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Rb25 Dropped On Crank, Possible Damage?

gold-3lt
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gold-3lt Enthusiast

gold-3lt

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Hi i need some advice on this.. Over the weekend i bought a complete rb25det which was loaded onto a commodore ute as a short motor to minimise weight. it was then decided that we would take the motor off the back of the ute while still on the engine stand. i had the heavier end with the engine stand and had my end just about off the tray when the guys mate who i bought the motor off couldnt hold the weight and simply let go causing his end to drop to the ground.

Now the only part that appears to have been hit is the end of the crankshaft and if you werent told you wouldnt even know it had hit the ground even if you looked at it close up. there is barely a scratch confused.gif. the block, tensioner stud? and sump appear to have not been hit at all.

Now i dont care if the bearings are stuffed because i was going to replace them anyway but i want to know if there could be any other damage?? on inspection after the fall the main bearings had previously been looked at and the main caps were slightly loose giving a gap between them and the girdle of maybe a mil max. also the very rear counter weight on the crank was sitting just between the girdle and block so i dont know if that would have evenly distributed the blow or not. Any help would be much appreciated.

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Daleo Grand Master

Daleo

Posted
Posted

Can you get hold of a magnetic base dial indicator?

dialbase-1a-250x250.jpg

Attach the magnetic base to the machined flat below the water pump gallery, and put the probe on the farthest point of the crank (as per the drawing)

Rotate the crank 360 deg, and measure any runout on the dial.

More than 0.10mm and you're possibly in trouble (should be basically zero). You might've dodged a bullet, there doesn't appear to be any great damage; but checking the runout is the only way you'll know for sure.

What kind of "ground" did it fall on? Dirt, Grass, Concrete, Baby Harp Seal? :ninja: Looks like it fell almost straight on the end of the crank; correct?

Daleo Grand Master

Daleo

Posted
Posted

Can you get hold of a magnetic base dial indicator?

dialbase-1a-250x250.jpg

Attach the magnetic base to the machined flat below the water pump gallery, and put the probe on the farthest point of the crank (as per the drawing)

Rotate the crank 360 deg, and measure any runout on the dial.

More than 0.10mm and you're possibly in trouble (should be basically zero). You might've dodged a bullet, there doesn't appear to be any great damage; but checking the runout is the only way you'll know for sure.

What kind of "ground" did it fall on? Dirt, Grass, Concrete, Baby Harp Seal? :ninja: Looks like it fell almost straight on the end of the crank; correct?

And by drawing; I mean picture...:blush:

Duncan Grand Master

Duncan

Posted
Posted

+1, just check the crank for straighness.

I dropped a motor off an engine stand years ago (wheels got caught in an expension joint in the concrete and it toppled forward. balancer was broken but everything else including the crank came up fine. They are pretty tough really

gold-3lt Enthusiast

gold-3lt

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  • Author
Posted (edited)

Can you get hold of a magnetic base dial indicator?

dialbase-1a-250x250.jpg

What kind of "ground" did it fall on? Dirt, Grass, Concrete, Baby Harp Seal? :ninja: Looks like it fell almost straight on the end of the crank; correct?

I may be able to get a hold of one as i know a few mechanics and im studying diesel fitting so i may be able to get a hold of one at the trade college. Thats what i was thinking of doing since the crank took the impact ( yes it appears to have fallen nearly straight on thge end of the crank but more on the bottom end of it. theres kind of a half moon shape in the concrete where it. It was just regular garage concrete not the really shiny hard stuff.

Other than the crank, what other damage could arise from this other than the bearings? I'll get a couple more pics up when i get the crank out. the girdle just doesnt want to come off easy.

Edited by gold-3lt
Daleo Grand Master

Daleo

Posted
Posted

I may be able to get a hold of one as i know a few mechanics and im studying diesel fitting so i may be able to get a hold of one at the trade college. Thats what i was thinking of doing since the crank took the impact ( yes it appears to have fallen nearly straight on thge end of the crank but more on the bottom end of it. theres kind of a half moon shape in the concrete where it. It was just regular garage concrete not the really shiny hard stuff.

Other than the crank, what other damage could arise from this other than the bearings? I'll get a couple more pics up when i get the crank out. the girdle just doesnt want to come off easy.

Sounds like you're on the right track then; even speak to your College teachers. Most will take an interest if you do; they rarely do it for the monstrous salary... Good time to learn.thumbsup.gif

You may well have gotten away with it; good luck.

gold-3lt Enthusiast

gold-3lt

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Ok hopefully everything is fine then. it only has 94,000 k's on it. If someone doesnt mind answering a few questions i have that would be great because i dont want to make up another thread if i dont have to..

I bought this motor with the plan of building a rb25/30 with vct, using a fully rebuilt rb30 bottom end and cast pistons with a power aim of 200 - 220kw atw on the first build but to have a motor capable of 300 kw with further upgrades and new ecu.

But now after buying this rb25 which is all there just stripped, marked and bagged up I am considering just replacing all the bearings, rings, studs, head bolts then just put it back together with a full gasket kit after getting the head and block cleaned and machined (light bore hone). This would save me a fair bit of cash that would other wise be spent replacing and modifying various parts on the rb30 bottom end and modifying the head to keep the VCT.

The problem is i have never driven a car with a rb25 or rb30det in it so i dont know how differently they respond on the street. So if anyone can help me make a decision that would be really good.

I love the sound of rb25's but ultimately i'm after a engine that has excellent response and torque with a strong mid range and ok top end while still being smooth and reliable. thoughts?

gold-3lt Enthusiast

gold-3lt

Posted
  • Author
Posted

Judging by your last sentence, you want an RB30 :thumbsup:

I think that might be the go :D . Put the 30det in my sedan and then just rebuild the rb25 to standard specs and put that in the wagon with some 4.11 gears and fmic. It may not be as fun to drive as the 30det but at least it will be nice and reliable. Don't really need two overly powerful cars anyway. the wagon was only ever meant to stay na but oh well.

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