346 flat head no start?

[Rod Dahlgren #19496]

OK-- I am back in... YES Distributor can be it-- I was just trying to figure out how to have Bruce check his... I have to think about what happens when the car starts.. If it is at slow idle and NO vacuum signal to the vacuum advance, then the point plate does not move, but IF the plate moves and IF the guides are worn ( a known problem with these distributors) THEN the points can go all overt he place if the plate moves off of the correct rotation. AND YES, those guide COULD have just finally gave up while sitting.

We know the point are working fin when cranking-- BUT after it starts-- we loose it real soon... Just about when the advance COULD begin to pull in...

Hmm--- Bruce can you take the cap off and look inside at the guides? Look at my photo, I have the red pointer on one of them (yes it is a spray tube from a carb-clean can) all three need to be in place and the points set by the book.. I like to set them at .016 tight.

So-- if we no suspect the vacuum advance is pulling the plate off-center-- disconnect it... See what happens..

[Rod Dahlgren #19496]

Bruce, After the 2 second period you say it will NOT start again until you let it sit for 20 minutes? Hmm-- OK--- So did you tell me that the test light STILL was on and did it flicker at all after the first 2- second burst?  Was there still a light at all after the 2- second burst?

IF SO--- I need to know IF there was any spark at the plugs after the 2- second burst and the 20 minute no-start status...

Seems like we may be close to eliminating the LOW VOLTAGE side of the coil-- we may be going to the high voltage side now..

[harry s]

If available I would get a 12V timing light wired to a battery pack or battery and check each wire for spark and continued spark as Rod suggests. You may be losing spark through the distributor or cap. I'm not sure how the condenser plays into this but I have had situations where they went bad after the last run and also be bad out of the box preventing the car fromo starting. Just for drill I would replace the condenser maybe with one from a running car. I think and hope you are getting to an AH Ha! moment.     Harry

[Rod Dahlgren #19496]

Harry, good thought--- Bruce, I agree---

[cadillac60]

Rod I have tried starting the engine with the Vacuum advance disconnected but that didn't change anything. The points are set at.017

The test light was on as long as I was cranking the engine. The light didn't appear to change within the 4 second cycle of starting and just cranking.

Bruce W

[Rod Dahlgren #19496]

Hm-- OK well, can you see the point contact condition? Nice and smooth, grayish color.. If so, I think the condenser is OK--- Easy enough to change it and see.... May as well do it just to get that eliminated. Next culprit will be the coil..  Usually they will heat up then quit.. Seems like there is not enough time for that to happen. AND coils work when the low-voltage field collapses with the point action--- No real magic there---
OK--- So have you done this: Do the start routine so it runs and stops, then pull the coil wire OUT of the distributor and hold it close to some metal point on the engine and have your helper crank the engine to see if there is any spark from the coil wire.

So that is how we do the coil test. need to know if there is loss of spark that causes it to die and then you have the 20 minute wait before you get fire again.

All we are doing now is testing the condenser and the coil.. Nothing else..

[cadillac60]

Had to go out--   Will try the coil test in the AM & get back.

Bruce W

[Tito Sobrinho]

WOW!   Rod gave us a troubleshooting step by step in the ignition system. Along his line of thinking, I would check if the breaker plate is rotating freely.

According to Bruce, with the carburetor on the car...no vacuum, but without it there is vacuum and for this reason, I still think that the engine lacks air intake due to the carburetor butterfly being completely closed when cold as it has to have a space for the initial cranking. From there on, the automatic choker will open it completely via the choke tube end installed in the exhaust oven opening.

[cadillac60]

Rod,

I tested the coil as you suggested & there appears to be a very strong spark.

Bruce W

[Tito Sobrinho]

Archembobo:

He did not write about a different supplied carburetor.

[rismt]

Bruce ... as a follow up to Art's suggestion attached are a couple of photos of the carb spacer he is talking about. This one happens to be 1/2 inch thick. As I recall the one that I replaced on my 39 motor was 3/8 inch thick, but, I could not find a new one in that size so I used the 1/2 inch which did not seem to affect the way it runs.

I am far from an expert on the reason for the spacer, but, I believe it has to do with insulating the carb from heat.

Here is the link to the folks that supplied me with the new spacer. I didn't see a listing for our carb anymore, but, perhaps if you contact them they can help you out if you need one.

http://www.ebay.com/itm/Stromberg-WW-Small-Rochester-2G-Holley-Carb-Spacer-Phenolic-Insulator-Riser-1-2-/261250518220?pt=Vintage_Car_Truck_Parts_Accessories&vxp=mtr&hash=item3cd3be8ccc

Hope this helps.

Bob Schwartz

[cadillac60]

Yes the fibre 1/2 spacer is there and has never been removed along with the carb gasket.

Thanks you

Bruce w

[gary griffin]

I would imagine the spacer is to insulate the carburetor from some of the heat in the block. Excessive heat in the carburetor would cause premature evaporation of the gas and in the expanded state not enough gas would get through the needle valves to keep the car running which is a condition we call "vapor lock" The flat  head carburetor is 3/4 surrounded by hot exhaust piping making it easier to have vapor lock.

[jenasp]

Hello. Did you get the car to start or is there still problems? I have been folowing this Whit great interest. J Aspen

[cadillac60]

To-day was victory day!  With the help of a buddy from our car club the 48 is up and running, very well I might say. It appears that the problem was not discovered early on  because we were working in an underground storage area, with poor lighting & had dismissed the timing chain as a problem. Once it was finally towed home and we were to go thru all the other possibilities, we at that stage found out all the  things that were not the problem. We then re looked at the timing and decided that  we would take off the timing chain cover. We found that the timing chain was extremely loose & had jumped two notches. After ordering a new timing chain gears & an oil seal & with the steady hand of my friend it was re & re. Once we got the car running it was timed & some adjustment to the carb it is now ready for the road.

I would like to thank so many people for their input & interest, especially Art, Rod & Steve

Thanks very much (until my next problem!!)

Bruce Watson

[joeceretti]

WONDERFUL! I am proud to be the first person to congratulate you after all this time. The members who cried timing chain and were shot down can gloat in their glory. I was simply a spectator watching, reading and learning.

It must feel really good.

[gene harl]

glad you got it running,,, way back on page #1  Leroy and I both said pull the  timeing case cover,    but was shot down...glad its running ......   Gene..

[n2caddies]

Whew,
Glad you got her running.
Randy

[cadillac60]

Thanks for your remarks & one always needs a cheering section, I learned a tremendous amount about what to look for if something like this ever happens again. I couldn`t believe how loose the chain was & there was no noise or rattling. I suppose over a period of years each of the links in the chain wear to loosen up the chain. It was explained to me that when the engine is turned off & the engine is in the middle of a stroke it could be like a sudden stop & with a loose chain just enough force to have the chain slip. Even though the gears looked ok at first glance, after cleaning them up the crank gear was worn on the edges & so was the cam gears, so these were all replaced.

Many thanks

Bruce

[Richardonly]

Bruce, 

I am so glad things finally worked out for you!  As a pat on the back to myself, I GUESSED than was the problem with the 3rd reply on page 1.

Is there a prize to the winner?  JUST JOKING and really happy that you found an end to such a long running problem.   All the work and testing you did must have taken 40-80 hours?

Regards, Richard