L23 Datto stroker build (56k = LOL)

[NFJ16]

thats come up really good Mark

[fveten]

Thanks gents.. I was getting bored with the other forum ....
Im keen to see how this build turns out Ryan /TK. What ignition system & headers are you planning on running ?

[TK]

Back onto this - finally!

Got the valves last week, but had too much other shit to do & wanted a clear shot for a couple of days on it.

1st dummy up went well, bearing clearances pretty good - no need to grind the crank.
Deck height was .062" - so I milled .060" off the top of the block (I even remembered to bolt the front cover on it so that got skimmed to the same height - the wonders will never cease, I used to forget the sods all the time & then have to set them up & mill them after).

Piston crown volume was 8.4cc, combined with 42cc chambers that gives spot on 11:1 comp - no need to mill anything off the head, just a light final skim.

Checked valve train geometry - no great, so I've ordered some new slightly thicker lash caps to get it spot on. It wasn't chronic & could have been run as it was, but the contact patch was sitting off centre towards the rocker pedastal & I'd rather it be spot on.

Just about to wash up all the bits (again) & get into the final full dummy assemble to check piston to valve clearance etc. Provided that all checks out good it'll be out for balancing tomorow & the head will go out for a flow test with the good valves.

The last bits & bobs I've been holding off on ordering will be here in the next couple of days & I hope to be very close to final assembly by the end of the week - with any luck I can put it together sat.

Pics tomorow.

[TK]

Okey doke, got the dummy up done:

Valves clear the bores - cool.
I'll touch up the edges of the bores around the valves anyway to help flow.

With no head gasket, valve lash at zero & cam timed the valves clear the slugs - meaning I've got at least .060" clearance - but with the cam timing retarded a bit I can get the ex valve to -just- touch & with the cam timing advanced a bit I can get the intakes to do the same.
Meaning it'd probably be fine, but it's getting a little close for comfort - pistons need the slightest of touch ups with the die grinder to make 100% sure nothing hits anything it shouldn't in the case of an over rev.
Not worth fly cutting them - needs a section about 1mm deep & 2mm across removed from the edge of the dish in the crown. Easy.

Other than that everything looks good, I'll pull it back apart in the morning, touch up the slugs & get it out for balancing.
Still got to machine the valve spring seats in the head & make up some spring spacers - I'll do that tomorow as well & then the head can go out for flow testing.

When it all comes back it'll be ready to screw together.

[TK]

Checking valve to bore clearance:





Checking piston to bore clearance - valves are set up with soft checking springs, so I can hold the valve open by hand as I turn the motor over & see the actual clearance between the rocker & cam, better than using clay as I can get a better 'feel' for how the piston & valve are interacting:



Head & all parts layed out for final checks:



Refaced rocker arms, springs & retainers & custom made spring seats (made from some old manley cro-mo retainers for a chev):



Original spring seats machined flat to take the new spring seats:



New spring seats are located by the step left from machining the original spring seats, they have location for the inner valve spring machined into them as well:



I wasn't happy with how close the valve springs were coming to coil bind with the .620" lift of the cam, they only had .060" before solid on the inner springs but plenty on the outer by the time they were set up with the seat pressure I was after - solved by using a flat spring seat rather than stepped to give less spring compression on the inner & more on the outer, now they have .100" before solid at the correct seat pressure.

Double checking rocker geometry with the correct height lash caps - the new ones aren't here yet so I pinched 2 of babs old ones & spun them down to the right thickness, all good now, contact right across the middle of the rocker pad:



All set up with valve opening jig etc ready for flow testing, it'll be tested with & without intake, should have figures thursday:



To give an idea of the work in this head it has been:

Stripped, washed & bead blaster clean
Pressure tested
A couple of spots of corrosion welded & weld milled for a good datum on the face for other work
Coolant holes for the factory heated intake welded up & manifold face milled lightly to true it
Guides & valve seats removed
New guides fitted & reamed to size
Seat insert holes machined oversize for the new larger tool steel seat inserts
New setas fitted
Seats cut to multi angle & seat heights blueprinted to within .002"
New valve guides removed again for porting
16 hrs of porting
Intake manifold checked for location on head, intake location raised to better match the raised intake runners.
Intake dowelled to the head with 4 dowel pins to ensure it goes on in exactly the right location'
Intake match ported to the head
Pressure test again after porting
New guides trimmed & the section that protrudes into the port shaped for better flow, then refitted - in the same locations & the same position (I marked them) as they were removed after cutting seats.
Seats given a final touch up with a synchro stone
Vac tested with the new valves to be sure of a 100% seal straight up
Milled lightly across the top face to ensure the cam tunnels are true when the posts are refitted
All the rocker hardware rebuilt/checked - rockers refaced, rocker post hardware has had a cleaning tap run over all threads etc
Rocker geometry checked (twice)
Valve spring seats machined flat to take custom made cro-mo spring seats
Spring installed height & seat pressure checked & fiddled

After flow testing I'll give it a final light mill on the gasket face, wash everything again & assemble it & shim the springs etc to get the installed heights spot on.


I'll post some pics of the bottom end later, now I've finished with the head I'll go pull that back apart & clearance the pistons etc.

[Babalouie]

Faaaaarkk......

[TK]

Oh yeah, valves are custom made single piece heat treated stainless by competition valves australia, they are 45mm intake & 38mm exhaust & have a bunch of nice touches to boost flow.

Took fucking ages to get them done, but they are nice pieces.

[HoonBoy]

Some details on checking the piston to valve clearance would be good. I have doubts in my mind about how it shoudl be done "properly"

[Babalouie]

Ok TK..,can you remember if the valves in my head were stock sized or bigger?

[TK]

Babs - yours were a fair bit larger than stock, 44 & 37mm I think, but I can't really remember.

[TK]

Ok, pulled the short motor back apart, before I did I 'clearanced' the crankcase breather baffle to clear the rod bolt (clearanced = hit it wiv a hammer untill it doesn't touch the rod bolt any more).
I've notched the piston crowns for valve clearance & while I was there I deburred the rest of the crowns to eliminate any hotspots & went over them with a flap wheel.

Sh'es all ready for balancing - exept 1 thing, I forgot to grab a front pulley & bolt from home for it, bugger, will have to wait untill tomorow to go out, I'll grab the pulley tonight.
Balancing will be done by God*.

No pics for now - gotta bugger off early, it's my birthday & the missus has organised some shit for tonight.

I'll post pics of the slugs & the rest of the rotating assembly tomorow.

*God = Peter Michaels, AKA PM Engines

[rowdytoot]

happy birthday Tony- awesome build.. can't wait til it gets dyno'd etc :D

[bbits_elements]

Happy birthday!

[Babalouie]

Happy birsday

BTW...to what weight difference would God balance the assembly?

[Kaiser]

No pics for now - gotta bugger off early, it's my birthday & the missus has organised some shit for tonight.


*God = Peter Michaels, AKA PM Engines

Happy birthday TK!