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I would sit and think a bit here. The vehicle is what it is, not a "WOW" barn find. You can pick up a good running Olds. 350 for minimum amount of money, clean out the fuel system, check tires, brakes and front end. Replace whats necessary get that air blowing cold and drive it. Keeping this car original with documentation isn't a factor with this project. Maybe sell the engine or parts to recoup some of your money. My 2 cents and remember enjoy and keep it between the lines.
Last edited by oldsmobilejim; December 15th, 2020 at 12:42 PM.
ZERO compression on #5, but 5 doesn't have broken piston?
Broken valve spring? Valve might go up and down, but might not always completely close. Depends on how the spring broke, and where.
Burnt valve? Wiped valve guide? I've seen guides so bad on the exhaust side, that exhaust gas pushed up between the guide and valve stem, destroyed the valve stem seals, and pressurized the crankcase. Faulty compression tester? Compression tester not properly screwed-into the plug hole?
I found a man in my town that sells the high compression pistons for $10 a piece. I think now i'm going to go back with just removing the bad pistons, honing at home, new connecting rod bearings, new rings, new gasket kit, new valve stems seals and call in it good. What I still don't get is how to measure for bearings. If I buy new connecting rod bearings and rings can they just be OEM size or will they need to be different because there new bearings? I don't know if that's a stupid question but i'm only 20 lol.
1. Do the cylinders have a ridge at the top? If there's a ridge...you need to bore the block, and that means oversize pistons and rings.
2. If the crank journals are good--not scored, not gouged, not excessively worn--then standard-size bearings would be fine. Double-check the clearance with Plasti-Gage if you can still get some--I heard it was discontinued.
3. Might be helpful to find an "Adult Education" night-school or Community College "Auto Tech" program in your area. If not that, a car-club could maybe provide mentorship if you provide "refreshments".
Look on the back of the bearing inserts, what numbers if any are there? Do you see .010, .020, .030 ? If yes then those bearings are oversize by the amount that has been ground from the crankshaft. If no numbers like that AND IF the crank doesn't need grinding you would put back original size bearings and check the clearances with plastigage.
Take it apart, take it to a machinist and ask them to inspect and measure the crankshaft. Tell them your goal and they should direct you.
After thought...mark all of the bearing caps, rods and pistons BEFORE disassembly, they must go back exactly where they came from. They may look the same but trust me, they are not.
Good luck!!!
Last edited by Sugar Bear; December 17th, 2020 at 11:41 AM.
At the end of may 2021 ill have my associate in Automotive Technology. I finished engine rebuilding but they only glazed over how to properly measure bearing and how clearances work. Also the LS engines we worked on were brand new so no scoring or damaged components. I think what you guys have said is smarter, just have it done right. The shop a city over does line boring. They do cam bearings, remove frost plug/oil plug, Cleaning, and then Bore & Honing for around $680. I only know one company that sells what i need for the engine but if you guys know more places that sell internal parts for the 394 please let me know.
Congrats on the upcoming degree. If it is an option look for a machine shop with some old school experience, as you've learned vintage engines have differences from the newer engines e.g., clearances. Technology is great but in this case some balance with old school experience may be best.
Consider telling the machine shop about your education and ask if they will show you things instead of telling you about it when the part is out of your sight. Every shop is different but most will appreciate that you are serious about learning.
Wow. Some of things you mentioned, I figured you were older. Glad to see a young buck in AT, I've always had a soft spot for a young gearhead.
Here's a thought. Get your auto tech degree, then if it's affordable take a precision machining course too if your tech school offers it. That way, you have become a double threat- mechanic AND machinist. Meaning you're very employable at good money about anywhere you go.
Hey 64 guy, I hate to be a pessimist but one thing you should know about. These cars are known for having a problematic transmission- The Slim Jim. I would hate to see you put lots of money into the car with a "soft" frame and then find transmission also needs major $ repair. Were you able to drive it a little before you took it apart to see if it seems to operate ok? I hope other more knowledgeable guys with comment on the odds of the slim jim being OK. Good luck on whatever you decide to do.
So i was able to drive the car 4 miles before i ran out of gas. I'm not sure if this is a trans issues or an engine issue but maybe you can tell me. It did have broken pistons. The gear shifts were smooth but whenever it switch into gear it would almost dies. Like 1st into 2nd it would be running very low. And when coming to a stop it would run rough then die. Almost every time I would decel it would die but if i was at a complete stop it would rev itself back to normal.
An overview of the so-called "Slim Jim"; actually the Roto-Hydramatic 375 "Model 10" transmission. https://ateupwithmotor.com/terms-tec...tory-part-2/7/
(Part of a series of truly wonderful descriptions of early automatic transmissions and their development)
Note that the Roto-Hydramatic uses a very goofy 8 inch "torque converter", but without a true stator; and which is empty of fluid in second gear. The small dump-and-fill converter is similar to the second-generation Hydramatic "Controlled Coupling" trans, but in this application is used as the main converter. This trans has a system to disengage the front clutch and re-fill the "torque converter" when slowing to a stop, which is supposed to prevent stalling the engine. Worth investigation, AFTER you've got the engine running properly.
Having said that...I'd be looking at all the usual engine tune-up issues for the problems you're experiencing.
Dwell
Ignition timing including centrifugal and vacuum advance
Ignition coil spark power, and primary circuit power (frayed wires, poor connections, esp. things that could connect/disconnect with engine movement from increased/decreased torque output and perhaps failed engine mounts.)
Spark plugs and gap, plug wires
Cap and rotor
Fuel pressure at idle and under load. Fuel filter condition. Carburetor condition including float level, idle speed, idle mixture adjustment and (if used) idle dashpot operation. A complete rebuild to stock specs is suggested.
Last edited by Schurkey; December 20th, 2020 at 01:06 AM.
If I'm replacing all bearings and seals, Is it smart to buy new pistons? I'm buying new rings but I can get used pistons for $80 vs $520 for new ones. There is only 2 bad pistons in my set. I am having it machined.
If the used pistons aren't banged up and wrist pin area is good you should be able to clean up and use. But...
Depending on how much overbore you have to do to clean up the bores, you may have to get new pistons. Wait till the machinist is done and see what you need. No point doing all that work only to end up with a loose engine or oiler.
Used pistons are fine if they are in good condition. The first time you start an engine with new pistons they become used pistons, granted with less wear. If they measure up and aren't pitted use them. Do have a machinist look at the bores or an experienced mechanic before buying parts.
If you have a ridge, you will be buying new, oversize pistons to match the amount your machinist is going to bore out of the cylinder wall.
WHEN you buy those pistons, make sure the compression HEIGHT as well as the compression ratio are correct. It's very common for cheap pistons to have reduced compression height, leading to all sorts of performance problems.
Use a glaze breaker to determine if the ridge is just carbon buildup or if metal has actually been displaced. That bore and piston actually don't look bad, I've seen way worse. This is not one of the cylinders you found broken piston skirts, right?
Are the used 394 pistons you found the same as what's in the engine? Same valve reliefs, dish etc?
If you have to get new pistons, drop the compression ratio to 9:1 if you can. That CR will tolerate modern gas better than orig 10.25 pistons and will still push that 88 down the road easily.
No this was the Cylinder with with no compression. #5. I'm in a situation though. I managed to get one piston out but the ridge I believe is so big with got 2 pistons stuck on the 3rd ring. There half way out.
Don't force the pistons, it can break the ring lands on the pistons. It may be stuck due to the ring being coked-up and/or a ridge at the top of the cylinder. Does your fingernail catch on the ridge or slide up over it? If a nail distinctly hangs up on metal not carbon, that is a lot of wear. The nail test is only an indicator, not a replacement for measuring.
To get the piston out, remove any exposed rings, put a piece of fuel line over the rod bolts so they don't scratch a crank journal, remove the crankshaft, lightly oil the cylinder wall from the bottom and tap the piston downward and out the bottom. The cylinder wall pictured does not look that bad, it may be ok after deglazing and honing.
About one of the earlier used piston posts, the used piston needs to be an exact match to the old one.
Anytime there is an appreciable " ridge " at the top of the cylinder it must be removed before trying to remove a piston from a cylinder .
The tool you need for this is called a ridge reamer .
They are available at auto parts stores . and some stores may rent them . Lisle Ridge Reamer 36500 | O'Reilly Auto Parts
On the cylinder with the piston halfway out , remove the exposed rings and push the piston back in .
Use the ridge reamer to cut the ridge at the top of the cylinder .
Then the piston can be removed easily and without damage .
If the block is worn enough to have a ridge, it's too worn to re-fit the pistons to.
If the worn block is bored to provide round, straight bores like it should have, the original pistons will be too small in diameter.
If you bore the block, you're buying oversize pistons.
Therefore, beat those pistons out the top with a big hammer, break the rings, smash the ring grooves--IT DOES NOT MATTER because those pistons are scrap even if you take them out gently. You put a "ridge reamer" in there to cut the ridge, you're very likely to tear so much metal out of the top of the block that instead of a .020 or .030 over-bore, you may have to bore .040 or .060 to clean up the mess made by the "ridge reamer". Or even need to sleeve the cylinder.
Ridge reamers are block-destroying tools especially in inexperienced hands.
Okay thanks for the insight guys! I got other question. With the high compression its running what octane gas should I be running? The highest in my town is 93 octane.
If you can get it to tolerate 93 without detonation, use that. My 64 Starfires don't like it. Course when these cars were built 100 octane was commonly available and that's what was recommended.
Factory base timing setting is 5° BTDC. Expect you'll have to drop it to 2.5° base and fiddle with the distributor advance curve.
If you can get it to tolerate 93 without detonation, use that. My 64 Starfires don't like it. Course when these cars were built 100 octane was commonly available and that's what was recommended.
But the rating method was different. Back then, the octane rating was based on the Research Octane method, while today's gas pumps advertise an average of Research Octane and Motor Octane; the result is typically 4--6 numbers less than the Research Octane number.
In other words, "93" octane fuel TODAY is roughly equivalent to "98" octane fuel of the 1960s.
I know that. And even detuned neither my Starfires nor my W34 Toronado like the stuff, and I've tried every gasoline brand available here. Blend it 60/40 with 100LL aviation gas, or even straight 100 octane unleaded, they're happy. It's like driving a different car.
It's a known variable that all gasoline here comes from Greensboro NC tank farm, and whatever EPA blend the Piedmont Triad has to use we get by default. Gas sourced out of Kenly NC or Charlotte is different blend. The old Gray Ghost wagon proved many times it would get 35% better fuel mileage on Charlotte fuel than Greensboro. 13.5 on drive to Charlotte, 20 from Charlotte back home, only difference was the fuel source. Less detonation on Charlotte gas on the 394s and Toronado too.
I took out piston #5 and found that the piston ring Lance was pretty much destroyed. No cylinder wall damage but I think this finally solves the no compression on #5. Also I don't know if this is much of a concern but the one of the crank journals has some nicks in it. Have a look:
The crank journal looks ok in the picture. See how the other journals look and then consider having a machinist measure and possibly just polish the crank.
What numbers are on the back of the bearing insert?
Great, your crank may be good with just a polish. Have it measured by a machinist.
Keep everything in precise order as you disassemble e.g., rods, rod caps, main caps. They must go back in their original position or machining will be needed.
Engine is ready for the machine shop. Piston, Crank, cam and lifter are now out. I looked up the block number and I'm a bit confused. The wiki says this particular engine was not in the 64 Oldsmobile Dynammic 88 but maybe its swapped? Also the engine has a 2 bbl but also this maybe swapped. If someone could tell me what this is that would be great. It maybe a starfire engine. The engine cast code is 585786-4 1/8. Thanks!
Last edited by 64Guy; December 29th, 2020 at 05:49 PM.
The 585786 block was used on all '63 and '64 394's , Including Starfires .
The 583832 heads were used on all '62 thru '64 394's and also 1961 Starfires .
Two barrel carbs were standard on Dynamic 88's with 4 barrel optional
The only difference between a Starfire engine and a 4 barrel engine was the pistons ( 10.5 to 1 ) and a " hotter " camshaft .
To tell if you have a Starfire engine , look at the machined pad above the center exhaust port on the driver side .
If the number stamped on the pad ends with an " S " then it's a Starfire .
I wouldn't put the "Starfire" pistons in. You'll be fine with standard pistons. What are your overall plans ? camcraftcams.com might be able to help with a new cam.
Young'un- WHY would you want to put 10.5:1 pistons in, knowing they won't tolerate currently available pump gas? Go with 9:1 and you'll be able to enjoy the car.
The Starfire pistons was just an idea but those pistons are like pretty much non existent. My plan is now to rebuild the motor with all need parts. It needs all bearings, pistons, pistons rings and gaskets. I really didn't want to put a ton of money into it but id rather do it right the first time rather than pull it apart again. I am trying to find new cheaper pistons but because its being bored to fix the ridge, pistons are gonna have to be overbored. There is only one company that sells the correct pistons with overbore options but there pricey. Here a link:
https://egge.com/part/egg-1000-l2180-8/. It also hard to understand what a bad bearing is and what is normal wear. I don't know if the crank needs to be turned or not to accommodate new bearings or if OEM sizes will fit.
December 15th, 2020, 12:35 PM
