Does this count as DYI?

[McAdam]

does making my own DOHC head for my venerable L28E count as a DYI mod?

[Dangler]

Dyi = ?

[Guest]

Dangler wrote:
Dyi = ?

you know DYI....Destroy Your Internals

I guess it is a DIY mod if you did it yourself, some instructions on what to do would be great however

[McAdam]

damn my typing. yes, DIY is what I meant. I am not doing it completely by myself, but we are not enlisting the help of any machine shops, because my freinds dad owns one! All work is being done by either myself or my freind. Parts are being sourced from the junkyard an/or made out of modified stock parts.

A little history lesson is in order to tell you "how to do it"

The nissan L series 4 cylinder first made an appearance in I beleive the '68 datsun 510. The 6 cylinder came out in the 1970 240Z. The 6 cylinder is just the same as the 4 cylinder, except it has a 2nd pair of cylinders (#'s 2&3 of the 4cylinder motor) stuck in the middle, thus making it a 6 cylinder. It was kind of one of the first "modular" motors. This theory is proved by the fact that if people want an EFI manifold (which the L4 never came with in the USDM), they simply take an L28E (L family of engines, 28 displacement 2.8l, E for electronic Fuel Injection) manifold, , chop the 2 middle cylinders out of it, and weld it back together and they have a manifold that will bolt on to thier L 4 cylinder..

The L6 never really evolved much and became extinct with the 1983 datsun 280ZX. It still had its non-crossflow 12 valve SOHC head. although, there was a factory SOHC crossflow head made in VERY limited numbers, and there was even an aftermarket DOHC crossflow head made in even less numbers. the DOHC head cost about $15,000 in 1980 dollars, when the yen/dollar exchange rate was about 200:1, its now somewhere in the 100:1, plus you have to account for inflation. not a viable option.

The L4 evolved into the Z series 4 cylinders with a cross-flow SOHC hemi style head with 2 sparkplugs per cylinder. The Z series motor then evolved even further into the KA24E with 3 valves per cylinder THAT motor eventually evolved into what we now know as the KA24DE, with its DOHC pent roof combustion chamber and fiarly decent flowing ports. You can put a DOHC KA24DE head on an L series 4 cylinder motor (its been done), all you have to work out is the camshaft timing.

So, I one upped it and said "hey, if you can put it on an L series 4 cylinder, why can't I make one for an L series 6 cylinder?" So, I gathered a few KA24DE heads from freinds that had blown up their 240SX's or done and SR swap and cut them up. I cut one right in half and I cut the end cylinders off of the other one. then put it alll together, so if you were looking at the head, it would look like this... 1&2,2&3,3&4, the numbers corresponding t the cylinder head chunks I had cut up. then I found some cams that were actually quite close and only needed minor modification (gee, which nissan motor is a DOHC inline 6?!?!?) and i shall have it done by april.

I have to keep a few secrets, because we may plan on selling these once we get it done. needless to say, figuring out how to seal up the passages for coolant and oil inbetween the head halves (thirds?) has been a bear of a problem, but I think we have it solved.

p.s. oh and ot the question of "why not just use an RB head?" all of the water passages and oil galleries are completely WRONG, the bore spacing and cylinder head bolt spacing is spot on though... plus RB's are timing belt, KA's and L6's are timing CHAIN.

p.p.s and to the question of "why not just use a complete RB engine?"

1. I like to have things no one else has, and 2. parts...... everything on this motor, save for the cams, is readily available at any corner auto parts store.

[Afsil80]

Definetly an interesting read and build.

I'm eager to see how she performs.

[Phats]

Yes, sounds very interesting, you should keep us updated

[Phats]

AND HEY, whataya mean parts aren't readily available for the RB, i got my timing belt and water pump in 2 weeks!!!!!!

[KA-T_240]

any updates?