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24 Valve DOHC head almost done!


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  • 2 weeks later...

Tbs,

Hey good luck on the head thing...hope you get her together and running soon, and on the whole making them thing, did you think of getting with edelbrock or world products or someone else and convincing them to cast the heads once you get the setup right? I would be really interested in trying it on my '78....another Idea....everyone was talking about the KA intake being for a long-stroke motor...why not do the same for the L-6? Let's say take an LD-28 diesel block,(with it's higher deck height like the LZ motors) get the diesel crank offset ground to 3.78" (or a billet crank)and use the KA con rods and pistons to end up with an "L from hell" with a displacement in the neighborhood of 3.8 liters, and take advantage of that KA head. I know I'm just speculating out of the box and don't even know if it can be done, but wouldn't it be cool?

I was also wondering about the possibility of increasing the deck height of the L-28 block with a custom plate, (with a head gasket below it) and use taller cylinder sleeves so the cylinder surface is sealed, then slap that KAx1.5 head on top and start showing 1JZ's that there's a new sheriff in town. Just thinking outside the box here, like all of us.

The timing cover could be sourced from an LZ-24 (it's deck height was in the neighborhood of NINETEEN MILLIMETERS higher than the standard L-block!)

That way a stroker could be built using the LZ pistons AND rods, :lol: would just have to get a custom crank made with the longer stroke.

I know, just shootin' the bull but wouldn't it be cool to have a "monster" L-series, being just about every other motor in town seems to have monster displacement these days (from the same external size!)

I'll look up the specs for the LD-28, if it's deck height is similar to the LZ-24 I'm definitely gonna try the "big-block" L-series idea.

Good luck and god-speed on that head,

later,

Bryan

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funny you should mention the desiel block! I was looking into that and already had a motor lined up, but then they crushed the car before I could buy it, boo hoo! The LD28 motor has the same deck height as the L20B 4 cylinder. you have to use that timing cover, and it bolts on. a board member here by the name of DAW has an LD28 converted to gas using the stock internals and putting a gas head on. I wanted to use the LD28 to get a decent rod/stroke ratio.. custom cranks and cylinder liners are spendy business. but, i suppose you could do it. only problem is, stock bore on teh LD28 is 84.5mm, so, you could really not get a big bore on this motor. and I dunno if it would match up to combustion chamber for an 89mm bore engine. just a thought..

 

McAdam

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Mack,

I believe (but not sure) that the diesel probably had some hella-thick cyl. liners, but even if it can't be bored out to 89mm, could just bore to 86mm and use stock flattie 280zx L28 pistons with the L24 rods, with the custom crank. The thing would still be one of the biggest L-series stroker motors in history because the bore size isn't the primary factor in the displacement...I've read on here that just stroking alone can get you close to 3.0L on these motors. (when using the 300zx 87mm pistons with the .040 overbore.) The deck plate idea was if I would decide to use a gas L-block and increase the deck height so the long stroke could be used without resorting to mega-short con rods. BTW, what is the deck height of the L20b? Is it the same as the LZ-24? I can't remember the deck height, it's been a long time since I've owned my 85 nissan pickup (LZ-24 2bbl, beat the tar out of it and it still ran well when I sold it, even at 180,000 miles!)

All the talk of modding a cyl. head, anyone consider using the QR25 head and modding it? I've heard that these heads flow really well and have a valvetrain that is easily capable of 7,000+ rpm (despite the QR25 having a 6,100rpm redline, and the NISMO race QR still can only rev 6,700rpm bacause of the terrible rod/stroke ratio!) Nissan basically built a factory stroker with the QR, the JDM QR20DE has the same deck height and 89mm bore but a MUCH shorter stroke (the US QR25 has a 100mm stroke!..that's like, just about the stroke of my BIG BLOCK 430 that's in my Buick sportwagon!) 100mm=3.94"! (this explains why the QR25 has nearly the same hp as the VG33DE (but, imagine! a LOWER REDLINE)and only 20ft. lb. less torque...with a very flat, v-8 like curve.....from about 2,000rpm all the way to 5,000rpm the QR25DE is putting out something like 85% of it's torque peak. (180ft. lb.@4,400)

 

The bore spacing I think is very similar to the KA24.

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  • 4 weeks later...

That's too cool!

As for naysayers, they said tungsten couldn't be drawn into a wire for light filaments---Edison didn't know that engineering "fact" so he did it anyway.

I'm sure there were a lot of metalurgists who said the light couldn't work, as it sat there glowing in front of them.

 

i have seen amazing things done with cast-aluminum heads. The key is having the parts in a jig when you weld them, preheating and cooldown done in the proper way, and hten judiciuos application of hydraulic pressure to straighten anything out needed for minimal decking at the end.

 

There is a company in Tulsa Oklahoma that does WONDERS on stationary equipment. Stuff you thought was wrecked beyond repair---they fix and barely break a sweat! I mean loose counterweights almost cutting an inline 12 cylinder Sulzer Diesel in half! Fixed.

Chucked Rod in a 3-Deck high Ships diesel with a ventilated block (you could WALK through the hole in the port-side engine block wall) in three places...FIXED!

 

Our stationary 10X10.5" V16's lost a rod, and they fixed that in less than 12 hours. Repaired the holes in the block and camshaft area, relined the upper and lower liner counterbores, and redecked the left cylinderbank, all in-place, and in the field! Totally awesome. I told them "if you ever come to fix anything in the L.A. area again, call me, I'll come down and watch!" They did several times in the next few years, and I was always amazed.

 

I know that didn't mention welding, but these guys showed me photos of welded stuff they did, and I stopped saying it was "unrepairable" after that! :D

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Guest norm[T12SDSUD]

All of this is very interesting and very "hot rod" creative and I hope it works but I have a question.

I know how you can weld the outer walls of the cylinder head but how will you do the inner walls?

Will you use some type of high temperature sealant on the interior walls and just press them together?

Or, can you get a small welding stick down in the bolt holes and weld it together and then run a drill bit down the hole for bolt clearance??

This really has me baffled.

Good luck!

 

 

Later,norm

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Ive been wondering the same thing that norm[T12SDSUD] was, or at least wondering how crazy the solution would sound.. heh

 

I was thinking that one possibility would be to weld the water passages closed befor assembleing the sections then runing external coolant feeds to each head section. High performance motorcycle engine builders do something similiar to that on old Suzi' GS1100 motors with the oil feed for the head.

 

I think in a pinch something similar might also be possible for the rb or mercedes projects/theories floating around.. completly blocking oil and water passages between the head and block and running external feeds into the head.

 

Man I wish I had a bridgeport in the garage, or a garage period!

 

Anywho.. very inspiring work-

Good luck, Sam

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well, the way I see it is to just cut about 1/4" away from teh outer walls of the cylinder head, weld up the inner walls (coolant passages) then close up the outer walls.

 

Laser welding wont work. I called around to a few places last year looking to do this. I was gonna use KA24E heads cause thats what I had 2 of sitting in my garage at the time. They told me that it would be no problem if it werent for the fact that cylinder heads are made out of a mix of scrap metal and garbage apearently. too many metals in the head and too many anomolies. If it was a pure aluminum head, it would have worked. heh, I wish that were the case, as they quoted me about $70 a weld. and Id only need 2 of em. ah well. this'll work just as well.

 

McAdam

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I don’t know tbs.

I have welded up a lot of weird stuff, but this looks like a challenge. The metal in the casting should take a decent weld. I have modified many castings in the past. Some are dirty alunimum and others are great. You wouldn’t think a head would be made from scrap.

The oil lines on a Jag are external, so that part is possible.

I don’t know a thing about lasers.

How are you going to weld the interior parts of the water jacket?

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