Smoke from oil cap?
 

Been having a great season w my ‘35 w an 8BA until now. I was almost home after an hour ride & thought I’d wind it up a bit up the hill to my house. Immediately following noticed a bit of smoke from engine compartment. Pulled in the drive & further inspection showed some smoke coming from oil cap? None from exhaust. Starts fine runs fine. I do have a PCV connected from rear crankcase vent tube to manifold vacuum. Any thoughts?

Re: Smoke from oil cap?
 

shouldn't the pcv valve be installed where the draft tube used to be?

Re: Smoke from oil cap?
 

Is the PCP valve ball free, i.e. can you hear it rattle if shaken? Maybe it is full of oil or crud.


Glenn

Re: Smoke from oil cap?
 

Probably calling it out wrong. If the draft tube is here I’m calling it a crankcase vent.IMG_2430.PNGhttp://IMG_2430.PNG

Re: Smoke from oil cap?
 

Photos please.

Re: Smoke from oil cap?
 

Possible that you have too much oil in it ? Running up hill could have had the crank whip up some oil , more that could have been handled by the rings , and it was vented by the cap ? Just guessing of course .

Re: Smoke from oil cap?
 

Make sure the vent at the right front corner of the oil pan is unobstructed The PCV can't operate correctly if there is no makeup air source.

Re: Smoke from oil cap?
 

There is not any vent on the right front corner of an 8BA oil pan.
It vents at the filler tube.

Re: Smoke from oil cap?
 

What he said.

Re: Smoke from oil cap?
 

compression check?

Re: Smoke from oil cap?
 

Hey guys, sorry to be so long but was away. So I did a compression test & 7 cylinders r 112 -115 psi but #2 runs from 39 to 80psi & different each time checked. Valve issue?

Re: Smoke from oil cap?
 

I think you've had compression issues or a piece of carbon broke off and is in the valve seat and that's not what's causing the blow by , bear with me . As you accelerated up the hill , VACUUM dropped to almost atmosphere, hence no or little vacuum to the PCv , temporarily allowing the fumes to fill and escape the easiest route . It may have filled all passages with oil vapors and oil so it may take a while to clear up .
It's just a guess but the PCv is nothing but a controlled vacuum leak .

Re: Smoke from oil cap?
 

I understand what ur saying but the reason I thought maybe valve not closing right letting the exhaust valve pull smoke from crankcase? Today I noticed while warming up before compression check the smoke from the oil input tube comes out put-put-put fashion suggesting exhaust valve effect? For now I removed the pcv valve as it failed from crud. If the smoke issue settles down will put fresh one in. Thinking of using a Mopar type oil cap w vent tube on side of cap to pcv to vent crankase after the smoke issuWhat would u think of Seafoam engine cleaner or what I did as a teen agent auto tranny fruit to clean any carbon out?

Re: Smoke from oil cap?
 

Stick a vacuum gauge on it . See if you have a steady reading if steady it's not a valve if low it's something else .

Re: Smoke from oil cap?
 

Well...if the smoke from the breather comes out in a puff-puff-puff fashion and compression is low on one cyl the news may be bad. A valve cannot do that-and also can't pull smoke from crankcase. It's time to put air pressure in the low cyl (with both valves closed on that cyl) and watch for air escaping from the crankcase vent. Possibly a piston/ring issue.:(


Terry

Re: Smoke from oil cap?
 

100% agree with cadillac512 (Terry).
Also, a PCV system should be a closed system to be ideal. It sounds like your setup is open if you have a stock oil fill cap and you see smoke.


Sal

Re: Smoke from oil cap?
 

As I indicated I ran 16 Oz of ATF THRU CARB. Shutdown let marinate 4 45 min. Restarted ran till white smoke stopped. Took a 1/2 hour ride & all but a normal bit of crankcase. smoke. Ran fine. Will check comp. on #2 tomorrow.

Re: Smoke from oil cap?
 

A PCV system will have a place for air to enter - such that the PCV can pull the fresh air through the engine. On a typical OHV setup there is a breather on one valve cover (air to enter) and the PCV pulls it across the engine to the other valve cover.

On a flathead ford - the system is obviously retro-fitted and I don't know where he has the 'incoming air side' of it nor the PCV valve. There should only be one intake side and the best situation is for it to be at the rear of the engine and make sure there is a baffle tube to direct it down into the crankcase. I'd weld up the front block vent tube (cap it) and put he PCV valve into the side of the tube (so it's hidden in the valley). Then I'd plumb my vacuum source under the manifold.

Re: Smoke from oil cap?
 

Terry, while #2 cyl. Had the lowest reading @ 39psi the real issue was it was different each time I took it. Lowest was 39 but it was as hi as 97psi. Pretty sure as Ggmac indicated I had piece of carbon messing w a valve or a carboned up valve. I think the ATF thru engine did the trick.

Re: Smoke from oil cap?
 

W regard to PCV, when hooked up originally I had routed the rear draft tube into pcv then 2 a vac port on the intake w stock breather cap on oil input tube 2 draw fresh air. When I rehook it up this time I’ll use s Mopar sealed oil cap w vent tube on it 4 pcv coming off the oil cap then going to same vac port on intake & will leave the original rubber draft tube coming out of the rear of engine next to gas pump / filter for fresh air.