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Saturn SOHC Teardown and Rebuild
- Thread starter spasm3
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Ok here are teardown pics.
I will have to bore the block , and turn the crank down. All the cylinders looked good except the one near the back of the block. The piston is scuffed and the bore is scored.
Looks like that cylinder was either small from the factory or it got hot.
Rods are fractured cap design, so keeping the cap and rod mated is imperative.
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All the bores save one looked this good.
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Scoring is too deep to hone out. this block looks like is is deeply rough honed then plateau honed finer.
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Aluminum bearings, some particle embedment visible.
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As far as the rings go, the oil control rings were not coked up. They were free and the ringlands fairly clean. ( I must add, i did try multible piston soaks with b-12 and ran kreen in the oil , no success reducing the oil consumption.)
So it seems the low tension is responsible for the coil consumption as the engine had good compression.
I will have to bore the block , and turn the crank down. All the cylinders looked good except the one near the back of the block. The piston is scuffed and the bore is scored.
Looks like that cylinder was either small from the factory or it got hot.
Rods are fractured cap design, so keeping the cap and rod mated is imperative.
[img:center]http://[/img] [img:center]
[/img] [img:center]
[/img] All the bores save one looked this good.
[img:center]
[/img] Scoring is too deep to hone out. this block looks like is is deeply rough honed then plateau honed finer.
[img:center]
[/img] [img:center]
[/img] [img:center]
[/img] Aluminum bearings, some particle embedment visible.
[img:center]
[/img] As far as the rings go, the oil control rings were not coked up. They were free and the ringlands fairly clean. ( I must add, i did try multible piston soaks with b-12 and ran kreen in the oil , no success reducing the oil consumption.)
So it seems the low tension is responsible for the coil consumption as the engine had good compression.
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Buy a piston and hone the hole. It'll run fine for many tens of thousands of miles like that.
What's wrong with the crank? Is it too far under size? If not- a little hand polishing and new std or .001 under bearings may fix it fine. I'll post some pics up some time of a 3.1 GM crank I hand polished. If done right, they can come out nice.
What's wrong with the crank? Is it too far under size? If not- a little hand polishing and new std or .001 under bearings may fix it fine. I'll post some pics up some time of a 3.1 GM crank I hand polished. If done right, they can come out nice.
Originally Posted By: The_Eric
Buy a piston and hone the hole. It'll run fine for many tens of thousands of miles like that.
What's wrong with the crank? Is it too far under size? If not- a little hand polishing and new std or .001 under bearings may fix it fine. I'll post some pics up some time of a 3.1 GM crank I hand polished. If done right, they can come out nice.
The scuff is really deep, my fingernail easily catches in it, If it was light scuffing, i would ball hone it out.
Crank has some light scoring, not sure i can polish it out, i might try though.
I just don't want to do all the labor of removal and skimp on a proper sealing bore, then still have oil usage.
Buy a piston and hone the hole. It'll run fine for many tens of thousands of miles like that.
What's wrong with the crank? Is it too far under size? If not- a little hand polishing and new std or .001 under bearings may fix it fine. I'll post some pics up some time of a 3.1 GM crank I hand polished. If done right, they can come out nice.
The scuff is really deep, my fingernail easily catches in it, If it was light scuffing, i would ball hone it out.
Crank has some light scoring, not sure i can polish it out, i might try though.
I just don't want to do all the labor of removal and skimp on a proper sealing bore, then still have oil usage.
I just took the top ring off the number 4 piston. In the scuffed bore i measured a ring end gap of .019 to .020.
I moved that same ring to the front cyl that looks good and the end gap is .023.
Perhaps that bore is too tight from the factory?
I might have room to hone it. without it being too large.
No, i don't have a dial bore gauge.
I would need to final hone to 400 for the moly rings.
I dont think i can hone those away with a 400 brush.
The cost of a coarse brush and a fine one , might approach the cost of a rebore/hone.
I will pm Trav, and get him to look at this thread and get his thoughts.
I moved that same ring to the front cyl that looks good and the end gap is .023.
Perhaps that bore is too tight from the factory?
I might have room to hone it. without it being too large.
No, i don't have a dial bore gauge.
I would need to final hone to 400 for the moly rings.
I dont think i can hone those away with a 400 brush.
The cost of a coarse brush and a fine one , might approach the cost of a rebore/hone.
I will pm Trav, and get him to look at this thread and get his thoughts.
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Don't know if this will polish out.
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[/img] Don't know if this will polish out.
Haynes manual lists bore diameter for this engine as
cyl 2 and 3 at 3.2280 to 3.2287
cyl 1 and 4 as 3.2283 to 3.2291
service limit 3.2301 max
cyl 2 and 3 at 3.2280 to 3.2287
cyl 1 and 4 as 3.2283 to 3.2291
service limit 3.2301 max
piston skirt indicates that (a) these are coated piston skirts; and (b) it's scuffed, maybe due to overheating, abrasion or lack of lubrication (doing too much/too frequent of the so-called solvent soaking from top down).
If you want your engine to run properly w/o issues, consider getting a new set of replacement pistons and then take it from there.
Q.
If you want your engine to run properly w/o issues, consider getting a new set of replacement pistons and then take it from there.
Q.
I would show the block and crank to a machinist, it looks like it was probably pumping oil up in that last cylinder also. I would bore it if you intend on keeping this car and possibly having the crank ground.
Sorry i cant tell much about the crank from pictures but minor stuff can be polished out deeper stuff needs grinding.
Usually when i rebuild an engine on a car i want to keep I have the block align bored and cylinders bored if needed with a new piston set.
Sorry i cant tell much about the crank from pictures but minor stuff can be polished out deeper stuff needs grinding.
Usually when i rebuild an engine on a car i want to keep I have the block align bored and cylinders bored if needed with a new piston set.
Originally Posted By: Trav
Usually when i rebuild an engine on a car i want to keep I have the block align bored and cylinders bored if needed with a new piston set.
Thats my gut feeling, overbore and new pistons. So the block, head ,crand, and flywheel go to the machine shop!
Usually when i rebuild an engine on a car i want to keep I have the block align bored and cylinders bored if needed with a new piston set.
Thats my gut feeling, overbore and new pistons. So the block, head ,crand, and flywheel go to the machine shop!
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Originally Posted By: spasm3
Originally Posted By: Trav
Usually when i rebuild an engine on a car i want to keep I have the block align bored and cylinders bored if needed with a new piston set.
Thats my gut feeling, overbore and new pistons. So the block, head ,crand, and flywheel go to the machine shop!
Yup. If you intend on keeping it for any period of time this would be my route too.
Originally Posted By: Trav
Usually when i rebuild an engine on a car i want to keep I have the block align bored and cylinders bored if needed with a new piston set.
Thats my gut feeling, overbore and new pistons. So the block, head ,crand, and flywheel go to the machine shop!
Yup. If you intend on keeping it for any period of time this would be my route too.
Contact Crazyoildude. He is a master engine rebuilder and owns his own shop. He'll hook you up...
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Originally Posted By: Bluestream
Contact Crazyoildude. He is a master engine rebuilder and owns his own shop. He'll hook you up...
Thanks, but i think he is in NJ, i'm in NC. So i will finish stripping the block down this weekend and taking it all in next week.
Contact Crazyoildude. He is a master engine rebuilder and owns his own shop. He'll hook you up...
Thanks, but i think he is in NJ, i'm in NC. So i will finish stripping the block down this weekend and taking it all in next week.
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Maybe I missed it but what was the OCI regiment? Conventional or syns? Ring lands are really clean is why I'm asking. We tend to speculate so much here that seeing an engine torn down is the ultimate tell-all about how a maintenance regiment plays out over the life of the engine.
Thanks for the pics
Thanks for the pics
Originally Posted By: zuluplus30
Maybe I missed it but what was the OCI regiment? Conventional or syns? Ring lands are really clean is why I'm asking. We tend to speculate so much here that seeing an engine torn down is the ultimate tell-all about how a maintenance regiment plays out over the life of the engine.
Thanks for the pics
I bought the car with 119k in 2008 for my son when he turned
16.
Synthetic was used at first changed every 3-5 as he short
tripped , HS was only 3 miles away. I used mobil one HM a
first. It used about a quart in 1200 then. Oil usage slowly
went up over time. I started using conventional Pennzoil HM
with short 3k oci's as he short tripped a lot in college. It
got to where it was using a quart in 400 miles, i was using
valvoline next gen hm that i got for $5 for a 5 quart jug( i
bought about 12-15 jugs). I quit changing oil when it was
using a quart in 400 miles. the oil pan is clean, the head is
not bad either but not spotless. 180,000 when torn down. I
still have about 6 jugs of the nextgen left.
At this point it was using a quart in 400, and i knew it was
going to need a clutch soon, so the i decided to just yank it
out and do both. Clutch had some miles left , but not a lot.
If anything it taught him to check oil , although since the
cylinder furthest away from the pump is scuffed, i suspect he
revved it up with the oil low, and sucked the pan dry.
Maybe I missed it but what was the OCI regiment? Conventional or syns? Ring lands are really clean is why I'm asking. We tend to speculate so much here that seeing an engine torn down is the ultimate tell-all about how a maintenance regiment plays out over the life of the engine.
Thanks for the pics
I bought the car with 119k in 2008 for my son when he turned
16.
Synthetic was used at first changed every 3-5 as he short
tripped , HS was only 3 miles away. I used mobil one HM a
first. It used about a quart in 1200 then. Oil usage slowly
went up over time. I started using conventional Pennzoil HM
with short 3k oci's as he short tripped a lot in college. It
got to where it was using a quart in 400 miles, i was using
valvoline next gen hm that i got for $5 for a 5 quart jug( i
bought about 12-15 jugs). I quit changing oil when it was
using a quart in 400 miles. the oil pan is clean, the head is
not bad either but not spotless. 180,000 when torn down. I
still have about 6 jugs of the nextgen left.
At this point it was using a quart in 400, and i knew it was
going to need a clutch soon, so the i decided to just yank it
out and do both. Clutch had some miles left , but not a lot.
If anything it taught him to check oil , although since the
cylinder furthest away from the pump is scuffed, i suspect he
revved it up with the oil low, and sucked the pan dry.
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Dropped the pistons off today for the machine shop. Surprised at how tight they are specd to run. They are hypereutectic ,the piston to bore clearance is on the box as .0005 ! Thats tight!
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