I was over at a friend's who has a custom shop, mostly dealing in flathead vehicles. When I got there, he had a '47 Mercury convertible pulled in with its engine removed. He played the guessing game with me, so I'll play it with you!

It's a gorgeous car, totally stock drivetrain, goldenrod yellow, restored in '74. The present owner bought it just to flip it. He was driving it last weekend, noticed it had a bit of a miss, so was fiddling with it, but couldn't fix the miss so he parked it. Next morning, he went to start it, no go. So he brought it in to the shop. Quickly determined that it had spark and gas, but zero compression on 7 cylinders, 100 psi on one cylinder.

Go ahead, guess away, it's a good exercise in diagnosis. It also gives you a feel for the life of a mechanic for hire! I'll only give one hint: the root cause has nothing to do with the engine per se, but the part about "he was fiddling with it" and "he bought the car to flip it".... I wouldn't tease you all like this but in the end there are some good lessons!

 

Let the professional do it.... is that the moral?

 

I will take a guess. It had some big huge rats nest under the intake and all that crap got blown into the exhaust valves when he started it. OR a broken cam but Ive never heard of that on a flathead.

 

Hmmmm........ with 7 dead jugs and one good one, my first guess would be a snapped camshaft or possibly a bad timing gear, but your hint indicates otherwise. This is a good one!

 

Cam-related problems were my first thoughts too, as well as the mechanic's. He quoted the owner about 3 hours based on the compression test. Now the motor is out, heads off, and looking at a complete teardown... PS the crank turned out to have over .050" of end play -- wouldn't have lasted long.

I'll fess up now -- because no amount of diagnostic skills would solve this. After teardown the owner fessed up to pouring some concoction of ATF or MMO down the carb while it was running, thinking the valves were carboned up. He was right -- there was a LOT of junk on the valves, and the concoction washed it all down onto the valve seats, preventing a seal, and outright sticking some of them in their guides. Only one set of valves survived (probably furthest from carb). The whole intake tract looked like it was coated with tar.

The cause of the miss turned out to be an intake port that got chipped at the gasket surface when the engine was rebuilt (prying against the edge of the port to pull the guide down). It exposed a corner of that intake port to the valve chest. It had been cootie-bob'd with RTV to seal it.

So there is a definite risk to pouring cleaners down the intake!!

Another thing, while I was there a guy was at the shop to look at the chipped intake port. He does a silicon-bronze metal spray process, which can build up cast iron surfaces by melting silicon-bronze powder onto a cast iron surface. To build up this broken intake, he was quoting only $25! He is investigating whether the process can withstand the heat of a cylinder -- can you say "cracked flathead block"?! If it would work, it might be a cheap solution to cracks in the valve seat area.

 

Dang! I guess the owner won't make a quick buck flipping it now! LOL. I even thought about how I've heard of old timers pouring very fine sawdust down into engines in order to "quieten it down" long enough to sell it. Good quiz Ross!

 

My 1st was the cam - After I reread your initial post with the "per se" my SWAG was that he somehow dropped 7 pingpong ***** down the carb.
Can you get anymore info on that metal spray process - I have a few blocks that are sitting around that needed pinned - I would rather spend even $100.00 per crack than the $1000.00 (Pinning, Boring & sleeving) per crack.

 

Sound like he may have a sugar or syrup in the fuel system. It leaves a caramel like mess like you mention. Yeah, I know, Snopes or whoever they are say sugar won't cause a problem. They quote their chemists but have no real world experiences.

 

Tsk, tsk, tsk. A couple hours under the hood, a little JB Weld, and an intake gasket and he'd have had it banging on all 8 and sellable. It sounds like now the corner cutting is probably going to force him to take a loss. At least the new owner will end up with a good deal!

 

The engine definitely needs to be vatted, but it "could" be cleaned up by hand enough to run, and my guess is the owner says to do that and throw in a new rear main thrust bearing, new gaskets, and call it good. If it weren't a convertible, I'd actually be interested.

 

Shoot Ross, nows your chance to snag a deal!
With the way your stacking up flatheads you should be able to find something to drop into the car and have a nice little project

LOL

 

Ross, do you mean you would not buy it Because it's a convertable? I got my first convertable in 2005 (miata) and I'll probably always have one now. My wife like going "topless".

 

I'd slip the flatty motor from my 49 f47 in there and and call it good... Any ways, ... before I read your diagnosis I would have guessed a pair of fried head gaskets but seldom do a pair give it up at the same time.

 

I had it exactly right but my computer kept locking up on this site!..slim

 

I did the atf down the carb while it was running on a straight six, and NO kidding, did it for quite a long time thinking it was running better and better, Then it hiccuped or backfired and started running away. BACKWARDS. I turned off the ignition. No difference. The carb was the exhaust and it was spraying and belching out filthy rusty oil and smoke all over the engine compartment. I know a 2 cycle will run either way, but never knew a 4 cycle would. This thing actually turned into a 'diesel' running on heavy oil laden fumes from oil (atf) pooled up in the hot exhaust system. It ran at high rpms until all the fuel in the exhaust was used up. I just sat there and watched. Stunned. If I could have gotten to my kitchen in time, I suppose I could have gotten a potato and stuck it in the tailpipe to stop the madness. Just a story as to another reason not to do this. Maybe off subject, but I'm a long time lover of flatheads, and oil, and grease, and rust............