Thread: wont idle right with the lumpy cam

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First off, disconnect the vacuum advance and do not use it again. Secondly, set the timing at 37 degrees @ 3000 rpm. Try driving it in this set up condition.

Next we will tackle the carb. If you have a dual plane intake on the motor, stick with it. If you are going to change carbs, do it prior to tuning. We can get your car to run great with any carb you choose. The cam you have installed, isn’t all that radical. Your advertised duration is in close proximity to my duration @ .050 and mine idles fine and the brakes work well.

I figured that removing one pcv would be too much, did you try to restrict it to half the size of the hose opening or maybe a quarter etc. etc.?? What this should do is speed up the idle which in turn will force you to adjust the idle screw to a lower setting, this is good. What you will have accomplished by doing this is leaned out the fuel ratio.

And hey, tell your dorkie brother to smarten up.

k.. finally got my timming set in runs better...i ran my vacum advance offa my carb so it only advances when i accelerate it runs really good except the ildes still a little funky but other than that its snappy as hell....i was talking to a fellow engine builder and he tolds me i'd be better off running a carter or edelbrock 750 he said for the time of setting the stupid thing up and for performance wise i'd be better off with another carb...

Originally posted by jayman54
k.. finally got my timming set in runs better...i ran my vacum advance offa my carb so it only advances when i accelerate it...i

Jay, the problem of hooking your timing to venturi vacuum is that it will advance it too far, causing detonation. Have you got the timing set at 37 degrees @ 3000 rpm without the vacuum hooked up?

The reason for abandoning vacuum advance is because your cam does not have enough vacuum at idle thereby causing you stumble at idle. You have to be able to set this motor up without any vacuum advance.

Vacuum advance’s purpose is for fuel economy by advancing your timing at cruising speeds and thereby giving you a bigger bang for your buck. It makes more torque under light load. However under harder acceleration it has to back off the timing so that you do not get pre-detonation.

In essence what you have done now is made a recipe for pre-detonation. If your timing is set at 37 degrees @ 3000 rpm without vacuum, now under heavy throttle the advance will take it past the 37 mark.

If you have the timing set at 37 @ 3000, what is your timing at idle?

i was told to set it at 33 degrees in advance so i did that at idle

Wow, I hope you are joking!

i ment @3000 sorry was thinking about idle

ok, whew!! Well a 350 can easily handle 38 degrees but a 383 can only handle 35. You can advance it another 4-5 degrees as long as you remove the vacuum advance, This will help your idle.

this may shound like a stupid question.. before i set the advance what should i set ther timming maker to 0 degrees? then advance it to 35 on the timming light and bring the marker back to 0 degrees and at what rpm should i be doing this at...all this timeing is getting me confused

SSSSSSSSSELL IT!!!!
you need an s-10 jay, ahh just kiddin, how did the other carb work out?

havent tried it yet still trying to figure out this timming

anybody???

Sorry Jayman,
I must have missed this thread for a few days and so I didn’t notice your question. Ok, here is what I do which works well with me. The following only works with a timing light that has a dial indicator on it which can be adjusted so as to keep the mark on the balancer at the zero mark on the timing tab.

I hook up the timing light and then start the engine. With the vacuum disconnected, I adjust the timing light to get the light to flash on the zero at the tab on the timing cover. Now I make a mental note as to where my gun is set. It will probably be around 10 degrees at this point.

Next, while keeping the gun flashing on the tab, I slowly bring up the rpm while keeping the light flashing on the zero. When I get to about 3000-3500 rpm, I let the engine come back to idle and now I look at the timing dial that is set on the gun. Chances are it will read30 degrees.

This means you have a total of 30 degrees of timing in your engine. It also means that you have 20 degrees of advance in your distributor, meaning, that from idle to full advance, you have 20 degrees happening. Now, with a mild 350 such as yours, you want to set it at 38 degrees.

So, seeing as you need an additional 8 degrees, have the car running at idle and set the timing at 18 degrees. This will equate to a total of 38 degrees when you are above 3000 rpm. As an added safety check, after you have the timing set to 18 degrees, set the gun at 38, rev it up to 3000 rpm and see if the numbers match. If not, make the necessary adjustment. When you are satisfied of a correct setting, shut the car off, tighten the distributor, start it up one last time and check your timing at idle.

hey jay what you need to do is go to the parts store and buy some rubber vacuum caps and cap everything on your carb..
then drill to holes 3/32 of an inch in your forward butterflys. then grab you a flat head and idle the puppy down put it in gear and see how she runs if it dies try going to 5/32 holes and so forth.
thyphoon knows whats up just listen to what he has to say once you get it in time and you compensate for that rough idle cam youll be good to go keep us posted

just dont forget to take the carb off the intake btw changing carbs isnt gonna do nething for you so ignore the losers that say otherwise... ohh and monte man your a retard dont waller out your jets thats dumb

Hey again Dom;
Sounds like it worked for you, good to hear. As for some of the rest of your post, you might want to make it a little less offensive, I know that the younger generation can handle words which you use, but on this board there are a lot of old farts like me, and some would find your post, unforgiving. If this happens, you will find no help or kind responses to any of your queries. Hey, matters not to me, I will still address your posts, if and when I see them.