lt4 fd

Hey what special procedures if any are involved with taking out the pistons. The motor is not in any vehicle and will be mounted on an engine stand.... any special skills or tools like you need when building the rest of the shortblock? Also how do I tell if the cylinders need to be honed and how do I do it?

Dave Feerst

Snap on makes a special plastic hammer for piston removal but there is no need to buy one if you are just doing one motor. Simply turn the motor upsidedown, rotate the motor until the rods are stright in the bore and unbolt the rod bolts. It is reccomended that you cut a piece of vacuum hose and slide it over the studs so they dont scratch the walls. then use a dead blow hammer to tap it out the top(heads must be off of course). If there is a ring ridge at the top of the bore it will need to be removed first. You will need a crank snout turning socket, a piston ring compressor, a torque wrench, Ball hone, and plastigauge for sure. You might need a ridge reaming tool, a cam degree kit, a rigid hone, Cam bearing installer/ remover (expensive, let a shop do this). If it is a 383 or 396 you will need to clearance the block. You can check the mores with a T-gauge and large micromoter. Check for general wear, out of round, washboarding, taper. I have never just honned and built. I always had either a .010 bore or a .030 bore but to each his own. You must use the ball hone in a drill and then wash the block throughly with dawn dish soap and water after honing.

lt4 fd

Thank you very much for the info I am not building anything actually just replacing the pistons and that is it... Out of all you listed besides the ball hone what do I need only to remove and install the new pistons?

lt4 fd

Im not replacing any bearings or anything but half of the rod bearing will come off with the small end of the rod when I unbolt it right? So far ive gathered I need something to turn the motor over with by the crank, a dead blow hammer, torque wrench, ball hone, piston ring compressor... whats plastigauge and why do I need it for piston replacement? Also what exactly is a deadblow hammer? Finally what is a ring ridge? Motor is an LT1 BTW
Thanks so far

Dave Feerst

A dead blow hammer is a nylon hammer filled with sand, it is called a "dead blow" because it wont bounce like a rubber hammer, You could try using another type of hammer but be careful. Plastigauge is to make sure the rod bearings have the right oil clearances. you tear off a piece and put it on the bearing and then torque the rod bolts to spec then remove the cap again and you can tell how much oil clearance there is by how much the plastigauge gets crushed.
On high mileage motors there is sometimes a ridge on the cylinder wall at the top of the bore at the highest point of ring travel. Ive never seen a ridge on the LT-1s I've pulled apart so you probibly wont need the tool to remove it.

lt4 fd

Great thanks for the info, this motor only has 73k on it so not very high milage.

Mystic97Z

after you wash it aren't you supposed to lube it up good with oil? thats what we did when we had my pistons out and honed my cylinders..

lt4 fd

Probablly a good idea.

92rslt1

why not replace bearings?

lt4 fd

I thought in replacing the bearings that I would need to have the crank resurfaced which adds to cost, especially considering its money spent on a stock crank, plus the price of bearings... its only got 73k on it so I doubt its that bad. Once im that concerned about the motor everything will be replaced at once.

Dave Feerst

I tore mine apart at 70k for my 383 rebuild at 70k and there was virtually no wear on the bearings. If his are the same way I would have no problems re-using them. Especally since once he knows how to do it, I bet it wont be another 30k Before its tore apart again to throw some forged stuff in there.

nateh

I have mine apart right now to replace a piston. I decided to replace the bearings and rings. I did get the crank polished. Mine had 85XXX on the clock and the bearings looked good, with a normal wear pattern. Even so, I decided to replace them. I also had a light hone done to make sure the rings seat properly. When I removed mine, I just took the rubber-coated end of a tool and pushed evenly and lightly on the rod bolts (after removing the cap). As soon as the top ring cleared, I was able to pull from the piston from the top and guide the rod from the bottom to keep the rod or bolts from hitting the crank throw or the cylinder wall. It wasn't too hard at all. Pretty simple actually.

92rslt1

so say you have .002 bearing clearance. would you replace the bearings? whats the acceptable amount??