7.4MPI harmonic balancer bolt size

[TBarCYa]

Can anyone tell me what size socket I need to turn the harmonic balancer bolt on the 7.4MPI? I'm heading this afternoon to look at a boat that has one and need to see if it turns. Unfortunately, I didn't know I was doing this when I left the house so I have to buy whatever I need.

Thanks.

 

[Scott Danforth]

NEVER, NEVER, NEVER try to turn a chevrolet V8 over by the crank bolt. you WILL strip out the threads on the crank snout requiring a new crank.

you pull the 3 short bolts holding on the front pulley, thread in longer ones and use a pry-bar.

or you pull the damper and use a crank socket.

depending on your damper, the bolts are 3/8" fine thread or 3/8" coarse thread. so you will need a 9/16" wrench to remove the crank pulley.

 

[Bondo]

NEVER, NEVER, NEVER try to turn a chevrolet V8 over by the crank bolt. you WILL strip out the threads on the crank snout requiring a new crank.

Ayuh,..... Absolutely, Don't do that,.....

Bring a battery, 'n use the starter,....

 

[TBarCYa]

I can't use the starter because the boat had a fire and I'm unsure of the condition of the electrical system or the safety of the fuel system. I just want to verify that the crank moves (don't even need to turn it a full revolution) before I decide if it's worth putting any time / money into.

 

[Bondo]

Ayuh,.... How bad was the fire,..??

Ya know, the drive turns With the crankshaft,..??

Lookin' at the workin' end of the spark plugs can give ya clues to what happened,....

You can try leverin' it with extendin' the 3 small bolts,....

You can pull the starter, 'n lever against the teeth of the ring gear,.....

You could pull the drive, 'n slide in another input shaft, that's been extended beyond the bellhousin', 'n lever from the aft,.,...

A socket on the center bolt of the crankshaft is Not the answer though,...

 

[Lou C]

Agreed, that will cause a new problem you don't need! If the boat had a fire, and the OE wiring harness is burnt up, it may not be feasible to repair if you can't get a new harness, or aren't skilled enough with wiring to replace what burnt up on the old one. I actually did this for a neighbor on his '68 VW Bug many years ago, but those VWs had really simple wiring harnesses. Cost him about $30 bucks of wire and terminals and a bit of my labor.

 

[TBarCYa]

Ayuh,.... How bad was the fire,..??

The inside of the doghouse looks amazingly clean considering there was a fire. The blower hoses have a little melting and one of the accessory belts is broken but otherwise the engine bay looks like there wasn't a fire. There is some soot on the foam on the inside of the doghouse but the foam is not melted. The fire basically ran up under the port gunwale and into the cabin and burned the foam/vinyl that covers the wall. There looks to be a blister on the outside of the hull that I'll address once I get it home.

Ya know, the drive turns With the crankshaft,..??

Yes but the gear reduction in the drive would make it extremely difficult to turn the engine.

Lookin' at the workin' end of the spark plugs can give ya clues to what happened,....

You can try leverin' it with extendin' the 3 small bolts,....

You can pull the starter, 'n lever against the teeth of the ring gear,.....

You could pull the drive, 'n slide in another input shaft, that's been extended beyond the bellhousin', 'n lever from the aft,.,...

A socket on the center bolt of the crankshaft is Not the answer though,...

Once I pulled the dipstick and found chocolate milk 2/3 of the way up the stick, I wasn't really concerned with stripping the crankshaft and I was able to move it a few degrees in each direction without stripping the crank.