jemidyette

I just had my 95 LT1 rebuilt as a 383, and I am slowly piecing everything together. I have the Canton valve covers (65-208) ready to install, however I'm not sure what to do with the hose that usually goes from the passenger side valve cover to the throttle body, as there is no hole in the passenger side canton VC. There is however a breather hole on the top of the driver's side. I am thinking I should just get a good breather on there and plug the hole on the throttle body and be done with it.

I definitely don't want to have any issues with crankcase pressure, so do you guys think the single driver's side breather is enough? Or should I just go and drill a big hole for the stock hose in the passenger's side cover? Thanks for the responses!

cohocarl

Don't know if this would solve the problem, but when I put aftermarket stamped covers on my L98, I picked up a breather similar to the one below that has a nipple on it so I ran a piece of heater hose up to the breather inlet on the T.B. If you did drill a hole in the cover, you'd need a baffle under it.

jemidyette

Hmmmm. So I'm still trying to get an understanding for this whole vacuum shindig. So basically your setup is a breather plus PCV? What is the benefit of pulling air from the intake (which is now not being combusted) in lieu of pulling air from outside the engine as a standard breather does? Sorry if this is a dumb question. I just want to make sure I understand this correctly.

eutu1984

The tube that runs from the throttle body is to let filtered air into the passenger side valve cover, the air is then circulated to the left side and pulled under vacuum through the PVC valve and into the intake from the the drivers side, I believe its important to have that flow so you are sucking the crankcase fumes out of the crankcase. If you were to just pull a vacuum from the drivers side valve cover i believe you may cause to much vacuum and suck in a seal or gasket. This is on a L98 I am not sure how it goes on an LT1

HlhnEast

looks like a good idea to me!

Weav's Vet

I had the high rise Cantons on my vette. I took a hole saw and put a hole in the drivers side for the PCV valve grommet and ran the PCV tube to it. Got a good breather cap and plugged it with rtv. Worked just fine.

You can't see the PCV valve in this picture but it's just like the fresh air intake on the right side.

jemidyette

Finally! I found somebody with the Cantons. It seems nobody uses these things. Couple questions for you -

1. Did you drill a hole in the passenger's side cover for the stock throttle body tube? Mine doesn't have that hole drilled ...

2. Did you have fitment issues with the accessory bracket? I found I had to use a grinder on one of the corners to make the driver's side fit.

3. Is clearance under the hood good enough? I was looking at a breather for the right side that is 3.1 in tall. I'm hoping it'll have enough clearance.

4. HP Increase?

p.s. I have the same intake manifold too! And painted red! I also have my air filter surround painted red too! I'd love to show our cars side by side. It'd be hilarious! Let me know if you're ever on the OBX.

beerme

I did this on my L98 383 and after a couple weeks the vacuum pressure was enough to collapse the hose. I ended up replacing with a breather cap and plugging the Throttle Body vacuum port. No known issues with this setup yet.

Weav's Vet

1. yes, drilled a hole and put a grommet in it for the metal tube that supplies fresh air.

2.Yes had fitment issues with the bracket, did the same as you did took a grinder to it. Also, had to grind the upper edge of the drivers side to clear the wiper motor.

3. I doubt that tall a breather will work. If you put one there do not make it functional! You do not want a breather that actually works if you are using the PCV system to suck out the fumes that gather in the engine.

4. I must have gained at least 20 HP from this!

Not my car anymore. Sold it to a forum member on here. You have good taste!

vetteoz

If you were connected to the correct port on the TB ,# 7 ,it is as noted above just a filtered air supply to the pass side cover , it doesn't have vac
The port below ,# 8 is full time vac for the canister purge which could give problems of the CCV system was connected to it

beerme

Thanks VetteOZ, I will need to go back and look now. I bypassed the coolant port on my new throttle body so as I think about it I may have connected to port 8 and didn't realize it till now.

Anyway I had removed and plugged the port so i am running a filter element on top of the valve cover, not sure there is any benefit in going back to running a vented cap and hose back to throttle body.

Thanks again...

MrWillys

Closed crankcase ventilation was mandated by the government in the 60's. Keeping it closed will keep the engine compartment cleaner, and really has no advantage one way or another other than being cleaner closed. PCV vacuum sucks it into the intake, so it need a supply also.
I have filled my unused ports on my throttlebody with JB Weld. The rubber plugs get hot and crack causing vacuum leaks that may drive you crazy, and cause idle surges, and other evil lean conditions.

jemidyette

Ok, so this is my plan. Cut a hole in passenger's side VC to allow for a breather with PCV hose going to throttle body port #7 (as seen in above pic).

I'm still unclear on what to do with the driver's side though. A hole already exists in the cover for a breather. Should I run another PCV breather to the manifold here? Or should I put in a nonfunctional breather and keep the original PCV in the manifold? I really don't understand why Canton made these covers the way they did. They are specially made for the 92-96 corvette and none of the holes line up.

Weav's Vet

Just get a nice looking breather and put it in the hole on the drivers side. Plug it with RTV or some other kind of sealer. Drill the hole for the PCV and connect it up. That's it.

cohocarl

I probably shouldn't be giving my thoughts due to my limited knowledge of LT-1's, but I would say no, not #7. Typically your P.C.V. valve needs a constant vac as in #8. #7 port is just a hole in the intake stream before your throttle plates. I treat #7 as a vent (sometimes in, sometimes out if hooked up to a breather on your valve cover, depending on if your crankcase has a positive or negative pressure). The P.C.V. valve somewhat closes off at high vacuum (during idle) and opens up at mid-vac levels to help re-burn crankcase fumes. (personally, I don't think there is much cfm flow through that little pcv valve)
So, lets say you under hard acceleration, there'd most likely be more blow-by the rings than compared to at idle, so the crankcase would vent the excess pressure through the breather cap, which have holes around the bottom to vent to atmosphere, (or suck in air if the pcv is working) along with the hose up to the "vent" on the throttle body (#7).

Please take my rambling for what it's worth. I'm not a certified mechanic or anything, but I run a "breather" on one v.c., and a pcv hooked to constant vac on the other v.c.
One thing to remember is a baffle under the hole(s) you put in. No baffle under a breather can make a BIG mess in no time. (don't ask me how I know) No baffle under the pcv valve lets it suck up engine oil.

Too bad you have to cut up the Canton V.C.'s. I've seen them and they are nice looking.

EDIT- Sorry, after I re-read your last post I think I read it wrong, Yes, a hose from the breather should go to #7, but the hose from the actual PCV valve should go to the manifold or a port on the T.B. that has constant or ported vac.

jemidyette

Only problem is that the hose going to #7 has no PCV valve. It is only a hose routing air from the crankcase to the throttle body. See pic.

On the driver's side of the manifold there is a PCV that is U shaped, going from one port of the manifold to another port right beside it that feeds into the crankcase. I can either:
1. Plug the crankcase hole in the manifold and place a PCV breather in the driver's side VC, where the existing hole is and run the hose to the manifold. See Pic:
-or-
2. Don't touch PCV in manifold, and place a dummy breather in the driver's side breather hole. I feel this might be the best option. Thoughts?

vetteoz

It already does on a LTI

vetteoz

As already observed , the other way around ; it is the CCV supply air going IN; the PCV valve is on the other side
The functionality of the stock CCV/PCV system is well documented.
At idle or high vac conditions, air is drawn in from the TB port though the pass side side cover and sucked out through the PCV valve
into the intake for the fumes to be burnt.
Under low vac (WOT ) conditions , the crankcase fumes pass back up the supply line from the pas side cover and into the intake
which is why some complain about oil in their TB's and how it got there


Plug the hole in the drv side cover and connect the pass side cover to the TB so you have same as stock
as noted , someone at Canton hasn't done their homework.
On LT1 covers, they put a hole where it is not required and have no hole where it is