Engine trouble

[Ken/Alabama]

I'm at wits end on this. Friend brought his 39 Zephyr over because it had a bad stumble. I pulled the distributor and set it up on my Sun distributor machine. Still had a miss in it. After further investigation I determined that number 11 cyl wasn't firing. Put a pair of NOS caps in the distributor. Still not firing on number 11. Pulled out pugs and number 11 shot water out. Pulled drain plug in oil pan and had water in oil. Removed the head and could see faulty gasket. Installed New gasket . Engine starts and idles great but when I start opening the throttle halfway or better the engine rolls over and will not rev on up . If I hold the throttle open and start to cover the carb with my hand it will pickup. So far I've replaced the carburetor with another known good one from a running car. Same with fuel pump, three different ones. Fuel pressure is two pounds. Changed power valve in carb. Blew the fuel line out from firewall to tank. Installed a temporary fuel line from pump suction into a gallon can of gas. Changed distributor and coil, condensers from my running Zephyr. Can't find any vacuum leaks and it idles flawless. Been on this for two weeks now and it's driving me nuts. I'm out of ideas. I have even replaced both ignition resistors under the dash but I'm thinking its a fuel problem.

[36and63]

It sounds like you are running too lean, if you have a manual choke get it going down the road and if it surges pull the choke slowly - if this smooths it out then you need to look at the jet ( jets) for blockage possibly. I had a similar problem and this was what worked.

[37 Cab]

Have you put a vacuum gauge on it? How fast does vacuum drop off when throttle opened slowly? Almost sounds like a restricted exhaust.. But how?

[Ggmac]

Blocked exhaust ? Gas cap not vented ? On The cyl with water , did the valves and piston all cycle as it should ( piston to top of cylinder , valves open and close with spring pressure )
Im leaning towards blocked exhaust , but I'm not hands on .

[richard crow]

drill a 1/8 hole in the muffler if a large amount of water comes out tha,ts the problem put a sheet metal screw in the hole when done

[Ken/Alabama]

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Originally Posted by Ggmac

Blocked exhaust ? Gas cap not vented ? On The cyl with water , did the valves and piston all cycle as it should ( piston to top of cylinder , valves open and close with spring pressure )
Im leaning towards blocked exhaust , but I'm not hands on .

Ruled out gas cap, have a fuel line from pump suction into a gallon can. Valves and piston working as they should, it starts and will idle perfect. I've been giving some thought towards restricted exhaust.

[FRANK PKNY]

Check you vacuum sound like a possible vacuum leak. The intake manifold gasket may have shifted while installing.

[Ken/Alabama]

Originally Posted by FRANK PKNY

Check you vacuum sound like a possible vacuum leak. The intake manifold gasket may have shifted while installing.

Never pulled the intake but that doesn't mean it can't leak. Thanks. I have sprayed carb cleaner around the intake to check for a leak. Wouldn't a vacuum leak cause rough idle ?

[Seth Swoboda]

Originally Posted by Ken/Alabama

Never pulled the intake but that doesn't mean it can't leak. Thanks. I have sprayed carb cleaner around the intake to check for a leak. Wouldn't a vacuum leak cause rough idle ?

Yes a vacuum leak will cause problems at idle.

[Ken/Alabama]

Originally Posted by 37 Cab

Have you put a vacuum gauge on it? How fast does vacuum drop off when throttle opened slowly? Almost sounds like a restricted exhaust.. But how?

Engine vacuum 20in at idle and steady. Drops to 5 or less with throttle wide open.

[FRANK PKNY]

20 at idle sounds good, but does it stay at five when running about 1800 rpm? or does it build back down? Sometimes these things are hard to track down. Your on the right track as far as what you have done. Can't wait to fine the elusive answer, I'm sure you feel that way also. When you do you'll be a happy old man! LOL

[revkev6]

haven't seen it mentioned, did you check compression after the gasket change??

[flatjack9]

At wide open throttle, vacuum should drop to just about zero. Clogged exhaust could be the culprit.

[Ken/Alabama]

Originally Posted by richard crow

drill a 1/8 hole in the muffler if a large amount of water comes out tha,ts the problem put a sheet metal screw in the hole when done

Removed the muffler. No change.

[scicala]

Originally Posted by revkev6

haven't seen it mentioned, did you check compression after the gasket change??

Wide open under a load (as in driving) the vacuum should be close to zero, not when parked and out of gear.


Sal

[37 Cab]

Any vacuum reading while parked under WOT should eliminate exhaust restriction. I would expect 0 vacuum when opening throttle and engine is falling over if exhaust were the culprit. might put a timing light on it and watch advance.

[Ken/Alabama]

Well Guys, It now will run like gangbusters. ! Installed distributor and coil from my 39 Zephyr with condensers and it will rev to the sky! If I use his coil and condensers on my distributor it try's to lay over . I think we got a bunch of bad condensers. Gonna retro fit a pair of IH200 condensers in the morning. The original style condensers for the V12 I understand have been discontinued plus they are expensive. Have four coils and they have all been rebuilt by Skip so I really don't think they are causing any problem. Still have no explanation as to why it acted like it was starving for fuel. Thanks for all the input.

[37 Cab]

Sometimes you just gotta take a break and reflect.. Go with what you know.. Glad you got it sorted!

[scicala]

I said it once before...…, I sure wish I didn't throw out all of those old condensers when I was younger.


Sal

[Ken/Alabama]

Well, life was good for a day. Definite Problem now with fuel starvation. Anyone know how much stroke or lift there should be on the fuel pump push rod?