MK1 GLD crank case breather modification

[barber]

Hi guys,

I have an old 1979 diesel MK1 1.5L. The rings are fairly worn and I have been doing a lot of reading into the crankcase pressure modification. I have split the crank case breather and joined it to the cam case breather which connects to the air box. Before I did this I just vented them both into a bottle with some coarse steel wool for a day and drove about 90km. Yes it was a bit smokey when sitting still at lights but it was in the name of science!

During this period I collected a little bit of oil, more than I thought approximately 50ml- 100ml!

My problem is that if I join my split crankcase breather hose onto my cam breather hose that it will be too much blow-by pressure for the air filter to handle?! My air filter already got oily and a small amount of oil build up occurred in the base of the air box however I am afraid this will fill the thing! I am aware that a small amount is needed to build up and drip down the inlet manifold to lubricate valve seats/stems however how much is too much?

I also have the problem that I kept blowing vacuum pump seals when the crank case breather was not modified. I think this was due to excess oil build up in the pump and either forcing it to blow or the oil not liking the rubber?

I have a feeling if the crank case breather opening was larger and I incorporated a oil catch can I could get away with not having to rebuild the engine. Quite frankly its my girlfriends car and I am not sure I can justify around $2000 in parts to rebuild the engine. Which is a shame because she is the second owner and its in amazing stock condition interior and exterior!

Maybe I can palm it off to one of you guys..........


Any help from the diesel guru on here would be great

Cheers,

Bill

[barber]

No ideas ladies and gentlemen?

[sports racer]

Send a PM to gldgti. He's the diesel guru.

He even converted his MK1 cabby to diesel power.

Have you tried running a crank case breather to a tin can with a small hole in the top of the can so there’s no pressure in the can. Put the can up high so the oil drains back into the crankcase when the pressure isn't so high. Use a 10mm rubber pipe (inside dia) so there's lots of room for the oil to go up/down the pipe.

I'm know very little about diesels but why do you need oil to lubricate the valve guides when diesel fuel contains a small amount of oil? Petrol engines don’t need the valve guides lubricated from a crank case breather.

Cheers

Paul

[barber]

Hi Paul,

Thanks for the reply, I will contact gldgti. I believe the small amount of oil that drains down is for the valve seats, which I guess makes sense in theory however you are correct the fuel is very oily. Probably something zee Germans thought necessary at the time, one guess would be that the diesel fuel back in the day could have been less refined than now leading to more grime and grit in it??!

Thanks again,

[sports racer]

I once had a V8 built by a guy who built racing engines. He left off the valve stem seals so that the oil would lubricate the valve guides. Great in theory on a proper race engine, lousy for a street engine because the oil formed a crust that eventually coated the bottom half of the valve stem all the way to the valve head. Looked like a pyramid on each valve.

I'd look at venting your crankcase to a container that lets ALL the oil return to the crank, none to the air filter.

Trouble is, like I said I know nothing about diesel engines other than I'd love a 1.9TDI in my MK1. The guys in England are getting 300hp and 5 litres per 100 ks.

[jex]

I have a mk1 diesel engine in pretty good condition here in Brisbane still in a car if interested. It has done about 50,000km since it was totally rebuilt. The injector pump had a $2,000 rebuild done on it about 10 years ago so is in good condition as well. PM me if interested.

[roccodingo]

Second paragraph. re ring the engine and get another 300, 000 Km's...


https://en.wikipedia.org/wiki/Diesel_engine_runaway

[jex]

There was a simple mod that came out to fix the problem on these engines. It was a plate that bolted along the top of the tappet rail under the rocker cover and below where the breather pipe exits, seemed to work ok by slowing down the oil vapour being sucked into the breather pipe. I used a catch can on mine for years which also worked. I had a couple of engine runaway's over the years until I did the mod, it's a bit scary when you don't expect it.