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dopsdad 10-10-2003 08:57 PM

delima = vacuum, valves, and timing
I have a 55 Chevy truck with a '63 283 engine. The truck ran like it had a big cam, very thumpy, and would choke out when given gas. I beleived the problem was the 2V carb or a lobe knocked off the cam. I rebuilt the carb, no success. Now I swapped out the 2v for a 4v. While I had the intake off I did a little cleaning and put new valve seals in. So this during this little adventure I messed with rockers, took out the distributor, and put on a 4v and intake that I've never used before. Wanna guess why I'm here. After more attempts than I can count, and a few shots of starting fluid, it barely ran for about 5 seconds. The distributor is points style with vacuum advance. Carb is early 80's with more vacuum nozzles than I can count (and a couple of electronic gizmo's to boot). First, where should I connect the timing vacuum on the carb? Second, what procedure should I use to make sure the rockers are tightened enough to open the valves without over tightening them? Third, how can I know the timing is in an acceptable range without having the advantage of the engine running?

I need to get out of this mess quick, we have to move in one month and the truck needs to be running!


lluciano77 10-10-2003 10:09 PM

Back the rocker arms off untill they are at zero lash. That will eliminate the possibility of a valve hanging open. You can readjust them after you get a good idle. Set the mixture screws on the carb at 1 1/2 turns. Try turning the distributor a little each way untill it idles. With the info you gave that is the best I can come up with for now.

dopsdad 10-11-2003 01:36 AM

can anyone address the vacuum issue?
Thanks lluciano. I'm not sure how to do the 0 lash, but I'll hit the internet to find out.

Can anyone address my vacuum and carb issue. The 4V Q-jet is from an 80's car with some sort of electrical connectors on the top. Will this carb work without the connectors? Where should I connect the vacuum from the timing? Will it work if I plug off everything just to attempt to get the truck running, or does the carb need some vacuum initially to work? This is by far the dumbest thing I've done, but I'd appreciate any help I can get. So far internet searches haven't produced much that will help me.


lluciano77 10-11-2003 01:41 PM

Zero lash is when you have taken up the slack between the pushrod and the lifter. You can tell by tightening the rocker arm and twirling the pushrod. Look in the Knowledge Base. There are a few links there that will tell you how to do it.

If you don't know what zero lash is that is probably your problem. I bet you tightened the rockers arms too much and your valves are hanging open.

The carb is a big issue as well. Get an 1850 Holley 600cfm carb on Ebay. You can find one for around $30. Rebuild it and use it intsead of the carb you have. The one you have isn't worth the trouble. It is an emissions carb and it was made in the dark ages of automobiles, (the mid seventies to early 80's). Junk it. It will eliminate a lot of problems in the future as well.

Here is an example:

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