pcv sucking oil ?

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65-440

65-440

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i noticed my car puffing dark smoke during hard throttle, and b/t shifts (4/spd) ... pulled plugs and found fuel fouled. compression even on all 8. replaced all plugs, rebuilt holley 770, adjusted timing and carb. drove car today and still getting a nice puff out of both tips. hard to pinpoint with bank due to h-pipe. I pulled the pcv and found the inside nice and oily ! any of you guys sucking oil through the pcv valve and blowing it out the exhaust ? only happens on hard throttle. factory valve covers have baffle .... thanks !
 
only when the baffle gets filled up with sludge i have seen the valve cover the problem.you said dark smoke... oil burning would be blue and a very light blue often mistaken people think it white. dark to me would mean rich fuel. if its your pcv valve just pull the hose of and plug it and see if it eventually goes away if it does then your barking up the right tree my guess.
 
valve covers are clean inside. its hard to say how "dark" it is looking through the rear view mirror, but its definately more than i would like to see ! And there is zero smoke on cold start-up, its only under that initial hard hit of the throttle. does not smoke when cruising.
 
Sounds rich on the acceleration from the comination of the main jets and accelerator pump both giving fuel at the same time.
You might try leaning down the pump shot and see if that clears it up any.
 
pcv only sucks what is presented to it....if you have excess oil in it, the engine is passing it to the valve

black smoke = unburnt fuel
 
i figured it was unburnt fuel, just was hoping it would clear up after the rebuild. i adjusted the accel pump according to holley, using a .015 feeler gauge. maybe try a smaller main squirter ? .. i believe the jets are 72 primary, 75 secondary .. i might be wrong, photographic memory not that great !!
 
I had just recently read that on that pump squirters sizes...that holley recommends starting by going up or down 3 sizes as a starting point

do you have the 50cc pump or original??
 
Not sure what size pump. I matched the original to one that came in the trick kit. Kit came with 3, 2 of the same size and one much bigger one.i used one of the 2 smaller ones.
 
is this carb a double pumper if so adjust the secondary pump to .030 and then more if needed. there is also a second position on your pump cam that may help you if you change that. i would not think it to be a jet size issue. if the smoke is on initial throttle push wide open. if it is blue smoke on initial push on hard acceleration. i would suspect guide seal but you say there is no smoke on first start up so i would guess that the seals are ok. if this is a vac carb you can do the same to the pump on the primary and see if it goes away but you may develop a hesitation on light throttle.
 
it is a 770 avenger, vac secondary carb.... i will have to research the primary accel pump size..... i adjusted my secondary throttle plates like this : turned set screw until it just touches the throttle shaft, turned 1/4 more .... are my secondarys not open enough ?
 
secondary's not open enough would not cause this issue your adjustment is fine
 
just took the main squirter off to check size, its a #25 ... found the stupid little needle valve missing underneath it. Fell out during the rebuild and i forgot all about it ! Hope i can find one somewhere, and soon ....
 
Summit sells the needle for about $10 for two.
Also make sure both gaskets are on the top and bottom of the squirter.
If they are missing, summit also sells them it packs of 10 for $10, but the top and bottom takes a different size.
I have extra of everything that is new pm me.
 
i replaced all the seals, just "misplaced" that needle valve ! should be getting one from a buddy tomorrow ... thanks for the info sireland67, wasnt sure if summit carried those !
 
I highly doubt the accelerator pump needle valve missing would cause your issue. If anything it'd cause it to hesitate. My guess is you need to jet the carb down 2-3 jet sizes. What size and performance level engine are we talking here?

As the others said if it were oil it'd be a bluish/white smoke. And as for the pcv valve and oil found in it, you'll find oil in nearly every pcv valve you pull. That's one of their drawbacks and one reason racers eliminate them and install a header vac kit. Since header vac kits don't always work well on a street car you can keep excess oil out of the combustion process by installing a catch can system in the PCV line and drain it every so often. I picked up a small tank off of e-bay that works fine and only cost $15 shipped. About every 2-3 months I drain it. Never has much in it but I don't want any getting into my fresh engine.
 
Oh yeah, if you can't come up with a needle valve PM me and I'll send you one. Got a bunch of them (new ones) in my Holley parts box
 
I dont think thats my smoke issue neither, but since i know its missing i def want to replace it ! Thanks for the offer, i will let you know if i cant come up with one locally... as far as motor goes, its a standard bore 340, 484" cam, eddy rpm heads, eddy rpm air gap manifold .. what size jets would you say, primary/secondary ?? i am almost positive they are 72 / 75 now ... dont want to go to lean either
 
Often excessive smoke and oil present in the pvc system is caused by blow by. are the rings shot?
 
MVRCorp said:
Often excessive smoke and oil present in the pvc system is caused by blow by. are the rings shot?
Click to expand...

i hope not ! guess i could do a leakdown test.... but wouldnt it smoke all the time with worn rings ?
 
It's not the pump, that's a 2 second deal. At most. What is compression? Doesn't need to be above 140. Cam same, mine 150, and worn out.but all within 10%. Check and read plugs.

If rich jets- have you blown all the soot out the exhaust? I;ve had rich on holleys and eddys. Holley- main primary jet or power valve. .110 in sec vac is no problem. Figure this out first, then read up on Holley cam placement. Doesn't sound like the problem.

Eddy- easier, but you run out of tuning parts before you get it tuned. And those jets, rods, and springs ain't cheap. And still can't tune a mild 440.
 
Some cheap aftermarket valve covers do not have a baffle under the PCV valve and allow an excessive amount of oil vapor to be pulled into the PCV system. Under hard acceleration your cylinder pressure goes up - therefore more blow by and more oil vapor to be pulled into the PCV. If it is a fresh engine it is entirely possible the rings are not seated yet. As was stated before, pull out the PCV valve and let it hang on the hose, then go for a drive and see if the smoke is still there. The crankcase will just vent to atmosphere, not a problem for a short while. If you still have the smoke on hard acceleration you have an excessively rich condition probably caused by an incorrectly adjusted accelerator pump, or float levels too high and the fuel sloshes back in the primary side on acceleration causing an over rich condition.
 
65-440 said:
I dont think thats my smoke issue neither, but since i know its missing i def want to replace it ! Thanks for the offer, i will let you know if i cant come up with one locally... as far as motor goes, its a standard bore 340, 484" cam, eddy rpm heads, eddy rpm air gap manifold .. what size jets would you say, primary/secondary ?? i am almost positive they are 72 / 75 now ... dont want to go to lean either
Click to expand...

Drop it down 2 jet sizes on each end and see how it does. Clean or replace the plugs when you re-jet it so you can see how it looks afterwards
 
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