Installing engine

[Erik the Awful]

Hmm... learned something new. The one-piece rear main seal 350s require a weight on the flexplate or flywheel. They're considered internally balanced with a bit of external weight added.

 

[Hipster]

I have seen part number differences from 87-95 flexplate/flywheels and 96 Vortec Flexplate/flywheels which is yet again different then 86 down zero balance 2 piece oil seal cranks. Piston weights are different between tbi/vortec I believe.

Advance sells reman crank/matched bearing kits for around $250 give or take. I have used a handful of them and usually get the "premium" version. Maybe you can find a coupon. If it doesn't measure you can take it back. The Scat and Eagle cranks and maybe other offshore cranks the journals are a tad small so you end up on the loose side of "in spec" and maybe hunting +.001 bearings Etc. Most aftermarket cranks are balanced to a generic number which may or may not be close so unless I was getting one balanced with the flexplate and balancer I would go the reman route ordered by application for less confusion if your doing a stockish 5.7 build.

 

[kmcode3]

Looking for tips. Pulled a Rod knocking 350, in my k1500 suburban. Trying to install "refreshed" from a salvage pull. Can not get the engine pat the calm shells at right angle to align with trans bell housing. Clam shells are an option to pull and maybe change the angle? Drives side will be a small miracle due to 4wd? Can i pull the engine mounted brackets to get the proper angle and reinstall once engine and trnas are mated. Or do i have to pull T-case and Transmission?

 

[Erik the Awful]

I've been most successful tilting the back of the engine down and the front of the transmission up. You can't put the bolts back in the shells with them on the mounts. Prybars help, just beware of how hard you pry. You're not trying to force anything, you're just using them for leverage in places you don't want to put your fingers.

 

[Schurkey]

If I needed to replace the crankshaft and purchase an after market crankshaft would I get an external or internal balanced crank? I'm not really clear on the difference.

A '98 engine will have a one-piece rear main seal crank. Therefore, it has an offset weight on the flexplate/flywheel. Therefore, it's an external-balanced engine UNLESS you spend real money to have an aftermarket balance-job done to make it internally-balanced.

Internal balance vs. External balance is made more-complex by hybrid versions, and the difference between genuine internal balance and "neutral balanced" flywheels 'n' dampers.

External balance is cheap, easy, and hugely more common than internal balance. The term is not always used properly. If there's any balance weight hanging outside the front main bearing, or outside the rear main bearing, it's external balance. The balance weight is supported by only one main bearing, instead of being hung between two main bearings. Often, but not always the external weight is not enclosed in the sealed oiling system.

Fords have used a slip-on weight that goes on in front of the front main, but behind the damper. Tucked inside the timing chain cover, inside the sealed oil system, but still considered external balance weight supported by only one main bearing.

Chevy has the one-piece seal cranks that use a balance weight on the flexplate/flywheel. Again, behind the rear main bearing, supported by only one bearing, and swinging around outside the sealed oil system.

Up front, the Chevy 350 one-piece seal cranks use a neutral-balanced damper. They're internally-balanced in the front, externally-balanced in the rear.

The Chevy two-piece seal cranks (except the 400 and 454) had neutral-balanced dampers, and neutral balanced flywheel/flexplates, so people called them "internally balanced" but they were NOT. The flywheel flange at the back of the crank had an offset weight behind the rear main, they were neutral balanced in front, external balanced in the rear, but using neutral-balanced flywheel/flexplates.

So far, the offset weights--the Ford slip-on weight, the offset-weight dampers and flywheels/flexplates--have an engineered amount of balance weight. One engine's crank-balancing parts (except for the crankshaft itself) would be interchangeable with another engine's parts of the same engine family. All the dampers have the same amount of offset, all the flexplates should have the same amount of offset. When the flywheel or damper or flexplate gets replaced with the correct part, the new one should bolt right on and NOT UPSET THE BALANCE.

Then you've got Buick, and doofus aftermarket balance shops, that take normalized, standard parts and final- or custom-balance the engine by fukking-up the balance of the damper or flywheel/flexplate because it's cheap and easy. The proper method is to keep the damper and flexplate at whatever the standard balance is, and do all the correction on the crankshaft. The Buick/Doofus way, the damper and/or flywheel/flexplate becomes unique to that individual engine, so when it wears out or becomes damaged, the new part has to be match-balanced to the old part or it screws-up the engine balance.

I had a 454 engine in my boat, that some moron "balanced" by welding some metal to the flexplate in addition to the offset weight that GM engineered into the part. THEN the guy who put the engine in the boat before I bought it, put the flexplate on backwards because the welded-on weight wouldn't clear the marine engine mount. Engine shook the whole boat.

Hmm... learned something new. The one-piece rear main seal 350s require a weight on the flexplate or flywheel. They're considered internally balanced with a bit of external weight added.

They're just plain ol' external balanced at the rear.

I have seen part number differences from 87-95 flexplate/flywheels and 96 Vortec Flexplate/flywheels which is yet again different then 86 down zero balance 2 piece oil seal cranks. Piston weights are different between tbi/vortec I believe.

The part numbers may be different because of a difference in the offset balance weight--although that would be news to me. As far as I know, all the small-block one-piece seal blocks use the same offset weight on the flexplate/flywheel.

More likely, there's some other reason for the change in part number.

The one-piece seal 454s use different offset weights on the flexplate/flywheel depending on whether the crank is forged, or cast. But I don't think that varies between TBI and Vortec.

Most aftermarket cranks are balanced to a generic number which may or may not be close so unless I was getting one balanced with the flexplate and balancer I would go the reman route ordered by application for less confusion if your doing a stockish 5.7 build.

As I tried to explain, the damper and flexplate "should" be standard parts, whether they're neutral-balanced or carry some engineered offset weight. The issue with a custom-balanced crank is the weight of the pistons, pins, rings, and rods along with the size and position of the crank counterweights which may or may not be identical to the GM part they're replacing. All the correction to make the balance "right" needs to be done on the crank counterweights--hopefully by drilling to make them lighter in the correct place, but sometimes by drilling then pounding-in a slug of "heavy metal" to make the correct place heavier. DON'T SCREW UP THE DAMPER or FLYWHEEL/FLEXPLATE.