Just finished getting a 72 1.7ltr. ready to start up after sitting for 29 years. Went over everything in the fuel, vacuum, and ignition systems. It turned over just fine without spark hooked up to it. Now for the moment of truth. Made sure I had fuel pressure and attempted to start it.

After about 3 tries, it fired up and started running!!!! After about 20 seconds, a rattling sound started, then got worse. I immediately shut it off. Then tried to turn it over again, and it would not turn over. I then got it on jack stands and blocked one wheel to put it in gear and see if I could spin the motor by hand with
transmission in 5th gear. The wheel will turn about 1/3 a turn in either direction and it locks.

Before I drop the motor and pull it apart to check for a dropped valve or worse, though I would see if anyone wanted to weigh in on what this might be....ideas?

Thanks in advance!

I had my 93K mile '76 2.0 DJet for a year or so. It was driveable tho I knew it wouldn't be long before I tore it down. It rattled most of the time over 3k RPM. It wasn't a rod or main bearing and it just didn't seem like knocking. Then one day I went to start it and it turned over a single turn and it locked up. I could turn the wheel by hand and felt the piston hit something. It wasn't metalic but it was pretty solid.

On tear down, #3 and #4 head was CAKED with carbon with lots of carbon loose in the cylinders. The other head and cylinders were not. I assume that the carbon broke loose and fell into the cylinder and the piston crunched it up against the head.

(Anybody have some ideas how that side got so carboned up? )

Good luck

Pop the valve covers off first. Also dig out a good light and a mirror and take a look at the fan. See if anything is amiss or looks jammed.

Also remove the spark plugs and see if the engine turns over. (NOTE: Have an extinguisher handy, because if it is hydro-locked, you will have four small fountains of gasoline!) There is an odd FI failure mode where the injectors turn on but never turn off. That can hydro-lock the motor.

--DD

OK, pulled the plugs, and they were not flooded. Also checked, and nothing was obstructing the fan. The carbon question is interesting, but I think that if that were the case, the cylinders would be seized, and that is not the issue.

Think it is an internal issue at this point. The motor will not cycle all the way around, so something in the stroke is causing the problem is what I am thinking.
Unless you guys can come up with some other good ideas of things to try, looks like I will dropping the motor tomorrow. Appreciate everyones comments!

Like suggested, pull the valve covers and check for an open valve with lots of rocker play.

Like dave said, take the valve covers off to see if anything in there is giving you problems. check to make sure that all the pushrods are fully seated in the rocker arm pockets. I was reassembling my 1.7 the other day and was trying to turn the engine over and got to one spot that it WOULD NOT go past. Noticed one of the pushrods was pressed against the outside lip of the rocker arm, not in its seat, so the when the valve was fully depressed, the cam lobe still had some more to turn but the valve restricted it form moving past. When you started yours up, during the rattling maybe it knocked one of the pushrods out of position and its jamming your cam. Worth checking since its easy to get to and feel around in there. Good luck!

#2 INTAKE was very loose....looks like a valve seat/guide has dropped. Its coming out. Will let you know.

I fixed one where a chunk went forward and wedged in the cam gear, which could have happened anywhere else on the crank. That stopped it solid, but the case was still good, and a lot better than it coming THROUGH the case.

Pull the heads, get them to the machinist,
Put em back on and drive.

On close inspection, this is what I found in the photo below. #2 INTAKE pushrod is bent. Any idea what might have caused this situation? I pulled the engine this
evening, and will start pulling it apart tomorrow. Curious as to what I might find...

Wow, never seen that. I'm REAL curious to know what you find.

When you turned if over before starting it up was that by hand or with the starter?

I tore down an old 1.7 where a couple of the valves had completly seized in their guides after sitting a long time. Guessing valve seized for whatever reason (crud or dropped seat maybe) or the pushrod sliped out of the rocker and jamed.

Pulled the head, and it was the valves that were seized in the guides. The damaged looks to be contained to the push rod. Probably the thing bent when it was turning over prior to starting. When it started on 3 cylinders, that is when the
noise really kicked in, and the extra force bent it to the point that it cased the cam follower to press up against the cam to the point it would no longer turn over. Once everything was off, everything spins like it should.

Took the head to the shop, and we took them apart. Had to drive the valves out with lots of force. Hopefully by the end of the week, everything will be rebuilt, and with a new top end on the motor, we should be back in business! New set of rings as well.

Thanks to everyone for your comments. It is always an experience to find out what happens with these cars. Based on what I saw, it looks like the previous owner ran it for too long with a bad thermostat, and the MPS was also on its way out. The extra moisture, combined with the extra carbon from running rich, was probably a huge part of the problem.

Check the condition of the cam lobe and lifter.
I had an engine with a valve/spring problem that kept the valves from opening as far as the cam was trying to open them and it wiped out my cam & lifters.
With the push rod as bent as that, the cam was trying hard to open that valve.

Jim