I have a 1985 318, stock short block with 360 heads and intake on it. I have always thought that 318's (non-magnum) were NOT interference engines, my timing chain just jumped a tooth or two, and want to know if I'm maybe looking at some bent valves to go along with my timing chain. Timing chain was slapping the cover at idle when I bought it, guess I waited too long!

They'll bend the valves if the cam timing gets too far off.

I think most(all?) American v8s are "interference" engines. I have a 318 with a bunch of bent valves due to a "silent" timing gear. And not just bent a little. That nylon coated cam sprocket has done in a lot of otherwise good engines. Besides the jumped timing, they are also known for clogging the oil pickup.

how far into to Iowa are you? I am (1) hour west of the state line (from Omaha/Council Bluffs) on interstate 80. I have an 85 Ramcharger 318/727/sure grip that you can have for $500. trans is out (have a spare 727 I will throw in), driveshaft MAY need replacing & need new radiator. A buddy sold it to me when my 65 dart was totalled & he purchased it from the original owner. clear title/never been wrecked/alum rims plus steel spares. rear springs are sagged some & the WS is cracked on pass side. Make my day brother. it was my DD up till a month ago when it dropped the driveshaft & prior to that the trans would not hit 3rd so I had to baby it around town

I know a 1970 318 IS an interference engine (no, it wasn't mine, but I got to swap it out...).

So is a 1974... mine lost its plastic cam gear teeth while idling at a light. In suburban DC at 5 PM on a Friday in the middle of six lanes of traffic. I put a new chain on and then found I had no compression. Junked the car. :P

yes it is.

only time I ever had a stock engine with 360 heads on a 318 and piston touch valve enough to leave small eyebrows from exhaust valve was when it was over reved and floated the valves.

I never had a bent valve from a jumped chain. now if it was jumped then over reved. I would wager it will bend a valve or knock a hole in the piston.

now I have had warped valves, burnt valves, dropped valves, but never with a jumped chain.

I wont say it cant happen though. I have been lucky to find the other weak spots first.

mid 70s to mid 80s the heads are open chamber 75 and up CC chambers with the pistons 80-100 in the hole. lots of room at TDC.

Depends on how many teeth it jumps, I've seen one tooth slide by and three teeth bend valves.

Probably not a bad idea to replace the timing set if you are wondering about it, or have 100K+ miles on it.

I think you are being generous. I would at 75K based on mine jumping a tooth at 80K when it was only 4 years old. I think age and heat kill those silent gear teeth. Put in a double roller to replace it in 1978. Noisier, yes. Still running 30 years later and 110,000 more miles.
Craig

The 318 with its .378/.399 valve lift and its very short duration, combined with the piston depth in the hole, should be able to tolerate some timing chain jumping. Now if the timing chain comes off, no it will definitely bend valves. The problem starts when the piston is chasing the exhaust valve up the cylinder. So you may want to check the level of the valvestems first before going any further.

Good Luck,
R.