• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Moss PCV vs. generic PCV

Share this page

Hooper11772

Hooper11772

Senior Member
Offline
Hi All,
I have a question regarding the PCV from Moss. I've read allot of posts discussing negative crankcase pressure in a 1275 to prevent it from leaking oil out the rear scroll seal. Since the last install i've noticed that I have a pretty steady stream of oil coming out of this exact location. So this year I figured I would try connecting the canister on the timing cover to the intake on my manifold for the SU carbs. I separated this by placing a GM PCV in the line from autozone.

Well, this solved my leak issue and I no longer leave puddles of oil under my car at idle however now i'm blowing smoke out of my tailpipe that if I place my hand in front of has oil spatter mixed in. It seams obvious that now i'm sucking oil from the crankcase into my intake manifold creating this problem. But if I disconnect i'm back to the leak issue.

Is there a difference between the Moss PCV for our vehicles and a basic PCV off the shelf that would prevent this? I also have my valve cover vented to the atmosphere as well if that matters. Any help with this would be great. I'm sure my neighbors would also appreciate the break from whit oil filled smoke.
 
I've played around with a few inline valves and wound up going back to the pancake valve you see at Moss. I could not stop oil vapor from being sucked into the intake, even with an oil catch can. Unless you're contracted to exterminate mosquitoes and don't want to coke up the engine I suggest going back with the original type valve.
 
So the pancake one will stop the vapor? I actually have never tried the pancake PCV from Moss since my car never came with one. If it works its woth it but I didn't want to purchase one and wind up still having the same proble. I hear you on the mosquito fogger. This thing is rediculous!
 
Try restricting the hose from the timing cover to the PCV with a nut jammed down the hose or find a valve cover with a tube on it and suck from the top of the engine, no oil up there to get sucked in.
Works for me.
 
tomshobby said:
I solved this problem on my TR6 by installing an oil separator. Don't see any reason one would not work on a Midget if there is room.
This is what I used.
https://www.goodparts.com/shop/index.php?categoryID=8
Click to expand...

I had started an extensive thread out here on the forum regarding crankcase ventilation. Since then, I have begun to rebuild the engine. I now have an aluminum valve cover. Should I drill into this and install a brass barb fitting to give it some more ventilation? I have the oil catch can set-up ready to be installed, but not sure if I need all of this to get proper venting. I have the PCV valve set-up also, but not the Moss one. I have a Weber DGV and Pierce manifold. Should I drill the fitting into the manifold (not that I like to drill holes all over the place), or use the one on the air cleaner? I've seen so many set-ups for this, but not sure which is the best. I just want to avoid damaging the new engine.
 
Yeah, I was kicking around the idea of the oil catch can but wasn't sure if that would really work catching all the oil from entering the intake.. I've seen them home made out of a water seperator for an air compressor as well. That was the route I as planning on going if I tried this. The kit above looks nice but seems pricey.

I guess i'll try venting from the valve cover to the intake manifild and blocking the timing cover vent first. Thats one setup out of the 20 I haven't tried yet. I hate exchanging one problem for another. I get the leak to stop but now i'm quickly sorrounded by a cloud of white smoke.
 
Oh what PCV off the shelf at a local auto parts store is a good one to get? I'm not sure on the one I have since it was used and kicking around the garage.
 
My separator drains back to a fitting on the oil pan. Have about 15,000 miles logged since it was installed and it has been working great. About half those miles were with an aux oil line to the rocker shaft. I had no problem of any kind with the aux line but removed it a few thousand miles ago because I just wasn't convinced I really needed it.
 
Back
Top