346 flat head no start?

[Paul Phillips]

Bruce
To me the test with the carb off is revealing. It sounds as if you either have a massive vacuum leak, or the throttle butterfly's are not opening. I am assuming you have verified the butterfly's opening when the throttle is operated. If no, please check that. A vacuum leak that major has to be a split hose, a ruptured diaphragm in the vacuum pump, or similar major failure in the vacuum advance, washer or wiper circuits. Try plugging all vacuum ports on the carb and manifold.  To me, a split diaphragm in the vacuum pump would be the biggest leak.

Hope this helps

Paul

[cadillac60]

Thanks Paul & Art I will check the Vac pump the butterfly valves appear OK.

Bruce W

[Tito Sobrinho]

Bruce, please read again my previous post (Lack of air). Just poking your finger on the butterfly choker is not going to tell that it works as they always flip due to  its spring and when "cold", it should have a space between the flap and the carburetor wall. I doubt about vacuum leak at the fuel pump because if you had this problem, the engine always start but with a rough idling.
Send your carburetor to an expert rebuilder and make sure upon its installation that the choke tube is well placed into the exhaust manifold oven

[Steve Passmore]

Worked on a 31 Chrysler many years ago that would try to start but couldn't, turned out the owner had assembles the carb directly to the manifold with no insulator or gaskets ever,    over the years of tightening the flanges had become warped with a good 60 thou clearance in the center, he was adamant that wouldn't make that difference but after I ground a good surface on the base of the carb and fitted some good gaskets she fired up!  It would have to be a bigger vacuum leak than the diaphragms to stop it starting.
I think your going for a record with this length of post Bruce .

[Richardonly]

Sounds like you are so close to the end of your search for the problem!

I have been following this post since it's start and I am happy that it "appears" to be close to the end.  I am also glad for you and the possible end to the frustration you have been through.

Richard

[cadillac60]

Steve, I am overwhelmed with the responses from the forum & very appreciative of the interest shown. I certainly wasn't  going for a record, but it is such a puzzle that it appeared to have got a lot of interest. Again thank you for your response.  I will test the vacuum at the wiper end of the connection from the pump. I am sure with turning the engine over there it should create enough vacuum to show if the pump diaphragm is ok.

Bruce

Art,
Thanks for your response and kind gesture in reference to the Carb.  The model No. on the carb is 595SA Carter and on the 48 it has the vacuum advance.

Bruce Watson

[cadillac60]

Art,

As mentioned in the last post The model No of the Carb that is now on the car is 595SA Carter  The Stromberg Model that was also used in 1948 was AAV26  380154  Both Carbs were 1 1/4 Dual Downdraft.  My car is a 1948 series 61 Cadillac.

Regards

Bruce Watson

[joeceretti]

I apologize for having nothing to add to help you. I have been following this thread and must say that I have learned a lot. I do hope you get this running soon. I am cheering for you.

[cadillac60]

Art,

Message sent advise that you rec'vd my info,

Regards

Bruce Watson

[cadillac60]

Joe,

Besides having so much advice from so many people now I have a cheering section!! The response is overwhelming,

Thanks
B. Watson

[cadillac60]

Art,

I got the UPS notice of shipping,

Thanks again,

Bruce Watson

[Richardonly]

I am hoping for the best for you!!!!!!!

Richard

[harry s]

Got my fingers crossed.    Harry

[cadillac60]

Thanks Harry & Richard, this has been a slow process but I hope it has paid off.

B. Watson

[joeceretti]

Waiting semi-patiently for a resolution to this.

[Richardonly]

Waiting here, too.

[cadillac60]

Art,

I put on your Stromberg Carb & unfortunately it made no difference, the car would not start.

Bruce Watson

[Rod Dahlgren #19496]

OK, I am back----  Bruce, have you tried to keep it running by using carb cleaner spray? Small shot, start it give it small continuing shots to keep it running.. Have you done this?  I think all of us would like to know if it will KEEP RUNNING with continued small shots of carb clean.
Need to know the answer to this one question first... then we go from there. Yes, I have other questions,, but one thing at a time.

[joeceretti]

Disappointed here, not as much as you, but I was hoping that was the problem.

[Rod Dahlgren #19496]

if you have seen the size of the timing chain in in the 346, you will dismiss this as the problem.

to check for a worn chain, you only need to remove the dist cap. . see where the dist rotor is pointing.. turn the engine slow ONE direction until you see the rotor move make a reference mark on the crank pulley and timing pointer.... then turn the engine back the opposite direction... UNTIL you see the rotor jut begin to move.. STOP and look at your mark on the crank pulley--- HOW MUCH did the crank pulley reference mark move from your first mark? if it moved away 1/2 inch or so--- the chain has wear, but not enough to jump.. it must move 2 inches or so to be able to jump.

so--- back to my last post-------- WILL IT CONTINUE TO RUN WITH A SMALL SHOT OF CARB CLEAN TO KEEP IT RUNNING?