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Remove Crankshaft from bottom, engine in..anyone? SBC 400

M

MuzachMT

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belgrade, mt
Hello,
I recently found a rod bearing chewed up my crank pretty good. I don't have a shop, motor stand, etc. Anyone ever crazily dropped a crankshaft out of the bottom of a motor while it is in the truck? ('78 Blazer, 400 sbc, auto 350 tranny here). My uncle swears he has seen it done and wants to attempt it.

I know the tranny will have to be slid back, about an inch? Along with everything in front of the engine. We would be working in a gravel driveway with wood laid down for a smooth surface for the jacks.

It is either attempt this, sell the truck, or get practically nothing for it as is. Unless it isn't terribly expensive to have a shop pull my motor (after I disconnect everything but the motor mount bolts). (Going to try to get a quote on that tomorrow).

Anyhow, any input would be awesome, calling me crazy, possible cost of shop to pull motor, crank, machine work..etc.., tips for dropping crank from below :p
 
Dropping it would be the easy part, trying to hold 8 con rods in position to reinstall the crank would be a major pain in the ass. Not worth the effort to even try.
 
it would be easier to just remove the engine and do the work
the engine crossmember is in the way, you could cut it out and buy a bolt in, or just lift the engine out and have it more accessible. The work is about the same. Rent the hoist, build a stand out of 2x4s to hold the engine mounts, and get'er done
 
Yeah, I thought the crossmember might be an issue and 4x4HIGH made a good point that getting it back in would probably be near impossible especially without gouging the journals or fresh bearings. How high do rent-able hoists usually go up to? truck is lifted 6" on 35's...I figured I couldn't get a hoist that could get it out.
 
Buy a cheap Harbor Freight engine stand - $50.
Rent an engine hoist for half a day - $20.
Money well spent.
 
I would recommend pulling a valve cover and seeing how much bearing debris is resting in the little crevices of the head.

Putting a crank in won't clean all the oil galleries that have bearing debris in them. And if the engine isn't clean you will be doing this job twice.

Engine needs to come out.

Realistically your options

Rebuild what you have (bottom end)

Replace engine. (used, crate, what ever you can afford)


Good luck, just trying to help you do it right the 1 st time.
 
I did this once in an old VW that I had. It was a pain, but doable. I sold it shortly thereafter though...
 
Much as it sucks too,I'd yank the engine out...its only 6 bellhousing bolts and 2 motor mount bolts,and six more on the exhaust pipes ,and some wires & hoses,it only takes an hour or so to get one out,provided the exhaust studs come off OK....................................................................................................A friend tried "cheating" this way once and after finally getting the crank out sucessfully without pulling the engine completely (it had to be hoisted up 2" just to get the oil pan off!),he had a reground crank kit to install,and I suggested he should have just kept going and yanked the engine right out,because the chances were good a rod was junk when the bearings spun,and it'd just ruin the new crank............................................................................................................................................................................................................he resisted,but had to pull it out eventually,while he was trying to get the crank pushed up into position,one rod went too far up in its cylinder,and the top ring on that piston managed to make it past the ridge and popped open--no way to get it back down without taking the head off,at the least...so,he ended up pulling the engine--then found a piston was cracked once he tore it apart...he ended up buying a nice running used engine for 250 bucks instead of rebuilding that one,and sold it in peices to get some money back out of it...We "rebuilt" a straight six engine in the chassis at school shop class,but it wasn't fun at all...our teacher "made" us do it the hard way,to show us how short cuts aren't always the easiest or best ways of fixing stuff....worst part was washing the block out after honing it,and having oil dripping in your eyes and face after taking off the oil pan...though it can be done,I'd say its not worth doing it that way...
 
We swapped a crank on a 6.5TD with the heads on and everything. Was kind of a pain holding all the Con-rods back and what not, but it was a PITA, and the engine was on a stand so we were able to stand over the engine upside down when we did it.. I wouldnt want to try it again with the engine in a vehicle.
 
sweetk30 said:
std hoist will work i have done it.

and fyi cheet. let the air our of the tires. :thumb:
Click to expand...
It's easier to remove the tires and drop it down on the drums and discs.
And yes, engine stands are cheap and you can rent a hoist, although at the prices now, I bought one.
I was going to reply, but I saw scott already pointed out the most obvious problem: getting it out is easy, put it back in would be the hard part, not worth it.:thumb:
 
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