engine cutting out down track after in 3rd gear!

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moparmatt19 said:
Ok question guys... will the vac advance work at WOT? Reason I'm asking is bc when I raced it I only had 14 deg at idle. And when I pulled my vac hose off the dizzy it was only pulling 20 max with the limiters I had in it. I think I was going all the way down the track with only 20 deg timing.
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vac advance will have 0 vac at full throttle. If you are saying that you have only 20 degrees TOTAL, that's why your rich at the track. more timing(32-38 ) will make it run much better and lean out the top end charge.
 
That's what is was then. I was going down the track with only 20 deg timing. And I think I might have had a fuel problem also. Might have to go to the 1/8 mile track and test it
 
Any suggestions on what plugs to use? What heat range to start with? Sorry but this is my first build like this and I'm still learning.
 
moparmatt19 said:
Ok question guys... will the vac advance work at WOT? Reason I'm asking is bc when I raced it I only had 14 deg at idle. And when I pulled my vac hose off the dizzy it was only pulling 20 max with the limiters I had in it. I think I was going all the way down the track with only 20 deg timing.
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Vacuum advance works with vacuum...at WOT there is very little vacuum...so the vacuum advance is not adding any advance to the distributor...vacuum advance is used while cruising a part throttle (high vacuum) to add more timing not at WOT....In fact at the track I would disconnect the hose and plug it at the carb..

check your timing with a timing light with the vacuum advance disconnected and plugged....as you rev up engine you should see the timing advance on the damper..
 
That will do it! I don't run vacuum advance on any of my cars with good sized cams. I run 18-20 initial and the rest in the distributor.
 

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Thanks y'all for the help on this! Ok another question. .. would I gain if I went to a mechanical sec. Carb? I've never used one. Always vac sec. But again I have never ran a engine built like this so I never thought I would need one... what's yalls opinions on this? Guess I should start a new thread.
 
I use NGK R5671A-7 in my small block with Eddy heads, I would assume they would work with stock heads. Someone correct me if I'm wrong...I haven't used stock heads since the 1990's.
 
Wait guys it's not any better with the timing fixed!! Drove to work today with it cruising down the highway around 50mph in 3rd gear floored it and around 4k + it started popping and cutting out! Kinda like hitting the rev limiter again. Please help!
 
Make sure your plug wires are not touching that are close in sequence on the distributor (for example the ones that are 1-2 spaces away on the cap). I had a similar issue YEARS ago and that was all it was...some properly placed plug wire spacers fix it.
 
Seems like one fundamental question has not been answered: fuel pressure. This carb uses 5-7 psi, not any higher, but it has to be steady. Pressure going low or high during a sustained fule use for any reason will cause your symptoms, and either could/wouldshow up at longer times at sustained fuel use, like in 3rd gear. A timing advance problem would show up in all gears.

I can't find anything in the OP's post where this has been measured for sure, and thus confirmed or denied as the issue. You're chasing your tail 'til you answer this, and wasting time to change carbs with this unanswered. The orignal post says that the original regulator is 'only 6 psi', making me think that the OP thinks he need more; not true! Make sure you are regulating at around 6 psi, and then put a remote fuel pressure guage at the carb inlet and test it during a run.

And OBTW, there is a fuel filter in most inlets in Holleys; check those for being plugged.
 
did you check/adjust fuel level in the carb bowls ? Does it miss if you brake rev it ? Do you have another distrib to try ?
 
It doesn't seem to miss in the water box. While heating the tires. About the different carb. I just thought about going to it anyways bc I'm going to make it a race only car. I'm going to hook up the fuel gauge and drive it today or tomorrow depending on my back. Might be going to hospital after work. I don't have another dizzy to try. I'm starting to wonder if the rev limiter in the distributor is acting up. If the fuel checks out ok I will check it texts I think. The carb is brand new along with the whole fuel system. Put new tank,sending unit, 3/8 line, never ran without a filter. So I don't think the filters in the carb inlets are clogged but I will check anyways to be sure. I need to check the rear fuel bowl float for proper height. Haven't checked it yet.
 
How long is it in the water box and how much throttle do you have in it when in the box? If not full throttle for as long as it is going going down the track to the time when it cuts out, then being OK in the water box is meaningless; you're just not pulling the same quantity and rate of fuel. This whole line of thinking on the problem is about putting out max power for a period of time and running low (or excessive) on fuel (low as evidenced by a drop in pressure if before the carb; or high by sustained excess pressure).

Is it the case that the engine goes A-OK past the troublesome RPM range in 1st and 2nd? Is there ANy sort of hesitation at 4k in 1st or 2nd, even just a hint?

BTW in the next set of tests, I would do the paper clip test on the secondary throttle plate pull rod out of the vacuum secondary pod and shut off after the shift to 3rd, just to make sure the secondary pod is pulling open in 1st and 2nd. You will also be able to see how far the secondaries are opening. It is probably just fine, but a lot of this is tedious testing of that and that to eliminate possibilities. Sometimes takes a while and a lot of runs.
 
Sounds like you are running out of fuel. Also after you adjusted the timing did you re adjust your carb? Your timing was way off so a carb adjustment is in order. You are idling at 1400rpm as well. That seems about 300 RPM too high. Carb needs some tweaking AFTER you get the timing situated.

I put a timing light on mine just about every time I take it out. It only takes a few minutes to make sure it is right.

1) Get your Timining situation & fixed
2) Adjust your Carb correctly
3) In that order only or you will chase your tail forever.
 
I keep the idle around 1400 bc even with the 3500 converter. It pulls the idle down to far when in gear and won't idle. Just slopes to a stall. Idles ok at 1100 in neutral. But pulls down to like 800 in agrarian d won't idle that low maybe I need to tweak the carb more to get it right.
 
Sounds like you got a Vac Leak as Well. You should be setting the idle at the highest vac reading..... 3500 Converter has nothing to do with it. You definitely need to fine tune your Carb, besides that You are either running out of fuel or your ignition is not up to the task as well.

Mine stalls to 4800....big deal.... Idle is at 1100 in Park and around 900 in gear. My cam is close to same as yours but Solid Roller. Lift is .634 at the valve.
 
Thought about this a bit more. Could your Rev Limiter be coming in early? I know the MSD units do but I don't have any experience with Pertronix units. Try upping your rev limiter to about 7200 and take it out for a whirl shifting where you normally do. If it does not happen then you found your issue.

Scratch this...... I see it happens around 4K RPM on the Fwy. Fuel or Ignition is my final judgement! Lol
 
I see you tried vacuum advance and disconnected it. I never use vac advance on any cam that's at all above mild. I always find out what the engine likes for total advance by researching on the web to get an idea and testing on my own car. After that I find out what's the highest initial advance the engine can take where it still cranks and does not ping or rattle at throttle tip in off idle. Once you know those two numbers, tailor the advance curve to suit your needs. I.E. if it likes 20 initial and 38 total you want 18 degrees of me hanical advance. Try to get all the mechanical advance in as soon as possible like 2000 rpm. If it pings you either need better fuel or a slower curve. Now about your fuel. What is the ggallon per hour and pressure rating of the pump? I run a Clay Smith high volume/ high pressure me hanical on my 440 and it works very good. Clay Smith sold me a simple Enderle bypass check valve to use as a regulator. My pump is rated at 16 psi and 160 gov. The bypass valve is nothing but a check valve between the pump and carb. It has a spring in it that can be shimmed to what ever pressure you like or need and the bypass fuel goes into a return line to the tank. My engine makes about 500 hp and this fuel system has been 100% flawless. I think the other comment that your pump may be pushing fuel past the needle and seat may be correct. Any high volume or pressure pump needs a bypass of some sort.
 
So your saying this engine should be able to idle at 900 in gear without it chugging and wanting to die? I've never ran this big of a cam so I really don't know. It just seems to bog down and want to die at that slower idle. I guess I need to get my butt to tuning it... I stay so freaking busy I never have time to mess with it. And I don't have anyone to help me with it... learning as I go. And it's not doing it at cruise speed at 4k rpm. It only does it a few secs after I floor it. Hard acceleration only.
 
moparmatt19 said:
So your saying this engine should be able to idle at 900 in gear without it chugging and wanting to die? I've never ran this big of a cam so I really don't know. It just seems to bog down and want to die at that slower idle. I guess I need to get my butt to tuning it... I stay so freaking busy I never have time to mess with it. And I don't have anyone to help me with it... learning as I go. And it's not doing it at cruise speed at 4k rpm. It only does it a few secs after I floor it. Hard acceleration only.
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I did the "only one car" deal when I was younger. I know what it's like to try and have a fast car and have to use it as an every day car. It might not be easy but you'll be miles ahead if you buy a beater to get to work ang get the groceries and be able to devote your hot rod to pleasure use only. .y daily driver is a 96 Subaru Legacy I bought for $2100 in Oct 2009. Get the ignitionn/timing sorted out first, then move onto the carb/ fuel issues second. You will get to the bottom of this my friend.
 
moparmatt19 said:
So your saying this engine should be able to idle at 900 in gear without it chugging and wanting to die? I've never ran this big of a cam so I really don't know. It just seems to bog down and want to die at that slower idle. I guess I need to get my butt to tuning it... I stay so freaking busy I never have time to mess with it. And I don't have anyone to help me with it... learning as I go. And it's not doing it at cruise speed at 4k rpm. It only does it a few secs after I floor it. Hard acceleration only.
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Yes, if you guet it tuned, it should ldle bow 1000 rpm in gear without chugging down and stalling. Forget about vacuum advance, it has no place on an engine with a big cam. Get the initial advance up in the range of 20 degrees and it will run and idle in gear much better. The throttle responce will be much better also.
 
Ya, being married have 2 young kids and work 6 days a week then daughter has cheerleading practice every day after work and having it as my driver it's hard to have time that it takes to get this stuff all tuned in and right. But with all the good help from y'all I think I will get her right soon. I have the timing right now. Hopefully tomorrow I will have time to check the float levels on the carb and adjust the idle mixture better with a vacuum gauge and get it to idle around 1000. Then tee in my fuel tester and drive it down the road to see if I have a delivery problem. If everything checks out then I'm going to turn the rev limiter off and see if anything changes.
 
said it was a brand new carb. Did you check for shavings and trash before installing?
 
Hughes 1111 double springs. Set at 1.8 installed height. With longer ferrea valves and special retainers
 
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