Replacing engine bearings, need help.....

[chrisexv6]

OK, I'm trying to replace the engine bearings in my 2.5. I keep breaking glow plug elements, and read somewhere that bad bearings would cause it, as well as lean conditions.

Fixed the lean condition, but still breaking plugs, so I have new bearings ready to install. Only problem is that I can't, for the life of me, remove the current ones. I've heated up the block in a 350 oven for 10-15 minutes, no go. Tapped the block a little after heating, no go.

What am I doing wrong?

-Chris

 

[Bill Hoskinson]

It takes 450 degrees to get them out. Just be very carefull not to damage the seal on the outer bearing when you remove it. At 450, it would take about 5-6 minutes in the oven. They will fall out when you tap on the crank case. Reinstall them the same way, but use the crank shaft to push them back into place. Make sure you dont have ANYTHING in the inner bearing journal, or you'll never get that bearing back in all the way.

IMO, if you have an engine with a bad bearing, you're better off to just buy a new engine anyway. Buy the time you wear out the bearings, the back plate, and everything else is worn out too.

 

[chrisexv6]

Well, I actually have a set of lightly-used internals to replace the existing ones with. Piston and sleeve with very good compression, crankshaft with no markings, etc.

The only questionable thing was the bearings (they feel a little rough, may have a little play, and since I keep beaking glow plug elements, I'm thinking the bearings are causing the crank to oscillate enough to cause a tad too much compression). Once the bearings are replaced, I pretty much just wanted to use this motor a couple more times, to verify that the rest of my drivetrain is OK and isnt causing overheating (making way for a Fantom 18, dont wanna wipe it out during break-in).

Ill try 450 degrees today. if it doesn't work, Ill just take my chances putting the Fantom right in.

Thanks for the help!!!
-Chris

 

[Bill Hoskinson]

Sounds like a plan.....

Make sure you pre heat the oven first, then go for 5-6 minutes at 450. If they dont fall out, use your crank shaft to break them loose, and they should come right out.

Worn bearings destroy lots of glow plugs, and if let go long enough, they will destroy the entire engine if the bearings make thier way out of the races.

 

[chrisexv6]

Yeah, I found that little tidbit by accident (the plug elements werent "ash-colored" like they would be if they were too lean. brand new and shiny, not burnt, but the elements were broken).

One more question.........I got the new bearings from Boca (great sales and service!!!), and the included "how-to" says that the inner bearing can be left with one seal and if I do that, put the open side towards the smaller crankshaft bearing.

Any qualms about only leaving one side open? I know they justify it by saying it will help trap some particles that might get in, while still allowing the bearing to get lubed by incoming fuel. I'm just not sure. I already have one shield removed, dunno if I should go ahead and remove the second as well.

Thanks!!!
-Chris

 

[Bill Hoskinson]

I have only had one set of Boca bearings, and I wasn't impressed. The outer bearing leaked like a siv.

I would stick to using the stock bearings if it were me....