Okay, was able to get out there again and double check everything.

I printed out the 1920 manual Dan posted the link too and set the carb using that. In neutral, with air cleaner on, engine warm with running a clearance rpm every three minutes to keep things right, took the thermal switch vac hose off and applied it to the door vac connection on the air cleaner once engine warm to hold it open and take away any potential false readings due to a faulty thermal switch. Gave it a squirt of carb cleaner by the way and didn't buzz initially and then started again. Vac at idle shows 16 lbs.

All timing and rpm done with car in neutral and basically same as above. Set timing down to 9 degrees initial. Was going to set for 10, but slipped when tightened so just left it. Makes for a starting point.

Chart below shows what results I got. In areas where timing did not change I rechecked it to ensure the number. All timing checked using the same dial back light and a verified tach instead of the other digi meter I was using that I noticed would freeze on an rpm occasionally (great eh?).

RPM Mech w/vac Variance
750 9 9 0
1000 12 29 17
1200 18 33 15
1400 18 34 16
1600 18 35 17
1800 20 38 18
2000 21 39 18
2200 22 39 17
2400 23 39 16
2600 24 42 18
2800 25 43 18
3000 28 44 16
3200 30 46 16
3400 31 48 17
3600 32 50 18

average 22.07 37.87 15.80

Note: did not want to run it past 3600 as did not want to over do it. Sorry about the chart. I've tried spacing it out, but still shows all pushed together. Hope you can make it out. First number rpm, second number advance mechanical, third number with vac/advance hooked last number is the difference between mech and w/vac.

I've not run the car with the tach inside to see cruise rpm and am just (incorrectly I'm sure) using the computer calculations for rpm at various levels to estimate best timing rpm level. When on the main roads into town as it were, 55 mph is used and on the other road 70 and 65 mph is used. Around town is 30 to 35 mph.
Computer calc for tyre: 235/60/14 Gear: 3.21 Speedo gear: 33.53 calculated, using a 34 gear

Estimated 1625 rpm at 35
Estimated 2553 rpm at 55
Estimated 3017 rpm at 65

My thought is, to get maximum mpg, that at around 2000 to 2100 rpm I'll need to have the timing advance in to the 47-53 degree range or so (going off a number I saw written on the site for ideal range for mpg, please correct me if that is wrong). This will put me into the timing being in at an average of 40-45 mph. Or is it advantagious to go for the 30-35 mph range that would be the around town number to get the most overall mpg? Driving is pretty much 50/50 in town and 55 plus.

Sorry, lots of questions as usual.

Looking at the chart it seems like what Ted said is maybe the issue on this dizzy. The mechanical advance seemed to freeze in the 1200 to 1600 range at 18 degrees. Right in assuming a spring issue here having to overcome tension?

Interestingly the timing froze again with vac advance on in the 2000 to 2400 range at 39 degrees.

Appears pretty much that the vac advance is all in by 1000 rpm so probably needs to be adjusted to move that up the rpm range slightly to be all in at desired average cruise rpm (suggestion) and need to get the mechanical degrees to increase down low/faster so mechanical advance is all in by the target rpm. Thinking right?

As always, help and suggestions greatly appreciated. Thanks also for taking the time to post. I promise that eventually things will sink in as can be a bit thick at times.

Cheers

_________________
From Mopars to classic Minis and back to Mopars in 19 years flat!

Will work for roast chicken crisps!!

It appears to me you have the right total mechanical advance, but that it's coming in too slowly. I would try a lighter light spring, but you may need a longer loop on the heavy spring to allow for more low speed mechanical advance. Also it appears you have an 8.5 or 9R vacuum advance can. You should be able to switch that for a 12R and improve the cruise economy. 10° initial should be fine once the mechanical advance is set to come in sooner.

Numerically lower rear gears to reduce engine speed will help economy, but that's a lot more work and expense to change than distributor springs and vacuum cans.

Thanks for all the data! There is no substitute for good test data!

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Joshua

I plotted your mechanical advance, nasty little non-linear advance spike at around 1200 RPM--not the smooth curve one would hope for (reality is so pesky compared to theory sometimes). A number of things can be afoot here--is the distributor clean and lubricated? Springs can do this but spring tension usually plots smoothly so it might be associated with the fastening point of the spring and not the spring coils themselves. I think DI did some testing of a number of advance spring combos and learned a few things--hopefully he will weigh in. [/img]

_________________
Slanted D150

Joshie225 - From the latest data I'm thinking an 8.5 can on it too. The thing is a reman unit and has no numbers on it sorry to say. May try a different can on it once I've got the mechanical dialed right.

tlrol - thanks for sticking with it. Yes, noticed the same issue when I graphed it on excel. Might be lubrication as the dizzy is a brand new reman one. I did pop a bit of oil in the shaft hole and on the dizzy drive gear, but I did not take it apart before putting it in to be able to do anything else with it. Didn't want to muck something up when just trying to get the car going again after the HEI conversion.

Do you know if DI posted findings or maybe Ted anywhere for lighter springs etc.? Is it just a matter of give it a go, see where you are and then take it out and try another?

I did see somewhere something about buying a Mr.Gasket spring kit (may have even been for a chevy or something) and using the silver spring in place of the small spring. Don't have any info on what this does or what can be expected for a change in advance curve on it though so don't know. As far as looping the large spring is this a try/test, try/test type thing or does someone have some data up on it?

Thanks again!

Oh, and what about the rpm to have all in?

Cheers

_________________
From Mopars to classic Minis and back to Mopars in 19 years flat!

Will work for roast chicken crisps!!

MoparBrit,

Your plot is great, however I would change your secondary spring, the heavy looped end spring. Try to find one out of a big block motor that has more coils on it and bigger looped end for a more linear progression. It is about an 1/8th inch longer than the one you have now. Doc turned me on to this spring. It will bring your curve in a little faster. I am all done with advance by 2500 and get a little more at 3000 rpm. It feels like there is more midrange power set up that way. I cruise at 2500 which is 60 mph for me.

You can take out the lithium grease on the weights and use 10-50 synthetic oil. It stays very linear year round.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

We must have been posting at the same time Ted.

Thanks for the info on the large spring. I'll have a look, but do you happen to know off hand if you can purchase these from somewhere? I don't get to make it down to the scappie (20 miles from here and dependent on others for transport) very much so if I could buy the right one new that would be great.

Do you know anything about the Mr. Gasket small spring swap?

Okay so makes sense on the all in on the advance then. So, for my set up and average cruise is the 2100 ish too low and I should go for more like the 55 mph 2500? Your post also supports my thought that I need to adjust the vac advance to come in full a little later and hit peak at cruise rpm, right?

Righto on the oil. tlrol suspected that they might be binding. Once I get the springs figured out and sourced I'll do the swap and get them lubed.

Cheers

_________________
From Mopars to classic Minis and back to Mopars in 19 years flat!

Will work for roast chicken crisps!!

Take a close look at the weight slots in the govenor plate to be sure ther are no deep wear spots. I have seen some with small dips in them that cause erratic movement of the weights, no matter which springs are used.
some filing / sanding usually resolves the problem.

Also remember, the spring posts are adjustable so you can fine tune the spring rates. Based on your info, go lighter on both springs. (move the outer spring post, inward)
DD

Thanks!

With luck I'll go ahead and pull the dizzy today if it ever stops raining that is.

Lots to check and do. Plan is to check the weights and smooth as needed, lube them with synthetic, try adjusting the pins and then see where I'm at.

From there it will be replacing springs and perhaps a different vac can. Just finished reading the cruise rpm post. Very helpful.

Ted, sounds like you are using the red small spring. I know there is one of these in the distributor I have here so might swap that in and see what it does.

_________________
From Mopars to classic Minis and back to Mopars in 19 years flat!

Will work for roast chicken crisps!!

This is the second time someone mentioned adjustable spring pins on the distributor. I must be missing something--where is the adjustment? Is it the plate below the advance weights? I have not pulled that out yet so that would explain my ignorance...

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Slanted D150

MoparBrit,

Unfortunately no one up here has these springs. I have gone to several car dealers and MOPAR Direct, no luck. We were born in the wrong era.

Yes, I did the MR. Gasket and MOPAR spring test. It was fun for about a week, but I am not into that much of a torque hit all the time. It was hard to keep the P235's from spinning. The springs are so light the engine just takes off with out allot of control. So unless your building a race car for the strip, don't go there.

I would dial in the curve to meet the needs of your cruising rpms. That will help to get best mileage.

Did you get a VC-208 can? It is a 11R. That should buy you the extra advance you need at cruise. I am running one right now and prefer it over the others. It is easy to dial in, I think I have it at 3 or 4 turns out now so it kicks in like overdrive. If I am cruising at 18" it kicks in pretty hard and gives a nice feel to the pedal as long as your not running too lean. You don't want to be driving so lean that the advance never kicks in. If you can't cruise between 15" and 18" or higher, then your too lean.
The power valve on my 1920 kicks in at about 10.5" I have my vacuum advance dialed out at that point so it doesn't ping.

Yes, the small red spring with the post rotated out to keep it tight, not loose.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Triol,

I will email you Doc's distributor recurve guide that shows the spring pins. They rotate on an ecentric. You can use a small box end from the bottom to rotate them.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Ted, not picked up a can yet. Saw two part numbers posted and was going to look for specs. The VC208 can you mention, so now I know it is an 11R and I also saw a VC239 listed. Not sure of the rating on this one.

My thought was to look at the weights, clean them up as needed, lube and do the adjustment.

Then retest and see where the curve comes in. Might just smooth out what I have, but pretty much keep it at the same level. My thought was to bring it in mechanical side a little quicker. That way at say 2100 or so I could get into the 47-52 range. If I can get the can at say the 11R to pull in 22 at that point then I'll need to get the mechanical side to be at 25 to 30. Sound about right?

I still need to find a 400 big spring right?

Occurs to me that I've been setting things with the vac tee'd into the choke pull off port. I also need to check the vac pulled on the advance port and map that out as well. Not sure what I'm getting there as not checked. Right now, with the above test, at whatever level the vac is off that port I'm getting full advance by the look of it at 1000 rpm.

EDIT: Found the specs listed by Dan (thanks dan) on another post.
Number: Start / Max

VC-93: 4.9" - 7" / 5.25° - 7.5° @ 13"

VC-173: 7" / 5.3° - 7.8° @ 10"

VC-184: 7" / 7° - 10.5° @ 11.5"

VC-185: 9" / 7° - 10° @ 15.5"

VC-208: 6" / 10° - 12° @ 9" - 11"

VC-239: 7" / 7° - 10° @ 11.5"

VC-244: 9" / 7.5° - 9.5° @ 6" - 8"

Looks like listed in distributor degrees so the max on a vc208 looks to be 24 with an average of 22 and the vc239 looks a max of 20 degrees with an average of 17 (mid point of range).

_________________
From Mopars to classic Minis and back to Mopars in 19 years flat!

Will work for roast chicken crisps!!

Ok, from underneath--clever...I have a spare distributor so I will take a peak at it and see what it is all about. Tweaking the distributor is a very subtle thing...quite fun however...

_________________
Slanted D150

MoparBrit,

I could only find one VC239, they are pretty scarce but they are a few VC208's out there. I have my local auto parts constantly hunting for them.
The last one came from the east coast. I want to have a few spares for my other cars.

Yes, if you can hit 30 degrees by 2500 that would be good. It is your preference if you want to hit it earlier. The slant puts out about 200 ft pounds of torque by 2000 rpm. Remember the old 100 to 125 HP rating was taken at 4000 rpm. We normally don't cruise up there......so we are utilizing the power from the bottom end torque. That is why the recurve can help.

Yes, I think it would be worth while to find the big spring. Send me your email and I can send a picture of it along with some others and Doc's guide.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Distributor Recurve Link

I alway grab extra advance springs whenever I have a chance, those are good to have around.
DD