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Senior Contributor
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Discussion Starter · #1 ·
As many of you know I built a Legere inspired 1.9 to 2.4. It seemed it took forever to get it done it and it seems it is taking me twice as long to fine-tune it.

With ported head, bigger engine, the dual DCOE Webers 40ies I found that the stock fuel pump wasn’t doing the trick. I went to a low-pressure high volume straight through electric pump, which caused some improvement.

I bumped the mains up to 180 from the 165’s (the emulsion tube and the chokes had already been maxed out for the 40ies). Things seemed smoother and this did not cause any carbon build up on the plugs they are nice and tannish still after 50 miles or so

I finally have the timing at what was listed as correct. I am at 15-degree advance at idle and 36 degree max advance at 4000rmps (the vacuum advance has been removed and the plate clamped down).

THE PROBLEM that I have been having if I stomp on it and run through the gears the car goes like a fiend. But if I step on the gas at say 70 in 4th gear it is difficult to get the car above say around 5500 rpms. Adding the elec. fuel pump and the big jets helped some because before around 5000 was the cut off point.

Sometime if I step on it just seems do nothing, the carbs make lots of vroom noises but it doesn’t respond like it should. The engine get loud and then just doesn’t sound right till I back it off, almost like it was fluttering.

Low end is fine and I have zero problems getting the car to respond strongly 1st through third gear. If I am at 3000rmps and stomp on it in third it takes off but if I am at say 4000 rpms in fourth it sometimes barely accelerates it seems.

Sometimes in 4th I can creep it giving it a bit more gas at a time till I am going say 90 with lots of petal left and sometimes trying to creep it up just causes the dead acceleration problem. After I have the problem if I back it off and downshift and slow down and then try again it goes fine.

I check the cam timing, it seems to be correct and the lifters are dead on.

Could this be some sort of vacuum leak that only rears its ugly head at higher RPMs? I do have a 3/16 line like Toto’s’ to vent crank gases

Wrong cam duration? The cam is 486 [email protected] w 108 separation
Sticky springs?
Bouncing timing? I am sort of at a loss anybody have any idea’s
wrong distrib springs? (I have 2 of the lighter springs)

Thanks
Calvin
:confused:
 

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boomerang opeler
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5,634 Posts
are the accelerator pumps in the 40's working?

use a mirror to look inside with the engine off and see if theres jets of fuel being pumped into each venturi if not you'll get a dead spot in mid rev acceleration but ok on full or slow acceleration

just a thought :D
 

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Senior Contributor
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499 Posts
Discussion Starter · #6 ·
seems to be pumping and the middle isn't dead. Might be the exhaust not flowing.. on the way back from the route 66 show I had about 100 mile run. I could creep it up to 6gs but same problem if I really stepped on it... lots of noise and power falls off at about 5500rpms. To power back up i have to slow down to about 2500rpm downshift and then go and then it goes no problem again. I just don't know where to look to try to straighten this out

perplexed,
C
 

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Super Moderator
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1,802 Posts
fuel

Calvin, what size fuel line are you running? You may be running out of gas at high demands.

I hate to be the one to tell you, but the best option might be to bite the bullet and take the car to a tuning shop with a dyno. It may be the only way you'll be able to see what is going on while it happens and be able to adjust for the changes. The good news is that you are coming up on the off season, and dyno time might free-up some soon. I recently spent 4 hours with a friend tuning his Rustang with a dyno and it saves SO much time and $ in the long run. (The 4 hours was @$350, by the way, and well worth it.)
 

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Senior Contributor
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499 Posts
Discussion Starter · #8 ·
I think the fuel line is 5/16..... I will chceck in the AM but I think that might be it. Matter a fact i am sure that at least some of it is 5/16 .

What size should I be running?

There is also the stock metal section from the old fuel pump to the last of my three fuel filters I am not sure what size that is. I sure hope that the fuel line IS the problem as that would be far less than a dyno ( I am curious what that would tell me though).

at least I have a good assortment of carb jets now from 135- 195 lol:eek:
 
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