Engine build ideas, need some help (looooong story)

[bajango]

I'm going to wail on it, I love the sound of screamers

[datzenmike]

Main bearings

 

L16/18....... 2.1631" to 2.1636 "

L20B.......... 2.3599" to 2.3604" also Z20/22/24. KA's are same diameter but narrower.

[hobbes_the_cat]

For what it's worth I liked my Unilite dizzy, worked fine and looked cool. The only negative for me was the cap and rotor are a bit harder to find and I had 3 broken ones sent to me from Summit before I finally got a good one. Matchbox dizzy cap and rotor is usually in stock at the local parts houses.

Honestly I didn't notice a performance difference between my Pertronix converted dizzy and the Mallory tho.

[racerx]

Car may run smoother with Electronic dizzy or Pertronix but nothing noticeable with HP gains.

[bajango]

Main bearings

 

L16/18....... 2.1631" to 2.1636 "

L20B.......... 2.3599" to 2.3604" also Z20/22/24. KA's are same diameter but narrower.

Sorry Mike, I mean the connecting rod journals, thats why I said nevermind. I'm still playing around with some different parts while I still have alot of time before I am home to start on the project.

[bajango]

What kind of complications could I run into using mismatched rods and rod bearings? For example I am looking into small block chevy bearings and jeep rods.

[Lockleaf]

Nothing, long as they match diameters and widths

[datzenmike]

Sorry Mike, I mean the connecting rod journals, thats why I said nevermind. I'm still playing around with some different parts while I still have alot of time before I am home to start on the project.

 

ALL L series rod bearings are the same. So are the Z series and the KA24E. All these rods will interchange however they definitely won't all fit.

 

 

What kind of complications could I run into using mismatched rods and rod bearings? For example I am looking into small block chevy bearings and jeep rods.

 

 

Jeep and Chevy???? wtf???? Won't work unless they fit. Why????

 

All the Nissan L Z and KA rods and rod bearing fit, you just have to select from them what will work. Here's some homework reading. It lists most Datsun pistons, rods, cranks and blocks and what combinations can be combined to make a hybrid engine. You can't just add crank, rod and pistons indiscriminately. They must fit the block selected and if too long will hit the head, too short and the compression will be low.

 

http://www.newprotest.org/projects/510/jasonGray.pl

[flatcat19]

SMH.

 

What made you think that you could just start plugging random VW, Chevy, Mopar parts in to an L block?

 

Sounds like a huge expense in both time and money.

 

You're trying to build an L. Keep it simple.

Nothing you do will be better than what's already been tested.

 

These motors have been around a long time. Many people have been down the path you're trying to forge.

If it would have worked, you have the info. Guess what...? It didn't.

 

 

It's a Datsun. Get it on the road and just enjoy it.

[scooter]

Ive looked where your going.

Stop while your ahead. The problem with l/z cranks is the rod journals are soo wide! An engine machinist can grind your crank throws down to honda rod size, but you arent gonna find a rod with a wide enough big end to have decent big end side clearance. Unless you weld the crank..... But then thats a whole nother thread.

[scooter]

There is actually some 4g63 rods that are promising, the crank will need to be ground down to 1.888 though, and slighty wider.

But that gets you a shelf 150mm aftermarket rod. With some good pistons the crank will become the weak point along with head fastening in a power adder scenario.

 

Nasty ass lz23 v2.0 comming soon.

[G-Duax]

5mm longer rod isn't going to change a whole lot as far as RPM limits.

Have you actually run the numbers on rod/stroke ratio, and how it effects max piston speed, and piston accereration limits ?

 

" power adder scenario" ?

 

I don't see this ending well.....

[scooter]

There isnt a off the shelf aftermarket rod what will work well for l/z combos. The 4g rods may be workable though with some crankshaft machining work. Custom pistons are alot cheaper than custom connecting rods.

 

Yes i know what rod/stroke ratio does, theorys on this are changing in certain applications.

 

I am now spraying a 100 shot at my lz23 with stock rods, i want to go more but i have connecting rod integrity concerns.

 

If i can run a 150mm rod instead of 145.9mm l20b rods, that will be an improvement. Not perfect, but better. Brings it up to 1.63 from 1.59.

[bajango]

Well let me see if I can make you guys understand what I am doing. I think I am almost getting everything working out the way I want it to.

 

Jeep rods-

155.57mm in center to center

56.096mm big end diameter

27.051 big end width

Jeep bearings are too small even at .060 undersized so I need an alternative

I would also have to mill a ~.125mm on both sides of the big end width for the side tolerances

 

I would need a piston with a 29mm compression height. RB26DETT pistons would do the job with 1mm milled off the top or I can run Mitsu 4g63 pistons at a compression height at 28.7. I haven't looked at all of my alternatives for pistons. I think some honda H22 ones worked too but I can't find the part listing now. I am at a deck clearance of .180mm below with the 4g63 pistons. That brings my rod ratio to 1.8.

 

I could run a specific set of small block chevy rods at 6" and have a piston compression height of 32mm (for example vg30) and be .950mm below deck as well. My rod ratio is at 1.77. I forgot what bearing I would be running for that now. I never recorded that. oops. I think they were big block chevy.

 

Do you guys see what I am trying to do? I figure as long as the tolerances are all met, the possibilities are innumerable. I'm just wanting to make sure I wasn't missing another small detail that will ruin my whole plan.

 

Nothing I have looked at lists small end with, so I would have to actually measure a set of in stock parts before I order what I want.

[G-Duax]

How would you like a set of unfinished 6" mechart rods ?

You can machine them to fit anything you want.

I bought them from Mechart before they closed the doors, and they provided machining instructions.

They are very strong, and very light.

 

This is a set of finished Mechart rods.

[flatcat19]

So, how much is this build going to end up costing if it works?

 

 

And the final result? 100hp? Maybe 120?

[G-Duax]

Oh, have faith flatcat.....

[racerx]

All he has to do is search on this site what has been done before.  Just my opinion, why try to build something that's been tried and spend money when the result is minimal. Sometimes people will ask and then you tell them but they keep on going because they already made up their minds and don't want to change because they are set in their minds.  I say do it! Then let us know if the experiment was worth it.

[G-Duax]

Exactly......

 

Before I built my all-motor 3-liter Toyota, people were getting a mear 225 hp out of them.

But I could see flaws in their attempts.

After years of work, and some failures, I'm in the 400 hp range.

 

Yes, I could easily built a turbo engine making 600 with a lot less work, but it's worth it when I put it to turbo cars, and V8 detroit factory hot rods.

[bajango]

The way I see it, I could build a turbo L with FI for ~$3000 and have more power. Or I could build all motor for L for ~$2000. I'm trying to keep it milder for a 521. It won't ever have the power to the ground potential of a 510 or Z.

[bajango]

So, how much is this build going to end up costing if it works?

 

 

And the final result? 100hp? Maybe 120?

Yeah, you may be right. The reason I'm doing all of this work is because I cannot find Z-E parts. It also helps that I work at a parts store where I can get a better rate on some parts.

[datzenmike]

Depends on the engine this is all going into. L16? The block does not have much bearing on engine power so you could spend the moon on it and still make 80 hp. A good strong bottom end helps with longevity. Power is made by the head.

[bajango]

Well hopefully the L20 will give me some umph.

[Stoffregen Motorsports]

It's admirable that you're willing to try something new, but...

 

The L motor has a max streetable horsepower of about 250. That's a fully punched out, stroked, L headed, dual 50 PHH monster. Building the bottom end to get the desired displacement is only half the battle. Getting the head to flow and building a valvetrain that will handle the cam required for that kind of HP will cost you, big time.

 

If you work backwards from a couple of questions, you can then decide what to do with the options available.

• What's your budget?
• What kind of HP do you want?
• Can you do the work; some, part or all of it yourself?

Ask yourself those three questions and go from there.

[flatcat19]

If you have a 20 block, look up building an LZ23 with KA pistons.

 

Plenty of power. It will toss that 521 all over the place on the cheap.