Newly rebuilt motor issues. I believe it is Webers

[tvacc]

Hi all.

Just an update and to get some feedback.

I am sure you all remember the Elan I bought that had the front jackshaft bearing reversed so that i was not getting oil pressure to the top of the motor. Car is now running. Rebuilt the motor.

After I started the car, great oil pressure. After I started the car and adjusted the carbs which are Webers, I was getting back firing from the rear carb. I removed a wire from each spark plug one at a time to see the effect on the motor. 1 and 2 acted just like expected with the motor showing a decreased rev or decreased "performance' equally for each one. Number 3 showed no difference, just like I had not taken the lead off the motor and number 4 was somewhere between the effect of numbers one/two and number 3 leaning more to number 1/2.

I then checked the compression and all is fine. So I have to assume that the rear carb is just not putting fuel or enough fuel into the cylinders.

So, I need some ideas. I have messed around with Webers before, but not that much. I know now to adjust them but as far as trying to figure out why this is happening, I am a little, not much, out of my depth. I have set float levels and change jets. Open to ideas.

[john.p.clegg]

Tony
I take it you have checked for a good spark?

John

[carrierdave]

Tony
Get yourself a colortune, you can then see if the cylinder is firing. Then go to the manual and set the carbs up as described. I would say that you need to adjust the idle mixture screws amoungst checking things like float heights etc

Did/could you see or hear the spark jumping accross to the plug when you removed the lead from the plug?

Dave

[billwill]

You might have a partly blocked jet in the Weber half for number 4.

[types26/36]

Sounds like the carbs are not balanced.....is the airflow through all four chokes the same?

[rdssdi]

Tony

What were the symptoms of the top end not getting lubrication?

Who installed the jackshaft bearings?

Bob

[tvacc]

I will try and answer all questions.

First, I bought the car with the top of the motor not getting oil, although I did not know it at the time. I only knew it would not start. Only had 3 miles on it after rebuild. It was rebuilt by a very well known garage in the Finger Lakes region of New York. Dont want to say who it was as that only causes issues. Basically I was told by the owner that the car arrived on a flatbed after the rebuild. He started it and drove it down the street and back. Parked the car and it would never start again.. I think what happened is that he was able to start it on the assembly grease, once it warmed up, lost that and that was that. Car was very hard to turn over. I put 2 batterys on it and then jumped it from my Ford 350 van. Nothing helped. Would just go...rrr.rrrr.rrr. Oil pressure gauge just moved a very tiny bit.

Yes, I did check for spark. Very strong and a sharp "snap" when I had the plug out of the #3.

Airflow is pretty equal across the board. Maybe just a tad less on the rear carb. they are pretty balanced and I have adjusted the idle screws. no change.

I do have a color tune, but as the spark is right "there" figured what the heck would the color tune tell me?

[UAB807F]

I do have a color tune, but as the spark is right "there" figured what the heck would the color tune tell me?

The colortune lets you see the cylinder combustion which means the color of the flame. If you have a rich mixture it's a strong yellowish flame, if it's right it goes blue, and weak mixture comes as pale blue-white (I think).

It's very handy for setting the idle mixture screws exactly right, although the settings in the manual are usually close. The best thing IMO is that if you blip the throttle you can see the effect of the accelerator pump jets as it should go momentarily rich then settle down to the normal blue flame.

But if Bill's right on the partly blocked jet, then colortune will spot it in a second.

Brian

[tvacc]

I bought the colortune back in 1969. I will have to look for it. I have not seen it in years. Let you know.

[twincamman]

Tony ..if it has fuel spark and the mechanical and electric timing is correct it should be eager to start . The issue may be
Your starter gone AFU or a bad ground to the chassis clean the ground first I had much the same problem a while a go ....ed

[tvacc]

I dont believe it is getting fuel as the plug is dry. Timing is right on. Starter starts the car right up. It just runs like it is missing a cylinder. Since I have perfect compression on all 4, I believe it has to be fuel. Since 1 and 2 are firing fine and 3 and 4 are giving me issues, it just must be the rear carb. I replaced the starter, points, everything. All that appears to be functioning correctly.

[elancoupe]

Rechecking float height is always a good thing. I have used the basic Keith Franck method of checking the actual fuel level as opposed to measuring the height from the carb top, the actual fuel level measurement method made a huge difference for me.



If you are convinced that the rear carb is the problem, you can prove or disprove by removing the carbs, switching the levers and retry.

[twincamman]

Ummmm there is gas in the tank????right?...and the float needle is not stuck in?...the plug is in good shape and the plug lead is good?and the dist cap is not tracking or cracked...and you have timed the dist and cam timing correctly ? All pits IHave fallen into ..the worst was a bare wire in the dist .took days to find Try placing the offending plug on the motor and crank the motor to confirm spark...A bad condenser will cause rough running .ed

[tvacc]

Ummmm there is gas in the tank????right?...and the float needle is not stuck in?...the plug is in good shape and the plug lead is good?and the dist cap is not tracking or cracked...and you have timed the dist and cam timing correctly ? All pits IHave fallen into ..the worst was a bare wire in the dist .took days to find Try placing the offending plug on the motor and crank the motor to confirm spark...A bad condenser will cause rough running .ed

All above have been checked except for inside the carb. Swapped plugs, swapped wires, but it has a strong spark. Dist cap is new. As is the points and condenser.
Cam and dist tuning is right on. Will do that this weekend.

[twincamman]

Well short of killing a chicken and performing a voo doo ceremony or calling in a priest that's allI have..Unless some shmutz is clogging a carb hole inside ..ed