PES crank case ventilation and oil catch can mod

[exarkun1178]

over the last few month i was losing a lot of oil. i had no leak under the car, and no white smoke out the back. however every 250 miles or so i would consume 1 quart of oil.

this volume of consumed oil was a big problem for me! after a bunch of inquires and a ton of questions to various people, i was again at the door steps of PES. i told them what i was experiencing, they then told me they'd run a few tests.

leak down as follows,
cyl 1 20%
cyl 2 15%
cyl 3 20%
cyl 4 15%

all well with in lotus spec

compression test,
cyl 1 242
cyl 2 254
cyl 3 257
cyl 4 240

lotus spec is 203psi, so very good!

it seems that blow by was the cause of the oil loss. ill do my best to explain what i was told about blow by and why on my S/Cer car i am more pron to it.

as the cylinder compresses a small amount of oil and gases make it past the rings and end up in the crank case(houses the crank on the bottom of the engine) there is a hose that then collects the gases and vaporized oil and feeds it in to the valve cover. at the other end of the valve cover are 2 more hoses that then take the crank gases and vapor oil, plus any other present gases and oil in the valve cover and routs then to post MAS intake manifold. once here its re introduced to the combustion chamber to be burned.

on my s/cer car the blower creates a huge vacuum sucking in air at the manifold and forcing it in to the combustion chamber. this 8 pounds of pressure causes more oil and gases to make it past the rings and into the crank case.

pause...

while this is happening, on the front of the motor, at the same time, the engine is sucking in air from those 2 vent hoses off the valve cover because of the vacuum created by the blower. in effect the system is sucking oil from the crank case and feeding it in to the combustion chamber.

test was done and in fact while driving aggressive there was pressure in the crank case.

in addition because this air was post MAS the ecu was "not aware" of this false air, and may not run perfect.

pause...

typical catch cans will do a good job of catching the larger oil and return gases to the combustion chamber to be burned. however one flaw is those gases are returned post MAS and is only a band aid as the loop still exists. another option on catch cans are to include a vent to the atmosphere. the negative to this is crank case stink. after a while the cars cabin will have this stink present all the time(think 60s cars) and is not emissions legal.

PES solution:

pes has re routed the ventilation system and included a filtered catch can. the gases and vaporized oil enters the valve cover as it always has. then travels the length of the cover and hits the 2 tubes. these tubes carry the air to the catch can. the gases and oil enter and swirl around. there is a filter in the center. this filter catches moisture and oil and drops it down to the bottom. the gases then pass the filter and enter the second chamber of the can and are then routed to the intake.... however instead of post MAS, they are routed before the MAS.

while the car is running there is a small vacuum that draws the vented gases in to the air stream, past the MAS and in to the blower to be burned. no longer will the oil and gases be sucked out of the crank case! as there is not a huge vacuum or sucking effect. plus all the air entering the engine is now passing the MAS. and i stay emissions compliant with no lingering funny smells.

[exarkun1178]

one more pic

[ZJChaser]

very similar to Racor Crankcase Ventiltation Filter Systems

[choi0706]

neat gates heaterbox hose.. I wished they had larger versions of that flexiable hose for main coolant use..

[insane]

So, you selling? How much?

[exarkun1178]

Originally Posted by insane

So, you selling? How much?

when i asked tony at pes about that, he said no, not at this time, probably not, no...

[exarkun1178]

i put 300 mies on the car in 2 days, about 1/2 an ounce in the bottom, and its a very light thin liquid, not heavy oil at all... and have not lost any noticeable oil yet...

[dstevens]

Originally Posted by exarkun1178

leak down as follows,
cyl 1 20%
cyl 2 15%
cyl 3 20%
cyl 4 15%
all well with in lotus spec

15-20% leakdown is a dead engine, despite what the marking on the gauge say. Less than 2% is normal. 0.5% on a new, freshly broken in engine with correct ring gaps. Hence the oil comsumption...

[exarkun1178]

according to the gauge they used, the lowest measurable number is 10%, and 10-40% was labled good, 40-50 fair, 50-+ poor. maybe it means 1.5, 2.0% i dont know, just based on what this gauge was labeled...

[Bane]

Originally Posted by exarkun1178

according to the gauge they used, the lowest measurable number is 10%, and 10-40% was labled good, 40-50 fair, 50-+ poor. maybe it means 1.5, 2.0% i dont know, just based on what this gauge was labeled...

It actually had the percentage sign on it? Or was it just labeled 10-40, 40-50, 50+?

I would assume that means 1-4%, 4-5%, and 5%+

For people that are interested in catch cans... check out the thread here (he did say that PES wasn't planning on selling their setup..):

Oil Catch Cans - to your Elise in 30 minutes or less

15-20% blowby =

[jim-clayton]

I checked my leak down last week. I had 2.5 to 3 percent using the single gauge Moroso tester. 13,000 miles on my car

Moroso 89600 - Moroso Single Gauge Leakdown Testers - summitracing.com


15 to 20 percent using the Moroso gauge would have indicated a very worn engine. Checking the compression and leak down is very easy to do. I would buy a nice gauge and check it for yourself.

It's unlikely that you have 15 - 20 percent leak down on every cylinder. The engine is too new.

[exarkun1178]

^^^ ill be getting my own kit this week end.

[exarkun1178]

well i had the car running over 500 miles since the catch can went in. a very small amount, maybe a half ounce(though less i think) was at the bottom, and it looked quite thin and light tan in color. any way, bad new, il still losing oil...