Saturn Rings


travelair
02-28-2012, 07:42 AM
Hello! It's time to rebuild the engine in my '96 SL2 5-speed. I've been pouring oil through it for years and years, and it runs like a champ. After many MMO and ATF soaks and treatments, the condition has remained unchanged.

But now, I'm losing compression, and the MPG is being affected. It's time.

My questions are: Can I use the new pistons and rings from the newer design? Are the old rings/pistons even sold today? How would I avoid them? Are there part number differences?

denisond3
02-28-2012, 09:14 PM
I dont know anything about new piston or ring designs & have never had to buy a piston. Im pretty sure the parts are still available.
I rebuilt two SL2 Saturn engines in our family; a 92 one summer and a 96 the next summer, that had both become chronic and typical Saturn "S" series oil-guzzlers. In both cases the pistons and the cylinders were fine - but the oil control rings on the pistons were pretty much staying deep in the groove. The compression rings sprang out from the grooves as I pushed the pistons up out of the cylinder, but the oil control rings didnt move out of the groove -at all-!
I spent quite a while scraping the crud from the ring grooves, (using an old compression ring that I broke into 3 pieces and ground the ends to a flat face with sharp edges), and got a lot of crud out. I also had the cylinders honed. Even though the original hone marks were visible to with 1/4" of the top of the cylinder: You always re-hone so the new compression rings will 'seat' themselves.
I got new rings (I think they were Hastings, but Im not sure - I know they were not chrome plated), an engine gasket set, and put the engine back together. The engines got the new rings, new crankshaft seals, new timing chain guides and tensioner. I didnt change the oil pump, nor the timing chain or the timing sprockets. I did replace the serpentine belt tensioner pulley and the idler pulley, along with a new serp. belt. and a new water pump.
I took both heads to my favorite machine shop. One of them didnt need any valve work & just got new valve stem seals, the other one (with 200K) miles on it warranted new valves. In both cases I made sure the machinist used his bead blaster to totally clean the passage in the head from the #4 exhaust port, back to the EGR valve. This passage can get filled up with dirty exhaust gas products.

There was a dramatic difference between the original oil control rings and the new ones. The cars went from about 500 or 400 miles to a quart, to going at least 4000 miles before they are down a quart - at which time we change the oil anyway.
I consider them a fairly easy engine to rebuild, once you get the many connectors unplugged that you have to reach from underneath & behind the engine! Note: I found on one of them that a lot of the bolts going into the block & head took quite a bit of torque to begin loosening, with the other one it wasnt so noticeable.
I never ever put a steel bolt back into an aluminum block or head, without coating the threads with something; threadlocker, antisieze compound, silicon grease or just axle grease. This prevents the galling that can occur between steel and aluminum.
I used a digital camera, took LOTS of photos as I dismantled; to help me put the wiring harnesses and hoses back where they were supposed to run. The most confusing place is from in front of the brake booster and going behind the block & up under the intake manifold.

My 96 was a 5 speed, so as per the shop manual, (and advice from the internet) I hoisted the engine and trans out together. The shifter cables were stiff and the ends rusty, so I replaced them along with giving it a new clutch & new clutch hydraulics. I would NEVER plan to replace those shifter cables if the engine was still in the car. It was a slow chore even when I was able to sit in the engine compartment to work the old cables out and the new ones in. It sure shifts nice now though.

I ordered most all of my parts from www.rockauto.com. I enjoy working on a car and having the FEDEX driver walk into my driveway and hand me the parts for the car! The only parts I got from rockauto that werent perfectly right, were the two shifter cables. The pair of them cost about $75, and the ends of the cables were oriented incorrectly relative to the other end of the cable. This made it hard to get the ends anchored under the shift lever, and I even made up brackets to hold them onto the ends of the shift select assembly. I suppose I could have spent 5 times more and gotten the OEM cables from a Chevy dealer, but Im okay with the parts I got for the price I paid. This was about the first time those cables were available from the aftermarket, so perhaps now they have fixed the shortcoming.

travelair
03-01-2012, 10:46 AM
Thank you for your response. I'm glad to hear the shift cables are aftermarket now. Finally! Mine have been shot for some time.

So your block was pretty well off? No over sized bearings or anything? Did you hone it yourself with a drill? What type of hone did you use?

Final question: when all was said and done, did you spend more or less than the cost of a low milage junkyard motor?

I've been contemplating that route as well. You did this twice, so I suspect you have a strong bias towards overhaul. Is it worth putting my family through the time it takes to rebuild? They'll be driving me to work once a week, while the SL2 is down.

denisond3
03-01-2012, 10:30 PM
I spent more than a junkyard motor would have cost. My total outlay was close to $1100 - but that included a new clutch and the hydraulics, the new shift cables, brake hoses and rotors, lower control arms, a new starter, and finally a replacement (junkyard) transmission too: Because it turned out my daughter & son-in law had been forcing the trans into gear, when they should have stopped trying to drive it, and they broke one side of one of the shifting forks inside the trans - and it jammed 2nd gear. When I told them this they gave me that 'deer in the headlights look'.

I suppose a junkyard motor would have cost $200 to $300. If I had bought one of those, I would have presumed it would have also needed new rings, etc. because the feeble rings and oil consumption is a well known Saturn "S" series problem. So I would have rebuilt it before I put it in. Doing that might have saved some downtime for the car....i.e. rebuilding an engine and then swapping it in (along with the new clutch stuff), but we had an extra car already; so I could take my time.

I think I would rebuild ANY engine I got from a junkyard, unless it looked 'recently rebuilt' when I took the oil pan off and measured bearing clearances.
I did put a junkyard transmission into my daughter's 92 Saturn, because the one that was in it when we bought it from a niece had a hole gouged in the transmission's differential - thanks to her 18 year old son doing tire-smoking starts. That junkyard trans cost $200 from a rural Pa junkyard, and has worked great ever since.
One reason I favor rebuilding my own stuff is because I am retired and I have plenty of time, tho limited money. And I need the exercise anyway.

My kids and their spouses are all video game enthusiasts, one son-in-law even goes to v.g. tournaments. I have no interest in virtual games. My 'gaming' is getting a car that doesnt run and that somebody wants out of their driveway, fixing it up, and enjoying driving it around the country. I doubt that folks who just operate a car they bought ever get the immense feeling of satisfaction from driving a car whose pistons they have fondled.

The honing was done on a machine at the machine shop - which does it better than my efforts with a cheap honing goody chucked in a 1/2" drill. There were no issues with the block at all, nor with the heads. Both engines worked properly when first re-started, and stayed that way. Did I mention that I also replaced all of the hoses carrying hot coolant? -- except for the one that feeds from the heater behind the motor & over to the bottom of the coolant recovery bottle. I didnt find that one for sale when I looked.

travelair
03-02-2012, 12:46 PM
I've already replaced much of what you did during overhaul. Mine won't go into gear, unless it's rolling slowly. I've become accustomed to simply holding pressure while stopping and letting it slip into first when it's ready. I sit at the light with the car in gear.

I've assumed this was because the pressure plate was shot. The clutch disk seems fine. You can floor it in fifth at 25 mph and it won't slip. I've started collecting parts now for the overhaul and I have a new flywheel standing by. What clutch assembly do you recommend?

My bearings are noisy. It clatters and knocks if you lug it, so you need to rev it pretty good when starting off. Without an oil pressure gauge, it's impossible to know, but I suspect that the psi is just above the limit needed to trigger the idiot light when idling.

I'm worried that the crank will need machining. Or it may be trashed.

denisond3
03-02-2012, 04:04 PM
I just bought a normal clutch 'set' from www.rockauto.com. It wasnt the cheapest nor the most expensive.
If it clatters and knocks at low rpm, are you sure its not the timing chain making the noise? I fixed up an SL2 for a friend, because it would make a slight clatter when it was first started - and none of the parts I replaced looked very worn. This was at 157k miles. The new timing chain, guides, sprockets and tensioner resulted in the same mild clatter close to idle rpm - even a cold idle. It stops once the rpm gets above about 1200-1400 rpm, and never makes noise when driving along. If the noises are actually due to excessive wear between bearings and the journal they ride on - then for sure you crankshaft would have journals out of round.

Flooring it in 5th wouldnt be a good test for a slipping clutch. Try flooring it in 2nd gear or 3rd gear, whatever speed will let the tachometer show 4000 rpm - and see if there is any slippage. If so - the clutch is due for replacement.

Its too bad the design of the SL-2 blocks (after 1993 anyway) doesnt give you a good place to install a mechanical oil pressure gauge - either a tube fitting or a pipe thread fitting for a sending unit.

travelair
05-27-2012, 10:53 AM
Its too bad the design of the SL-2 blocks (after 1993 anyway) doesnt give you a good place to install a mechanical oil pressure gauge - either a tube fitting or a pipe thread fitting for a sending unit.

I added an oil pressure guage. You need a metric adapter (M14 1.5 to 1/8NPT) and it screws into the oil pressure sensor port on the oil galley. There are two other plugs which could be used on the galley, but when I tried to remove one, it was firmly stuck. I chickened out because I don't know how much abuse that part of the motor will take before cracking. Interestingly, leaving the sensor unplugged does not trigger the idiot light. There are T-fittings which allow reconnection if you so desire.

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