Ka dohc head on l20b

[TFM1066]

been using the toyota crank gear for years and its only like 8.00 bucks

[datson4life]

Sick! Didnt know about this topic just saw that work of art in person yesterday, looking forward to seeing it run

[datzenmike]

Hey datzenmike my new sprocket is cnc machined from blank of chromoly. It is the correct L series crank diameter with the correct ka24de single row teeth. As of last night I got the cam timing dialed.

Why not just use the L or Z series double row sprocket? Cost zero.

[The Stig]

I think the number of teeth on the L/Z is incompatible with the upper sprocket

[datzenmike]

Right... I was thinking of the single cam. L, Z and KA E are 20/40 crank/cam sprocket.

[docbainey]

is this what you are trying to do?

 

http://lescollinsracing.com/engine/projects-engine/l-series-4v

[The Stig]

Yes that's almost exactly what he's doing

He gave credit to someone from that shop on the second or third page of posts

 

And yes it's been done

[docbainey]

Yes that's almost exactly what he's doing

He gave credit to someone from that shop on the second or third page of posts

 

And yes it's been done

Didn't know that bloke worked there.

 

If you watch the slide show there are technical solutions shown to some of his problems, like the chain tensioner. Also, it's interesting that they did an L18 rather then a L20B. Shorter deck, more angular displacement of the connecting rod Vs less angular movement but greater rod weight. js

[scooter]

everyone wants a destroked kade with a full counterweight crank...

 

I wonder if les' l18 based kade was bored to 89mm or not, the valve reliefs in the bores make me think not.

 

if so, theres more to be had in an l20b crank/z22 block combo, cause anything you can do to unshroud the valves with the side of the chamber and the bore is huge.

 

if no one does this by spring, maybe I will....bwahahaha

 

even though his is l18 based, I don't think you can get his numbers he claims out of a ka24 just because its twisting soo much

[Stoffregen Motorsports]

How much does he claim? At the flywheel or rear wheels?

[blackmarkit]

So the 'yota sprocket didn't fit?

NO the toyota sprocket was 33mm. The Lseries crank snout is 35mm. its much closer than the ka sprocket but when machining it the sides get super thin by the keyway.

 

Didn't know that bloke worked there.

 

If you watch the slide show there are technical solutions shown to some of his problems, like the chain tensioner. Also, it's interesting that they did an L18 rather then a L20B. Shorter deck, more angular displacement of the connecting rod Vs less angular movement but greater rod weight. js

Im doing the L20 because i wanted a 1.75 rod ratio and with z22e rods and Mitsubishi 4g63 forged pistons i get between a 8.5:1 and 9.0:1 compression. perfect for a hot rod street motor. low enough to run boost and regular fuel. all the parts are easy to come by and relatively cheap.

 

How much does he claim? At the flywheel or rear wheels?

i think if i remember correctly peter mcdonnell was making 290 hp on a enginie dyno.

[Stoffregen Motorsports]

290 hp is not totally outlandish. We used to make 300 hp on the 12 valva KA24 with 44 Mikunis. The KA24DE race motors are making almost 350 hp.

 

If he spins it high enough, I wouldn't doubt his numbers.

[datzenmike]

everyone wants a destroked kade with a full counterweight crank...

 

I wonder if les' l18 based kade was bored to 89mm or not, the valve reliefs in the bores make me think not.

 

if so, theres more to be had in an l20b crank/z22 block combo, cause anything you can do to unshroud the valves with the side of the chamber and the bore is huge.

 

if no one does this by spring, maybe I will....bwahahaha

 

even though his is l18 based, I don't think you can get his numbers he claims out of a ka24 just because its twisting soo much

 

 

So what exactly is the engine below the head. Says L18 block but 1998cc? L20B crank? confused.

[blackmarkit]

I could be wrong but I think the main bearing sizes were different. L16 and l18 are one size and l20 is a different size. Also I know there is something wrong in the chiltons and Haynes manuals about l20b main bearing sizes.

[blackmarkit]

I think this is right.

 

L16, l18 - 55mm main journals

L20b - 60mm main journals

 

So as far as I know you couldn't put a l20b, z20, z22, z24, in a L16 or L18.

 

Unless there is enough material to grind the crank or align bore the mains.

[Stoffregen Motorsports]

Well you can't bore the mains, but you can cut down the crank. If he's really making that kind of HP, he's probably running a billet crank though, custom ordered.

[datzenmike]

Did a little number swapping...

 

L18 block bored to 90.3 mm custom pistons and rods on an L18 crank = 1940cc engine. B&S 90.3 x 78

 

L18 block (adjusted) to fit L20B crank, custom pistons and rods to fit = 1951cc engine. B&S 85 x 86

 

These are 'close' to the advertized 1998cc.

 

Can't see why you would build an L20B using a shorter deck L18 block. The L20B rods would have 20mm less space for them.

 

 

 

I could be wrong but I think the main bearing sizes were different. L16 and l18 are one size and l20 is a different size. Also I know there is something wrong in the chiltons and Haynes manuals about l20b main bearing sizes.

Yes some Chiltons and Haynes are wrong because the FSMs are also wrong.

 

Rod bearing journals for L16/18 L20B Z20/22/24 are 49.961mm-49.974mm

 

5 bolt crank main bearing journals for L16/18 are 54.942mm-54.955mm

6 bolt main bearing journals for L20B, Z20/22/24 are 59.941mm-59.955mm

 

My '84 720 FSM lists the Z20 and Z24 as having the L16/18 journal size!!!!!

[The Stig]

docbainey:

Actually I was making an assumption as when I was google searching that name Les's web page came up among the results...

But I have no Idea if he works there my point was that it had already been established that this had been done and (I think) being first wasn't what Blackmarkit was trying to do

[Stoffregen Motorsports]

 

Can't see why you would build an L20B using a shorter deck L18 block. The L20B rods would have 20mm less space for them.

 

Maybe he's got rules telling him which engine block he can use, or that the block has to be original type. Is this motor in a race car?

[The Stig]

Did anyone wondering about the use of the L18 block consider that it might be required in the rules of the series to maintain the original spec block?

 

And most inline fours that are designed for racing typically have square and under square bore to stroke ratios because there is very little low RPM use on a road race track and typically the most powerful cams are aimed at the higher RPMs

[datzenmike]

Very true. As shown you could get about 2 liters from an L18 casting. I think there were fully counter weighted L16 and L18 cranks available from the factory and with six bolt flywheel too. (on the SSS engines?) The stock L18 stroke with 90(ish) bore would get you close to two liters. Red line, as defined by a peak piston speed of about 4K feet per minute (this changes with the weather) is about 8K.

 

Using the L20B crank or similar stroke would redline at 7,200. ish)

 

You would need custom rods and pistons for these.

[Stoffregen Motorsports]

The 6 bolt cranks were a Datsun Comp item that were built custom. They are very rare.

[datzenmike]

I heard they might have been on the SSS engines?

[hosestop@msn.com]

I have a six bolt L18 crank in a tilton race motor that got 8k rpm s has euro disc pistons , ran hard !copied tilton cam shaft also , and still have head from it .

[The Stig]

The 6 bolt cranks were part of the Japanese FIA homoglation parts that were offered in the old NISMO and NMNA catalogs from the 70s and 80s I don't think they were cheap

Nissan ran a factory twin cam version of the L series in the 70s and 80s and there were lots of trick parts from that program

And while there are 4 counterweight L18 cranks from the JDM market most of them are fully counter weighted so that 6 bolt L18 racing crank made of spendium would not be the best use of a budget unless you needed to run the entire FIA package to meet the rules, but then you couldn't run a KA-DE head

Besides if you needed 6 bolts you could "turn" down the mains on a a L20b crank to fit a L18 block if that stroke was the target