Infamously Famous 1.8 Engine Build

[EUNOS 96]

sorry i should have been slightly more descriptive with that tool. basically what it does is it is a split metal sleeve made of spring steel that has a little ball on a threaded dowel down the center. you slip the end into the hole to be measure and twist the handle until it just barely fits in the hole. by twisting th handle it pulls the ball into the handle spreading the steel tip to the size of the hole. once it is a secure fit you carefully back the tip out of the hole and measure the tip with a micrometer. it is essentially a way around using a dial bore indicator on a hole that is just too small for most dial bore indicators to get into.

in lamence terms, this tool expands to the size of the hole so you can measure the diameter in comparison to the valve stem associated to that hole

[The Platypus]

Ah, that makes sense.
Thanks for explaining.

[EUNOS 96]

back to class yesterday. spent the entire day setting up the rottler CNC for shaving heads, and went to put on jason's 5 valve VW head first. takes about an hour to dial in and get everything just right, long story short, mine went on and here's the pornography:





video:






in increments of 0.0020" we shaved off exactly 0.0130". roughly about 0.25:1 more compression from this. fun, not too aggressive, and look at how sexy it looks! perfect surface.


shooting for valve grind and seat cut on thursday, stay tuned!

[— kung fu jesus —]

THAT is a beautiful cut my friend. Holy CRAP!

[The Platypus]

That is actually sex.

[EUNOS 96]

haven't forgotten about the thread, don't worry guys! I will go on to say that the valves i intended to re-use, as decent as they seemed, had no room for grinding as far as improving the surface and I've decided to go down a better route...


so expect some fancy boxes, some 3 angle/2 radius (radius, 60*, 45*, 30*, and another radius) cut seats, and a lot of assembly happening next week!

on another good note, i recently got on the crew with the guys down at 949 RACING and sonny won the E3 class enduro at Infineon Raceway, Sonoma! awesome shop, really cool guys, and really looking foward to spending a lot more time down there.

[EUNOS 96]

seat cutter being a complete douche bag and not cuttin properly. look for updates by thursday evening once i get things worked out. so far the supertech oversized valves are in han, seats are half cut (exhaust side) an not holding as much vacuum as i want... might be a problem with endplay in the cutter. whatever the issue, the only thing between me and a complete motor is installing the valves an putting everything together. hurry up and wait, story of my life!


stay tuned

[EUNOS 96]

holy shit balls. finished machining the head. 10 years later the seats are
cut and holding good vacuum, time for some campfire stories and pics to go along
with them.



so what i'm trying to achieve here is take a valve seat that is factory cut
at a simple 45 degree to meet a simple 45 degree faced valve, and then cut it to
a 5 angle equivalent seat to match up to a 1mm oversized front and back cut 3
angle high performance valve.













here's the attempt:





simple enough, get a carbide cutter for lots of dollars, slap it on, cut it,
call it a day! fuck no.



so what this here is doing is taking the valve to be used, measuring with a
scribe to the point of desired face contact on the valve so i have a referrence
to measure the cutter for the mill to. this ensures that i have the ideal
diameter cut for the valve to seal properly which is crucial especially when
installing oversized valves:







and here is the cutter measured to the same location. obviously intake and
exhaust will be totally different:





a small pilot (like 0.599 or a 2.395 something i used) for the mill installed
into the valve guide ensures the mill aligns properly to the centerpoint of the
valve and is supposed to hold it center to force the cut to be nice and
concentric and even:





and down i go with my attempts to cut some pretty seats:









prior to measurements everything seemed to be going well. it took me a while
to get to the point of even cutting because my old valves turned out to be kind
of shit, and my new ones were an unexpected ~$300 expense and required new
measurements. i ended up having to cut the intakes like 3 different times and
the 3rd time was because the machine is quite a bitch. let me tell you about
endplay, and this thing called shrouding.



we all know what end play is, at least i hope you do if you're intending to
follow this sort of thing. the mill has a maximum end play of about 0.8mm when
fully pressed to one side at the furthest most tip of the cutting tool without a
pilot guide. and this is where shrouding almost "drove me to drugs" as my
professor would say. in small aluminum head 4-5 valve import motors, there is a
notorous amount of what is called valve shrouding. it is essentially the area
around the edges of the combustion chamber that were too shallow to mount valve
seats so it was slightly machined like a bore down to the seat by the original
manufacturer seat installation. let me show you a picture of what i mean:



a keen eye will point out this isn't a miata head pictured, because it's just
a google image that very clearly shows what i mean. the miata head is even
tighter and more restrictive where the shrouding limits how far out a pre-set
multi angle cutter can cut, and restricts airflow in the head from incoming air
and outgoing exhaust be blocking off the outer edges of the valves from air
flow. well in this particular case, i was goign so far oversized, and such an
extreme multi-angle performance cut that the shrouding provided enough force
against the flat edge of the cutter to push it about 1/5 of the rotation in away
from the seat edge itself and throw the cut off center:





so what i needed to do was with a completely separate cutting tip i had to
mill out and deshroud the area which benefits airflow as well as allowing the
cut to work right:













and here is a good side by side of a shrouded versus a deshrouded on the
exhaust side:





so as the head sits now:




the only bit of work left to machine in the entire engine build as of now is
grinding the valve stem tips to the desired installed height and put it all back
together! engine finished assembly is in the near future so stay tuned.

[iamdallas]

So beautiful

[Jace]

good class. 10/10.

would attend.

[EUNOS 96]

at the mercy of the shipping and handling gods... ordered some super thin lifter bucket shims and some spring seat shims, once they're here time to put it all together. taking much longer than i anticipated but now i know what to have ordered and ready sooner than later the next time!

[moerdogg]

So much good stuff in this thread! Thanks for sharing all that you've learned.

[— kung fu jesus —]

The deshrouding info jogged my memory. I remember this from way back on m.n when FM started offering engine work. There was a lot of back and forth between the guys at FM and some D prep guys, IIRC. Maybe this was on the old Power Forum mailing list, I dunno anymore.

Glad you got it figured out. How many babies were punched in the process?

[Keep]

most miata related worthwhile thread of the decade.

Thank God for a non hellaflush, slammed, or will a 13b fit in my car thead bullshit!

Thanks!!!

[EUNOS 96]

finally got all the parts for the shims together and finished the machine work on the valve stem tips



bevelled the edges to avoid damage to the rubber seals:



off with the old lifter shims

on with the new... much smaller and flush with the buckets

well i appologize for not updating sooner and being short on pics but the past few weeks have been hell. the rest of the motor went together pretty smoothly





and now its done! out with the old and in with the new



pictures and videos coming soon once the tune is right and its all buttoned up.