while it was running and slowly drops off when the engine was turned off.

Lindsay,
I assume the pressure relief valve is okay, I'm not sure how to test it.

Art,
The filter feels like it snugs up to the adapter okay. I can feel the compression of the filter gasket to the adapter. I'm going to get a NAPA filter at lunch and try again.

Gerry,
Did your leak actually push the filter gasket out from between the housing and the filter body?

Thanks for all of your input.
SJ Jackson

If oil pressure is okay, then the filter must be bottoming out on the center hex fitting. Moss has been dancing around this problem for years, refusing to acknowledge that there is any problem, saying if you buy their filter it will fit (which is not always true). It is obvious from the continuing complaints and reports that the problem is real.
See here: http://mgaguru.com/mgtech/faulty/ft026.htm

If you must use one of these adapters you have two choices.
1.) Cut down the center hex fitting to be thinner.
2.) Hand select oil filters that will have more internal clearance from this fitting.

It is likely that Moss will never change the design of this part as long as the customers do not return the parts.
Barney Gaylord

Barney,
Do you think it might be the plugged oil line in the block? I had a machine shop familiar w/ MG engines do the work. I would hope they know which plugs to put where in the engine.

I'm not committed to the spin-on adapter and am willing to go back to the cannister setup if that will solve the problem. I was going to try the NAPA GOLD 1516 per your website to see if that had more clearance.

If the filter clearance turns out to be the issue, I will most definitely return the spin-on adapter setup to Moss along with my complaint.

Thanks for your time.
SJ Jackson

Hi Steve, sounds like Barney has probably hit it, but just in case; the pressure release valve is the big hex nut low down on the right hand side of the block (looking from the front), undo it and as you clear the last thread on the nut it will spring away from the block under spring pressure (be ready for that!). withdraw the spring and usually the valve plunger will come out with the spring. If the plunger doesn't come out with a bit of fiddling about with the spring, you will need a suitably sized piece of wooden dowel that you push into the open end of the valve to withdraw it with or use Barney's method http://mgaguru.com/mgtech/engine/of111.htm . If the valve comes out easily on the end of the spring it should be ok, but check the free length of the spring. If it takes rather more to extract it, the valve is probably the cause of the high pressure. You will have to push fairly hard on the hex as you turn it when replacing the valve!
Lindsay Sampford

Lindsay,
What should the free length be? The length mentioned in Barney's article is for the MGB engine. Will it be the same?

Steve
SJ Jackson

Three inches Steve.
Lindsay Sampford

Steve,
there is another possibility. On my first car, I replaced the canister filter with a spin on adapter, and tightened the center hex fitting too tight, which I believe twisted the adapter and caused the gasket to leak. (I blew out 5 quarts of oil in 30 seconds, twice.) I loosened it up, checked the gasket in place and carefully tightened it up a lot less than max tight. Never leaked a drop after that.
Mike Parker

Steve, the original set up has got to be more environmentaly friendly than the canisters. With the originals you only chuck a piece of oil soaked paper away, not a piece of steel as well. Save the planet, drive an MGA with a standard oil filter!
Lindsay Sampford

Thanks Lindsay, I'll keep both in mind.

Mike, I'm going to give it one more shot with a different oil filter. I tightened the center bolt per the instructions, but will back it off a little when I check the main gasket.

More tomorrow.

SJ Jackson

Steve J, -- Probably no issue with incorrect plugs in the block. Since oil pressure topped out at 80 max, the pressure relief function seems to be working properly. Most likely the filter does not seat properly on the adapter.

NAPA Gold 1516 filter is one that would always jam on my Moss adapter. This is made by WIX and is essentially the same as the WIX filter being sold my Moss for this application. Apparently the Fram filter fits, the NAPA and WIX filters do not, and I don't know yet about the K&N filter. As noted on my web page, you need to check the mating underside relief on any filter before installing it on this adapter.

Free length of the pressure relief spring is 3-inches for all MGA and MGB engines. With no shims this results in about 50-psi relief pressure. MGB gets higher relief pressure by using a thick button in the back of the PR valve poppet to preload the spring to higher force.

You can increase relief pressure in earlier engines by stacking 1/4-inch medium helical spring lockwashers inside the back end of the PR poppet. Each washer added bumps the relief pressure up about 6-psi, so 2 washers would change it from 50-psi to 62-psi. This does not necessarily do anything useful for your engine, but it might make the passengers feel better to see higher pressure on the gauge.

Useful output of the oil pump is up to about 12 quarts per minute in the 1500 to 2000 rpm range until it hits relief pressure. At higher speed all of the excess oil flow gets dumped over the relief valve to return directly to the sump.

Higher relief pressure requires more power to run the oil pump once it exceeds 50 psi. More pressure makes very little difference in the amount of oil passing through the bearings. As excess oil flow gets dumped past the pressure relief valve back to the sump, all of the energy used to pump the excess oil will be converted into heat in the oil. Higher relief pressure means more heat and higher oil temperature.
Barney Gaylord

Lindsay funny you should say that,do you own a Volvo? Late model Volvos have a plastic cannister with a replaceable element inside and that is exactly what they say
gary starr

No, never felt an urge to own a Volvo, but I guess if I lived in near darkness for half the year it might seem more attractive! It's just that most of the cars I have ever owned have had paper filters; Austin A35, Morris Minor, MG Magnette(2), MG midget, MG 1300 and MGA, so it just seems to make sense.
Lindsay Sampford

Barney,
I'll take some measurements on the Fram filter I have to see if that is the problem. Thanks for the information about the pressure relief valve, good to have.

I looked at my cannister setup and noticed that the head assembly is missing. Anybody have an extra one for the early Tecalemits? I'll check Ebay next.

Thanks,
Steve
SJ Jackson

I have a Moss adaptor that I purchased about 1997, have used both Fram and Wix filters on it without problems.
J Heisenfeldt

I just measured my adapter and filter. The nut on the adapter is 65 thou proud of the sealing face. On the WIX 51348 filter, the metal cetre is 79 thou below the gasket face. Deduct the two numbers, leave only 15 thou for tightening! As the thread seems to be .060 pitch, that is 1/4 turn. I can turn it that much, but not sure how much farther it will go when lubricated. Sure is not much to play with. I have not yey put it in service so can't say if it leaks or not.
What is the easiest way to reduce the retaining nut thickness - on a lathe?
Art Pearse

Hand tightening is commonly noted to be 3/4 turn after the gasket touches. The thread is 16 threads per inch, so 3/4 turn is about 0.047-inch compression for the seal. This is exactly why they jam on the adapter.

A lathe would be great if you had one. This is the way the parts should be fixed in a flash before they are sold to the unwary consumers.

I haven't done this to one of these adapters (yet), but I have done something similar with other parts. You might chuck the stud in a power drill (held in a vice or clamp), and go after the flat side of the hex fitting with a grinding wheel in a Dremmel tool (high speed hand grinder) while the stud is rotating to keep it straight and square. I have even turned down a few small parts using a hack saw blade against the rotating part.
Barney Gaylord

All, I tried the NAPA 1516 filter with the same messy results I had with the Fram. I measured the Fram filter and had .096" from the top of the gasket down to the filter center. The NAPA filter measured in at .110". Inspecting the filters after I removed them, I didn't see any obvious signs of rubbing against the hex nut inside the adapter.

I'm going to try one more time noting the 3/4 turn that Barney mentions above and see if that helps.

I'm not having any luck finding the head assembly for the cannister setup (early Tecalemit) either.

I'm so close to driving the car for the first time!
SJ Jackson

Steve, which head assembly are you looking for? The Service Parts listing shows two different ones. I have an early motor assembly that might have what you need.
G Goeppner

I need the head assembly for the early Tecalemit cannister assembly. It doesn't show up in the VB catalog, but does in the Moss catalog.

http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=29212#17

Is this what you have?
SJ Jackson

SJ,
I have a basic question, and this will not help with a solution to your problem, but which way up is your adapter/spin-on filter? You mention the gasket "around the top of the filter" which suggests you have the adapter pointing down and the filter installed from below. All the applications I have seen have the filter fitted from above. This makes it easy to fit a replacement filter.
Main reason for fitting the adapter and spin-on filter is to ease oil and filter changes.
The original Tecalmit cannister with throw away paper filter, is a real b.... to install as it is quite difficult to align the long central bolt while the cannister is fouling the chassis. Not so difficult if you have a pit or a hoist, but lying on your back under the car on stands it can be a very frustrating exercise.
Peter.
P. Tilbury

Steve, I'll have a look when I get home, but I think its more like #18 or #19 from the Moss catalog page. I have the whole filter assembly (i.e. #13 or #14), would that help?
George
G Goeppner

Peter,
Yes, the filter installs from below. I can imagine that the original system is quite a pain, but I'm not sure what else to try in order to fix my issue.

George,
I would be interested if you have a complete #13. It looks like I could use the same hard line that I have.
SJ Jackson

Steve, I converted my 1500 from the early filter container with the pipe entry to the later type where the pipe is fitted to the head unit and used the same feed pipe but I think I remember having to adjust it very slightly. Lindsay.
Lindsay Sampford

I have a Moss adaptor purchased sometime around 2001 /2002. It has the filter hanging upside down. I have had no problems with leaks at all, although I do recall one filter that was stuck on there pretty good, and was a bit of a struggle to remove with a good quality oil filter wrench. Maybe that one was bottomed out at the same time as the 3/4 - 1 turn occurred, I don't know. I have used either Valvoline or Fram CPH-3600. I have a spare CPH-3600 and I just measured the clearance at about .135". The hanging filter is no problem to remove and install. Its a little close to the starter making it a tight access for a filter wrench, but it is still possible. I found out the hard way, if you want to remove the starter, you first have to remove the oil filter. I think a hanging filter is better than the top mount filter on the MGB engines. I have an MGB also, and they need a filter with a good anti-drainback feature or else every time you start the car after sitting for a few hours you have to wait for the filter to fill up again before oil pressure shows on the gauge. The hanging filter is always full of oil.

Ralph
Ralph

Lindsay,
Do you still have the early filter container? Willing to part with it if you do?

Steve
SJ Jackson

Hi Steve, yes, i've got the container but the head part is broken, that's one of the reasons I changed it for the later type; which I just happened to have. If it's just the container you want, you are welcome, but I am here in little old England so I don't know whether the shipping might be expensive. Lindsay.
Lindsay Sampford

Back to machining the Moss adapter - I guess a hand held Dremel will do the job, it does not have to be true flat, but will I have to extend the thread by one more turn, and what is the right die for this?
Art Pearse

Hi Steve. I have the late Tecalemit head assembly as I thought, but I also have an early Tecalemit head assembly I pulled from an engine last night. You can have it for the cost of postage from the Chicago area, I can get it to the post office on Saturday. BTW, what is the purpose of the 2 springs in the head?

George
G Goeppner

George,
PM me at jack2318@comcast.net so we can get it in the mail.

Steve
SJ Jackson

Cancel my question about the threads. they stop short of the nut so do not need extension.
Art Pearse

All, just a quick update. I had a friend with a lathe turn down the thickness of the hex from .270" to .190". I also made sure to go 3/4 of a turn on the oil filter(s) once contact was made with the filter gasket. Same results as before, it pops the gasket out after about 10 seconds of running and proceeds to dump oil onto the floor. George was kind enough to send the head assembly for the original cannister assembly and I installed it but have not tested it yet.

I'm off to Breckenridge tonight to MG2009 as a spectator. Hope to see some A's there.

Steve
SJ Jackson

Steve where in Co is your car?
R J Brown

RJ,
I'm up in Loveland. Did you make up to MG2009?

Steve
SJ Jackson

All,
Another update. I refilled w/ oil and started the car. I had to tighten up the cannister bolt some more to stop a leak, but all seemed well. The oil pressure gauge max'd out (more on that in a second), so I shut it down.

Next was to check the oil pressure relief valve, boy was that a pain to reinstall! The valve assembly looks correct according to the Moss catalog, 2 washers out on the cap nut, spring (3") and the valve. No split lock washers to increase spring pressure.

I was looking at my oil pressure gauge and noticed that it stays at ~80 psi and never drops down. I'm beginning to think that the gauge has a problem (air in the line maybe).

What do you think?

Steve
SJ Jackson

Air in the line will slow the reaction time for the gage, but it will still read correctly. It sounds like you have a broken gage. I wonder if the return/dump passage from the relief valve to the sump is blocked. Maybe a brass plug in the wrong hole? Gasket blocking the hole? That would give you extremely high oil pressure and probably damage the gage too.
Ed Bell

If this is a freshly rebuilt engine, having had machine work done on the block, I would suspect that the shop put a brass plug in the bottom of the block where it should have an open hole for bypass oil to return to the sump after it goes past the pressure relief poppet.

If this oil return hole is plugged it will defeat the pressure relief valve and cause horribly high oil pressure. It might (maybe) idle with 80-psi pressure with cold oil, and the idle pressure might drop a little lower (40-60 psi) with hot oil. But if you rev the engine speed at all it will peg the pressure gauge, and pressure could go high enough to blow out rubber seals or even burst a spin-on filter canister. It might blow the seal(s) out of the original style heavy gauge bolt-on canister as well if you rev the engine.

See here: http://mgaguru.com/mgtech/engine/of101a.htm
It is hole "E" in the bottom of the block that must NOT be plugged. You have to remove the oil pan for inspection.
Barney Gaylord

Ed and Barney,
Thanks for your input. Looks like I'll be dropping the oil pan.

Steve
SJ Jackson

I was finally able to get back to the car and drop the oil pan to check for blocked passages. Here's what I found, see attached picture. Having this one passage blocked be enough to send my oil pressure sky-high? Next, what is the best way to remove the plug? Drill it out?

Thanks.

SJ Jackson

Barney was onto the fault on 15th June! Did a machine shop put that extra plug in? What are you going to say to them?!
Lindsay Sampford

Yup, that's exactly the problem. Yes you can drill it out. Since the hole is supposed to be wide open it doesn't matter if you bugger it up a bit in the process, just get the plug out so it will have a return port from the pressure relief valve. This happens all to often from "pro" shops.

Definition of a "professional" is someone who gets paid for what he does. This does not necessarily mean he is any good at it. Some amateurs are more talented than some professionals.
Barney Gaylord

Lindsay, I'm going to let them know about this along with the 2 freeze plugs that weren't properly seated.

Barney, they said they had done MGA engines before, but I didn't verify it w/ my local MG shop. Lesson learned there.

I'm going to drill out the plug this week and update everyone afterward.

Thanks for everyone's input.

Steve.
SJ Jackson

Steve, an alternative to drilling out the plug is to drill/tap (1/4 - 28), then pull out with a suitable bolt/washer and a socket. Works well, just another option. Good luck, George
G Goeppner

Success! I drilled out the plug, put the oil pan back on, filled it with oil and started it up! Oil pressure is about 65 psi at startup and started to slowly drop as the engine warmed up. Thanks again to all who offered input.
SJ Jackson

This thread was discussed between 15/06/2009 and 12/08/2009

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.