Driver's side Cylinders 50-60 PSI, Drinkers side 130-140 5.7L 350 1986 K10 Suburban Crate Engine

[beastmazter]

The piston tops don't look like they had a bunch of detonation going on. Best guess would be that something happened with the previous rebuild to make that bank be slightly smaller bore than the other side. The guy that assembled the engine didn't check all of the ring gaps and for some reason they were too tight on that bank.

You are already .030 over on that block. Can you still see any crosshatch on the cylinder walls? If it really only has a few thousand miles on it, I'd be very tempted to just run a $40 ball hone through it and get a new set of .030 over flat top pistons pressed on those rods. Measure and file a new set of rings for the correct ring gap and send it.

I can see the cross hatch. They look fine, not much different from any other cylinder I have seen in my other working engines.

I wouldn’t mind doing a ****** ball hone and putting new pistons in, I have done it once before and it was really easy. I know these aren’t balanced from the factory so there is some tolerance.

I’m debating between taking my time and just doing what I know will fix it, and just sending it. If it goes belly up I use the money I would have spent at the machine shop, on a new engine.

Or put in a cheap marketplace 350. Rebuild this one and find something fast to drop it into.

 

[Ricko1966]

Woah i didnt know it was possible for the spark plugs to get hit by the piston. How does that happen??

As for your question, i would go for it. You don't want to revisit yanking the engine and visiting the machine shop for as long as possible.

Whats the rush on finding a cheapo 350 while this one gets fixed? Might as well let her sit no? Keep the motivation on the proper project!

The spark plugs didn't cause this.It leaned out on one bank and broke the ring lands. It probably has a dual plane manifold and a plugged main jet. I'd pull the pistons on the other side and inspect them,use one of them to have the machine shop get you 4 pistons to match,ball hone,put cast rings in it and new rod bearings.It may burn some oil but will buy you tons of time to build the engine you want. You'd be absolutely amazed how long my uncle nursed his 300/6 ford after I did this same thing,for this same reason(broken ring lands) he drove it for about 15 years after that. He donated it to the humane society still running, some lucky dog or cat is probably still driving that truck.

 

[beastmazter]

The spark plugs didn't cause this.It leaned out on one bank and broke the ring lands. It probably has a dual plane manifold and a plugged main jet. I'd pull the pistons on the other side and inspect them,use one of them to have the machine shop get you 4 pistons to match,ball hone,put cast rings in it and new rod bearings.It may burn some oil but will buy you tons of time to build the engine you want. You'd be absolutely amazed how long my uncle nursed his 300/6 ford after I did this same thing,for this same reason(broken ring lands) he drove it for about 15 years after that. He donated it to the humane society still running, some lucky dog or cat is probably still driving that truck.

The intake that's on it now is not dual plane, but I am not sure if that's what was on the engine when it was in operation by the original owner. I believe the person I bought it from added a few bits and pieces. Definitely makes sense of what I am seeing.

Tore it down further this weekend. More not goodness.

Main bearings and journals have scratches. Finger nail catches along the journals.

Closer inspection of the cylinder walls I can sense vertical scratches with my finger nails, nothing to actually catch a nail on, but I can feel them.

I am checking out an 80's 350 from an older gentleman on Tuesday. He put it in an old 60's truck that he used sparingly back in the 80's. Said had less than 100 hours on it. Scrapped the truck and the engine sat in his barn since. Still turns over and you can her compression. Going to scope it, if the cylinders look decent I may snag it. Tear it down and replace rings, seals etc.

I like the story of reviving old stuff, sounds like a fun project to me! and I have wanted the infamous 350 since I was a kid. Holding off on an LS swap for now.

Let me know if there is anything I should look for that should cause me to walk away from this old engine. Everything else local has been pretty high mileage.

You must be registered for see images attach

You must be registered for see images attach

 

[Ricko1966]

Your arms are going to get tired.pull the cap watch the rotor feel for compression on all 8. Before I put it in I'd pull the pan,wiggle the rod caps look at 1 rod bearing,1 main bearing. If he'll let you you can run compression on the ground with a battery a starter a pair of jumper cables and a remote start switch.

 

[beastmazter]

Will do! I am bringing a scope. It’s sat for 40 years. Should I expect a certain level of rust in the cylinders?

 

[Ricko1966]

Run it through 2 revolutions by hand.make sure it doesn't size. Then run compression if it checks out good that's about all you can hope for.If there's tons of rust,you probably won't make it through 2 revolutions by hand. 1 if it's bad enough the rings aren't going to go past it. 2 if it's significant but not enough to keep the pistons from moving the rings will scrape the rust to the top,pack on top of the pistons and not let it turn over. Then you'll know the heads have to come off,to evaluate.

 

[beastmazter]

Awesome, thanks for the advice. I don’t think I will be able to do compression. Slammed at work and renting a truck to grab it. It’s going to be a quick mission. It’s already turning and making woosh noises out of the spark plug holes. I’m feeling lucky, we will see.

 

[beastmazter]

Picked up the engine last night. PO fogged it and made sure it was sealed up decently before storing away. Crank turned smooth as butter, compression on all cylinders, pulled a valve cover off, and it looked factory fresh inside. I ordered all the bearings, rings and gaskets to do a refresh on it, but I may just do rear seal and oil pan gasket and call it a day. Chances of screwing something up are higher being a backyard hack. Have the Haynes 350 techbook and the tools necessary, but may not be worth the risk everything is as clean as what I saw under the valve covers. Also doing everything in a cramped shed.

You must be registered for see images attach

 

[beastmazter]

I may have lucked out pretty big, this engine is CLEAN.

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

 

[beastmazter]

Ope! Spoke too soon.

You must be registered for see images attach

You must be registered for see images attach

Noticing some hanging metal and pretty sloppy drilled holes from balancing.

You must be registered for see images attach

You must be registered for see images attach

 

[Bextreme04]

Honestly doesn't look bad at all. I'd maybe do some plastigauge to make sure the bearing clearances are fine. Put a fresh set of main and rod bearings in(after you have plastigauged to see if you need a different size) and probably a new oil pump just to be sure. It almost looks like a brand new engine that maybe got ran long enough for break-in and maybe lost oil pressure and got shut down fast or got started up for break-in without priming it first. The abrasion you are seeing on that main cap could be from the 20-30 seconds of turning on the assembly lube before the oil filled all the galleys up.

Looks like a stock crank too. Thats how they look from the factory. What you need to worry about is if someone put some mallory metal in that drilled hole and then just welded it in place. The right way to do it is to drill from the side and place the metal in that way.

 

[beastmazter]

Honestly doesn't look bad at all. I'd maybe do some plastigauge to make sure the bearing clearances are fine. Put a fresh set of main and rod bearings in(after you have plastigauged to see if you need a different size) and probably a new oil pump just to be sure. It almost looks like a brand new engine that maybe got ran long enough for break-in and maybe lost oil pressure and got shut down fast or got started up for break-in without priming it first. The abrasion you are seeing on that main cap could be from the 20-30 seconds of turning on the assembly lube before the oil filled all the galleys up.

Looks like a stock crank too. Thats how they look from the factory. What you need to worry about is if someone put some mallory metal in that drilled hole and then just welded it in place. The right way to do it is to drill from the side and place the metal in that way.

Thank you for the bit of optimism. The engine is really clean so I have been really exited up until this point.

It’s going in a vehicle that will not be my daily, is not a race car and was just kind of rotting in someone’s field. I want to get it on the road and have some fun with it, not spend 20k on it. I am totally cool with “not by the book but it’s probably going to be fine”

I haven’t a clue how concerned I should be by this. It doesn’t look good, that’s for sure.

I am going to break the engine down and have a closer look at everything. Worst case I buy a new stock crank from summit for $200 and throw it in, I have all the standard replacement bearings already and a full seal kit.

Should I polish the journals? I can slightly feel scratching.

 

[Bextreme04]

Thank you for the bit of optimism. The engine is really clean so I have been really exited up until this point.

It’s going in a vehicle that will not be my daily, is not a race car and was just kind of rotting in someone’s field. I want to get it on the road and have some fun with it, not spend 20k on it. I am totally cool with “not by the book but it’s probably going to be fine”

I haven’t a clue how concerned I should be by this. It doesn’t look good, that’s for sure.

I am going to break the engine down and have a closer look at everything. Worst case I buy a new stock crank from summit for $200 and throw it in, I have all the standard replacement bearings already and a full seal kit.

Should I polish the journals? I can slightly feel scratching.

If you feel some ridges and aren't experienced in this.. I would take it to a local machine shop and have them check it out. It is usually ~$50 or less to have it professionally polished and inspected for roundness. Ask them to measure and record the main journal sizes while they are at it. Then get a bore gauge set from harbor freight and measure your bearing clearances. It will cost you a whopping $100 to do all this and it will give you the FOR SURE bearing clearances with your crank and the bearings you have bought. To measure the bearing clearance you just make sure all the surfaces are clean and dry and then install the bearings in the mains. Torque down the main caps(with no crank installed) and then measure the size of the bearing(you can find many youtube videos on how to do this). Once you have those measurements you can subtract the machine shop measured journal size from the measured main bearing size and you'll have the clearance. It should be somewhere from .0020-.0030".

The cheaper, roadkill way to do this is to just run a fine emory cloth over the journals to smooth the ridges out. Run it around the journal(with the scratches), not across it. Then get some plastigauge and assemble everything dry with a bit of the plastigauge across each journal. If it is "close enough", then clean the plastigauge off, put some assembly lube on everything, and send it. Cost for plastigauge and emory close is probably ~$20. I'm driving my 1993 Honda Civic right now with ~260,000 miles on it. It blew a head gasket and was smoking pretty good. I pulled it down and found massive amounts of carbon buildup and everything was wet with oil. I decided to do the bare minimum because this is just my beater commuter car, so it got a new headgasket and I bought a $10 block of billet aluminum to use as a flat plate and stuck 320 grit sandpaper to it and used it to "surface" the block and head. I figured the oil probably came from either weak rings from it overheating or worn valve seals, so bought a set of valve seals for $20 and a new set of NPR rings for $40. ****** ball hone was $30. Pulled the pistons and sure enough the oil control rings were glued into the piston by carbon deposits, so I ****** ball honed it and then cleaned the pistons and installed new rings. Then replaced the valve seals, cleaned the valves, and lapped them in. All in... maybe a weeks work and about $250 in stuff. Engine fires right up now and runs like a champ with no smoking and no loss of compression. I bet the dang thing goes another 150-200k miles before someone has to do it all over again.

 

[Big Ray]

Gotta love a happy ending.
Watched Roadworthy Rescues the other night.
Derek ****** balled a sb400 he had sitting around. Put a dang supercharger on it!

Ran fine!

 

[Bextreme04]

There's a few things that will destroy an engine fast. Not having enough oil pressure and having too tight tolerance are the big ones. Having absolutely filthy assembly conditions is another. Other than that.. these things will take a beating for the most part.