3rd Rebuild on 98 5.7

[Aaron Davies]

It’s been rebuilt two times, by a private shop. This will be the third time, spun rod bearing, the first two times they rebuilt it.

Of course now, they refused to do it and I’m debating if I want to do it myself, which is what I’m gonna probably end up doing, because I’m not gonna pay to have it done at a shop again.

I wanna make sure I do it right. I’m a certified mechanic but never done an engine rebuild. I wanna upgrade the proper components, for better performance,sound and handling.

The only thing that hasn’t been replaced on the internal components of the motor is the pistons, the piston rings and connecting rods. I want to replace and possibly upgrade those as well.

I’ve had the block bored out, the heads are NOT cracked, and are new. I know I’m going to replace the connecting rod bearings and the crank shaft bearings for sure and obviously I’m thinking the crankshaft at minimum, along with the timing components, so anything additional recommended for performance upgrades and additional component replacement, please send it.

Let’s hear it. What do you guys think?

 

[Aaron Davies]

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[Schurkey]

Of course now, they refused to do it

Good. They're likely incompetent.

I wanna make sure I do it right. I’m a certified mechanic but never done an engine rebuild.

The usual problem with first engine builds is lack of cleanliness. When you think it's clean enough, clean it AGAIN with HOT, soapy water. Don't forget to use "rifle brushes" to clean EVERY oil passage, including the ones in the crankshaft, and between the main bearings and the camshaft bearings.

I don't allow Floor-Dry (Kitty litter) in my shop. Floor-dry = dust.

I wanna upgrade the proper components, for better performance,sound and handling.

The only thing that hasn’t been replaced on the internal components of the motor is the pistons, the piston rings and connecting rods. I want to replace and possibly upgrade those as well.

There's no reason to change usable connecting rods if the RPM is going to be kept moderate.

Spending money on pistons and decking the block to achieve proper squish/quench distance is probably wise.

I’ve had the block bored out,

Was it honed using a torque-plate? If not, you need to reconsider.

Many machine shops want the pistons in-hand, so they can get the proper piston-to-wall clearance. Supposedly, this clearance is built-into the pistons themselves. You'd bore to the nominal oversize, and the pistons are made small enough to get the needed clearance...but there's always exceptions.

I’m thinking the crankshaft at minimum,

If the crank hasn't been ground so far undersize that you can't get bearings for it, and it's not otherwise damaged...the ONLY reason to replace it is to buy a stroker crank. Which then means you're perhaps going to be spending money tuning the computer.

so anything additional recommended for performance upgrades and additional component replacement, please send it.

Let’s hear it. What do you guys think?

LOOK at the specs for the GM 383 replacement engine. Supposedly they can drop-into a 1500 truck with no computer tuning (although you'd get better performance WITH tuning.) If you want to avoid the tuning, plan to get the stroker crank, and this is a 1500 truck, use the same compression ratio, same cam, etc.

If this isn't a 1500 truck, or you want more/better...start looking at tuning options. Either someone to do it for you, or tools to D-I-Y, and lots of advice.

Consider an aftermarket balance job. Not intensely critical especially on lower-RPM builds using stock components, but fairly essential if you're using aftermarket crank, rods, etc.

 

[PlayingWithTBI]

Just a few notes on the 383 stroker;

The traditional way to convert a 350 was to bore it to 4.030" and put in a 3.75" stroke crank from a 400. You need to clearance the block to accommodate the longer stroke. Now you want a 1 piece seal crank made for this era (86+) of engine.

Blue Print's "383" is actually a 377 using 4.000" bore and 3.75" stroke. They cast their own blocks and use all new parts.

The GM Performance 383 is 4.000" bore with a 3.80" stroke. Same as Blue Print (new parts) but, different cam(s).

The roller cam that came with my Blue Print short block is 230/236° @ .050" and .510/520" lift so, I needed bigger valve springs too. It's also a Vortec style block so, I had to drill a few small holes in the T-Stat to allow for enough bypass to prevent hot spots, when warming up. YMMV

Quite honestly, I wouldn't do one without tuning. You'll need more fuel to maintain the same stoich AFR (14.7) when cruising, ~12.5+ when stomping on it, and modified timing tables to rev it up to 5700 RPM some of these combinations want for peak HP. Mine doesn't like to idle under 850 RPM either but, it sure sounds cool!

 

[Hipster]

It’s been rebuilt two times, by a private shop. This will be the third time, spun rod bearing, the first two times they rebuilt it.



The only thing that hasn’t been replaced on the internal components of the motor is the pistons, the piston rings and connecting rods. I want to replace and possibly upgrade those as well.

Rebuilt two times by a shop and no new rings were installed? It doesn't sound like it's ever technically been rebuilt.

 

[Aaron Davies]

Good. They're likely incompetent.


The usual problem with first engine builds is lack of cleanliness. When you think it's clean enough, clean it AGAIN with HOT, soapy water. Don't forget to use "rifle brushes" to clean EVERY oil passage, including the ones in the crankshaft, and between the main bearings and the camshaft bearings.

I don't allow Floor-Dry (Kitty litter) in my shop. Floor-dry = dust.


There's no reason to change usable connecting rods if the RPM is going to be kept moderate.

Spending money on pistons and decking the block to achieve proper squish/quench distance is probably wise.


Was it honed using a torque-plate? If not, you need to reconsider.

Many machine shops want the pistons in-hand, so they can get the proper piston-to-wall clearance. Supposedly, this clearance is built-into the pistons themselves. You'd bore to the nominal oversize, and the pistons are made small enough to get the needed clearance...but there's always exceptions.


If the crank hasn't been ground so far undersize that you can't get bearings for it, and it's not otherwise damaged...the ONLY reason to replace it is to buy a stroker crank. Which then means you're perhaps going to be spending money tuning the computer.


LOOK at the specs for the GM 383 replacement engine. Supposedly they can drop-into a 1500 truck with no computer tuning (although you'd get better performance WITH tuning.) If you want to avoid the tuning, plan to get the stroker crank, and this is a 1500 truck, use the same compression ratio, same cam, etc.

If this isn't a 1500 truck, or you want more/better...start looking at tuning options. Either someone to do it for you, or tools to D-I-Y, and lots of advice.

Consider an aftermarket balance job. Not intensely critical especially on lower-RPM builds using stock components, but fairly essential if you're using aftermarket crank, rods, etc.

I really appreciate this, Sir! I will update the thread as I work on the project. I am rebuilding it with my 77yr old Grandpa in August. He wants to learn more as he street drag raced in the 60's and 70's, but his best friend always did the wrenching.

 

[Aaron Davies]

Just a few notes on the 383 stroker;

The traditional way to convert a 350 was to bore it to 4.030" and put in a 3.75" stroke crank from a 400. You need to clearance the block to accommodate the longer stroke. Now you want a 1 piece seal crank made for this era (86+) of engine.

Blue Print's "383" is actually a 377 using 4.000" bore and 3.75" stroke. They cast their own blocks and use all new parts.

The GM Performance 383 is 4.000" bore with a 3.80" stroke. Same as Blue Print (new parts) but, different cam(s).

The roller cam that came with my Blue Print short block is 230/236° @ .050" and .510/520" lift so, I needed bigger valve springs too. It's also a Vortec style block so, I had to drill a few small holes in the T-Stat to allow for enough bypass to prevent hot spots, when warming up. YMMV

Quite honestly, I wouldn't do one without tuning. You'll need more fuel to maintain the same stoich AFR (14.7) when cruising, ~12.5+ when stomping on it, and modified timing tables to rev it up to 5700 RPM some of these combinations want for peak HP. Mine doesn't like to idle under 850 RPM either but, it sure sounds cool!

Very good information and again I really appreciate all of this guys! I have some thinking to do then. I may keep my current block as a spare build and go the Blue Print 383/GM Performance 383 block route.

 

[Aaron Davies]

Rebuilt two times by a shop and no new rings were installed? It doesn't sound like it's ever technically been rebuilt.

I can see other's are starting to see my frustrations and concerns lol. I bought this truck 1 year ago, this last February. I rebuilt my transmission with a certified Master Rebuild, and between that, the motor and all the other components, I'm $16k into her and refuse to do anything incorrectly!

 

[Aaron Davies]

So here's what I am looking at so far, I'm not in the position to put a crate motor in.

Amazon.com Shopping Cart

Let me know if that link doesn't work.

 

[PlayingWithTBI]

Let me know if that link doesn't work.

Nope, it shows "Your Cart is Empty"