always faster

I got a proform tall VC set black crinkle.The cap is a pushed type cap.It seems to hold fine but keeps falling off after some dyno run and a lot of heat.Seems that the rubber is getting to soft to stay there

We did a comlete dyno day.The cap was holding fine for 6 WOT passes then the cap would fall.We gave the car a break for lunch time (a little more than 1 hour) .This gave the car some time to cool down( outside temp was 9 degree celcius or 48degree fahrenheit).Then gave it another 5-6 run.The cap would hold but again at the 6th run the cap would fall

I saw on this board that some member run those cover but they did modify/weld something to use a screw type cap.I would like to do the same.

Woul like some pics and details of what to weld and what cap to use. please

And just for the fun fact it did a 660whp/580wtq @ only 8.5 psi on a v3 si,14-15 degree timing and 91 oct gas, need to add .5 of 50/50 meth and it done

LedfootLarry

Too much crankcase pressure, you could try this as a temporary fix if you like, although this works for mine at 13 lbs.
This cap has a baffle , and dumps into a catch can.

NITRO UK

OP yeah had the same problem, could be c/case pressure.

The cap with its parallel rubber wall doesn't help , I'm trying a breather like Larry suggested, got a nice billet one off eBay .

The grommet has a nice ridge on the outside so when you push it into the cover it kinda clips in , then installing the breather which also has a ridge on the tube also clicks in , seems pretty tight and can't see that popping out , if it does I'll tap and drill the ******

Can post a pic if you need it .

neutron82

I don't have proform valve covers but the tall gm covers I have came with a push in oil cap as well which I did not like... what I ended up doing was have the hole welded shut

LedfootLarry

Your avatar face scares me

always faster

So even if my forged block is fairly new, that im only pushing 9.4 psi max @ 7000rpm and that i can do5-6 run back to back without a poblem i could have too much crankcase pressure ???

Im already running a double catch can.So my valley cover goes in a catch can then out of the catch can to the intake.The pass side VC is going in the catch can and the catch out to the air filter.

-Is my catch can setup ok ?
-Do i absolutely need breather cap connected to a catch can or i could use a breather cap without a catch can ?
-With a cap connected to a catch can, where is the fresh air side connected ?
-Any baffled push in cap that dont need a catch can if possible?
-Other way to lower crankcase pressure ?
-And why is it a temporary fix ?

Thanks
Eric

JDS99

Mine did the same. Even with 2 -10an vents to atmosphere. The cap that comes with it has zero grip with a little oil on it, and would just weep and vibrate off on mine. I did find a solution to seal by using a 1.25" grommet and solid billet cap from one of the parts stores. Can't remember which.. it actually squeezed the grommet though and sealed fine.

I've since changed my breather bung locations, and went ahead and welded a threaded cap on it. It's 1.5" diameter with an oring to seal cap when threaded on. Pretty cheap on ebay. http://www.ebay.com/itm/221854541004

Valve covers are with coater right now, but can see cap in this pic:

Millenium Z06

Mine did the same thing on a N/A motor, proform has an updated cap with a stepped rubber grommet that solves the problem. I gave it away to a friend having same problem and have a Rev extreme clean side separator which doesn't have the problem but I did have to put rubber o-rings in the grooves on the separator.

neutron82

horror fans may recognize it, it's captain howdy from the exorcist

that cap looks good, I couldn't seem to find one like that when I was looking... either the hole was too small or the cap itself looked more like a "tuner" oil cap and I didn't like the design... I just have an old valve cover that I swap on when I do the oil change... my coils are relocated so it isn't that big of a deal, just the 4 valve cover bolts and remove my breather hose

always faster

A friend of mine with a 402 n/a had the same issue with those VC and got rid of them since hes really impulsive ... I was already aware of this problem but forgot it until the dyno session...

Do you got the part number for the updated cap ???

always faster

Should i run a breather cap with my setup and why?(obligation,mandatory)
Or try the updated cap or just go directly to the link you provided and have a bung welded up with a screw type cap?

always faster

Well didnt go the way i want it today.
The cap fell off at the first run of meth tuning so i probably got a excess of crankcase pressure.

What should be the best way for me to cure this problem ???
Do i need to run my pass side valve cover vent to a venting catch can ???
Do i need to run both valve cover to a venting catch can (single or two ???)

The rest of the dyno session will be on hold until i fix this issue.

Thanks
Eric

neutron82

what kind of catch can/vent system are you currently using?... if the lines are not big enough it may not vent out enough pressure... I have a -10 bung on each valve cover similar to jds99 and run those lines to a dual inlet breather can mounted to the driver side of my radiator cradle... you could use 2 breather cans if you wanted to, one for each valve cover, and probably mount the other one under the passenger headlight or wherever you want really

NITRO UK

Hi
At this point I would try the new cap first , saves tinkering with welding and repainting , or get a breather which should seal up the hole and be a breather.

The breather I got unscrews so you could seal it/block it off internally so it just becomes a large cap , kinda gives you an option with one part . You should be able to connect it up to a catch can if you go that route .

Hope all that makes some sense

always faster

Saikou Michi twin, 3/8 hose
Valley cover go to dirt side of can and clean side goes to the side intake
Pass side cover go dirt side and ckean side go to the air filter

neutron82

I don't think the 3/8 hose is adequate and the vent on the proform valve covers is ridiculously small, many people drill them out and that helps and may be fine for an n/a car but on a boosted car is still too small in my opinion... same with the catch can, I had the same one when I was n/a but got rid of it when I added the blower and went with a breather setup... mighty mouse makes some nice catch cans that seem to work well with boost if you would rather run a catch can over a breather can

Millenium Z06

No but if you call them, they will give you one.

Edit, heres their response to me:

Millenium Z06

Also, follow this procedure.
https://www.corvetteforum.com/forums...ve-covers.html

always faster

Proform kept the same number(141-629 black) but with an updated stepped grommet.The main problem is that a lot of ealer got the old model in stock.

Thanks for your help, new cap is on the way directly from Proform

always faster

Since i wanna make it rigth and after reading your comment and doing some search on the forum what do you and evryone think about that:

-Driver side cover : weld a -10 an fitting on it and weld shut the original spot
-Pass side cover: weld a -10 an fitting on it and weld shut the original spot

-Connect both valve cover using -10an line to a dual inlet Mighty Mouse single breather catch can( but i would get oil smell)
or
-Connect both valve cover using -10an line , tie both hose together with a "y" than run it to the catch can dirty side and clean side to the air filter.Is this possible or i should avoid connecting both line together ?

-Valley cover : keep the 3/8 line since the oem fitting is a 3/8 and connect it to Mighty Mouse single pcv catch can.I dont think that i can anything more.

Is this ok, looking to order quickly to finish the project.

Opinion are welcome.