Problem starting a 383 that has sat for 28 years

[WissaMan]

We felt so good about getting the 440 running the 68 New Yorker, we decided to try and start up a 68 Newport that has sat equally as long. Unfortunately, success eluded us but I'm not sure why.

So this Newport I bought in '91 as parts donor for my 68 New Yorker. It ran when I bought it and I drove it to where it has sat since then. We checked the oil and it was fine. Hooked a battery to it and it cranks. However, instead of the typical chug chug cranking, it just spins "evenly", almost as if the spark plugs were removed, except slower. All I can think is that the valves aren't opening/closing.

Could it be that it still had the original nylon coated timing chain gear and that just gave out as soon as we turned it over? If that's the case, would the valves open/close, but just out of time with the crank? Or would there be no valvetrain action at all?

 

['69FuryIIIConvertible]

Stuck valves or possibly bent push rods?

 

[Davea Lux]

Pull the valve cover and see if the rockers are moving. If they are not moving, the nylon gear likely expired as you tried to start the car. If the rockers are moving, the valves are probably stuck. You can try putting some light machine oil, diesel or Marvel mystery oil in the cylinders. Give each valve stem a shot of a good penetrating oil such as PB Blaster and let the car sit overnight. Then crank the engine and run a compression check to see how many cylinders are working. Crank the engine to expel the oil from the cylinders before you run the compression check so you do not foul your compression gauge. The odds are pretty good if the valves are stuck open or the timing chain has failed that some of the valves are likely bent as a result and the heads will have to come off.

It is always a good idea on a long inactive engine to be sure everything is well lubricated before attempting to start the engine. Using a breaker bar on the lower pulley bolt will give you a good feel if anything is contacting the pistons that shouldn't be.

Dave

 

[WissaMan]

I thought perhaps stuck valves, but it "sounds" as if most or all are stuck, not sure how probable that is. Can the valves contact the pistons on a 68 383?

That was our next step to pull a valve cover and observe. However, there's lots of detritus all over the engine bay so I'd want to pressure wash or blow it off with compressed air first.

I wanted to get it inside before I start pulling off fenders and doors and was hoping to perhaps drive it in under its own power. But we'll just tow it if necessary, so it's not a huge deal if it doesn't start. We'll still pull a valve cover just to see what's going on but if there's no valve train movement we're not going to put any more time into trying to start it...

 

[Davea Lux]

I thought perhaps stuck valves, but it "sounds" as if most or all are stuck, not sure how probable that is. Can the valves contact the pistons on a 68 383?

That was our next step to pull a valve cover and observe. However, there's lots of detritus all over the engine bay so I'd want to pressure wash or blow it off with compressed air first.

I wanted to get it inside before I start pulling off fenders and doors and was hoping to perhaps drive it in under its own power. But we'll just tow it if necessary, so it's not a huge deal if it doesn't start. We'll still pull a valve cover just to see what's going on but if there's no valve train movement we're not going to put any more time into trying to start it...

'68 383 4BBL still has flat top pistons, so if a valve stuck all the way open, it likely got hit. After that many years, the lifters would have all leaked down so it would not be as bad as a timing chain failing on a running engine. A zero compression scenario suggests a completely failed chain which will be obvious with a valve cover off.

Dave

 

[Davea Lux]

As a follow up, if you decide not to start this engine, be sure to lube the hell out of the cylinders so that it is not stuck at some future date when you might want to rebuild it.

Dave

 

[1970cat]

you could pull the cap off and see if the distributor turns evenly while spinning it over.