More Engine Discovery... New Timing Numbers!

[BIGREDRASA]

Jimbo, the old way was to find a machine shop that had a distributor machine. You might call around to any local hotrod clubs. There has to be one of those machines in the Atlanta area. It will cost you to have someone set up the dizzy, but it might save you a lot of time and aggravation.
If you must proceed on your own, remember, one thing at a time; and take notes, notes, notes. 8)

 

[Anonymous]

What about a Dyno shop? would they have something like that? maybe I should call around. Maybe the machinist who did the rebuild would have one.... they are an old shop, been in business for 30+ years.

 

[BIGREDRASA]

That's what you need. Old mechanics in old shops, with old-time skills.

 

[Anonymous]

OK, so I made some adjustments on my own, the car ran too hot again today... and I can keep playing with it till I get it right, I do not think I can hurt it any more than I already have.

Here is a play by play on what I did.

1. I pulled the wires one at a time and moved them around the cap in counter-clockwise fashion, the can was hitting the oil stick and I could not move it any farther inward.
2. I backed the timing down to compensate for the plug wire move.
3. Started the engine, and set the initial timing to 14 degrees (this raised the vacume to 16 inches and raised the rpms, etc...
4. I backed the curble idle screw out till it hit 900rpms...
5. adjusted the mixture and noticed a big difference in the way the screw affected the engine, before they did nothing till they were almost closed, now they act like they should about 1 turn out things sputter, add another turn and things improve and vacume improves slightly.

Now the engine was at 14 degrees, 900 rpms, and it dropped to 12 inches vacume again, almost exactly like it was at 7.

I advanced the engine to 16 degrees, again the vacume and engine went up, I backed the idle down more, and closed the mixture screws another 1/2 turn.

So right now it is sitting at 16 degrees, slightly unsteady idle at 900, and a slightly unsteady vacume reading of 14 inches. It runs cooler, and I drove the car around the block a few minutes ago, no ping, but the engine might still be running rich. I do have a noticeable drop in power, it was punchy before, it is a little flat here.. it idles a little better, smoother, but not that much different.


The thing is as I drop the rpms the vacume level drops too... get it down to 700 and the vacume comes in around 10 inches and it begins to surge really bad, could be the power valve will not stay closed at 10 inches, so dropping it at or below that is no good. but keep it at 900-1000 rpms and it idles like a champ.

I am going to drive it for a few days set like it is now.. timing 16 degrees, vacume 14 inches, and rpms 900... it stays pretty steady and is not running hot... see how this goes...

I may try to set the initial even higer, like 21, and attempt to dial in the carb there, and eliminate the vacume advance and see how it runs like that...

thoughts?

 

[Anonymous]

I just took it out again for another drive, a little better. I tweaked the mixture again, getting it more stable at 14 inches.

Brakes work better....

FYI, I ended up backing out the curb idle screw about 2 1/4 turns in this whole process this afternoon. (seems like I can now work on the carb and get that right for once)

 

[Anonymous]

As Joe alluded to, have you check your balancer to see that the indicated TDC is actually at TDC? Mine had slipped, and I could not get the car to run when using a timing light. I assumed I had the distributor in wrong etc. I timed it by ear, and I think the timing mark was between 90 & 180 degrees. Once I replaced the balancer, I was able to time to factory specs with no problem. Hang in there, you are making progress.

 

[Anonymous]

This balancer is brand new... nice one too.
It was on TDC mark when it was put together? can it slip that quickly?


where to go from here?

 

[Lazy JW]

Keep up the good work! This thing WILL run right, it just may take a while. I would check the timing marks and also mark the pulley at 5 degree increments up to 40 degrees at minimum, that way you can verify the advance at higher rpm. You can also verify the accuracy of your dial-back timing light. And leave the vacuum advance unhooked until everything else is working correctly. Marking the pulley isn't too difficult really, just calculate using Pi and measure carefully around it with a flexible steel ruler, then mark it with a felt paint marker or something similar that is easily visible with a timing light. I wouldn't be at all surprised if you needed as much as 20 degrees initial advance (without the vacuum). This may be an appropriate application for setting the timing with the vacuum guage to find where it works best. If you do end up with that much initial advance, then the centrifugal advance will probably need to be modified to limit the advance to 15-20 degrees so as to end up with 35-40 total. BTW, distributor machines take all the fun out of it
Joe

 

[Anonymous]

Sorry I may seem like an idiot, but I do not get why you mark the pulley? how can you tell one mark from another with the timing light? If my pulley had marks every 5 degrees, once I got past 25 degrees how do you know how many marks you are at? do you mark a number on them? 0,5,10,15,20,25 etc....?


just a little more on this one? I can do the pulley easier with a wheel, marking it is no problem, what to do after is the question?



One last question,

there is still something squealing on the engine when it is first started... I replaced the alternator, but it seems like it happens when the engine is warm, start it and it lags for a second, give it some fuel and it screaches?
Maybe a loose belt? would they squeal if they were loose or tight or both?


I will get there eventually, but I am still looking for a mechanic to do the distributor, but I don't want to re-curve this one, I think I should buy a Mallory unit first... I would rather do this right on a decent dizzy. Specially if this is going to cost me some dollars anyway. Is the better unit worth the money?

 

[BIGREDRASA]

Was this a new dizzy? You can't go wrong with a new Mallory, but make sure you buy from somebody who understands you when you tell him/her what you have. A new unit won't be any better if it isn't curved to meet your needs. You might want to also check your cam company for curve recomendations.

 

[Lazy JW]

Yes, I mark every ten degrees with a double mark. Different colors would work also. It actally is pretty easy to see the marks advancing as you rev up the engine. Whatever method you use to mark it is fine, so long as it is accurate. Then just rev up the engine and watch with the timing light as the centrifugal advance changes, writing it all down as you go. You need to know what your distributor curve is set at now, so as to be able to alter it to suit your engine, regardless of who does the work. Even if you have a mechanic do the actual work, it is good to know what is going on. But actually, you are a mechanic now A Mallory distributor will work fine, but no better than the one you have now, and not until the curve is set to what you need. There really is no mystery to recurving a distributor anyway, so don't give up on this one yet. I would suspect a loose belt to be causing the squealing, but you can place a wooden broomstick on the water pump and listen for it there too.
Joe

 

[Anonymous]

Jimbo,
I don't know if you remember me but I contacted you a while back about having a simialer problem. Here's another idea. Now I have the H/W carb but this may apply. Your idle a 900 still sounds like a possible pointer to your problem and the fact that the carb vac is dropping to low as your closing the throttle plate. Take a look at the throttle plate and it's relationship to the idle mixture passage. At idle the plate should be blocking the passage restricting the amount of fuel passing there. If it's completely open this would cause rough idle, rich, and the low vac numbers. I don't know if the throttle plate is adjustable like the H/W but see what you have there. It may even be bent. I'm sure you have checked for leaks at the throttle shaft right? Sprayed a little carb cleaner there? I'm running about 14d enitial and 55d all in with no ping, still don't think it's quite right but getting closer every time I change the idle mix jets So hang in there, I'm sure a lot of people are pulling for you.

Steve

 

[66200i6]

Steve, I'm sure there are a number of inliners that would be interested in the Idel, Main and Air Jet numbers you are using. I know I would. I ended up having to teardown for a rebuild before I was able to realy dial mine in. So I havn't ran my DFV long enough to be satisfied with the tuneing.

What jets are you running now?

Thank, Ric.

 

[Anonymous]

Morning Ric,
I'm running a 68 200 with a 78 head shaved .050, 260 cam, headers and the Electronic Ignition, pretty much the standard buildup here. I've got a 64 Econoline PU which has the motor sitting between the seats which makes it interesting for on the road tuning ). The carb is the Holley/Weber DFEV which is a flip, linkage on the valve cover side, of the ones most of you are using but identical front to back. This worked great for the cable linkage I went with and I could use the head bolt to secure the cable support. Anyway the numbers in the carb are as follows:


Main Jets primary stock 132 now 150 secondary stock 150 now 150

Emulsion Tube Stock primary 16 stock secondary 15

Butter fly Stock primary 132 stock secondary 131

Air corrector Jets 180 180

Idle Jets Primary stock 45 now 60 Secondary stock 50 now 65

I'm still playing with the idle Jets but there was a drop in RPM's from 750 to 650 right after the first change so I might be looking at the Mains again. Smooth idle, good response but I'm thinking a little soft on the top excelleration, let's say around 2800 rpm. I've also got a 9" rear with 3.50 gears and a C4 by the way, shifting is at 20 and 40 mph at hard excelleration. I know this isn't probably the right place to post this but I'm running a good 50% cooler than when I started and I'm betting on the change from a Aluminum/pressed steel water pump to the Cast Iron one as being the biggest improvement. Take a hard look at the impellers and you can see what I mean. Problem is I added the Elec. Dizzy at the same time so can't be 100% sure but would love to here back from others on that subject.

Hope this helps,
Steve