At a loss... HELP

Okay I have a 225 slant 6 that I recently put in a comp cam kit (k64-241-4) with 220 lift 264 duration, offenhouser intake, clifford shorty headers, a new distributor, and a 450 cfm quick fuel carb. I also had a .3 head shave and 3 angle valve job done. There is also a new fuel pump and fuel filter... Everything is put together and the thing starts right up. The issue is that there seems to be a "spot" where it seems as though its not getting enough fuel, it hesitates for different periods of time, then all the sudden ramps up like a bat out of hell. The weird thing I noticed is that I am only getting it up to around 3500 rpm and it stops. Another issue is when I get it idling in park where it wont die after putting it in drive it idles around 1000-1200 rpm and when I put it in drive, the transmission bangs hard but the rpm drops to around 600-800. I know this is too high of an idle which is causing the banging, but as stated before, it dies when put in drive if it is set any lower. Sometimes when driving I either stall out immediately from a stop or it builds up rpm then hesitates for a while and then boom I start gaining speed and rpm's then it shifts into second and so on... I have checked vacuum, timing, fuel pressure... I am at a loss... Any help would be much appreciated!

Where is the timing at?

twayne24365 said:

Where is the timing at?

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initial timing is 10-12 total timing is around 30 give or take...

That's all tuning. You need to bring the inital timing up to 18*. Increase the centrifugal to give a total of 38*, and get the lightweight spring to get the advance moving earlier. Then slow the idle speed down to 6-700 using the idle speed screw. Then reset ti idle mixture screws to the best hot idle vacuum reading, then back them out 1/8 turn. Then see what it does in gear. It sounds like not enough initial timing, and a lean carb at idle.

Well this is a 264/264/110 cam with lifts of .440/.440
and the .050 is 220*/220*
with lash of .010/.012
So since you are having trouble with the vacuum, back the lash off to .013/.022 cold and start over. I'm betting currently, it is just too tight.Not that the spec is too tight, just that the hot setting may have ended up too tight. If, at.013/.023, it runs better,then it may have been that one or more valves was too tight, and now you get to figure out why.
A compression test before and after the re-lashing might be useful, or a leakdown test cold vs hot.
I also agree with moper in post#4, that you could easily crank in more timing; both idle and power.

My take on this is that your engine does not make enough torque at 700 to idle at the normal throttle setting. The usual culprit is idle-timing. But I have found slantys to be somewhat fussy about tight valve lash.
So in your case, if the assembly has been proved to not have any vacuum leaks between the top of the carb and the combustion chamber,and that the Vcan is hooked up to the sparkport, then increasing the valve lash will get you results. If it doesn't, then I would look at the cam timing next.
I hate to see you spend 3 days on the carb, when all the while the intakes were not getting enough seat-time.

I also think you have multiple problems.
insufficient valve lash
insufficient timing
lean carb circuits, other than perhaps the MJ
a lazy accelerator pump.

You can skip the valve lash and spend 3 days on the rest of the tune if you are so inclined, but I sure wouldn't. Then after re-lashing, you might be able to, or have to, undue the 3 days work that you previously did. So I highly recommend the lash adjustment first.

At this stage I wouldn't even put a timing light on it. Instead I would push and pull the D this way and that way, and let the engine tell me what she wants for idle-timing. I made the mistake of trying to force my ideas about valve lash and timing, onto my slanty once, and wasted many hours, not listening to her.Eventually I listened and that's when she woke up.

moper said:

That's all tuning. You need to bring the inital timing up to 18*. Increase the centrifugal to give a total of 38*, and get the lightweight spring to get the advance moving earlier. Then slow the idle speed down to 6-700 using the idle speed screw. Then reset ti idle mixture screws to the best hot idle vacuum reading, then back them out 1/8 turn. Then see what it does in gear. It sounds like not enough initial timing, and a lean carb at idle.

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I don't agree. Most slants do not like that much total timing. 28-30 usually works best.
I'm wondering if the timing is changing at too low an rpm. It could be that at the in neutral idle rpm, the centrifugal advance has already started, and when the rpm drops, when put in gear, the centrifugal advance decreases, which lowers the idle speed to the point of stalling.

what year distributor is it I can look up the specs a number would be best.

I agree it sounds lean at idle. My 69 slant did like that for years (slowed way down or died going from N to D). Turns out it was the Holley 1920 carb all along (thru several), until I finally got a carb that worked great.

halifaxhops said:

what year distributor is it I can look up the specs a number would be best.

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cardone 30-3610

Thanks everyone for the help. I'm busy with family this weekend, but next week I'll try these avenues out and post the results! Thanks again everyone!

Does your quickfuel have adjustable air bleeds? May want to hang a few wire strands in there to see if that helps the lean idle. The 3000 rpm bug may be the transition circuit in the carb from low to high speed circuits.

Charrlie_S said:

I don't agree. Most slants do not like that much total timing. 28-30 usually works best.
I'm wondering if the timing is changing at too low an rpm. It could be that at the in neutral idle rpm, the centrifugal advance has already started, and when the rpm drops, when put in gear, the centrifugal advance decreases, which lowers the idle speed to the point of stalling.

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You've got more experience with them than I do Charlie. But every one I've had a hand in tuning loved the curve and setup listed. That is only a few over the years however.