Trouble With Hills

How much vacuum is above the throttle plate? (Answer is none) is it a ported vacuum source?
Does it even matter at wot when there is no vacuum. (Again no vacuum at wot so the pot is doing nothing)
Does the vacuum pot advance the timing or is it retarding under vacuum? (Counter rotating distributor? Advancing under load retarding at idle)


I would pull the hose and put the jeep under load (hill) make small adjustments with a means to measure performance. Repeat repeat repeat.

 

Millions of F-heads never had any vacuum ignition timing at all. KISS Principle?

Just sayin'.

 

This is an L head though... Pretty much the same thing though.

 

The one I have been modifying.

 

I'm thinking you are describing a lean condition, possibly due to the header? Lack of back pressure. What do the plugs look like, go up in jet size possibly.

 

Snowshoe?

I think I hear the cap'n
I mean Admiral if your talking bout another.

 

So, to me, there may be two issues here.
Pinging is obviously a timing issue. I don't think it is a curve issue, but more a total timing issue. All of the graphs show 30 degrees max timing. I would like to see if the issue went away if that dropped to around 20 degrees. If I were to pick a curve I think A would be my first choice.

Carb backfiring is usually a lean mixture. Assuming it only happensfurther up the hill and not at the bottom, I would be curious to see if the bowl is being emptied under WOT. A lean mixture may also be contributing to the pinging issue.

 

The plugs look good to me, but I'll post a picture. The graphs also have dotted lines, which are the max advance. The max advance can be changed by using a different colored bushing. Hard to see in the picture. Some are below 20 degrees.

 

That is a possibility. I can get different jets for the Weber. I do want to get the timing fixed first and see if that solves most of my issues.

 

So many mods. You are sailing by dead reckoning, and a long way from shore. You need to find some definite landmarks, put yourself on the map again...

 

Thats why I want to get match the advance curve of the HEI to the stock 4 cylinder distributor.

 

I have no idea what may be modified on your engine. The standard L head produces max torque at 2000 rpm and it’s 2200 for the F head.
As scoutpilot mentioned the standard advance was
5* BTC for 69 octane uncracked gasoline.
For today’s cheap 87 octane I will suggest your baseline idle advance be set to 7 or 8 BTC.
My standard engine idles and runs perfect at that advance.
There is no way to guess your ignition advance in degrees of spark BTC.
Go find yourself an F head crankshaft pulley then copy the location and file a timing notch onto your pulley.
I can sell you a spare indicator that bolts onto the timing cover or you can find an early F head timing cover with the degree marks stamped upon it.
In the meantime I’ll see if I can find any reference to Willys vacuum advance curves.

 

Pickups both versions, Wagons, Henry J's, Jeepsters all used a Vacuum advance distributor with the 134L and F The Vacuum advance improves drivability and mileage. If you look in the service manuals for those vehicles they give spec's for the distributor. My IAT-4405 is from a 134F OEM application was a 61 FC.

 

I don't think everyone is understanding what I am looking for. I am not using the vacuum advance now. Not interested in hooking that up for the moment. My initial timing is properly set. I have checked that with my crank degree kit I have.

I need the timing advance curve for the stock mechanical advance on the stock distributor. Then with that information, I can match that curve to one of the curves in the HEI spring kit I bought so at least I can return the advance back to stock so to speak. What I think is happening is, the HEI mechanical advance is either advancing too far to say, 40 degrees, or its reaching its peak too early or too late for what the L head wants.

If I knew where the stock L head advance peaks out at and at what degree, I can set my HEI up to do the same, or close to it.

Im assuming that an engine would want its max advance set at its peak torque?

The stock distributor has 2 different springs on the weights, so that tells me it has a mini peak like one of the HEI curves when two different springs are used. The weight with the lighter spring advances first, then the stiffer one advances more at a higher RPM.

 

I am thinking I have to set the HEI up to one of these 3 curves, but I don't know which one is closest to the stock distributor. The other 3 curves have the max advance well over 4000 RPM, which I know I don't need.

The dashed lines are where the advance will stop based on what color stop bushing is used. Hard to read, but red is at the top, silver, green, blue, purple and then black is on the bottom.

Looking at these graphs, I guess what I need to know is the maximum degree advance and the RPM point that is achieved at.

 

The typical 134 distributors were auto adjust.
The typical CJ AutoLite had an advance of 11* @ 1500 to 1750 RPM and a maximum advance of 22* @ 3000 RPM on certain Jeep models.
In the 1959 AutoLites we’re not available and the service standard became Delco Remy for a year or two. It had very similar specs.
The DR’s had an advance of 10 to 12 degrees at 1950 rpm.
But yes exact specs depends on model and vintage.
Figure at least 11* @ 1500 / 1750 up to 22* at 3000 RPM.
I would probably set it up as chart “E” suggests.

 

This is the exact info I was looking for! I will do that and report back.

 

All I can say is WOW! I changed those springs out and what a huge difference that made! Much better performance and the issue is gone!