Distributor and Carb Upgrades...What order?

[karls59tr]

I've been trying to track down a stumbling /missing problem I'm having with my TR3 so I'm going to take the advice of this Forum and send out the Dist to have it recurved and Vac Advance checked. I've also discovered from Competion manual that the carbs should have to the RH needles (richer) if you are running a header like I am so I'm going to switch out the needles to RH. Odd thing is the plugs are looking sooty black which is an indication of Rich mixture!??? My question is: should I put the recalibrated Dist in first to see how it runs then switch out the needles if needed or change the needles and Dist and then test? Karl.... TR3 with rebuilt motor,rebuilt carbs,TR4A intake manifold,heat shield,wrapped exhaust header.

 

[Brosky]

The first thing to do is to get the ignition timed and firing properly and Jeff at Advanced will do just that when he rebuilds your distributor. All you'll have to do is set the timing and make sure that the plugs are new and you'll be ready to go. That is, as long as your coil is fine. If any doubt, replace it and make sure that all wires are in good shape.

Then and only then, should you begin to adjust the carbs.

 

[Brosky]

Karl,

Do you have Stromberg carbs on the engine? If so, I have an Excel spreadsheet that you can enter the existing needle part number in one block and then the one that you desire in another and get a graph with how much richer or leaner it will make the mixture across all 13 points of measurement on each needle.

All of the data for every needle is in there all set to go and the formulas are all completed to create the data and graphs.

 

[Banjo]

Ignition system first, then fuel.
the old phrase is "90% of carburetor problems are in the ignition system."
Get the spark 100% then adjust the carbs.
How's the throttle shafts on the carbs? worn shafts can cause problems.

 

[70herald]

I've been trying to track down a stumbling /missing problem I'm having with my TR3 so I'm going to take the advice of this Forum and send out the Dist to have it recurved and Vac Advance checked.

Hi Karl
I have been dealing with the same problem with my Herald, and think that I have solved it.
First of all send the dizzy out for rebuild. I put a crane XR700 points replacement in mine and am very happy with it. Now when I got the dizzy back the engine missed terribly. Turns out that the old dizzy was so wobbly that the rotor had been hitting the (new) cap and mucked it up, so you probably should replace it also at the same time to avoid problems. (ie don't be cheap like I was
Stumbling under acceleration / or load particularly if accompanied by backfiring can be caused by too lean a mixture. Right now, my engine is running a bit rich at idle (but seems to be lean under load), I probably need a new needle(worn at the bottom), that is the only thing I didn't replace when I rebuilt the carb.
Also sooty black plugs can be caused by long idling, so for the time being, I wouldn't get to worried about it. First thing to do is to make sure you have a spark at the correct time for each cylinder.

 

[SBooth]

You may well have a carb problem, but I took my Strombergs apart 3 times before I cured a hard miss w/ my TR4A by replacing one new coil w/ another new coil.
Steve

 

[Andrew Mace]

..."90% of carburetor problems are in the ignition system."

Or as the great Dick O'Kane said: "Carburetor is a French word meaning 'leave it alone.'"