pcv, hw 5200 mystery

[Anonymous]

Right. I have a 1962 Falcon with a 1967 200/6 with pacemaker headers and a DUI dizzy setup and a HW 5200 carb.

I've been futzing with my rebuilt Stovebolt HW 5200 since I bought it a few months ago, and I wrote a post the other day mentioning that I couldn't get the idle circuit to jet correctly. According to the manual, the idle mixture screw should sit at 1.5 turns out when everything is at its happiest.

Mine sits about 3.5-4 turns out with an idle jet of 80 - the largest available jet. i.e., I can't richen it any further. And I shouldn't even be close to that rich anyway. Anyway it's running very rich at idle and gets crappy mileage in the low speed circuit.

One suggestion is that I have a vacuum leak in the system someplace. I have only two vacuum lines: one from the intake to the C4 automatic tranny, and the other to the PCV valve on the rear of the valve cover.

Today I ran all new lines and fittings for all of that and I found that if I disconnect the PCV line and plug it at the manifold, the engine ran terrible until I .... can you guess? ... cranked down the idle mixture screw to 1.5-1.75 turns. Right where its supposed to be! Hot dang!

But, you know, geez, I'd like to have a properly working PCV setup. So I replaced the valve, the hose, and the manifold fitting. No change. With everything connected, and the mixture screw out 4 turns, I get 22hg on my vacuum meter. I get about the same with the PCV plugged off and mixture set at 1.75 turns.

So why is it that the mixture apparently is only happy when the PCV is disconnected? I think I have a good fit at the valve cover. When I lift out the PCV valve the engine idle drops and stumbles. The line seems not to be leaking.

I'm confused. I don't get it. I need some ice water.

 

[xctasy]

Check the posts here on 32/36 Webers and 5200's. Stovebolts adaptor is great, but the gaskets are trash. Buy some stock Weber 32/36 gaskets, and mount them upside down. Make sure you open the four stud mount holes up so that they don't cause gasket leaks when torqued down. Some of them have a teflon bush, and it becomes a four point ridge which allows each of the two long sides to leak air. Oh, and use Chapstick to stick the gasket down.

If you check the posts in idle jets, you'll find that there is a photo somewhere on the differences between the common el cheapo gaskets and the good Weber ones. Then recheck the idle srcew setting. Some of the fittings on the carb may need to be changed if you still have no joy.

Best wishes,


Deano.

 

[Anonymous]

Hmm. I saw the post, but my gasket was not the one with the four teflon rings in it. As an exercise, I sprayed the carb with carb-cleaner around the gasket to see if it made a change in the idle speed. It did, it lowered. I tried again an hour later and then it made no difference. Hmm. Clearly this is voodoo.

I'll see if I can hunt down a gasket tomorrow and change it just for the hell of it. Meaning that I'll order one and hope the right one shows up three weeks from now.

Thanks for the advice. I hope its just a gasket problem and not a the-whole-carb-is-screwed-up problem. I'll report back after I have the gasket changed.

 

[JackFish]

What's your initial timing set at?

 

[cfmustang]

Well, your definately on to something now.

First, I would get some sheets of quality gasket material at the local autoparts store, use the one that came with the adapter as a template and make your own. That is what I did and it works nicely.

Secondly, I suppose it is possible that the new pvc you bought is defective right out of the box. They aren't exactly the higest quality little items...

 

[Anonymous]

I'll go ahead and replace my gasket, but somehow I don't think its going to solve the issue because the idle mixture is correct with a strong vacuum when the PCV is disconnected. If the gasket were at fault, it still wouldn't work, right?

That is, if I connect the PCV suddenly I require half as many turns (leaner) to even it out.

I know the PCV valve works okay. I replaced the one I had couple of months ago, and I bought this one last night. They both function the same and both pass the suck/blow test.

 

[Anonymous]

Hmm.

I changed the gasket, complete with chapstick. Here are the new finds:

1) The mixture can be leaned some more. I'm now at 2.25 turns - a big improvement.

2) It idles more roughly, regardless of where I tweak it to.

3) When I shoot around the carb with cleaner the thing that really makes a change in idle speed is when I shoot the main pivot on the linkage. In fact, the car almost dies when I spray it. I have no idea what that means.

I'm still a whole turn out from where I should be but I'm pleased with the results so far. Thanks for help in this ongoing problem.

Also, in answer to the timing post, my timing is set to 12 degrees. I've seen where others have set theirs to 14 degrees, but mine seems to work best at 10-12.