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Stroker Redux


Xnke

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A few here have converted the LD28 to gasoline. More have used the crank to make an old L28 sing a little lower note. Even as we speak, those LD28 crankshafts are getting scarce, and expensive when you do find them. But what if I still want a little more stroke, you say, seeking the longest rod throw you can stuff in that chunk of cast iron love we call the L? So here's the question:

 

What about the forgotten '81-'84 Maxima L24E rods? With a 44.91mm big end bore, you can take that L28 crank and offset grind it out a hair over 5mm to get 84mm of stroke, 1mm more than that precious LD28. Now before you scoff at the idea, there are some usable combinations out there. After playing around with the Ozdat tool, I came up with the following:

 

L28 block, bored and (likely) sleeved for 90mm

L28 crank ground out to 84mm

L24e rods, small end reamed to 21mm (comes as 20mm)

Need a piston solution, pin height needed is 32mm

 

Total Displacement 3.2L

 

L28 block, bored and (likely) sleeved for 90mm

LD28 crank ground out to 88mm

L24e rods, small end reamed to 22mm (comes as 20mm, not sure if it's possible...)

FJ20 90mm pistons

 

Total Displacement 3.36L

 

Or, for the more conservatively minded:

L28 block, bored for 88mm

L28 crank ground out to 84mm

L24e rods, small end reamed to 21mm (comes as 20mm)

still looking for a piston solution, need 32mm pin height

 

Total Displacement 3.0L

 

 

So, let's hear why it WON'T work, and then let's figure out how to make it work. Eh?

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You now know how Rebello makes their 3.2, 3.3, and 3.4 motors.

 

 

 

I confronted dave at rebello on the phone with this situration a couple years ago, and he about died when He knew that I knew what they did to get that big of displacement on 89 and 90mm bores.

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I confronted dave at rebello on the phone with this situration a couple years ago, and he about died when He knew that I knew what they did to get that big of displacement on 89 and 90mm bores.

You CONFRONTED him? He about died? As if offset grinding a crank hasn't been done for the last 50 years or more?!! Nice job Sherlock.

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You CONFRONTED him? He about died? As if offset grinding a crank hasn't been done for the last 50 years or more?!! Nice job Sherlock.

 

 

 

 

"NICE JOB SHERLOCK"

 

 

 

VERY DISRESPECTFULL, no matter what the circumstance. I was always under the impression that direct name calling with what some would call HARSH name calling is UN-ACCEPTABLE.

 

 

Am I missing something here, or can we tell people "nice job sherlock" without any remorse?

 

 

I am all about following the rules as long as everyone follows them.

 

 

 

 

My post was stating FACTUAL information, about things tha ACTUALLY happened.

 

Where is the harm?

 

 

Where is the tech?

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"NICE JOB SHERLOCK"

 

 

 

VERY DISRESPECTFULL, no matter what the circumstance. I was always under the impression that direct name calling with what some would call HARSH name calling is UN-ACCEPTABLE.

 

 

Am I missing something here, or can we tell people "nice job sherlock" without any remorse?

 

 

I am all about following the rules as long as everyone follows them.

 

 

 

 

My post was stating FACTUAL information, about things tha ACTUALLY happened.

 

Where is the harm?

 

 

Where is the tech?

The sherlock comment was a bit over the line. I shouldn't have said that. I apologize. Please let me rephrase:

 

The idea that one can get more displacement by welding and offset grinding a crank is not a new idea. It's been around for many decades. I'd be surprised if they weren't doing this on flathead 8's back in the 50s.

 

The attitude in YOUR post was what I was responding to. The post read like you thought that you "showed up" Dave Rebello and that he was mortified that you had figured out his secret. That is ludicrous, but in keeping with the attitude you have displayed and been warned about so many times in the past. As an admin it is my job to keep people from flaming others, and in attempting to temper your comment I stepped over the line myself.

 

So how about you knock off the attitude and I'll back down from calling you Sherlock?

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Ok, enough fighting.

 

 

Back to the topic at hand:

 

Spending some time looking at piston specs, rod measurements, and crank throws, but not actually having an open block to look at, this is all speculation on what will fit. I've got the junkyards of the Nashville and Louisville areas available at the expense of a long drive, but most of those places won't sell you a scrapped out crank, let alone give you a scored up junker. Everyone I talk to wants to sell the whole engine, or not at all.

 

So I'm looking for an old L28 crank, preferably with the main journals in good shape, and I could care less about the condition of the rod journals. As long as it's not severely bent, cracked, or has been otherwise tortured, I figure it'll do. Who's got one, and better yet, what's the best way for me to get one short of driving a datsun with a rod bearing out?

 

I'll probably spend this evening looking at alternative rods, like the 4G63 or something.

 

EDIT

 

With the 4G63 rods...the LD28 block+stroked LD28 crank gets a good rod ratio...and 3.4L displacement with some 90.5mm KA24 pistons

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You now know how Rebello makes their 3.2, 3.3, and 3.4 motors.

I confronted dave at rebello on the phone with this situration a couple years ago, and he about died when He knew that I knew what they did to get that big of displacement on 89 and 90mm bores.

 

 

I'm just curious as to why you didn't mention the method as to how rebello would do such a modification.

 

what I think they would do is offset grind the crank like mentioned, and possibly run a thicker headgasket, with a taller piston and a compression ring that seats itself lower at TDC to allow the piston to peek over the gasket with more margin/tolerances for expansion/error with the ring unseating itself into the thin gasket area, and making a bad seal. and of course, longer rods.

 

Are you sure Dave wasn't surprised that you CONFRONTED him, and the means for such a call, because I'm not a machinist I can think of a lot of ways to gain displacement on an engine, it's just that some people don't see the need to spend megabux to get an extra .04 liters or so.

 

how would you do it, brian? everyone knows you're good with your stuff.

 

I'm curious, because neither your's nor jmortensen's post had ANY tech at all that was not previously mentioned by the thread starter. accusing john of not posting tech is a little hard to swallow when it's clear that you didn't either.

 

 

 

 

can we just get back to HOW and now WHO?

 

cause I'm pretty sure none of the people reading (myself included) give a hoot about who's done what and how it was done unless tech actually presents itself.

 

 

Lets not disappoint the poster because of a squabble like this. we all want real answers.

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Yeah, i read all the DAW posts. He's probably still around over in one of the other forums i am a member of, i'll see if i can get ahold of him.

 

 

Anyway, now i gotta find an LD block...

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Well, I looked into getting some 4G63 rods this evening. Got some buddies down the street who are DSM fans...they're gonna look around and find me 6 weight- and condition-matching ones.

 

 

Next up on the list of parts to source is the L20B timing cover. Time to call the local scrapyards, and see what can be had.

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Ok, so it's confirmed. I'm going to be doing an LD block conversion at some point.

 

What I need now are as many detailed photos of the bare L series block as possible, specifically, the PCV tube area, the oil filter area, and the top deck surface, as well as pictures of an LD block in those same areas.

 

Anyone taken the time to photograph there block lately?

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