oil seepage is from Kent crossflow head gasket

[twobone]

So other than a dirty engine and a bit of smoke, should I really care about a seeping head gasket?

 

I also assume this is best left to a professional given the need for tight tolerances and torue requirements?

 

Thanks

[Ian7]

Yes, you need to assume the worst. If oil is getting to the outside edge of the gasket, you need to verify that water isn't getting in to the oil passages across a crack in the gasket you can't see.

Check oil on dipstick for "milkshake" appearance regularly.

[twobone]

Oil is clean. Guess I better get it done at the beginning of next season. Only 90 days here till snow

[TheDingo8MyBaby]

It's seeping to the outside of the engine? You sure this isn't just the valve cover gasket?

 

Is it smoking out of the exhaust or where the oil is seeping out of the engine?

[twobone]

Its a real mystery to me. The exhaust side of the engine is perfectly dry.

The intake side is mist wet from the head gasket down on the intake side, mostly at the front around the distributor.

 

My car is dry sumped and runs very high oil pressure. 70-100 PSI. I checked the breather hose that runs off the block above the fuel pump and it is lightly blowing crankcase fumes.

 

 

The car only leaves a tiny bit of oil on the driveway, but does smoke under the hood when hot.

 

There is a little burst of smoke on start up, but

[twobone]

But...there is no smoke from the exhaust and the car runs fine.

[Kitcat]

Are you sure its oil and not coolant? I had a similar prob and it was coolant/antifreeze mix (leaky hose). It finally shorted out the distributor.

[twobone]

thanks will check it out. The hood underside is very sooty so I think its oil burning off.

[bsimon]

My car is dry sumped and runs very high oil pressure. 70-100 PSI.

 

70 PSI should be about the highest oil pressure you will ever see in a cold xflow. Typically 60 (4 bar) is full pressure with warm oil. If you're getting anything over 70, I'd suspect the relief valve is stuck shut or maladjusted.

[twobone]

Learned a few things tonight.

 

My oil filler cap is vented which contributes a lot to the underhood soot and smoke.

 

I'm also starting to think the pressure sender reads wrong.

 

The sender sits on top of the aftermarket oil filter housing.

 

I suspect the pressure is pretty high there.

 

I checked the flow into the dry sump oil tank. If I really has 80psi in the system, I would expect it to gush, not pour.

[twobone]

In terms of the wetness on the carb side, I'm starting to think that the oil condensation from the filler cap is more apt top collect on the cooler side of the engine where is more stuff to condense on.

[Kitcat]

My X-flow pumps a fair amt of oil out thru the filler cap but it pretty much lands on the hot side and burns off. When I am at a stop light after the car is warmed up, I always have a faint haze of smoke of burning off oil. Since I only use a quart of oil every 1-2K miles or so, it hasn't been a concern.

 

Mike

[bsimon]

My oil filler cap is vented which contributes a lot to the underhood soot and smoke.

 

Filler cap should not be vented! You want he scavenge section of the oil pump to extract any blowby (smoke) and process it through the separator features of the oil tank.

 

I'm also starting to think the pressure sender reads wrong.

 

It wouldn't be the first oil sender that failed on a Caterham. I suspect that more senders go bad than remain accurate. 100PSI seems a bit strained for a Pace or Titan oil pump.

 

I gave up on Caterham senders (VDO in my car) and installed a mechanical gauge for peace of mind.

 

I checked the flow into the dry sump oil tank. If I really has 80psi in the system, I would expect it to gush, not pour.

 

The flow into the oil tank is relatively low pressure. The scavenge section of the pump is designed to move large volumes of oil and air out of the crankcase and into the tank for separation. They don't use much pressure as it would tend to entrain more scavenged air into the oil.

 

Only the pressure section of the pump is designed for the higher oil pressures needed to lubricate the bearings and such. The pressure tap at the filter is the true oil pressure.

[twobone]

I recently read that it would be better to vent the rocker as well as the pressure in the rocker system can inhibit the flow of oil up into the head. Now that may be overkill unless you are running a high rev racing engine.

[bsimon]

I recently read that it would be better to vent the rocker as well as the pressure in the rocker system can inhibit the flow of oil up into the head.

 

But you are already venting the rocker cover. The hose from the rocker cover goes to the top of the tank, which is in turn vented to atmospheric pressure through the catch can. If there is pressure in the head, it will flow out to the tank. If there is a vacuum in the head, it would be relieved via the same path.

 

Some builders actually close off the vent line with a check valve to create a large vacuum in the engine. It's supposed to make the piston rings seal tighter and create less "wind resistance" for the crank. I'm not a big fan. I think there may be more wear issues with sealing components, including the rings themselves.

 

Bottom line, all engine breathing in a dry sump system should be done through the tank.

[twobone]

Sorry, just to clarify, if I seal my filler cap, I will only have the crankcase vent into the dry sump tank. Is that kosher?

[bsimon]

That is correct.

The only communication a dry sump system should have with the outside world, is though the the oil tank.

[twobone]

KitCat, thanks, I think it was a coolant hose. I refastened the hose and now i think the engine is drying up.

 

Also, I sealed up the oil filler cap and no more underhood smoke. The smoke goes into the dry sump tank and then back out a breather hose that leads under the chassis

[Kitcat]

twobone:

 

How did you "seal" the oil filler cap? Do you have the type (as I do) that does not screw in but just squeezes in?

[twobone]

Yes, it is press in

 

I just used silicone gasket seal shot into the venting holes of the cap

 

Cheaper than a sealed rocker cover