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

[beastmazter]

That would be pretty cool, I just have the tank now, it's a 4 gallon pancake. Would like to eventually install it under the Suburban with pump to fill, this would be a cool build. I will keep my eye out for a junk fridge or AC. Sounds like my friend is willing to load up the compressor and bring it over! I will report what I find.

 

[beastmazter]

Hooked up to air, very healthy stream of air coming out of oil fill when air pressure (about 130 psi) is applied to cylinders 1, 3, 5 and 7. Stream sounds and feels the same for each cyl.

 

[beastmazter]

@Ricko1966 took the heads off, had to see what the heck was going on. Without fail, it was a mistake of my own making. Spark plugs were hitting pistons, I imagine that contributed to some sort of displacement of the head or gasket. Hoping the damage is contained to the head.

Going to clean up the head and put a straight edge on it, maybe I will get lucky and just need to slap in new gaskets, but I imagine I’m going to be looking at a bit more than that.

I picked up plugs for a sbc 350, need to pay attention to actual specs next time, I am a pro at learning lessons the hard way! Haha

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[Ricko1966]

Did you try air in the other bank so you know how a healthy bank reacts?

 

[beastmazter]

Did you try air in the other bank so you know how a healthy bank reacts?

No, but it did occur to me right after I ripped the head off, that I should have done that. I have the head cleaned up and back on the truck already. I will test the other bank tonight to see how it reacts.

I had to order a heater core also since mine was leaking and since the coolant is drained, no better time than now to do that also. Core and thread sealant will be in tomorrow, will torque things down and see if I got crazy lucky.

 

[beastmazter]

@Ricko1966 Torqued down the head. No change to the free air flow into the crankcase. The normal bank pressurizes like a mostly-sealed cylinder should. Definite difference. It wasn't too surprising, knowing air was flowing into the crankcase, I couldn't think of a way the head or gasket would be causing that. Clearly an issue with rings, or maybe I even cracked these aluminum pistons?

Looking for a cheap replacement engine to use while I re-build this one.

 

[Ricko1966]

@Ricko1966 Torqued down the head. No change to the free air flow into the crankcase. The normal bank pressurizes like a mostly-sealed cylinder should. Definite difference. It wasn't too surprising, knowing air was flowing into the crankcase, I couldn't think of a way the head or gasket would be causing that. Clearly an issue with rings, or maybe I even cracked these aluminum pistons?

Looking for a cheap replacement engine to use while I re-build this one.

That engine can be fixed in 3 afternoons maybe less if you can get the machine shop to cooperate. Worst case you pull those 4 pistons and need 4 pistons the machine shop swaps the pistons on the rods the next day you put it back together on day 3. Best case ,you pull the 4 pistons you have shattered rings,you clean the ring grooves ball hone the block new rings and rod bearings. 2 day adventure.

 

[beastmazter]

That engine can be fixed in 3 afternoons maybe less if you can get the machine shop to cooperate. Worst case you pull those 4 pistons and need 4 pistons the machine shop swaps the pistons on the rods the next day you put it back together on day 3. Best case ,you pull the 4 pistons you have shattered rings,you clean the ring grooves ball hone the block new rings and rod bearings. 2 day adventure.

I like the way you think. I was trying to think of ways to pull the cylinders in my driveway, probably easiest to pull the engine to do it and I may have just tracked down a cherry picker I can borrow. I wasn't sure if it was a good idea to replace the 4 pistons and not the other 4. Which is why i defaulted to replacing the engine for now.

3-4 day process isn't bad though.

If I bring them to the machine shop, would they balance the new ones off the old? I could see that working. Do I need the same pistons to match the other side? I searched briefly and didn't see an exact match to what I have.

Appreciate your help! I used to work on RV's, the seasoned guys were indispensable with their knowledge on how to fix the occasional F#$% up.

 

[Ricko1966]

All you have to do is pull the pan and pop the pistons out the top,no need to pull the engine. You can leave the good bank alone. Buy new to match old pistons.You or your machine shop can match weight on the pistons if neccesary, weigh what came out get close on weights going in, juggle heavy rods to light pins,light pistons to heavy rods etc. As long as what you put back is roughly within 2 grams of what you took out it'll be as good as your average rebuilder. Wrap crank journals in cardboard and masking tape,push oily rags to the bottoms of the cylinders. After you hone, pull the rags out through the top,the OILY rags will pull most of the debris up with them, so cleaning is easier. I've done this lots of times,usually if I do a head gasket,I default to rings,rod bearings,and a valve job.

 

[beastmazter]

I tested compression on the good bank and found a noticeable difference. Replacing head gasket didn’t help at all. Which wasn’t to surprising.

Took a step back to regroup, then got sick. Finally back at it today. Everything removed from the engine, ready to be pulled. Found a lift to borrow, going to tear into it in my shed so I can get out of the wind and cold.

Should be out this week, will report back on what I find. My driveway has so little room to work, pulling the engine is going to be so much more enjoyable.

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