OK, so I just put a 283 into my 29 model A. I don't have the room to reinstall the draft tube on the back of the block because of fire wall clearance and I'm leaving this week to drive out to Brooklyn, NY for the Rumblers CC show. My question is if I plug up the hole just for this trip will the crank case breath ok just from the "oil fill" intake manifold or do I need to have both? I have the stock undrilled valve covers. It seems that the engine would do fine with just the breather on top of the oil fill tube but I'm not sure. What do ya fellas think? Thanks HAMBers......
Later engines had a similar fitting (bolt thru the top) with a hose that went to a pcv valve into the carb. Some had an add on kit with the pcv hose in a rubber plug that fit in the hole. Either of those options would fit with your clearance issue, whether you actually use the pcv or not.
I used to run the chevy in my last roadster, (fairly radical motor), with just the front breather and occasionally, if I really nailed it I would dump some oil out of the breather and blow the cap off. Nothing a cotton tube sock around the breather didn't cure. I have a 283 in my new roadster and I just used the later, (65?) tube fitting and a hose to the rear port of the Holley with an inline PVC of unknown origin. This seems to work well. I'm not sure what I'll do when I put the 4 Strombergs on.
even if its a breather cap, itll build a lil pressure and ooze out the valve cover gaskets. and possibly push out yer intake end gaskets like mine did, which will leak pretty good.
No, I don't think it will vent right. Can you re-rout it forward a little bit? Inside there is a de-fuser that the tube hooks to, I would try and make it work somehow. I have one on my 350 and without it I would blow oil everywhere out the oil breather. I put a sock over it, but it didn't help much.
Use an inline PCV from the road draft hole in the block to the base of the carb. If you don't have the fitting to connect a hose to that hole in the block you can get one from some of the Corvette restoration parts sources but, they're a bit spendy. A more economical solution is to use a brass freeze plug with a brass hose fitting brazed or epoxied into it.
No it won't "breathe right" Do a search on PCV valves and road draft tubes. I would think that the worst that can happen is just a big oily mess. Over the long haul it will build up sludge and acids that can damage an engine but there have been lots of people that don't understand a breather system that have put many miles on their engines. Bring extra rags and cleaning supplies. One thing that can help with the oil mess is to use a tennis wrist sweat band around the front breather. It's just a bandaid to slow down the oil some but it can help some.
The tri five parts houses sell a kit that replaces the draft tube. It has an adapter the goes in the hole in the block,then a hose runs from the adapter to a threaded pcv valve that screws into the carb base. You could toss the pcv valve and just run the rubber hose down the back of the engine similar to the draft tube.
I have plugged mine on my 327 and now I am getting blow by out of my dip stick. I have the room, so I am installing the down draft without the "trash can" to vent the crank case. If you can't add the down draft, looks like you'll have to drill those valve covers!
On the bright side, nothing in your engine bay will rust! Used to use "scrunchies" around the breather tube at the base of the breather cap on my 3 deuce setups. Those things girls use for their pony tails. Kept most of the blow-by from getting everywhere. But like the guys said. a PCV setup would work much better.
Do you need the baffle that attaches to the lifter valley? Mine is missing, so I was going to run a front vent, oil fill, a breather in each valve cover and a pvc in back. Will taht be enough?
I had that happen to my '57 Chevy truck too, but people still tell me "That's not possible". The breather has a filter to filter the INCOMING air, not keep the oil/vapors in the engine. The road draft tube and later the PCV are designed to draw the vapors OUT of the engine.
yep, didnt plan mine real well the first time, lol. a pcv is needed to draw out the pressure or it goes out all the weakest seals
I say yes. The PCV can suck the oil spray out of the valley with out the baffle. They needed it for the road draft tube and the PCV will be stronger than the R.D. tube suction.
It should be easy to find one. Check some machine shops and ask all the old Chevy racers in your area. Someone in your area has several in their can't throw it away bin.
Corvette Central sells the vent can (mounted in the valley) P/N 301155 for $39.00. Might be cheaper than e-bay plus its new. They have a hose/grommet kit P/N 152056 for $12.00 ( this is something you can fabricate yourself) which was used in 1963, or the vent tube P/N 152106 which is $57.00. Check out their website. Different years had different variations.
Thanks for all the info guys! Like a dumb ass I measured and made the fire wall and motor mounts without the draft tube installed. Thats what I get for drinking to much beer while I'm wrenchin'. Looks like I'll try to rig up a cheep PCV set up before heading out.
Here's what you need. There are two of them on eBay right now (Tuesday am). Run eBay search: Chevy PCV Good luck!
I plugged my road draft tube with a rubber shock bushing I just had laying around, fits in the tube really snug and a generic sbc pcv valve from any parts store fit snugly into the center of the bushing. Couple years and it still works perfectly and I no longer smell fumes when stuck in traffic.
Well I think I've found a cheep set up from Auto Zone. It's just a valve cover gromet and a PCV valve. It fit snug in the hole in the block and works great. If anyone is looking to do the same thing here are the part numbers from Auto Zone: Spectre valve cover gromets (2 pack) P/N 5339 Deutsch PCV Valve P/N PCV302 Thanks again fellas......
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