manually cranking motor

[pulleyman123]

I am trying to manually crank a 1987 4.3Lcobra. I pulled all the plugs. I can only get turn about 20degrees then the crankshaft recoils back to no progress. Is this a sign of sticking valves? Is there anything else I need to do to get everything moving besides pulling the plugs? Is there anything I can put into the chambers?
Thanks

 

[dcg9381]

Re: manually cranking motor

I am trying to manually crank a 1987 4.3Lcobra. I pulled all the plugs. I can only get turn about 20degrees then the crankshaft recoils back to no progress. Is this a sign of sticking valves? Is there anything else I need to do to get everything moving besides pulling the plugs? Is there anything I can put into the chambers?
Thanks

That's an interesting results - with no compression, I wonder if it's normal for the 4.3L valve pressure to push back on a deflected crank.. I'd think that it's not normal.

You can use any good fogging oil in the cylinders - WD40 if you have it.

What are you turning the crank with?

 

[pulleyman123]

Re: manually cranking motor

5/8" socket, breaker bar

 

[Windykid]

Re: manually cranking motor

Pull the pan and check for a broken rod.

 

[tommays]

Re: manually cranking motor

There is just as good of a chance as it being a OUTDRIVE problem SO pulling it would rule that out

As it sounds like your twisting the coupling and is turning back

Tommays

 

[MikDee]

Re: manually cranking motor

I'm gonna ask a coupla silly questions, First back to the basics, is the drive in neutral? and are you turning the crank in a CounterClockwise direction? (the proper direction of rotation), trying to turn it clockwise will bind up your water pump impeller in the drive, and make it hard to turn. Finally, is your starter drive disengaged?, or it will bind also.

 

[pulleyman123]

Re: manually cranking motor

Tommays, you were correct. I pulled the outdrive off and now it spins. Good Call, you relieved that frustration, but now there is more fustration. Obviously now I'm going to have to tear the outdrive apart and work on that. Actually, before I do that I am going to make sure I can get the motor running on it's own. Am I correct in thinking that I can attach my garden hose to the male threaded hole to the left of the drive on the outdrive? (running the engine with the outdrive off.) Is there any other concerns when trying to run it without the outdrive?
Thanks Alot!

 

[Bondo]

Re: manually cranking motor

and are you turning the crank in a CounterClockwise direction? (the proper direction of rotation),

Ayuh,......

While Most of the motors We work on are in fact Lefthanded,.....
Normal people aren't looking at the flywheel, but are looking at the Pulleys.....
And,....
While your statement is Technically true,.....
It's extremely misleading,+ Not very good advice.......

Am I correct in thinking that I can attach my garden hose to the male threaded hole to the left of the drive on the outdrive?

I don't do OMCs, so I can't be sure whether that's the water intake hole,....

It's a 'ell of alot Easier to just scab your garden hose into the hose from the outdrive, to the T-Stat Housing, anywhere along it's length will work Just Fine......

 

[MikDee]

Re: manually cranking motor

Ayuh,......

While Most of the motors We work on are in fact Lefthanded,.....
Normal people aren't looking at the flywheel, but are looking at the Pulleys.....
And,....
While your statement is Technically true,.....
It's extremely misleading,+ Not very good advice.......

Bond-o That statement is true, not misleading, and it is good advice, for anybody who knows the small block Chevy.

 

[wire2]

Re: manually cranking motor

Bond-o That statement is true, not misleading, and it is good advice, for anybody who knows the small block Chevy.

He said he's using a 5/8 socket on a breaker bar, that tells me he's turning it at the pulley end, where the proper rotation of virtually all SBC is clockwise.

Look at any old movie featuring cars from 1900 to the late 20's, anyone starting one will turn the crank clockwise, with their right hand.

Even Orville & Wilbur Wright crank the prop on the front of the car engine on their first airplane CW.

And, if Pulleyman was to turn the wrench CCW against the seized outdrive, the bolt would simply undo.

 

[Don S]

Re: manually cranking motor

Meanwhile, back at the locked up drive, frist thing you need to do is drain the oil and look at it. If you see a lot of metal on the magnet and metal flake oil (you will understand that if you have it).
If the oil is bad, and you have even one damaged gear, you will probably need all new gears and bearings.
Don't even think you can do that yourself. It takes a lot of spcialized tools to rebuild a drive. Without them, those new parts will probably be trash in no time.
Take it apart by all means, but don't spend any money on it till you find out why it's locked up. I've seen them that way many times, it's not a pretty sight.

 

[pulleyman123]

Re: manually cranking motor

There was no metal shavings on the screw. The gear and pinion look rusted together. Hopefully tomorrow I will take them apart then take a look into the lower unit and see how everything looks.

 

[MikDee]

Re: manually cranking motor

Wait, So Sorry! I just got in, and have to apologize, to pulleyman, Bond-o, and wire2 also, for any misunderstanding, Yes, you're right the SBC does run clockwise! and should be cranked that way,,, after posting, I re-thought it, and it finally dawned on me Duh! I really knew better all along, but temporarily lost it :redface: Peace! Mike

 

[Dakota47]

Re: manually cranking motor

ok doka

 

[Don S]

Re: manually cranking motor

The gear and pinion look rusted together.

You need a new drive.

 

[Mkos1980]

Re: manually cranking motor

For anybody else reading, I advise not to use the crank bolt as a turning point. I've seen many in the past snap off. Better advise would be to use a strap wrench on the balancer or pulley.

 

[Don S]

Re: manually cranking motor

Better advise would be to use a strap wrench on the balancer or pulley.

Only problem with that, is the harmonic balancer can also be damaged as the outer surface is mounted on rubber.
If the engine has the spark plugs removed and can not be turned using the crankshaft bolt or even using the alternator nut with a tight belt, then it's time to find out why it turns that hard. Cause it sure ain't gonna run that way.