Broken timing chain or cam... :(

shane416ex · Jan 2, 2010

I got an old 77 mercury marquis. I got it for $300 from an auction. I ran great till about 3 weeks ago when it wouldn't start. I finally messed with it today and I ended up pulling the distributor and seeing the it was good, looked down the hole and the cam gear was not spinning while turning over. I'm a chevy guy so I figure the timing gear fix would entail about the same work but I'm not sure I want to mess with a 300 dollar car. Any toughts on this break and wether or not my diagnosis is correct? Oh yeah, the motor is the mid block, or big block 400. I've heard it called both.

340SHORTY · Jan 2, 2010

the cam gear is made with nylon gear teeth.. I bet they have broken and the chain has slipped. a new set of gears and chain will cure it.. about 5 hours or so depending on the amount of alcohol beeing consumed....

shane416ex · Jan 2, 2010

It's not the gears. I can see the cam down through the manifold. So I'm still thinking timing chain... Unless you mean the timing gears... Thought maybe you meant the distributor and cam gears. But either way I got what you are saying.

Bunk1 · Jan 2, 2010

Drain the oil thru a screen and you'll understand.

Mike G · Jan 2, 2010

I believe he is refering to the cam drive gear not the distributer drive gear.

zukkev · Jan 2, 2010

Broken nylon cam gear...$100 for parts, and a few hours' time will get it going...did it run well before? That should be your deciding factor into fixing it or not...

Binder · Jan 2, 2010

Before you go further use a long screwdriver and make sure the oil pump still turns. It's definately a broken timing gear or chain but something likely made it break. Usually if the oil pump siezes it will just sheer the roll pin on the distributor but maybe this time the timing chain was a bit weaker..

zukkev · Jan 2, 2010

Binder said:
Before you go further use a long screwdriver and make sure the oil pump still turns. It's definately a broken timing gear or chain but something likely made it break. Usually if the oil pump siezes it will just sheer the roll pin on the distributor but maybe this time the timing chain was a bit weaker..

Yup...forgot about that little potential issue...thanks Binder for bringin' that up....

junkyard jim · Jan 3, 2010

timing cover is easier than a SBC Chev. It's a flat plate! Took me about 2 1/2 hours before my injury (now it would take all day) Also drop the oil pan and clean it out of plastic chunkies.

shane416ex · Jan 3, 2010

Yeah it ran good before but it's still a three hundred dollar car... Litterally a brand new tranny though so I'm thinking about parting so of it our and selling the rest to pull a part. Very straight car, just a huge ass boat. Anyone interested in the tranny? lol I would imagine it's a C-4, but I'm not a ford guy so I don't know if any of the huge 4 door boats came with the C-6's.

zukkev · Jan 3, 2010

It'll be a C-6 most likely if it came behind a 400...

junkyard jim · Jan 5, 2010

Swing by Pull-a-part and score steel gears and chain from a truck 351M, 351C or 400 (maybe 460?) and have it back together. 2wd C6 for a 400 isn't a big seller (at least last summer when I tried to sell my '77 F350 12' flatbed with 400/C6/D70 on duals with 4 new tires. I got $700 at the scrapyard because the price was up at the time)