L23 Datto stroker build (56k = LOL)

[Kaiser]

Sorry, I've just committed to Project 2.35 ... I have budgetary needs of my own.

[munyard]

good work TK, seems like youve wasted no time in finding the porting limits of the L heads, the intake flow figures are as good as ive ever seen on this valve size.

as you know the holdup from here on is real bad valve shrouding so going to a bigger inlet valve in its original position is no use -ei the 45mm inlet you used is spot on.

but the other drama biting at ones arse is quite often the intake is now not the hold up, its the exhaust thats falling behind at less than 70% of the intake, cos the port is so low in the head. -this would be familiar territory for you with heaps of (iron but on inlets) V8 heads and the too dam sharp short turn?

my photos might be a bit less of the shiny, but ryan was going blind anyway..
this is my solution to the exhaust issue and it then only needs about a 36mm valve to get 80% + of the intake flow. some heads dont live through the procedure and no it isnt really worth it and im not finding poeple allways want to pay full rates for the hours involved, but they are milled a pair at a time and its a nice accurate and controlled process done off the digital readout.

overall though there's heaps of other ways of making the exhaust work, with the extractors etc, and the cam you now have should work out nicely.
keen to see how it all goes, and many thanks for the flowtesting and feedback on the throttle bodies.

i am also eternally gratefull, that we could skip the very tiring argument that we need at least 55mm tb's to make the power and 42mm is too small, it will make no bottom end with the butterflies so close to the head crap crap etc. good to see less of the crackpipe and more of the logic and real world experience..

also could someone clever tell me how to make the photos come up on these pages (not have to click on hims)

and apologies TK but how badly did my buddy shaft you for the nismo gasket?

http://www.performanceforums.com/for...1&d=1245761615

http://www.performanceforums.com/for...1&d=1245761615

[TK]

Didn't get shafted bad at all on the gasket!

To get pics to load straight up you need a photobucket account - easy enough, then upload them to there & link them to here.

Can't find my Dato 1600 service manual (yes, I have an original 1970's service manual for them, somewhere!), anyone got a pic of the oil pump/dissy drive shaft alignment? - can't remember which way it goes.

[Babalouie]

TK

I think this is it:


If you draw a line between the dizzy boltholes, and the top hole is 12 o clock and the bottom hole is 6 o clock, then at TDC the dizzy shaft should be at 11.25.

[Swill]

? From memeory it should be fat to the back and more like 1.35 using babs clock example so the key way thing should be straight up and down in that photo

[Babalouie]

Swill

You mean like this? (this is how I did it...but I usually assume I that I did it the wrong way) :D

[Swill]

Yep that looks better

[littlefireyone]

That's so much more then win, it's

[Euroboost]

This is going into the 1600/Bluebird Coupe isn't it?
Mega win!

[TK]

LOL, I sat down & figured it out with a dissy dropped in, got it right!

All done, ready to be glad wrapped & popped on a pallet.
I'll pull the trumpets off for freight so they don't get damadged.
Only things I can't do are fit the water pump - I don't have bolts for it, so Ryan will have to pinch the bolts from the old motor.
I've drilled the intake for vac take offs for the brakes, drilled all 4 TB's so hopefully there is enough vac to run a booster - I haven't put fittings in tho, I'll leave it up to Ryan what style of fitting to use, they are tapped for 1/8" bsp fittings.

[bbits_elements]

Wow.

[TK]

Just realised there are no pics of this yet:






Billet cro-mo lightweight flywheel, sprung centre ceramic button clutch plate & motorsport cover with cro-mo casting.

Supposedly the combination of cro-mo friction surfaces & sprung centre make it much more drivable than traditional button clutches & it's built to handle a strong CA18DET.
Next rung down the ladder using a stock flywheel was going to be borderline on good enough, this is kinda overkill, but it won't give trouble!

I know one of the guys at Extreme - used to work with him many, many years ago, he showed me how to build a dual diaphram brass button clutch using 2 stock dato clutch diaphrams in the cover & an old circular saw blade for the plate, I had that clutch in my 1600 for a coupla years & it copped bulk abuse. Was shit to drive tho.

[Guido]

That is dead set sexy.

[9triton]

Heres some thinking material:

Based on an engine of 3.78" stroke & 3.407" bore.

...
Now, for valve lift around .550" on a 45mm valve to achieve the right port velocity for peak power at 6500rpm you need around 1.95" square of port cross section at the smallest point - this translates to around 40mm diameter port.
With a 40mm dia port this engine has a calculated max port velocity in the region of 255 ft/s, but in a real running engine this would be more like 240ft/s - perfect for peak power.

....
Peak power port velocity should be 220-240ft/s, I've gone on the high side of that to promote torque as much as possible whilst only sacrificing minimal top end HP.

.....

TK - just trying to understand the figures here : when i use something like this :
http://www.wallaceracing.com/piston-speed-velocity.php

and plug in 3.78 stroke , 3.407 bore and 6500 rpm and CSA = 1.95 sq"

it gives me 319 fps as port velocity- ie not the 255 fps

(get the same if i use a manual calc for avg piston speed)

question - does pipemax/EAP etc use some other calculation factors

- or are the EAP/pipemax calcs designed to give you velocities (ie 255 fps) which are related to 28" H2O flow bench velocities that are (and can be )measured on a flow bench?

any insight would be great.

[TK]

Yeah, pipemax will give velocities the same as you'd measure on a flow bench at 28" with a velocity probe.