Oil Problem

[Bungy]

I too never would have thought that there would be a vacuum at that end of the hose. However that hose is connected to the air cleaner when the engine is running. Remove the hose at the other end and how much vacuum would you have? I would think it would be much higher then 2-3 inches therefore sucking the gases out of the lifter valley and not putting clean air in.

 

[Bungy]

Disregard that last post. After rereading mpris' post and scratching my head a few more times it now makes sense to me. The vacuum is created by the carb sucking out of the oil fill tube in the front. I'll admit it takes me a little while but I eventually catch on.

 

[64ss409]

mpris did a good job of describing the closed positive system on the 64/65's. There is no"pcv valve", instead there is a .100 orfice at the base of the carb. I am unable to repost the pic even though I renamed it, so here is a link to the picture. (hope this works)
http://www.348-409.com/forum/attachment.php?attachmentid=696
Ron

 

[gearhead409]

Ron

i might be wrong on the 64s but i always thought the 63 and 64s used a pcv valve made by ac spark plug. it's number is type cv 590. it has a valve in it and works like a late model pcv does on todays cars.

 

[mpris]

Gearhead, you are right about the PCV valve part number. However that part number (AC-CV-590) was only used on the 283 and 327 engines. All the 409 engines used a fixed metered orifice in the rear of the carburetor.

Poocho

 

[gearhead409]

Poocho

i don't have a complete 64 engine but the two QB 63 and the two 65 complete truck engines i have has this valve on them. my GM parts book also states this valve was to be used on all 63-64 8 cyl. engines.

 

[SS425HP]

PCV system

On my 425 horse 63, there is a 90 degree fitting from the rear of the front carb with the PCV valve screwed into it, then a hose to the rear of the intake, where there is a 90 degree bent tube that fits into the rubber bushing that is where the old draft tube used to bolt on. On the oil filler tube, there is about a 3/8" tube sticking out the side, that has a hose that goes to the air breather. The cap on the oil filler has a seal in it. That's how the closed system was on the 63 425 engines. The 64 had a bigger hose from the oil filler to the air cleaner. Think it was 1/2".
At least that's the way it is now, and that's the way I remember them being set up.

Fred

 

[gearhead409]

Fred

the way you explaned your 63 pvc system is exactly the way it is on my 63 engines except the valve is on the rear carb. 64 engines use a larger air cleaner hose as you have said and the system works in the reverse direction to the 63 engine.

 

[Ronnie Russell]

They both "SUCK" Sorry guys, I couldnt resist. I am referring to ---both vetillate with vacuum.

 

[SS425HP]

PCV system

Gearhead, you are right. The PCV valve is on the rear carb, and the line for the vacuum advance is on the rear of the front carb.

Ronnie, I'm not saying it's a good system. I guess the idea was sound at the time, and it works on a good, tight engine. The more blow by you have, the more junk goes through the motor, which is not good.

Fred

 

[gearhead409]

i've been reading these threads for several days now. the key to 29coupe348 problem is as Fred said " good tight engine". 29coupe348 has said in an earlier thread that his engine was getting "real tired", you can only put so many band-aids on a blowby problem. he needs to rebuild that 348 this winter and then either crankcase system will work fine.

 

[Ronnie Russell]

good, sound, logical advice from gearhead. I wish 29 success ,, his car deserves to run as good as it looks.

 

[mpris]

Gearhead, you may be right about the 63 and/or 65, but according to the 1964 shop manual, the 64 409s used a fixed orifice. See attachment.

Poocho

 

[bobs409]

I have the 63 shop manual open and it lists AC CV-590 for the pcv valve for 283 thru the 425hp 409 for '63. Looks like '64 was changed as Poocho shown.

I don't have a '65 manual yet so not sure on that year.

 

[CHEV601234]

The '64s received the PCV (CV-590C) in 49 states. California cars were required to have the CCV system (Closed Crankcase Ventilation). That was the one with the sealed cap on the filler and the metered orifice fitting in back. The CCV was also optional in the other 49.

 

[gearhead409]

Poocho

your right i'am right. ain't this website great! we all have learned something here, thanks.

 

[W Head]

PVC story

A number of years ago, there was a drag racer in Austin, Texas who used PVC valves to go quicker. He ran 2 PVCs in each valve cover with no PVC baffels in the covers. He ran 2-4s with 1 inch carb spacers and plumbed 2 PVCs to the front carb spacer and 2 into the rear carb spacer. Ran a 8 qt. oil pan with 80 wt. oil, put in 7 qts. of oil and one qt. of nitro. This mixture was sucked into the combustion chamber. He said it was good for a 1/10 off his normal time. He was turning the engine about 8500, so there was a lot of oil mist in the valve covers. I only saw the car run once and moved from Austin. The car really hauled the mail. I heard he finally got caught. I really do not know if this really worked or not, but he thought it did. If I tried this the nitro would have blew up in the oil pan.

By the way,on both my 348 and 409 I have PVCs installed. Used the rear manifold vent and PVCs for a 340 Hp 409, and have a filtered oil filler vent cap. 348-the PVC is on center carb. and 409-PVC is on rear carb. Both work great, but both are new emgines. I just did not like the road draft tube.

W Head

59 El Camino 348-3,2s
59 Impala 409-2,4s

 

[Ronnie Russell]

W Head, thats quite a story. 80 wt. oil and 8500 rpms!!! Sounds like he could have turned 10,000 rpms with 30 wt. oil. You gotta hand it to that guy, he was trying different tecniques and pushing the envelope. Nitro in the oil pan;; thats quite a pcv system. By the way for those who are keeping score, 998 for pcv systems----- 1 against ,, It gets mighty lonely here at the bottom.

 

[Ronnie Russell]

Oh, I get it. The nitro thinned the 80 wt. I would have liked to see that experiment. Big glass jug--pour in oil--pour in a little nitro--stir it up-- check the viscosity with the stir stick. But you say " he got caught" not " he blew it up" Guess he measured right!!

 

[SS425HP]

Nitro in oil

We used to change the oil because it got diluted with Nitro!!!!!!!!! It won't burn in the pan, but kick a rod out, and you have BIG FIRE. We used to warm up, and make one pass on an oil change. Then change the oil, and make 2 passes. Never more. I don't think nitro lubricates very well. Also, if much nitro was going into the combustion chambers with that set up, you would need to be way richer on the jetting. Has to be something for the nitro to burn, or it will find something. Generally aluminum. Like pistons. I'd say he was lucky he got caught. Then again, at WOT, where is the vacuum to pull the nitro vapors into the intake?
Had a friend in the early 60s, that thought ether was the trick. He bought a box of ether pellets, and dropped some of them in the tank. Swore it ran better. After about a dozen, the car kept quitting. Finally had to take the tank off his 58 to get the pellets out. He had never opened them. They don't dissolve. Didn't do a thing for the car, but he swore it ran better.

Fred