Installing vent tubes in lifter valley

[lastchevelle]

On a SBC w/mech roller. Anybody have this done? A guy I work with looked at my engine block that's on the stand waiting reassembly and he said it'd be a good idea. Also opening up the oil return holes in the back of the lifter valley. I "Googled It" and found a few different sites where it was discussed. It's supposed to force all the oil to fall to the back of the pan and prevent oil from falling on the cam and crank and causing windage. What I read was you could do it with a roller but not with a flat tappet, but some said they'd done it with both with no problems. Others said "GM put the holes there for a reason!" The guy I mentioned earlier went to The School of Automotive Machinists(SAM)in Texas and does engine building on the side and said he could do the work for me for $150(parts&labor/new cam bearings). I agree with him about opening up the return holes but I'm unsure of the vent plugs. What do you guys think? It is a race only engine so wouldn't be any street miles.

Thanks.
Matt

 

[Hitman]

Did it on my stock block 383. 1/4 NPT tap and got after it. I didn't open up the holes in the front and back, but did deburr the hole in the back.

 

[fastheavychevy]

I opened up the holes front and back and deburred the lifter gallery and made it smooth. That way oil gets back to the pan faster. As far as the vent plugs dont you need those in order to get some oil to fall on the cam. I know the cam requires the splash and drips to keep it lubed.

On a SBC w/mech roller. Anybody have this done? A guy I work with looked at my engine block that's on the stand waiting reassembly and he said it'd be a good idea. Also opening up the oil return holes in the back of the lifter valley. I "Googled It" and found a few different sites where it was discussed. It's supposed to force all the oil to fall to the back of the pan and prevent oil from falling on the cam and crank and causing windage. What I read was you could do it with a roller but not with a flat tappet, but some said they'd done it with both with no problems. Others said "GM put the holes there for a reason!" The guy I mentioned earlier went to The School of Automotive Machinists(SAM)in Texas and does engine building on the side and said he could do the work for me for $150(parts&labor/new cam bearings). I agree with him about opening up the return holes but I'm unsure of the vent plugs. What do you guys think? It is a race only engine so wouldn't be any street miles.

Thanks.
Matt

 

[gman415]

I "think" a roller lifter gets oil to the wheel internaly, and should be enough. My old motor had them with no issues. My new one is an SHP block and has the webbing for Hyd Roller so I didn't do it.

 

[art]

I open the front and the back. It takes about twenty minutes with a carbide cutter and one or two tootsie rolls to do it nicely. There will still be oil leaving the crankshaft as it spins, so I wouldn't worry too much.

 

[HP JUNKEY]

Circle track motor builders plug them right up , epoxy screen in the front and rear oil return holes and epoxy magnets in the valley. The cam gets its oil through the cam bearings and the lobes are lubed from the oil splashing around "down below" The oil that would drain through those holes would hit the rotating cam and ultimately create some resistance to its rotation. It sounds pretty "petty" but every little thing helps make HP. The screens keep upper engine failure "pieces" from entering the lower end of the block and the magnets pick up any metal particles as the oil drains down through the front/rear. Alot of builders use a crank scrape, it removes oil from the weights making it spin more freely. Here is a pic of my lifter valley.

 

[D&A Machine Shop]

Wouldn't do it on a street engine but we do this on our race engines all the time without any problems. If it is ready to assemble then be sure you have it jet washed
and new cam bearings and pull all the galley plugs so you can make sure there is no debris anywhere.
Check out this video this is what we do on a street engine.
http://www.youtube.com/watch?v=zp7s5VqprvU&feature=channel

 

[PRO 48 Fleetline]

Im running the Stefs vent tubes on my 406 it has a lunati voodoo solid roller.
Heres a shot of mine so far.

406
Scat crank and 6" rods
11.1 Mahle forged flat tops
[email protected] 590" Lunati voodoo solid roller
210 Pro-Filer 2.05 - 1.60's
750 Mighty Demon
Hurricane single plain
4,200 stahl
narrowed 9" with 4.56 gears
STREET CAR lol

 

[Dyno Donny]

If you are going to use the engine for racing then install the vent pipes. If it's street/race and will see street miles such as driving to the track then don't, your cam and also your wallet will think you. This is a case of something that is used on an all out effort race engine not being a good idea for a street engine. The cam in a street engine needs all of the oil for lube that it can get because of the life expectations. If you plug the oil drain back holes and take one of the oiling sources away, then the cam will wear a lot faster. If you check a cam close from a block that has been plugged you will find that in a few seasons it will have a lot more wear than a street engine cam that has been run in an engine without being plugged. Most of our circle track cams start to show excessive wear after a couple of seasons. Once the wear starts then it's a rapid down hill ride from that point on.Most dedicated race engine will see less miles in a full season than a street engine does in one trip driving to town on a grocery run.

 

[PRO 48 Fleetline]

If you are going to use the engine for racing then install the vent pipes. If it's street/race and will see street miles such as driving to the track then don't, your cam and also your wallet will think you. This is a case of something that is used on an all out effort race engine not being a good idea for a street engine. The cam in a street engine needs all of the oil for lube that it can get because of the life expectations. If you plug the oil drain back holes and take one of the oiling sources away, then the cam will wear a lot faster. If you check a cam close from a block that has been plugged you will find that in a few seasons it will have a lot more wear than a street engine cam that has been run in an engine without being plugged. Most of our circle track cams start to show excessive wear after a couple of seasons. Once the wear starts then it's a rapid down hill ride from that point on.Most dedicated race engine will see less miles in a full season than a street engine does in one trip driving to town on a grocery run.

I agree if your complete combination isnt thought out well.
Im running a 15% over melling select pump witch also goes hand in hand with the breathers.
And you must be running a solid roller cam or those poblems you mentioned will apply!