Rebuilt motor or replace the rings/pistons

[Mango™]

Question, I am considering changing the rings and pistons on my 1991
S-10. It has 153k miles.
The truck has smoked for 3-5 years. For the last year it has been sitting in the sun baking. I got it started but I want to fix it up for my son.
We have chaged the EGr valves and plug and wires. The number 1 plug keeps getting build up of carbon from buring all the oil. Every tank pull means add oil.
I am going to replace all the plugs, wires, 2 valves, rings and pistons, oils and filter, air filter, fuel pump, breather filter. I am hoping that clears the smoke problem so i can get it inspected.

OR
Should I buy an rebuilt motor for $2500 with an 3 yrs/36k mile warrente?

Any suggestions?

Thanks

[movin2stereo]

$2500.00,WOW!I got a crate engine for $1600.00.You better check around.

[Mikado14]

Originally Posted by Mango™

Question, I am considering changing the rings and pistons on my 1991
S-10. It has 153k miles.
The truck has smoked for 3-5 years. For the last year it has been sitting in the sun baking. I got it started but I want to fix it up for my son.
We have chaged the EGr valves and plug and wires. The number 1 plug keeps getting build up of carbon from buring all the oil. Every tank pull means add oil.
I am going to replace all the plugs, wires, 2 valves, rings and pistons, oils and filter, air filter, fuel pump, breather filter. I am hoping that clears the smoke problem so i can get it inspected.

OR
Should I buy an rebuilt motor for $2500 with an 3 yrs/36k mile warrente?

Any suggestions?

Thanks

Before I would go swapping motors, have you checked the compression and performed a leak down test? You may have only bad valve seals and they are a cake walk to repair.

[04 blazer]

Definitely check around. I got a rebuilt engine from a local engine shop for my '91 S-10 for $900.00 and it had a 2 year/24,000 mile warranty which I have already surpassed (40,000 miles) and it runs great.

[OverBoardProject]

Mango, what size motor does it have?

If it has a 2.8L drop in a 3.4L from a comaro, everything bolts on from the 2.8 but theyre better motors. You'd need the 2.8L oil pickup, oil pan and either the flywheel or flex plate. (I can send you 2 good links on the subject)

If it's a 4.3L or a 4 banger stick with what you have

[BlazerLT]

Sounds like valve seals to me.

[vtmecheng]

Listen to Mikado14, you can tell a lot by a compression test. Also run a vacuum test with the truck running. At idle you should get 18-20 Hg, quickly rev the engine to 2500 RPM and you should almost get 0 Hg and this should happen quickly, snap the throttle closed and you should quickly get around 5 Hg higher then at idle, this will then drop back down to idle vacuum. If when the throttle is closed the vacuum doesn't reach 5 Hg over idle or gets there slow then your rings may be bad.
With bad valve seals just replace them, with bad rings get a crate engine.

[Mango™]

I do appreciate your answers, where can I get an compression test done and what does it cost.
I do an have 4.3cl v6. The $2500 was the first place I called.

Thanks again

[vtmecheng]

If you don't want to get a compression tester and do it yourself (if you can do all the work with replacing rings you can do this) any shop will do it for you. You may even be able to borrow a compression tester at your local parts store, like Advance or Auto Zone. Worth a shot.

[Mango™]

I looked up the compression tester and I have no idea how to use it. What would an garage cost to test it. Can you give me the main idea how to use it and maybe I will use it from Autozone.

Thanks again!

[OverBoardProject]

Really not that hard, first remove the spark plug, then insert threaded part of tester. Then just crank the motor over until it stops moving (3-5 seconds but best with a remote starting button) and it stays at the highest compression setting until you press the button to release the air.

If 1 cylinder seems low check it again after your done, they seem to clear up for the second round

[Mango™]

How would I know if there is low compression or not.
What should the pressure be, will it come with an booklet?

Thanks

[Mikado14]

Originally Posted by Mango™

How would I know if there is low compression or not.
What should the pressure be, will it come with an booklet?

Thanks

I looked through your post but did not see what engine, maybe I'm missing it. However, in round numbers, say the compression ration is 8:1, you will be looking for a pressure that is 8 times greater than atmospheric or roughly 120 psi. An engine size would help.

[OverBoardProject]

He says it is a 91, 4.3L further down. I don't have those specks in my books

[Mango™]

91 4.3 thanks!