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L 20 B Rebuild...a work in progress

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A heartfelt thanks to hobbes_the_cat for hooking me up with this L20B block and W58 head. I'm going to keep a journal here for anyone who's interested and place progress pics all along. I appreciate all the feedback and advice!

 

Sorry the first round of pics aren't that great, I'll get better!

 

Nick

 

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Nice start... keep your l16 around, plus no one really wants them, at least you'll have the matching numbers in your possession if you ever need or want it. Plus I think you can scavenge some parts off the l16 for the l20 swap... I know at least motor mounts dizzy and oil pump ...

Good luck...

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Upgrade the oil pump to a KA oil pump........

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Looks like a good start!

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Oil pump, check. I also heard putting L18 pistons in an L20 gives you a couple more ponies. And to take off the truck fly wheel and replace it with a lighter one. 

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There should be no difference between the l18 and l20 i believe they are the same at 85mm. Unless the l18 had flat top pistons stock. Not sure. but either way a set of flat top pistons would be a good option.. don't know if they need a need the valve relief in the face or not.. There's a lot of guys here with the l20b motor so you'll get alot of good opinions with this post...

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There should be no difference between the l18 and l20 i believe they are the same at 85mm. Unless the l18 had flat top pistons stock. Not sure. but either way a set of flat top pistons would be a good option.. don't know if they need a need the valve relief in the face or not.. There's a lot of guys here with the l20b motor so you'll get alot of good opinions with this post...

The dish in the L18 is supposed to be smaller than the L20B.  You do not need a valve relief in the pistons.

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L20Bs are 8.4 compression. L18 pistons would give a 9.2 compression but hard to find. Going up one point of compression might give you 3-5 hp at full RPMs and less where you drive at. The increased compression will probably ping so you either lower the timing or run more expensive higher octane gas. I don't think you will fine any L18 pistons. 

 

L18 or L20B you will want to bore the block and buy matching over size pistons and rings.

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The L-18 pistons have a 4cc dish and the stock L-20B is 11cc if i recall correctly.Good luck finding L-18 pistons.I found a set for my build but had to use .040 oversize.

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I thought it had to be something like that... went back to my book and found this comparison chart....

20170315_222257_zpsxhrveiff.jpg

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L20Bs are 8.4 compression. L18 pistons would give a 9.2 compression but hard to find. Going up one point of compression might give you 3-5 hp at full RPMs and less where you drive at. The increased compression will probably ping so you either lower the timing or run more expensive higher octane gas. I don't think you will fine any L18 pistons. 

 

L18 or L20B you will want to bore the block and buy matching over size pistons and rings.

 

Increasing compression will make the motor more driveable/responsive at all RPM.

 

8.4:1cr these days is low, some modern NA motors are running 12.5:1, granted that is extreme and has EFI and all the mod cons to allow it.

 

But with the right fuel, electronic ignition and a quality tune, upping the compression to 10:1 wont be an issue when tuned properly and will be quite noticeable compared to 8.4:1

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I would STAY AROUND 9 to 1 .

I WOULD SPEN MONEY ON A SET OF SIDEDRAFTS AND HEAD PORTING

 

I FOUND some Ferdral Mogel boxed L18 pistons a long time ago. Got them stashed soemwhere

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I WOULD SPEN MONEY ON A SET OF SIDEDRAFTS AND HEAD PORTING

 

 

Dude........that's like 2k right there....

 

........at the least.....

 

........did you forget this was Ratsun??

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Speed costs money. More speed costs more money! KA is more bang for the buck. Purists of the L series would build a 5000 dollar 2.3 or 2.4 L series. My L 2.3 in the little photo of me leaning against that black wagon in the corner there made 149 hp and 175 torque at the wheels. If your not a purist, KA bro! Makes 135 hp at the wheels and goes really good for cheap! Like 1500 dollars or less cheap. Just sayin...

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I'm with banzai510(hainz) on this one. You want to make HP with an L you do it through the head. (please note the capitalized HP meaning big horse power)

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All HP comes from the head.

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Digging in...only had time to pull the first piston, my mother in law is in town and we're playing tour guides but here goes: 

 

All things considered the engine seems ok so far. It is locked up and the second piston was much more resistant, I hit it with some PB Blaster and let it soak but didn't have time to go back to it. I'm hoping it was bearings that locked up the engine and the cylinder walls are still good. More pics to come.6019A7CF-DEFE-4656-8488-0D8111C27F1D_zpsC33207DE-CB31-44B9-BEC1-FE948AF3F7B6_zpsD66C87DC-26A2-42E2-9A90-723E6C662AEA_zps4189D769-10A8-44BC-85B0-4A6BDD483226_zpsDF1B3A3D-A457-4BB9-A06F-AA76D6C93A46_zps7E43570A-22A2-4CF6-995C-3AE271F5D1B4_zps

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Check the wear ridge at top of cylinder. Excessive ridge will catch the ring and you may damage the ring land pounding it out. Engine looks like it could have done with more frequent oil changes. Just some cylinder rust.... doesn't take much to lock up the engine.

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Thanks, Mike! I was using the wood handle of my rubber mallet to push the pistons out, slow and low pressure. I'll be sure not to force it.

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You could always pull the crank and pull the piston out the bottom.....

If you plan on boring the engine make sure you reinstall the main caps before you do.

I think you wanna torque them to spec too not sure but I did....

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So finally got back to work on the block...looks like some serious damage on #3. Now do I replace just the rod or the piston as well? Also does the crank look damaged beyond repair? The fact that all the lobes are brown but the #3 is black, plus the wear on it is concerning. Not sure a machine shop can rescue this one.

 

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You have a two options.. 

 

Find another crank

Have this crank turned down and install new oversized bearings.

 

Finding another crank might be cheaper.

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