Blow-by Causing Oil Leaks

[duefocena]

After chasing oil leaks in my (Perkins parama 30hp 3cyl) diesel and paying the " licensed mechanic" $400 to replace an o ring it was this forum that suggested it was blow by. Opening a relief bolt in the valve cover, pressurized exhaust shot out.
Anyone have a lead on rings for this engine? I'm told they might be $200 per cylinder.
The engine runs great and doesn't use oil. Could it be anything else?
Mechanic suggested we open that breather from the valve cover and run a hose to the air intake.
Happy Thanksgiving to all

[Vyndance]

Not familiar with a Perkins 30 but it should have some sort of crankcase ventilation already. If not there is your problem.

[duefocena]

Thanks Vyndance,
That's what I would have thought. So far I have found no breather. The breathers I've been familiar with were always in the valve cover. Anyone know of where else?

Thanks,

Paul

[cal40john]

Originally Posted by duefocena

Thanks Vyndance,
That's what I would have thought. So far I have found no breather. The breathers I've been familiar with were always in the valve cover. Anyone know of where else?

Thanks,

Paul

Atomic 4s and old chevy V-8s have a breather cap on the oil fill pipe (which isn't on the valve cover.) It's on the transmission on the Atomic 4, this works since the transmission shares oil with the engine.

John

[Jesse]

I've worked on engines with crankcase breathers but they were flatheads. Every Perkins I've seen was vented from the rocker cover,including my buddies three cylinder tractor. If the intake manifold is plumbed to accept a vent hose or pipe it is likely that some missguided soul has modified your engine. A little blow by is normal and is usualy vented to the air intake manifold to relieve the pressure problems you are experiencing. Another symptom of a plugged vent is oil being forced out the dipstick tube. This should be corrected imediately and your mechanic has the right idea.
Best of luck and happy sailing

[duefocena]

Jesse,
You are right on the mark as the dipstick tube used to leak at it's base. I pulled the tube and put an o ring at the bottom which resulted in a leak coming from the shaft of the cut off. What might clog a breather?

[DeepFrz]

Take a look at "Walker Air-Sep". Not cheap but effective.

Walker Engineering - Marine Products

[GordMay]

Perkins 100 Series Perama M25/M30 Workshop Manual ➥ Perkins 100 Series: 103-06/103-09/103-10 Perama: M25/M30

Or ➥ http://www.google.ca/url?sa=t&rct=j&...y-PtZA&cad=rja
http://www.annatefka.com/perkins/ser...1_complete.pdf

Perkins Service Data ➥ http://www.annatefka.com/perkins/ser...1_complete.pdf

[jzk]

Originally Posted by duefocena

After chasing oil leaks in my (Perkins parama 30hp 3cyl) diesel and paying the " licensed mechanic" $400 to replace an o ring it was this forum that suggested it was blow by. Opening a relief bolt in the valve cover, pressurized exhaust shot out.
Anyone have a lead on rings for this engine? I'm told they might be $200 per cylinder.
The engine runs great and doesn't use oil. Could it be anything else?
Mechanic suggested we open that breather from the valve cover and run a hose to the air intake.
Happy Thanksgiving to all

Do you have a ton of black smoke?

[T1 Terry]

The breather usually comes out of the high part of the tappet cover and looks like a walking stick hanging down the side of the engine. Someone must have decided that it was blowing smoke or oil out of there so they blocked it off.
My recommendation would be to remove the tappet cover and check the oil seperator gauze is still in there, if not you will need to get another one or even a complete replacement tappet cover. Next you need an oil catch can that will hold about 1 ltr, can buy them on E bay. you can ether run a hose from the top of the can to the intake manifold or to a pipe welded into the exhaust that runs down inside inside the exhaust pipe for a bit in the same direction as the exhaust flows. This is the better method because it creates slight vacuum in the crankcase helping to minimise oil leaks.

A few questions,

Opening a relief bolt in the valve cover, pressurized exhaust shot out.

When you say exhaust shot out, was it just oily fumes or actual exhaust smoke?

T1 Terry

[duefocena]

Terry,
Thanks for your input! There are no breather tubes coming from the valve/ tapper cover. The bolt removed is in the cover and literally blew at high volume, built up pressure in the form of fumes. I don't have much smoke from the engines exhaust. Is there a gauze inside the cover?

[duefocena]

Jzk,

Thanks for your interest. No, there isn't much smoke from that engine. Considering that all diesels smoke.

[T1 Terry]

Originally Posted by duefocena

Terry,
Thanks for your input! There are no breather tubes coming from the valve/ tapper cover. The bolt removed is in the cover and literally blew at high volume, built up pressure in the form of fumes. I don't have much smoke from the engines exhaust. Is there a gauze inside the cover?

my first thoughs were a blocked exhaust and worn exhaust valve guides and the exhaust was forcing it's way into the crankcase but that now sounds unlikely.
While the engine was running did it continue to blow at high volume or once the intial pressure was released did the air stream only seem slight?
If it was constant high volume either an exhauster (vacuum pump) is pumping into the crankcase or there is serious engine damage like a hole down the side of a piston. If the pressure rapidly dropped away then a gentle air pumping in and out was sensed (a thumb over the hole) then it appears a breather needs to be installed or at least found where it was before it had been blocked off.
I've seen this sort trick done with truck engines just before the truck is sold, the poor unsuspecting buyer soon discovers the engine is stuffed.

T1 Terry

[Jesse]

A kinked hose or one made of the wrong material for this aplication would shut off a crankcase venting system as the inside of the hose swells while reacting with the oil fumes. There is a waxy substance produced by the combining of oil and water vapor that can form in crank vents but I don't think it would build the kind of pressure that you are experiencing. I suspect someone has blocked the vent intentionaly, we can only guess at the reason why.
Look for a hose or tube leading from the intake manifold, usualy located directly after the fresh air intake. Following it should lead you to the vent which is usualy on the rocker cover. If you can find one check it for blockage.
I have seen people change the oil filler plug from a vented cap to an unvented thermos type which would cause the type of problem you are experiencing. It has to be vented or it will blow every seal or gasket in the oil system as fast as you replace them.
Don't give up, it has to be there

[duefocena]

Hi Jesse,

There is a plug in the valve cover. The one we unscrewed when all the pressured gasses escaped. It shows in the manual so it wasn't put there nefariously. For the life of me I can't find another vent. No other tubes from the intake manifold , nothing from the crankcase.
Do you think putting a hose from the vent plug to the air intake will ?!@/
Things up? How about a hose from the rocker cover plug to the exhaust?

Thanks for any help. A rebuild is beyond my pay grade. The rings for one cylinder are $375.