Is This Block Rebuildable?

[Rabbi]

This is a 6 bolt block i purchased recently for next to nothing. It threw a balance shaft bearing.


Does everything look rebuildable? (sorry about picture quality, best i can do)


Whats the chance of doing any major block damage when throwing a balance shaft bearing?


Thanks a ton guys.

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[Nanan]

Unless the block is cracked, has a hole blown out, or has a nasty DEEP scratch it should be fine.

If it just spun and tossed a BS bearing then I would guess it is fine, get that thing hot tanked and checked for cracks/scratches.

If it passes then time for a decking, line boring, and a cyl cut or hone depending on surface trueness.


Balanceshafts are a meh thing, block off the oil ports in the front side, get a plug for the front case, and get a stubby shaft for the oil pump.

 

[96gsdsm]

You might be pushing it with that rust. I don't know man. How bad is it?... I'd knock out the freeze plugs and have a look-see inside with a flashlight, make sure you throughly check over the block for rust, and for dents/dings/scratches in any of the machined surfaces.

 

[Rabbi]

i thought surface rust wasnt a problem since it could be honed and bored out?

 

[96gsdsm]

Depends on how bad it is. You have to keep in mind the tolerances here are tiny.

A block bored .020 over is going to be 1/2 of a millimeter... which means 1/8 of a millimeter of material wide for the entire circumference of the piston bore.

.040 ... which is about as big of pistons as your going to find easily, and readily available... is going to be 1 full millimeter wider in circumference and would mean that you would be removing 1/2 of a millimeter of material for the circumference...

I'm sure you get the concept.

Grab a micrometer... or at the very least... a very accurate metric ruler, and try to eye it up to make sure that it can be cleaned up.

I would consider the block junk if you have to go more then .040 over... I'm sure there could be many arguements from people on here that are doing just dandy with .060 bores, but that's my personal oponion.

Something to keep in mind... The more material that has to be removed, the greater the chance of someone screwing it up.

 

[96gsdsm]

Oh, and just for referanceing purposes... if you have a way to measure it I would recommend checking to see what size bore it's at now. (To determine weather or not it's been bored out before, to determine how much room you have for overboring it.)

85mm = stock
85.25 = .010 over
85.5= .020 over
85.75 = .030 over
86= .040

etc.etc.etc.

you get it.

 

[96gsdsm]

i thought surface rust wasnt a problem since it could be honed and bored out?

Sorry for being a post whore here guys... just thought I should mention that surface rust can not be honed out... it has to be bored.

 

[1g_tsi_awd]

I think that rust is going to cause a problem... I would honestly say, I wouldn't even attempt a rebuild on it... You are looking at .040 over, maybe a little less...

Like 96gsdsm basically said, It is a questionable call.

 

[Dream On]

Take it to a machine shop. They'll tell you. You'd have to anyways.

 

[BrokenTsi]

You wont be able to press in a new bearing for that balance shaft most likely. I had the problem once in one of my engines and I had to drill a large hole through the front of the block. Then, I tapped the oil hole for the balance shaft and blocked it off with a bolt. I threaded the block as well and plugged up the HUGE hole I made with another bolt. Pain in the butt.

In the end, I decided to throw the block away.

 

[wvturbo2]

I know guys that have had blocks laying around and they would leave it sitting outside. I stayed away from up a block at a dirt cheap price, because it had just been sitting out in the weather. Goto Machine shop and get the verdict

 

[96gsdsm]

I'm in agreement with everyone here... find the most reputable machine shop around... drag the block in... and get an oponion.

We're going off pictures... they see stuff like this every day. If they really know their stuff they'd be able to tell you in a minute or 2 if it's even worth trying to bore it.

 

[Siral3x]

Hey man I recomend Varney's Automotive in Muskegon.MI for a machine shop. I took my 6 bolt down there and it was no good. The guys showed me cracks and stuff that you can't see unless the block is hot tanked. They are very very good priced, and have been building race V8s for 30 years.
Now I invested 2k in parts, to find out that my 6 bolt is shit, and I'm on hold with them.
Does anybody got a good 6bolt core to spare??