Am considering options with a 93 dohc that has one #3 cylinder running 180psi. Engine has 120k and has the oil loss problems, 1 qt per 500 miles. Am planning on doing an 'in-frame' rebuild with rings, hone, bearings, timing set, oil pump, valve job & seals, clutch(maybe), water pump. Might as well pull it, right?
Anyway, questions I have are:
1.) Where does one find a straight bar of steel in order to check the 'deck' & cylinder head for warpage?
2.) Is there any ball park numbers of machining costs for a shop to repair a cylinder head or bore cylinder sleeves as need be? Should valve guides normally be replaced?
On the head warpage I would take the head to a shop and have it checked with you get a valve job done on it. On the oil consumption, it is not realy that bad and if it runs well otherwise I would switch to 10w30 in winter and maybe 15w40 (not 10w40) in summer and stop using 5w30 you will likely cut oil consumption in half or more and get more life ot of it. 5w30 will go through a worn engine pretty quick at times. On more thing if you take this route, do change oil about every
2000 to 2500 miles or so as even though you are adding to it, it is getting dirty faster and increasing wear potenail and oil consumption too.
180 psi doesn't seem like bad compression to me, what are the compression readings on all the cylinders? What are all the readings dry? and after adding oil through the plug openings to seal the rings? Have you done a compression leak down test? Dry and with oil added? Can you hear air leakage into intake or exhaust manifolds? Do any of the plugs indicate more oil fouling than the others? Have you tried any of the chemical ring cleaning procedures? Have you used a borescope to check the condition of the cylinder walls?
Always make a teardown and rebuild your final and NOT initial strategy. I do agree that IF it is necessary to remove the head, then a head rebuild and inframe ring job should probably be done. Your oil consumption problems MAY be due to worn valve SEALS which CAN be replaced without removing the head.
I agree with SnoMan that your first strategy to deal with excessive consumption should be to try different oil viscosities, (and change your shifting techniques to a less 'spirited' driving style). I also agree with reducing oil change intervals on engines with higher consumption rates. If cost is a major factor (or the difficulty getting at the filter if you do not have any ramps) then it is better to only change the filter every second change rather than to extend the oil change.
I would continue babying this engine with oil and viscosity and driving style changes until engine removal is necessary for clutch replacement. You can do a much better (and easier, and very importantly cleaner) rebuild with the engine removed.
Re question #2, get local quotes for rebuild/valve job on your cylinder head from several automotive machine shops. They will normally check for warpage if asked, and will also check for valve stem/guide wear. Valve SEALS should always be replaced, your machine shop/rebuilder may have the equipment to install a better than OEM type of valve seal.
If your cylinders need more than a light (must do) deglazing (or you need a new clutch) then you should remove the engine for complete out of frame rebuild with rebore (requires new pistons) or replacement with better engine block.
IMHE there is a lot of variation between individual compression gauges and they are not what we would call 'calibrated'. Similarly there is a lot of variability due to the procedure used, and as you say, the motor should ideally be at operating temp, but the maximum compression obtained will still vary depending on outside air temp and altitude (density altitude for any pilots) and humidity and condition of starter and battery and whether all other plugs are removed and throttle position and oiled or non oiled cylinders. The number of strokes to pump to max is also another important and variable indicator. There are also other factors that may confuse a compression test like a plugged air filter or catalytic converter or loose muffler baffle.
IMHO compression readings should be considered relative to each other and relative to other indicators like oil consumption rates and plug fouling and evidence of blowby like dirty PCV valves and dirty engine internal (and often external & underhood). They can be a good indicator for valve problems but are not a very good indicator of ring condition and often an engine with seized oil control rings will give great test results due to the amount of oil on the cylinder walls and compression rings.
The psi readings were 215, 210,175, 205, from 1 to 4. Repeated #3 and it went up to almost 180. This was a wet test. Haven't done a leak down test and cannot hear any air leakage. #3 plug, when removed looked fouled compared to the other 3,( #1, #2, #4). Tried MMO soak, & it didn't do it. Don't own or know anyone who has a borescope.
I am not a youngster and no spirited shifting is going on with my Saturn. I would think that by biting the bullet now, the engine, ie block, may not get totally destroyed and cost even more to replace/repair.
I'm already babying this engine. The clutch is getting shaky at
120 k miles, and I did allow someone to relearn to drive to get a license and the learner couldn't get the hang of my manual shift Saturn.
I won't comment on #2 or #3, but a straight bar of steel can be purchased in the form of a metal ruler at Staples, OfficeMax, etc. If you want to get fancy, buy a ground rod or bar at
formatting link
Delivery is sometimes the same day from those folks. Just don't look around that site too much. They carry just about EVERYTHING at somewhat decent to not-so-decent prices - but make buying ANYTHING efficient and convenient.
Do a dry test followed by a wet test. An increase when wet indicates ring leakage which is sealed by the added oil, most engines will show some increase when wet. If there is little change when wet then this indicates that the valves are the limiting factor. If the three good cylinders increase when wet but the low cylinder does not then this would be a good indication of a bad valve in that cylinder (or perhaps less likely, a gasket or similar problem). In the event that there is a scored #3 cylinder I would try that cylinder again after wetting with a heavy oil to see if that made any difference as a heavy oil may fill the score enough to raise the compression, but a borescope is better for this as you can also inspect the wall for crosshatch and the color of the wall between the top rings can indicate how effectively each ring is sealing.
Based on what you have reported, I suspect a valve problem in #3. A leakdown test or even just applying shop air pressure to the cylinder (using an 'air hold' fitting in the plug hole, which can be purchased or fabricated from a spark plug by a welder) may allow you to hear leakage into the intake or exhaust manifold (or both).
If the bad valve is on the intake side it may show as small rapid fluctuations in a vacuum gauge connected to the intake plenum but a burned valve is more likely on the exhaust side. which can sometimes be heard as a roughness or popping in the exhaust but this is doubtful as the sound must make it through the catalytic converter and the muffler..
One of the downside of 4 valve engines is that they double your chances for valve and seal failure.
Many aviation mechanics and repair shops have borescopes and would allow you to take a look inside if you pulled the plugs in their parking lot. (Offer money, lunch or case of good beer.)
I mean no dissrespect, but as a 1cam (2400 rpm sweet spot) owner I feel that many 2cam drivers use too high a shift point. I doubt that you are doing any serious damage to the engine IF the low compression is caused by valve leakage. A broken ring which is scoring the cylinder is another matter, but if that is the case the damage is probably done already and only a borescope will give you an answer. If the leakage is caused by a burned valve then it will probably continue to get worse and the compression will continue to drop.
Only you can make your personal cost effectivness decision regarding repair and it depends to no small degree on your estimate of the remaining life of the rest of the car. You do not have a lot of miles on the unit but some would say it is getting a little old in years.
The neccesity of a clutch replacement makes the engine rebuild timing decision much easier. Once the engine is out of the car a ring and valve job does not seem like such a big additional expense.
AFAIK the OEM seals are of the rubber umbrella type. There is an aftermarket wiping lip type seal (which I believe was originally mfg by Perfect Circle and often called a PC valve seal) which requires machining the top of the valve guide for installation. I have used these seals on SBC but have no experience with Saturn head rebuilding. There are some experienced racers here and some may reply, or you may wish to search this group in Google groups or the forum at
formatting link
or
formatting link
Rebuilt valve guides do make an engine run very smoothly and IMHO this is worth doing right. Another downside of 4 valve engines is that the cost of a valve job doubles.
You are doing the right thing by asking questions and doing a repair based on a well thought out plan.
This car blew oil from day one. Everything is telling me that this 120k mileage auto that has had oil problems from the get go and is gotten considerably worse since is in need of some serious rebuild work now or it's going to really fail altogether and there I'll be, with a nearly worthless vehicle. By getting the work done now, maybe the cost will be less than I fear and will be able to drive a solid and dependable car once again, and that gets great gas mileage compared to others. I've driven this vehicle since early 1993 and I can tell it's really not well anymore. If I could afford another great gas mileage vehicle that would be guaranteed for at least 30k miles I'd do it if would be less than a rebuild on this one. Between a rock and a hard place.
I've owned my Saturn for over 13 years. I've been reading this forum for almost that long, and have been involved in my car club for almost ten. Of all the people I've known and still know that burn oil, I don't recall any of them that have had a motor failure. I don't know that I'd make the same assumption that you are - that if an engine consumes a lot of oil, it is an indicator of worse things to come. That is not necessarily so with these motors. These motors are stronger than most people think, even in an oil-burning state. Just make sure the oil level is checked often and stays topped off.
What I DO know from reading is that many people who have torn into their engines as an attempt to cure oil consumption are not always successful. If that is a trait inerent in the design (my '94 used a quart between changes since new), rebuilding to factory specs probably won't give any guarantees.
I've never rebuilt a motor and probably won't. Weighing that option against buying a low-mileage used motor makes it not very cost-effective. For parts and machining, a rebuild may run $1500 or so. The last motor I bought was off of eBay. With 19k on it, it was around $200. If you have some patience, it is worth watching for deals out there because I do see them come and go. I've bought three used motors this way with low mileage on them, and was very satisfied with all of them. In fact, one of them is currently in my race car and just can't be killed. :)
BUT, if you're looking to do a rebuild because you want to be hands-on, do most if it yourself, and learn as you go... well, that's a different story. But time and cost will still be a factor.
If you're not able to wait for one to come along on eBay for a very low price, local salvage yards will probably have offerings for a bit more money. But, they will still be cheaper than a rebuild, in both money and time.
Did I miss something in this thread? Besides the compression difference and oil consumption, what are the symptoms that make you think it's not well?
I fully agree. If you keep it full of clean oil is can run for a long time. Bearing failure is different. When you get a rod knocking, your time is a lot more limited. Bearings fails from dirty oil or lack of it The biggest "danger" you face with a oil burner is letting it run low on oil and then damaging the bearing. It can burn a lot of oil and live as long as the crankcase is kept full.
Thanks for the advice on the steel bar. Have a business guy next door who can get stuff from McMasters. Didn't think of them, actually am not thinking real great since seeing my auto in trouble. He has an account with other similar companies as well.
Thanks, a little good luck my way would be most welcome at this point. I've looked a bit into perfect circle rings and perfect seal rings too. Not sure if perfect seal rings are really for Saturns. Either sounds better than what hastings rings do. I've been reading a lot from saturnfans.com and turbosaturns.net forums as well. They are helping me a lot in seeing what I'm up against.
Loss of power going up hills, the smell of oil while driving it, the #3 plug is now fouling quickly after being replaced with a new plug, and the rate or amount of lost oil has increased. Used to be 1 qt every 1000 miles. Again, I've looked high and low from the local salvage yards and have not found any luck there. One local yard told me they're not getting too much anymore by way of Saturn's. Why that is, I don't know. 6thplanet is keeping an eye open for me. I've been driving this for 13 years and just recently it's simply not the way it ran from even a year ago. I am not as experienced as you are but I do believe this engine is failing. And I am a tad concerned about having to do this myself for a lot of reasons. Getting another old engine may not be any better than what I've got now and would not be guaranteed either. Should a sound engine become available real soon that I could afford, I'd probably go with it. Between a rock and a hard place.
Of all the points raised in this thread SnoMan's is by far the most important.
Nothing can turn a merely tired or sick motor into a catastrophic failure (that is probably beyond economic repair) faster than running low on oil. I have never seen an engine failure caused by a worn out dipstick.
Very very few engine failures are caused by mechanical or material failure, most are caused by lack of oil or coolant.
I did not drive my car today. Yesterday I heard a new noise and the engine, when I shut it off, sounded real strange and I could hear something new while sitting in the driver seat. The oil level is topped up. This is after doing a compression check the day before. I had my buddy listen to it today while briefly starting the car so he could hear what I was hearing and he didn't like the sound of it either. Someone wrote and told me to be patient for a $200 19k mileage dohc engine on ebay. Well, show me the engine! I haven't seen a deal anywhere close to that since I've been looking. If you found one for yourself, consider yourself lucky. Half the freaking middle east oil has disappeared going through this engine and if I can get this fixed, I am going to try. If this fails, I'll get a freaking short block.
This reminds me of something related I recently read. When someone was told that they needed to learn to be patient, they responded, "how long is that gonna take?"
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.