My son's band played about 100mi away up in West Palm Beach Fri. night and used the '70 4dr. to tow the utility trailer/equipment. Ran normally on the ride up. Apparently the timing gear or chain expired when he shut it off or tried to start it up there. 129,000mi. orig. 307. Ran pretty good, uses some oil. I put a crescent wrench on the alternator pulley and I'm able to turn the engine without much resistance. The distributor rotor doesn't turn. I turned it through several revolutions w/the wrench and now I'm wondering if it bent some valves and that's why it turns so freely. Acts like it has little or no compression. We turned it quite a bit trying to start it. I'd like to "get away" with replacing the timing set. Car is my son's driver, so we'd like to get it going quick. Anyone familiar with piston/valve collisions with a broken timing set? I guess I could check for bent valves with my air pressure screw in the plug hole doodad I use to change valve stem seals.

When my cam gear wore out and the chain jumped, all I needed was a new timing gear set. You might want to put a sleeve on the damper. There's probably a groove cut into it where it meets the timing case cover.

RB,
Take the valve covers off. If any of the rockers are real loose...those valves are bent for certain. If it happened when he shut it off, you might get luckey and none are bent.
Good luck smile.gif

I had 1 that went and jumped a tooth or three while I was driving it. No damage other than replacing the chain/gears. I had another just starting to go on my truck and took it straight home. On both occasions, there was a distinct knocking noise from the chain slapping/cutting into the timing cover. You son should have heard that noise. :confused:

I wasn't aware of these engines having any troubles with pistons hitting valves. The early Ford Escorts would when the timing belts broke but I never heard of it with a "real" engine. :D

Well, one nice thing is you can get a chain/gears for about $20 and a few bucks for gaskets. Very inexpensive job. Will take a few hours to do though...

Any motor that is an "interference" motor will canabalize itself when the timing chain/belt breaks. This includes most new cars and high performance "real" engines. They run the piston to valve clearance so tight, anything that slightly messes the timing up will smack a valve. That old 307 has piston to valve clearances measured in miles so I think you can just put a new timing set on, reset the timing, and fire it up. graemlins/hurray.gif

Jeff

I had this happen on a stock cam 350. I bent all of the exhaust valves and the exhaust pushrods. I replaced the pushrods and timing set. Car ran fine with the "slighty" bent valves. In fact I didn't even know they were bent until I had the heads done a year later.

Thanks all for the tips/suggestions. I was thinking this afternoon I drove about 400mi. this weekend, 200mi. to get the kid and the utility trailer and 200mi. to get the car and tow it home. I'll probably see about it tomorrow or the next day. I'm not usually lucky in cards or cars. Wonder how much timing gear nylon mess it takes to stop up an oil pump pickup? I got a chuckle out of "your son should've heard that noise". With 4 or 5 of 'em in there hollering at each other and the music blaring away, they might realize if it wasn't running when the scenery stopped going past the windows.
Thanks again, Howard

I've had a bunch of small block cars over the years with the same "929" cam as that 307 that tossed their chain... most recently a 78 El Camino 305 2-barrel that lunched it at about 320,000 miles, man they just don't make them any more like they used to.... didn't hurt any of them. I doubt it bothered yours either.

Just change the chain, it will be fine. Be sure to have a new timing cover on hand when you tear it down, I'll bet money it wore a hole in the right hand side at the bottom where all the slack coming off the crank gear would have gone. :eek:

Now a big block on the other hand, it will destroy everything on the intake side, even with a stock weenie cam. Guess how I know. graemlins/angry.gif

Sorry to hear about that, Howard. I hope it works out and you're not out much time, money and aggravation.

So did they make the gig?

Yeah Justin, it tore up when he tried to start it after they played. Got $36 worth of parking tickets before I could tow it home. At least they didn't tow it away. I think they made about $120 for playing the show. Did you get the trailer picture I emailed? I'd post it here if I was smart enough. I have complete, running, fairly fresh +.40 350 in the rusty '68. At least it doesn't use oil. I kinda feel like I'd be wasting it in the 4dr. though. It runs pretty stong and has a nice "lopey" idle. BUT, it's more work and would take longer to get it going too.