Oil leak

[Mickfrad]

Took the car out for a run to a car show in Oakham. Not to far away for its first trip this year. 

 

When I got home I drove it in the garage shut the door and walked away. 
This afternoon popped back outside and I have oil on the alternator and down the chassis on the passenger side. 
The only place It looks like it’s coming from is the distributor housing. Everywhere else that side looks dry even around the clamp which is where I would expect it to blow out from if the seal had gone. Any ideas ? 

[Rick-Manta]

Engine bay leaks are almost always somewhere from the rocker cover gasket, but perhaps making its way along the top of your water pump and collecting around the distributor? The timing cover and even head gasket (hopefully not) could also be weeping oil to form there. Without some well lit close up pics, it'd be hard to tell.

[H-400]

As you wrote: The thin paper seal between the dizzy and timing house. Would clean everything with brake cleaner, fit a new gasket and check the spot while running. By the way nice looking Manta👍

[®evo03]

Any pics of the leak, as mentioned above. 

And very nice manta 👍

[cam.in.head]

as mentioned above, there is (supposed to be !) a thin paper gasket under the distributor flange but this often gets either forgotten or damaged whilst setting the timing. it shouldnt realy leak that badly in that area thou as its not realy under pressure .

as also mentioned its usually the rocker gasket and then it runs down but also worth making sure the rocker cover breather is not all bunged up ! this can lead to a pressure build up and it has to escape somewhere !

[Mickfrad]

Will check breather pipe and make a new gasket for the dizzy. Cam covers got a new gasket, head and timing chain cover all look ok. 
 

Oil all over the top of the alternator 

 

 

To me it looks like it’s coming from the side of the dizzy as in the last picture. But don’t think oil gets in there and if it did it would show when I took the cap off. 

[cam.in.head]

i think you need to clean it all off and see for sure where its coming from. 

the distributor does have an oil lubrication point and also has a drain hole underneath where it can drain from if you manually oil it from the top. 

as i mentioned before also if the engine breather is blocked you can get pressure build up that has to find its way out somewhere. this is not the breather pipe but the actual gauze inside the rocker cover.( although technically i suppose the pipe could block up !) the gauze is worth removing and cleaning especially if its never been done.at least for your own peace of mind.

[ANDY ABBOTT]

Try cleaning it off, jack the back end up and run it up to speed whist someone looks for where the oil is coming from. 

[Jessopia74]

If the screw groove (like Archimedes screw) on the shaft is carboned up, could that allow the oil to work up the shaft into the disi ?

[®evo03]

It's a weird place to have an oil leak, is there a seal missing on bottom of distributor shaft? 

Is the vacuum ok? 

Edited May 24, 2023 by ®evo03

[cam.in.head]

yes thats another leak point.  if the throttle is oiled up AND the distributor vac diagragm is split oil can work its way down the tube and into the distributor.its a long shot but worth checking,

[Mickfrad]

Hopefully get some time tomorrow and investigate a bit. 

[Mickfrad]

Pulled the dizzy today and checked with it out of the way for any leaks, everything’s dry. Definitely oily round bottom of dizzy and oil in vac chamber when tipped. Vac pipe was clear and breather pipe all ok gauze in cover taken out and cleaned when I had it powder coated. Paper seal was still in place at bottom of dizzy. Could vacuum be sucking oil up into the dizzy if diaphragm is split. Cars not smoking. I have another dizzy to clean up and try. Will let you know how I get on. 

lots of oil dripping from here when pulled out. 
 

oil round bottom of dizzy and from drain hole. 
oil dripping from vac 

[®evo03]

Is diaphragm split? This is a weird situ. distributor looks to be getting loads of oil too 🤔

[hoobby]

For oil to get past the diaphragm it must have a hole in it or split then it will suck oil up with the vacuum for the advance.

Edited May 28, 2023 by hoobby

[Mickfrad]

Just tried with a vacuum pump appears to be working correctly and holding vacuum. 

[cam.in.head]

as far as i remember the distributor gets a small oil feed to the bottom bearing from the timing cover ?

but this will then oil the bearing and then run away down the shaft as it should. the only way i can think of oil getting up into the distributor (especially with the  vacuum unit being tested ok) is if there is a buildup of crankcase pressure. or the distributor flange is all gunged up .?

on a carb model the breather is quite large and has a second smaller manifold suction one aswell

but on an injection it only has one and the pipe and gauze needs to be 100% clean especially on a higher mileage engine which will have greater crankcase pressure anyway. 

clean and fit the other distributor and take it from there .

 

oh yes and oil in the vac unit and pipe is not uncommon and happens due to oil in the throttle body finding its way down the tube due to vacuum,heat and capiliarry action. bit of a faf to empty out but worth it as a vac can full of oil wont be doing its job as intended.

[H-400]

To be sure about the crankcase pressure I fitted a camcover of a carb CIH and connected the big rubber tube to a sort of catch-tank basic made of an empty brake oil can that fits nice into the bracket of the stabilisation bar:

No NASA tech... Don't do this with a new modern car, there's always a pressure sensor that goes nuts 🤪

[cam.in.head]

the only problem about using an open catch tank is the smell that following cars will get and give old cars a bad reputation !

using a closed catch tank fed back into the system will stop oil but not pressure build up !

bit of a catch 22 situation 

[Mickfrad]

Another dizzy fitted today with a new gasket and car fired up and run upto temp. I checked the breather pipe which appears to be venting ok. I then zip tied a rubber glove round the oil filler hole to see if it was over pressurising. It inflates slightly on revving then deflates nothing unusual but not under load.
 I then did a compression test 

Dry  1. 160  2. 163  3. 166. 4. 162

Wet  1. 175. 2. 177  3. 170  4. 172

Engines probably due a rebuild but will have to wait. Now needs a good run out and see if it still leaks. 
spotted some drips of oil on the floor and a leak around the oil pump which may be coming from the crankshaft oil seal which could be blown back towards dizzy by the fan.
Looks like that’s my next job. 

[cam.in.head]

compression test is relative and depends on accuracy of our guages anyway. 

i check mine regularly so i can notice any differences as they occur . rather than comparing with other people.

the front oil seal is at least an easy job to do and a std size seal.