Determining bearing size??

[Jan in CO]

A former Jeep mechanic on our fire department told my hubby that we can install bearings in our granddaughter's 94 Dodge Intrepid's valves to try to correct a rod that is knocking before it goes out completly. Found the site on Chiltons online that describes the procedure, however, hubby isn't sure how to determine what size bearing to buy. Any tips? Getting a complete new or rebuilt engine is out of the question, she doesn't have the money, but this kit would be doable. The same mechanic also said he didn't feel it was necessary to completely pull the engine, either. The site recommended it, however said it could be done without doing so. Any thoughts from someone more mechanical? Experiences? Thanks, Jan in Co

[fixer1958]

Valves don't have bearings per say.
If it's hammering now, it's not likely installing new bearings are going to help much.
Depends I guess how bad the crank is chewed up.
Why did it spin a bearing to begin with?

I wouldn't do it.
You will be spewing more profanity than you thought you were capable of.

[Old Vet]

Originally Posted by Jan in CO

A former Jeep mechanic on our fire department told my hubby that we can install bearings in our granddaughter's 94 Dodge Intrepid's valves to try to correct a rod that is knocking before it goes out completly. Found the site on Chiltons online that describes the procedure, however, hubby isn't sure how to determine what size bearing to buy. Any tips? Getting a complete new or rebuilt engine is out of the question, she doesn't have the money, but this kit would be doable. The same mechanic also said he didn't feel it was necessary to completely pull the engine, either. The site recommended it, however said it could be done without doing so. Any thoughts from someone more mechanical? Experiences? Thanks, Jan in Co

Bearing come in many types. Any thing that holds a piece that turns must have a bearing. I doubt that will fix your problem but it wouldn't hurt and may help. As the bearing wears out it will make things loose and may be causing the knock. On a 94 engine it will take more than just those bearing's replace to get it running great.Ask the mechanic about a rebuild kit and see if he can help. The rebuild kit is not that much but the labor will be expensive and most mechanics can do the work.

[greif]

Chiltons online that describes the procedure


please copy and post this so we can understand better

[agmantoo]

A 94 Intrepid with a knock cannot be worth the effort and expense. The risk of future failure outweighs the reward many times over.

[foxtrapper]

Something's getting lost in the translation, for there are no bearings in the valves, and valves don't cause a rod to knock.

Assuming it's actually rod knock, that's done from below, through the oil pan. You cannot measure the bearings until you open the engine and get a micrometer on them. That will also let you examine the condition of the rod and the crankshaft to see if it will work or not.

If you want to play really cheap, there are ways to shim worn bearings to reduce or even eliminate rod knock.

Both the above techniques are money wasters in my opinion. They are band-aids that don't fix the problem and tend not to last long. Far better is to do the job right. The cost of doing the job right isn't much more than the band-aid.

Since valves were mentioned, it might be a valve problem. Most likely here would be a collapsed lifter (if hydraulic). In which case nothing is being damaged, but the engine isn't running as well as it could. The only fix is to replace the offending lifter. If it's mechanical lifters, it's simply a matter of readjusting them.

I rather suspect the mechanic is talking about cheap band-aid approaches because he's being berated into it. I strongly suspect he's not keen on any of these, and would prefer to actually fix the problem.

[Ross]

Don't all 90's Chryslers knock for the last 150,000 kms? Unless this a real low milage machine I'd use synthetic oil changed often until it lets go. Unless she drives it like a Ferrari that shouldn't be anytime soon. There are exceptions of course; but, I'm kinda cursed with that kinda repair. After the time and expense into the engine the tranny would fly apart. JMO

[sammyd]

we had bad valve clatter on ours for a bit, then pieces came out the side and it quieted right up..........

[haypoint]

I assume we are really talking about a rod or crank bearing.
If the engine hasn't been replaced or rebuilt, the bearings will be standard. If the engine was rebuilt, it may have had the crankshaft "turned". The worn areas on the crankshaft can be ground down in .010 increments. So, you might find an engine with the rod bearings .010 oversized to make up for the smaller diameter due to the grinding down in a crankshaft grinding machine. It is normal to stamp that change into the end of the crankshaft. You might see: .010/.020 stamped into the end. That means the rod journals were ground and polished down .010 and the main journals were ground and polished down .020.

Wnen the engine is apart during rebuilding, the rod caps and the main braring caps are often numbered or a punch used to number them, one punch for the first one, two punches for the next one, etc.

When you remove the old bearings, if they are oversized, it will be marked on the back of each bearing: STD or .010. Since you are not having the crankshaft turned, you'll have to use bearings that match what was in it.

You may discover that the "knock" has damaged both the bearing and the crankshaft. Then you'll have to decide to reeplace just the bearing and it won't last long, or pulling the crankshaft and have it turned or replaced.

If the mixup on calling this a valve problem is a miscommunication, good luck. If the mixup between a valve and a rod reflects your mechanical skills, I doubt the Chiltons manual will be enough to bring you up to speed on this repair.

[cfabe]

Unless the rest of the car is in particularly good condition, I don't think the repair is worth the effort. I'd run it until it dies.

If the car is in good condition, you could consider installing a used junkyard engine after yours dies.

[Wis Bang 2]

Plasti-gauge is sold to check crankshaft bearing clearance. You open the bearing journal in question [usually all of them during a re-build] and place this little piece of plastic on the center of the bearing and then re-bolt and troque the journal to crush the plastic so it conforms to the 'space' between the bearing and the crankshaft journal. Thenthe squashed plastic is removed and compared to the chart on the package to determine the excess clearance. If the clearance is less than the manufacturer's specifications AND the journal surface is not scored; you can shim a new standard bearing to prevent clearance knocks.

This may be done in chassis on a diesel road tractor but is much harder to do in chassis on an auto. Usually the engine is removed and placed on an engine stand that allows one to rotate the assembly around allowing you to stand and work instead of laying on the floor.

Usually the engine block is stripped down and soaked in a cleaning tank and the camshaft is removed and new camshaft bearings installed along w/ new timing chain/sprockets and the head is sent out to be checked +/or shaved and the valves re-ground and the valve guides replaced...all seals and gaskets get replaced

You need special tools [torque wrenches, etc.] as well as the engine 'specs' and an understanding of what they mean along w/ a gasket set and new oil seals. Some large diesel engines have the bearings [two half circles in each journal] swapped at 250,000 miles and are overhauled between 500,000 and 750,000 miles making the effort worth doing.

This auto may not be worth the effort and a engine swap w/ a 'good' junkyard engine is usually alot cheaper...

Last fall my DD had the one head crack on our 99 Grand Am while she was away at college. The JY engine was around $500.00 and the labor was around the same; with tax it cost me $1285.00 and was done in 3 days.

The shop had been recomended by the state trooper who pulled over to assist DD and her roomate when they broke down. They took the time to remove the new ignition coil packs on the bad engine and swapped over the new water pump and thermostat they had replaced a month b/4...

What you want to do is not something most amatures can do.

[Jan in CO]

Lots of miscommunications here, beginning with me! I called it valves, thinking that was where the rods were that were knocking. After reading your advice, we decided to sell it to one of the u pull, u pay places, which offered over a hundred more than the metal scrap yard. Decided to drive it to the place, and it made it about 10 miles before the banging became VERY loud and hubby went back for the trailer. I absolutely could not do any of this mechanical work!! Thanks for all the ideas, I think scraping it was the best one. She now has another car and is working on getting it up to speed. Thanks for all the good input! I knew I could depend on ya! Jan in Co

[davel745]

If in fact it turns out to be a spun bearing. To fix the problem you need to pull the engine and have the crank ground and the rod ends checked and install the correct bearings. The reason to pull the motor is so the reground crank can be bedded in the block correctly. (Block must be turned bottom up). You may be able to get a replacement crank also.

Good Luck

Dave