rod bearings

[zerg1024]

i want to change my rod bearing and i see that there are different sizes. what size would i get i have 125000 miles on my car and i think that it is time for that to get done. do i go for the standard size or what?

 

[yamahaSHO]

Clevite only sells one part number(that I know of) for the show application. I cannot remember the part number but you can get them from www.shonutperformance.com

When installing them, use some plastigauge to check the clearances.

 

[Yamaha V6]

No, Clevite sells multiple sizes of the SHO Rod Bearings, all based off the root part number (CB1435P), with an optional oversize identifier (+.25mm / +.50mm / +.75mm, or inch equiv. +.010/+.020/+.030).

They are more of a special order, and take longer to get in, usually, same price.

My 91's were +.25mm, Chris Benvie's original blown motor as received was +.75mm!!! (WHO in their right mind builds a supercharged SHO motor with a turned .030" crankshaft???)

 

[Yamaha V6]

To answer your question though...

You will not know for sure until you open the engine up. However, there's a better than average chance it'll be the stock size.

 

[yamahaSHO]

No, Clevite sells multiple sizes of the SHO Rod Bearings, all based off the root part number (CB1435P), with an optional oversize identifier (+.25mm / +.50mm / +.75mm, or inch equiv. +.010/+.020/+.030).

You mean undersized?

 

[SHOMurph]

If you car has over 150k its a good idea to change your rod bearings. So many motors are going down now with spun bearings.

This might need to become the first maintainance done to every SHO now. Its more important than a 60k.

 

[sdpatt]

Unless the crankshaft is removed from the engine and the bearings are machined, you will use the standard size bearings.

 

[Yamaha V6]

No, if the crank is UNDERSIZED the bearings that make up the difference would be... OVERSIZED, no?

a) unless he's the original owner, there's always that possibility that the engine's been rebuilt, which is why I left it open.

b) with the variances I've seen in cams, shim ranges used to gap correctly from the factory, I wouldn't be surprised to see "Friday" engines with re-turned cranks. Not saying it's true, but I wouldn't be surprised.

 

[Chris Benvie]

My 91's were +.25mm, Chris Benvie's original blown motor as received was +.75mm!!! (WHO in their right mind builds a supercharged SHO motor with a turned .030" crankshaft???)

Kevin Mahoney, Protech Automotive.

 

[Yamaha V6]

Murph, I have been touting Rod Bearing Swaps for well over a year (was actually accused by SHO Shop of making it up as a money making idea!). If you lose a Crank Sensor, you need a tow. You lose a bearing, chances are, you need an engine.

Does everyone need rod bearings? NO. Can you be sure you don't until you take the time to tear it apart & look? NO.

At which point, if you're staring them in the face, you may as well change them. It takes about as long to do bearings as it does to do a 60k, and the parts are a LOT cheaper too. The down side to rod bearings vs 60k is, you usually notice a performance re-gain after a 60k, and you won't after bearings.

 

[roswell998]

Murph, I have been touting Rod Bearing Swaps for well over a year (was actually accused by SHO Shop of making it up as a money making idea!). If you lose a Crank Sensor, you need a tow. You lose a bearing, chances are, you need an engine.

Does everyone need rod bearings? NO. Can you be sure you don't until you take the time to tear it apart & look? NO.

At which point, if you're staring them in the face, you may as well change them. It takes about as long to do bearings as it does to do a 60k, and the parts are a LOT cheaper too. The down side to rod bearings vs 60k is, you usually notice a performance re-gain after a 60k, and you won't after bearings.

Can you get a pretty good idea of the rod bearing condition by checking oil pressure?

Like.........if pressure high probably OK.....pressure low possibly bad rod bearings (and/or other things)?

 

[SHOMurph]

Murph, I have been touting Rod Bearing Swaps for well over a year (was actually accused by SHO Shop of making it up as a money making idea!). If you lose a Crank Sensor, you need a tow. You lose a bearing, chances are, you need an engine.

Does everyone need rod bearings? NO. Can you be sure you don't until you take the time to tear it apart & look? NO.

At which point, if you're staring them in the face, you may as well change them. It takes about as long to do bearings as it does to do a 60k, and the parts are a LOT cheaper too. The down side to rod bearings vs 60k is, you usually notice a performance re-gain after a 60k, and you won't after bearings.

yeah its like playing Russian Roulette with your car. I've seen SHOs with bad bearings and only 140k on them. On my 90 car w/160k the bearings didn't look too bad.

Its a good idea to save the car when you love to turn the motor around 7k.

 

[Yamaha V6]

Well, I spun one motor at 72k, and another at 105k, so it really does vary. One was an unknown maintenance history, car beat on but strong runner, the other was a well-maintained M1 oil fed baby. You're absolutely right - there are SHOs out there at 200-300k on the original bearings, and there are those that are rotting in the boneyards because of a blown engine at 120k.

You just don't know. Good oil pressure is an indicator, but not the end-all. Both of my engines wer doing pretty well, never had an oil light at all, even after spinning.

 

[Rockledge]

If you car has over 150k its a good idea to change your rod bearings. So many motors are going down now with spun bearings.

This might need to become the first maintainance done to every SHO now. Its more important than a 60k.

I also came to this conclusion myself which is why replacing the rod bearings was the first "major" maintenance item that I did on my SHO, within a month of me buying it, before I did any 60K work. I wanted to take a peek at things down there to make sure my SHO was worth the amount time, effort and expense that I was willing to put into it. Fortunately, everything passed scrutiny and now I have tremendous peace of mind with those new bearings in there.

 

[yamahaSHO]

No, if the crank is UNDERSIZED the bearings that make up the difference would be... OVERSIZED, no?

a) unless he's the original owner, there's always that possibility that the engine's been rebuilt, which is why I left it open.

b) with the variances I've seen in cams, shim ranges used to gap correctly from the factory, I wouldn't be surprised to see "Friday" engines with re-turned cranks. Not saying it's true, but I wouldn't be surprised.

But they still call them undersized bearings as they refer to the size of the crank

 

[shojuan]

But they still call them undersized bearings as they refer to the size of the crank

You know, I can never keep it straight what they call them. But it's not too hard to figure out that a reground crank in going to have smaller than stock journals (ie. undersized) and the bearings are going to have to be thicker than stock to make up the difference (ie. oversized).