Weber Upgrade on my 258

Ok so I finally got my weber installed on my 258 and at the same time I put on the TFI upgrade.

Before the two upgrades my valve cover leaked, as do many of the 258's. After the upgrade my valve cover leaks even more than before. My PCV valve is new so that isn't the issue. I am wondering if I didn't hook something up just right when doing the carb swap. Or maybe upgrading from a 1 bbl to 2 bbl. Also I need to retard my timing just a bit, and lean out my fuel mixture some. Just haven't done that yet.

Any help or comments on this would be appreciated.

 

Usually the 258 has a bent valve cover. Bending results from overtightening. If you tightened any of the valv cover bolts, that will make the leak worse.

Remove the valve cover and examine the metal around the bolt holes. It's probably dished in from overtightening. Use a small hammer and a flat surface (I use a steel bar cutoff as a dolly) to flatten the bolt flange. Tap, tap, tap ... nothing drastic. Then get a rubber Felpro valve cover gasket and glue it in to the valve cover with your favorite gasket cement. Clean the mating surface on the cylinder head. Apply a thin coat of silicone gasket sealer to the gasket surface and drop the cover on. Tighten evenly and gently - a nut driver or one of those palm ratchets is plenty of force - just until the silicone oozes out of the joint evenly. Let it cure a day.

That's my method - the cover may still seep a little - it's hard to get them to stop 100%. Even my brand new '75 258 would seep.

 

I haven't touched the valve cover yet. That was going to be a project in the near future. But it seems strange that it would start leaking more severely after the two upgrades. I am wondering if somehow my PCV system isn't functioning properly? The PCV valve on the front end of the valve cover wasn't changed at all during the carb swap. But there is another rubber tube coming out the rear of the valve cover that used to attach into my old air filter set up.

This is the tube that has got me confused. I have it hooked up to a port on my carb that is used for a vapor vent to canister. Is this correct or do I have something screwed up?

 

Sounds to me like that hose is the fresh air intake for the PCV system. If you're using the "kit" air filter for the Weber, what do you have connected to the hole in the bottom of the cleaner?

 

Nothing!




Sounds like I've got the fresh air intake pluged into the vapor vent port.

See pic...

View attachment 22781

So if I plug the fresh air intake into the air filter, do I need to plug this vapor vent port?

 

Yep. (Exactly what I did)

 

Do you happen to have a picture of your setup?

And what did you plug the port with?

 

I have the same carb but it's on an F head, so pic wouldn't do you much good.
I happened to use a vinyl tube cap but, if I hadn't had one that fit, I would have used a piece of vac hose with a plug in it.

 

Thanks for the help Homebrew, I will switch that hose when I get home tonight and see if my valve cover leak returns to its usual old self.

 

Hope it helps. I was mostly just concerned that you had a 1/2" hole in the bottom of the aircleaner dusting your engine

 

Well that is a concern as well, and my major concern was that I new that PCV system wasn't hooked up correctly.

So I got the clean air tube hooked up to the bottom of my air filter, but haven't got anything pluging that vapor port yet so I dind't get to test drive it yet.

While I'm thinking about it though does anyone know of anywhere to pick up or fab up a shorter throttle cable assembly (including the exterior sheath)?

 

You can purchase a new shorter cable from 4wd.com or the like.

Sounds like you got your breather tube hooked up to a filter fresh air source (carb air intake).
You can buy vacuum caps at any FLAPS, you'll find them in the HELP section. They make all different sizes and are made to plug open ports like you have on your carb.

 

you don't have to plug the vapor canister port. that isn't the source of your problem. i "extended" it using a short piece of rubber line, but it isn't plugged, nor does it go to a canister (don't have one).

i *think* i have photos of my throttle cable setup somewhere. i'll check.

wally

 

Thanks Wally those pic's would be awesome!

I don't have the canister either, so would plugging the port be a bad idea?

I think I found the source of the problem (having the clean air intake of my PCV system hooked to my vapor port) After changing that to the correct setup, the valve cover has stopped leaking as bad. (It already leaked before) So back to normal you could say.

As for the throttle cable setup, mine seems to have too tight of a bend in the cable causing some unwanted binding. I figured if I could get a shorter cable I wouldn't have to bend it so severely. But I would sure like to see how you've got yours setup.

 

If you're talking about the bowl vent to the vapor canister, I suggest you run it around to the choke stove air supply port on the air horn. Then it will function just like the bowl vents inside the air cleaner.

 

I'm not quite sure if that's what I'm talking about Tim. :|

The picture I've been working off of I posted on the first page post #5

They call it the "vapor vent to canister (optional)"

Is this something I should be routing to anything or is plugging it ok?

 

pic of weber carb accelerator linkage. note that i re-used the original bracket for the cable attachment, and used the kit-supplied bracket as a spring-return holder. it's been working for several years now.

i was having the same problem with the accelerator sticking when using the weber setup, so i altered it to the way it appears.

edit: i seem to remember that i had to trim a little bit from the inside end of the sheath around the cable (toward the bracket), since the weber has a longer range than the carter yf.

 

Well, I don't see a place to put it to on the air horn, so you can either cap it or vent it through a filter. Usually the bowl vent goes to either the vapor canister for recovery of the fumes, or it's vented to the air, or it's vented to a source of filtered air.

Filtered air can come from inside the air cleaner, or from a separate filter. Another thread suggested mounting a fuel filter somewhere and running a hose to it, leaving the other end open.

 

Thanks Wally, That helps out alot!

I'm pretty sure I don't have the canister, so venting it to the air seems like my simplest option.