[bubbahotep]

Yeah this is a radical cam lift 510/512 with duration at 236/246 if I remember. Its a street driven 383 stroker with 6500 miles on the entire drivetrain and ignition system is practically new from head to toe

Battery is a few months old red optimum, timing is retarded at start by an MSD ignition/advance computer and an msd6 box. MSD high torque starter is a few months old but prior to that I had a 10 year old summit starter. Total timing is 38' but only when its programmed to advance (no weights in the distributor). I idle at 18' and I could idle at 38' full advance and still not get a knock or ping.

The only old part is the plugs which I thought I cleaned off over a year ago and thats what you see here after 1 year of very little use. Not more than 10 miles at a time and few tire spins

But from the opinions Im seeing it seems my plug readings are not valid.

On a cold start with no choke mechanism I can fire up on a freezing cold day after sitting a week with no problem. Idle is rough until a few minutes and its warmed up. Same goes for starts on hot days after sitting a while. Its when I try to start after driving, park for 20 minutes for example, and then go to start I sometimes (50 50 chance) get that starter wurrrrr where you can tell the cylinder fired and is trying to spin the engine backwards. And if I let off the starter during the time the engine attempts to pop backwards.

After start the car runs perfect and timing is dead on, throttle response is tight and she moves without hesitation.

I agree it appears as a timing issue but MSD techs swear that their computer is retarding me 20' which would be 18' start timing (because Im locked at 38'). And why would the problem be on HOT starts only and never on a cold? Ive made posts about this on here before.

So, that leads me to the plugs which are NON RESISTOR + Hot type plugs. My guess was that maybe the plugs, when warm, are causing some ignition interference and I hoped that the colors would indicate that the plug is wrong anyway.

[Rich27028]

are you saying you have 18 degrees initial timing -- if so that seems to much for me-- -- more like 10 or 12 degrees should be in the Ball park and about 36 with full advance--just my op ion

[68NovaSS]

[QUOTE]From Rich27028:

are you saying you have 18 degrees initial timing -- if so that seems to much for me-- -- more like 10 or 12 degrees should be in the Ball park and about 36 with full advance--just my op ion[/QUOTE

Before getting too excited about Rich27028's advice, read here...

http://www.hotrodders.com/forum/oil-level-158150.html

It's like, are you kidding me? Good for a chuckle anyway.

[Rich27028]

hey i didnt save that thread -- it was a good joke while it lasted--
what was nice was every one was a gentelman and didnt go off the deep end --that evening the mod called me and ask if i had a son and was my car ok--
some times we take life to serious and its fun to pull some ones chain --

i was serious about his timing --its to far advanced- and his motor should not shake all over the engine bay-- and good lope is different than shakeing--
id be worryed about the kicking back on the starter--

[barnym17]

The fact it will fire right up with no Choke on the coldest day means to me she is way rich.How much of your idle transfer slots are exposed at the base idle setting? They should appear square when looking from under the carb not have the blades open so far they appear rectangular. It sounds like with your cam you have the throttle blades opened to far in order to get an acceptable idle causing it to be pulling fuel from the main metering circuit instead of just the idle cicuit.

[bubbahotep]

Originally Posted by barnym17

The fact it will fire right up with no Choke on the coldest day means to me she is way rich.How much of your idle transfer slots are exposed at the base idle setting? They should appear square when looking from under the carb not have the blades open so far they appear rectangular. It sounds like with your cam you have the throttle blades opened to far in order to get an acceptable idle causing it to be pulling fuel from the main metering circuit instead of just the idle cicuit.

Hmmm, something I never thought to look at. Didnt think Id have a problem with the 12hg of vac I have and I have no partial throttle problems which I thought was a sign of a problem

When I say that it fires up, keep in mind I have to give it a pump of gas and hold the pedal down partly or she'll stall until warmed up. But it will start in a second and so long as I keep the rpm high enough it wont stall until warm and then I can idle at 900rpm or so.

I gotta pull the carb and see whats doing from underneath. At least its 1 less thing to guess about

[bubbahotep]

If my wife knew I snuck into the garage on MOTHERS DAY I'd be dead.

Anyway, here's the pic which is hard to view because I cant focus on the openings:



The openings are NOT square and if I had to guess Id say theyre way over .070 or more. I think .040 is the ideal? Theyre not hugely rectangle but you can see the left side one a little better than the right. I wish I could get a better pic and will try. But Id say its close to twice "long" on the opening as it is wide. Follow me?

[cobalt327]

Tried to pull some detail up on the image:

[bubbahotep]

I got a better pic, hope it has more detail than the enhanced one above



You can see the long opening and theres also a tiny tiny little round hole just above the plate which, if my openings were SQUARE, would be covered I think. In the photo, the left plate, you see the rectangular opening and to the RIGHT of that is a little shiny spot. Thats the little opening which would NOT be exposed.

Looks like I got issues here?? lol

[cobalt327]

Maybe just my eyes. Lightened and contrasted:

[bubbahotep]

The puzzle comes together now: I remember I used to have the idle timing at FULL ADVANCE of 38' before I installed the MSD computer for timing. It was hell on the starter but the car never had a problem. A few years back I installed the MSD computer, keeping the locked out timing of 38', but the computer can control the idle time which I have at 18 or 20'. With the lower timing I remember I had to bump up the idle screw and thats partly why Im too rich now

So, this week I think I'll just adjust the MSD computer to give me 38' timing at idle (the car never pings), then lower the idle speed screw, remove the carb, and see where I am?? YES or NO?

Or should I do the old trick of holes in the plates or fiddle with the secondaries to let more air in??

Which way is better?

Old rule was "get the highest possible timing you can without detonation" and I know I can go beyond 40' with no problem. 38' was recommended

[barnym17]

Close the primaries till they are approx. square, open the secondaries slightly and try it before drilling the blades.A lot easier to drill out material than put it back in. Does you timing box have a start retard feature if so you could lock the timing and use it to start it to keep from hurting starters.

[bubbahotep]

the MSD has a built in 20' start retard. I'm at 18' start no matter what because I'm locked at 38'

Once I set the plate back to where it's supposed to be, then adjust secondaries, where do I get my increase in idle rpm from? I'm exactly 1 full turn less on the idle screw to get the plate back. Is advancing my timing my only means of raising the idle speed?

It's no issue I just want to confirm it as such. Or will the secondaries be taking care of the needed rpm??

[oldbogie]

Originally Posted by Jmark

YEa, it's real bad. That's out of my new engine too! But back when my PCV was sucking herds of oil and it ran down number 2 cylinder. I do have a bad stem or stem seal on that one too as it still fouls some but not every 100 miles any more. But I live with it and just swap it out every 3 or 4 months. Sorry about the side track, another boring day here.

Mark

Yeah, my Scottsdale did that when it ate a couple cam lobes.

Bogie

[bubbahotep]

This post probably needs a new title since its all carb at this point. lol. Heres whats happening:

I lowered the idle screw until I got a square hole. I could remove the screw and still have the hole the same size so at least NO IDLE screw pressure is a good starting point without removing the carb again

I then adjusted the little secondary screw under the carb (small inset screw). I turned it 1 full turn as a test and reinstalled the carb

Car starts easily, seems to have no kickback, but unless I dive out from the drivers seat to give some throttle shes gonna stall. Anything under 2000rpm seems to idle like total crap and she'll stall at whatever idle speed its set down to. I estimate its at 500rpm.

I did not yet increase my timing at idle which is 18'

If I increase the secondary openings (I can move the plates manually from the side of the carb) I can raise my idle rpm so she wont stall. This is the same as turning the screw under the carb without actually doing so. If I adjust the idle screw it also does the same BUT that defeats the purpose here since I want to keep my plate where they are.

So, should I increase the secondary openings MORE (which is sucking in more gas to do so) until I get a good idle or should I raise my idle timing more? Or both?