I’m sure Dan will ask…
1) Stick or auto transmission?
2) What rear gear ratio?
3) Primary use (long road trips, or short beer runs, etc)?

 

I’m sure Dan will ask…
1) Stick or auto transmission?
2) What rear gear ratio?
3) Primary use (long road trips, or short beer runs, etc)?

Yes, he included a work sheet for the details. I’ve been reading forum posts of people who had theirs recurved and noticed a performance improvement. I guess I’m just curious as to what specifically. Like better idle? Overall running better? More power?

 

we are the original family owners of my powertrain so I know the car well
Dad never wanted to spring for the $10 recurves during tune ups back in the day
when he gave me the car in 82 I never bothered either. actually never thought about it

I had the original dizzy rebuilt in the 90s. they never curved it

about 10 yrs ago I sent it to Tim whom since retired

the car ran like a bat out of hell through all RPM ranges. its so smooooooth.

I threw pop the keys told him to take it for a spin and he come back grinning

so yeah it makes that much of a difference

 

Thank you for the reply! I’ll report back here after I get it back. Also, I plan on giving the distributor a cosmetic facelift. The vacuum advance nipple and housing is pitted and badly worn. Is it as simple as buying a new one and replacing it?

 

When I sent my distributor to Dan, he told me he had been recurving Ford distributors for decades and he had never seen one that was correct from the factory. The Ford distributors are good hardware, but they were mass produced and there was never any point at which those distributors were calibrated in any way. Thus, when new, the ignition curves were all over the place. But the engines ran fine and that's all that mattered to Ford.

 

I see a Dan and Tim listed can someone post some more complete contact info for them? I'd like to see about having my 428 distributor redone.

 

Dan is at https://www.mustangbarn.com/

I don’t know who Tim is.

 

For what it's worth, I was really displeased with my distributor when I got it back from Mustang Barn. Had tons of problems tuning my motor and going in circles. I ended up having to tear it down and discovered that the vacuum advance springs he installed were way too big; they were sitting loosely on the tabs and wiggled easily when touched. No way it could have been properly curved. He also failed to mention that my distributor was from a 1963 motor, despite sending it off with all the information about my car

 

I have to ask, did you go back to Dan and voice your concerns?

 

I'm a satisfied customer of Dan's work. He'll ask a number of pertinent questions. Be honest in your response an you'll get what you paid for.

 

I believe Tim is no longer is business…I might be rembering this incorrectly. I agree with others that Dan at The Mustang Barn provides excellent service and work. @alex1965 is the first post I have seen in my almost eleven years here of a dissatisfied customer. @alex1965 I would bet a simple phone call to Dan would have made your situation whole.

 

Dan has mine at the moment, he found it was way off. Way too much advance and all in way too soon. That explains why I could never set the timing right. I always had to set the initial timing too low so the all in wasn’t too high and it didn’t advance too quickly. Looking forward to getting it back in a few days.

 

Well I'm gonna talk to Bob about my sparkulation distribuuushun !

 

I don't know how your advance curve looked like and if it was any good, but one of the springs being loose is normal. That way, the advance mechanism is hold back by only one spring initially, until the point (RPM) where the slack of the other one is reduced to zero. From that point on, two springs are holding the mechanism back and the advance rate is slowed down. For the (generic, from Google) curve below this happens at ~1700 RPM.

 

If I can stop driving mine long enough, I intend to have him re-curve mine...and the two for my sons'.

 

Looks like you'll be waiting until next winter LOL. I tend to not do any upgrades that will take me "off the road", spring summer and late fall.

 

It was something I was wanting to do on my GT40P. It has a 90's Mustang 5.0 factory cam. As it was it ran damn good! It ran better then I thought it would. Last year I worked over my Duraspark distributor. I welded up the unused 16L slot I think it was to 8L spec of .385" which will give 16° mechanical advance. I have my initial set to 14° BTDC and swapped springs to bring full advance in around 2500ish. Yes maybe I could get better results by a pro but this didn't cost me anything but my time. I want to also mention I didn't just jump into it either with random specs. I know from years of reading topics on GT40P heads they have efficient combustion chambers and don't need a whole lot of riming. In most cases just 28°-30° is all they need. I also believe in running as much initial timing and as quick as tou can without hard starting or detonation. It should run normally. My engine has 9.5:1 compression. It starts very easily, no ill effects . It runs very well on 87 octane. It does not rattle no matter how hard I've lugged it. All in all I'm very happy in every aspect and feel I've done a pretty good job. Now as far as performance. It runs and drives smoothly, no unwanted side effects. The throttle response is incredible! It pulls really hard, much harder then before. I mean you can feel it pushing you back in the seat! Again I just didn't randomly jump into it. I knew what I wanted to do. It's not to say forget sending it to a pro. Unless you're familiar with distributors and tuning, it's a job for a pro. I'm just posting to say, yes it's definitely and highly recommend to have your distributor recurved

 

I don't understand how you can correctly recurve a distributor's centrifugal advance without having the car on a dyno or at a drag strip test & tune session. I have also seen how an engine with light springs to bring in advance earlier idled like crap because the lack of spring tension had the weights bouncing around below 1000 RPM. Likewise the vacuum advance needs to be dialed in to deal with possible high load, low RPM pinging and surging/bucking at cruise, so again that requires road testing. When it comes to modifications every engine will have its unique needs. You probably can get close with what is basically a mail order tune by sending out the distributor, and maybe that is good enough for the masses, but expect to be leaving some performance and drivability on the table.

 

With the proper given engine spec and intended engine usage, an experienced "Distributor Machine" operator can setup and recurve a distributor with or without the vacuum advance. Like any experience, the owner needs to provide accurate data. Otherwise, It's another case of "garbage in - garbage out".
There is no "loading" of the distributor, no atmospheric anomalies that affect a distributor curve. Just adjusting mechanicals to prescribed plan. However, a Dyno session and test track will reveal the outcome.
Yes, I've had my distributors recurved and would do it again, if I change my engine specs. Just easier.

 

Getting prepared to send my stock 289 distributor in to Dan for a recurve and was curious what some of the benefits to doing this are.

I’m running a slightly hotter than normal cam in my engine, with stock heads and Tri-Y headers with dual exhaust. 4 barrel 650cfm Edelbrock carb.

Dan didn't do mine, Tim O'Connor did back when he was still working.
My motivation to recurve was that I had retired my '66 GT from track duty, removed the race carb and gone back to the Autolite 4100.
The above 5000 "crispness" disappeared with the smaller carburetor and I wanted that back, so I had it recurved for the cam and other
aftermarket stuff still on the engine. I got about 85% of the top end back with the recurve.....
Excellent mileage AND good above 5000 rpm now.

 

Distributor has been sent off! Sent him my specs, although I don’t have a cam card, so I just said I have a mild cam. Does anyone know if he replaces worn parts and cleans up the distributors he recurves as part of the service?

 

I'm guessing you didn't have that conversation? Yes, will check the bushings. If needed he will replace them. I guess, if your plates are worn he will advise. You can email Dan and give authorization, just not sure what turn your discussion took.
Mine was clean when it left my garage and was clean when returned and didn't need any parts, just the curve.

 

The distributor is on its way back! He told me my mechanical advance was going all in at 2,000RPM. He adjusted it to have 14 degrees at 2,000RPM. The vacuum advance was also too high. He adjusted it to have 38 total timing with a 12-14 initial timing setting.

 

Did he provide your "built-in" mechanical degrees ? Typically, "All In" is a total of Initial + Mechanical, @ a given RPM. Dist. Vac may or may not be considered, which can be up to 6º (?)
As an example, my distributor has a mechanical of 18º + Initial (18º) for a total of 36º. This is "All In" @ 2500, or so, Rs. I do not run any VAC.

It appears your "mechanical" is 22-24º? Am wondering how Dan got your's so ?

 

My advance curve is a straight line 😉

edit: but that wouldn’t necessarily work for you. My deal is a little different than some.

 

Yesterday I met up with @2nd 66 and a friend of his to go to Watkins Glen for their charity event, 3 laps (we got cheated with 2 laps). I filled up at the station by my house. Topped of the tank after meeting up with 2nd 66. Put 4.4 gallons in after 92 miles, 20.9 mpg. That's with a 4 speed, 3.55 gears and a 25.25" tire. I was driving 60-70 mph. Would have been faster but didn't have my Valentine with me. I think my home brew recurve did ok.

 

@ReturnToHangar. When you got your dist. back from Dan, where did he say to hook the vacuum advance up to ?
Ported or Manifold ?
When he did mine he was very clear on Ported, contrary to what most say here...

 

Most likely he set the vacuum advance curve to factory specs. Therefore, to function properly the vacuum signal needs to come from the carburetor timed spark port. Connecting the vacuum advance to manifold vacuum WILL result in a cooler and smoother running engine, but the initial timing, vacuum AND mechanical advance curves need to be altered accordingly.

 

Thanks Woodchuck, so if My dist was set up for the ported advance by Dan and I wanted to try the full mainifold vacuum i assume that I would have to retard my initial timing a little (currently around16deg) what would I need to do with the advance curves ?
Would I need to send it back to Dan again ?

 

Connect to full Vac and leave the timing unchanged. Document the change. Go for a run and get a sense of how the engine likes or dislikes the change. If it likes, either leave where it is for a while, then, bumped another couple degrees, for a spin. Each time, return home and note the experience.
You can check the "curve" by connecting a timing light Vac plugged (if necessary), starting at 1500 Rs note the timing on the damper, proceed through 2500 to 3000 in 500 RPM increments. Place it in Park/Neutral with wheels blocked. Do this in the drivea-way as she 'll be screaming at 2500-3000 and stationary.
Then you'll know how the "dizzy" is Advancing and where it stops is your "All-IN BY" Rs.

If it's way off and your process is "spot on", then, contact Dan strategize.

 

He lowered the vacuum advance to compensate for increasing the mechanical advance. He also told me to use ported vacuum.

 

Great plan !
thanks

 

+1. Your timing light check in your driveway must be with vac disconnected, or else it will affect your total base+mech timing that you're trying to read for WOT effect. There is no load in your driveway, and vac will be high. Once total is set with the light at perhaps 36° to begin testing, I would start testing by connecting to ported vac with this setup, as the curve is designed for that, along with the greater initial advance. The way to set initial is to set it at 3500 (or whatever you find to be all-in) for 36° total, and it will settle to whatever is left for idle. Easy and uncomplicated.

With ported vac, you should see about ±12° initial + 24° by 3500 = 36° total, while part-throttle cruise at 2000 should have 24 + 10 vac = 34°. That's really light, and IMO the curve should be all-in much earlier, so cruise is much higher in the mid-40s. That's more of a truck/tow curve, and odd he did that — if you have the numbers right.

I am not suggesting to use manifold vac yet, but the numbers would change to 22 idle, and the same as ported for 2k and 3500. The only change is at idle. So, 12 initial + 10 manifold vac = 22° at idle. That may be fine, but is not what he set you up for, and you need to baseline with what he gave you and how you should first run it.

I'm a manifold-vac guy, but the distributor must be set-up properly for that. Just moving from ported to manifold vac will not be correct curve, and needs to include testing for peak efficiency idle timing and other factors for a re-curve. No big deal, but you can't just swap nipples and say it's great or it sucks. Not a fair, reasonable, or beneficial comparison.

 

Yes it will increase RPM and you can turn that down when you are done setting timing. Seems you only have a cam, carb and headers. If your engine is of the low compression type they usually like more then 36deg of timing. You can try 38 total take it for a drive and if you hear no pinging (sounds like shaking rocks in a can) then you are fine. ALot of people will keep turning advance up until they hear pinging and then turn it down to the last no pinging setting.

 

If he set the mechanical advance to 24 shouldn’t it be optimal at 12 degrees BTDC? I’m just curious as to how the engine is increasing RPM past this point.Is that the goal of timing? To increase RPM to max until it starts pinging and then back off?