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jcd0402

L20B Rod Fitment Help

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Okay guys I'm having a hard time because I fail to comprehend what other rods fit on the L20B without modifications.

 

Recently I sent my L20B to the machine shop since I got it with a messed up rod bearing. (It spun) Now I'm having trouble finding an U60 labbeled rod. So I was thinking maybe there were other rods that fit on a stock engine. Since I think I've read that z20e and z20s rods fit without modifications. But I want to be sure, before I screw up my freshly rebuilt head.

 

Thank you

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L20B rods are 5.75" 146mm -- Z2.2 are the same. check the c/c length of the others.  Contact me if you still need one, I'm in AZ

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Unless you really hammered it, rods that had a spun bearing can be fixed.

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L20B rods are 5.75" 146mm -- Z2.2 are the same. check the c/c length of the others.  Contact me if you still need one, I'm in AZ

The rod is at the machine shop right now thogether with the engine for rebore. Previous owner had it all torn apart. I do know that the rod had u60 stamped on its side. I'll post pics of the rod bearing and rod as soon as I get home.

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Only L20B and early Z22 rods will fit the L20B crank and stock pistons.

 

L20B and early Z22 rods are....... 145.9mm long between big and small end center lines

Z20 rods are................................ 152.5mm, you would need to change all the rods all AND put Z20 pistons on them.

There are other combinations but nothing replaces the stock ones.

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I've got a set of new Z20 pistons, that I will let go cheap, cheap.......

They are.5mm os (87.5mm), and for the LZ20S (35.5 pin height).

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I've got a set of new Z20 pistons, that I will let go cheap, cheap.......

They are.5mm os (87.5mm), and for the LZ20S (35.5 pin height).

I already ordered a new set of pistons and rings, going 0.30 over the std size. But thanks for the offer!

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This would be the reason as to why I believe I need a new rod. 

 

IMG_20170921_172331068_zpsufdpilpz.jpg

This would be the reason as to why I believe I need a new rod. 

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This would be the reason as to why I believe I need a new rod. 

 

IMG_20170921_172331068_zpsufdpilpz.jpg

 

 

And Photobucket is why you need another picture hosting site.

 

 

Crankshafts can be ground down and a smaller bearing used, or just replaced. Rods, it's just easier to replace them.

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I don't see anything wrong with it except the bearing being screwed up, is there something else wrong I didn't see?

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Be nice to see the picture.

 

I have seen rods blue from the heat, bearing shells softened and pounded out to the sides of the rod, bearing shells razor sharp and thin, bearings spun and welded to the crank, and rods snapped off and thrown through the side of the block. Once the bearing shell slips it usually blocks any oil flow from the crankshaft and if going fast enough it's seconds till it destructs.

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I don't see anything wrong with it except the bearing being screwed up, is there something else wrong I didn't see?

If I remember correctly I believe that is the surface of the rod without a bearing. 

 

My bad that is the rod with the bearing on. But the pitting also occurred on the rods surface, and it shows multiple lines on it. *

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Be nice to see the picture.

 

I have seen rods blue from the heat, bearing shells softened and pounded out to the sides of the rod, bearing shells razor sharp and thin, bearings spun and welded to the crank, and rods snapped off and thrown through the side of the block. Once the bearing shell slips it usually blocks any oil flow from the crankshaft and if going fast enough it's seconds till it destructs.

IMG_20170921_172339450_zpsfbuftstj.jpg

IMG_20170921_172326271_zps8hcevmyb.jpg

IMG_20170921_172250859_zpsiamx7pxp.jpg

 

You can also notice that one bearing cracked,and that one looks like it got hot. Making me think that all of this happened because of lack of lubrication. 

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Still no pictures showing for me. What does the crank surface look like? No wait it won't matter.

 

 Is the rod blue from the heat or not? If undamaged, and this is possible as the bearings are 'soft' you could re-use it. If the bearing spun inside the rod then the crank is likely needing to be turned down to an undersize or replaced..

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Still no pictures showing for me. What does the crank surface look like? No wait it won't matter.

 

 Is the rod blue from the heat or not? If undamaged, and this is possible as the bearings are 'soft' you could re-use it. If the bearing spun inside the rod then the crank is likely needing to be turned down to an undersize or replaced..

No the rod doesn't look blue but some bearings did have a very small hint of blue. Crank surface appeared to have some minor marks on it, nothing too deep to be non-repairable. I already took it to the machine shop, they made me order 0.030in overbore pistons, 0.020in undersized rod bearings and 0.010 in undersized crankshaft bearings. Yet, I was told that there was a large possibility that I had to change the rod, since it showed scoring on its surface (not the bearing surface).  Tomorrow I will head there early and get a second opinion, good thing is that they already finished with the head and valve work. 

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A shop will have you do this so there is no liability later... they're just covering their asses. If the crank is mirror smooth and is measured and passes it's good. If the bearing actually spun then it's extremely possible the crank journal is bad. You don't need all of them turned down if only one is in need of it. They are just looking for work.

 

 

Over boring is a good idea because when done you have basically a brand new engine with a couple of hundred thousand miles of driving ahead. Sometimes you can just hone the cylinders and put new rings in but you won't get near the same mileage.

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Ask them to measure the crank to see if it can just be polished.

 

Also make sure to get good tri-metal bearings. Aluminum bearings are horrible and have lots of problems. Clevite makes tri-metal bearings and anything stamped with an "NDG" is a factory type bearing.

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Just got good news!!!! The shop owner finally got to better inspect my rods and said they can be bored.  

 

The bad news now is that I receive my new set of pistons with one of the 4 being broken. So they'll have to wait on me till I get the pistons to bore out the cylinders.  :mellow:

 

Anyways, Thanks for the great info guys!! Will be hearing from me in my project datto post soon.

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Rods bored???

 

So I assume the crank is being turned down? if you are buying oversize bearings for it?

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Rods bored???

 

 

I thought I read that's possible... take material from the parting joint, reassemble rod then hone to size ....

I could be wrong....

If that's the theory wouldn't that effect the install height of the piston?

Should all 4 be done to match?

Maybe it's minimal or not even possible.. I really don't know for certain....

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Resized.

 

They take so little material out that the change in length is negligible. Ideally only a few thousandths.

 

Yes, they should do all four, but that's more of a balance thing.

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Yup, resized as Stoffregen said. They remove material from the rods and the crank. But the removal is so minute that I would like to think it won't mess with the compression. 

 

About the weight difference, I do believe there will be some, but nothing that can't be fixed with a grinder and a scale. :)  

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The thicker bearing would make up for it.

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The thicker bearing would make up for it.

True, maybe that's why they made me get a 0.020 undersized rod bearing . To take .010 from the crank and .010 from the rod. 

Just making a guess, I'm not really sure. 

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I think only the rod cap bolt area is trimmed to make the big end less oval and more round. They don't remove 0.010" all the way round the rod and cap.

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