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I think the valve curtain on the exhaust represents the single greatest impediment to flow on the L-head... again this is only opinion and collected snippets of wisdom. it's a bitch but I'm not sure how much port work on the exhaust benefits flow without a higher lift cam and/or a larger valve seat

oh and im sure you've head this already but: DONT TOUCH THE BASE OF THE PORT OTHER THAN TO POLISH IT!! or you will kill all flow (I hear)

alternatively; go to a Head machine shop and pick up some of thier smashed(bent) valves - they will be happy to give them to you in all sorts of diametres if you ask nicely or throw them a beer-sized amount of money. if you hold the stem of the valve and push it to where the head of it can clear no longer, then twist it... you leave a nice clearly visible scratch where you need to removed material... also consider a tapered port using a succession of valve diameters at different depths. (this is probably much more useful when taking a "reshaping" approach to porting rather than a "hogging out" approach) Since the valve steal is much harder than the aluminium of the head it will leave a visible mark without much effort and will not wear down after repeat use. Remember to try to make your approach to each port exactly the same... I've found it helps to work in stages on all ports simultaneously so that you dont forget how much to work each area or have some kind of methodological drift cheers! -poit

Bodyworks? I went to that exibition when it was in sydney a few years ago. Awesome preparations... we have many similar at uni... but no dogs hmmm... Springs to mind- The guy behind body works made a really freaky preparation with a human cadaver riding a cadaver horse. On a more mechanical note. Last time we were in japan we took some photo at the nissan museum where they made cutaways of a older DOHC formats. *rummage around* ahh here we go

I remember I had one of them on photobucket from a while ago... I'd probably be happy to lend these to anyone who wants to pick them up from my place in sydney with some kind of assurance of return. I have all the intake and exausts on an e88 mould but this is the only photos I have untill i get home to oz. Cheers, -pete

Also, I used a tungsten carbide cutting tool but you need a steady hand... smooth finish can be achieved with a flapper wheel after but the carbide wheel is pretty smooth anyway if used correctly.. plus you dont have to change it every 5 minutes. cheers +1 -poit

I actually had some cutaways of the intake and exaust ports made up... I've got some photos somewhere but cant get to them for at least a week and half 'cause im overseas atm , I found them to be extremly useful though... the greatest "danger point" is in raising the roof of the port near the intake face... annoyingly I feel this is also probably where some of the greatest gains could be made. Practice on junk, Use a new condition head for the "real thing" as a corroded water jacket will waste hours of work and port first then decide if your mistakes are worth fixing or starting again before getting refacing+/- welding paid for. I think anything over 40mm total port raised from the roof is getting so thin you are looking at probable welding money. (anything and everything i say is purely opinion, conjecture or rumor) Prost! -pete

+1 for NAPS... Have an adaptor made for a 60mm TB and get the runners portmatched as deeply as possible. NAPS do no have the EGR bump at the runner mouth(which is a good thing!) Anecdotally it's worked very well for me in the past with programable EFI. -Pete

yeah they are pretty groovey luxo-barges... the 330 coupe suprising has quite a american-muscle inspired streak in the design -along the same lines of the laurel and 240k coupes... i guess thats why all three are fairly popular in bosozuku car circles. I think it's going ot be a unique and cool build... back on manifold and engine though... If anyone has a set of l26/l24 flattop pistons: what is the crown thickness, is there an option for a maximum-crown thickness for this bore? (aftermarket)? I'm looking at options for piston/combustion-chamber semi-dish machining. I should have some progress on the ITB's soon.. need to tap the vacuum balance tube holes and add fittings before welding can commence... watch this space!!! -pete

agreed... the r30's i've seen have run very late model e88's; the e30 head is not what you want i'd consider finding something with better flow before dropping a cam in, that head will slow you down in upper RPM ranges. e30's pop up a bit here and there in my experience... they "belong" on l20a's but can be found on l24's... for curiositys sake, does it have an oiler bar? -pete

Quick update: This is one of the 2bbl flanges that will hold the runners to the head. I did some reshaping and then placed it behind an untouched one so you can see how much cross sectional area i'm gaining and where (all from the top). The diameter is 37mm but to get to the height i wanted from the cylinder head port is had to go up to ~40mm max oval shape... as a result im considering filling the extra few mill at the base of the port using an epoxy... dont want to weld the short side. I dont feel i require anti reversion on a minimal overlap turbo grind cam btw (mark.. ) I can take a photo of this later. this is a quicky of the head im using - modified late model e88... i still need to do a bit more CC reshaping and unshrouding plus volume balance the head, but it's coming together very nicely I've decided to put together a home flow bench and calibrate it to spit out some ballpark flow numbers for me and y'all so keep tuned for that. This is the 260c coupe being put together at the same time... it took a massive front impact and we had to swap rails all the way from the front right (see the "kink"... need to hide that ) all the way back under the driver seat. in these cars thats a single peice to that far back so it was the safest approach... though alot of work ... just goes to show cars *can* come back from the dead This is the donor.. you can see how extensive the transplant was... all good now though!! it seemed a tragedy to trash an okay car to save a wreck but the coupes of this year were WAY rare and I may never catch another one again (my vin has 3 significant figures:P) plus i'd feel terrible taking one out of the world *ghost car hauntings!!!* hope that helps show how things are going and the direction of the build a bit more... always pleased to hear feedback!!! Cheers, -pete

have you done the standard compression/rings/oil tests?? seems silly to blow money on a head when your bottom end could be skruwed? -pete

A) no way anyone guesses it... without knowing i wouldnt have though in a million years they'd be making these "over there" "in those days". B) Yeah, maybe i'm being a bit callus but really think its going to be a non-issue, the injectors are only moved back a few CM and the adjusted angle places the spray pattern dead-on with the apex of the short side radius... as long as the fuel pressure is sufficient to atomize, i can't see any significant pooling occuring in that short period. Regarding triple carbs - I nearly completely agree excepting that I'm using polished ports/manifold and some carb-users prefer to leave these textured? However, from the stroker builds using mikunis i've seen on japanese threads most have highly ported and polished ports and manifolds... i wonder how they idle?? (who cares if they go "vwroooom!!" really loud at 8krpm...) DatZed - given the n47 contribution perhaps we should rename this thread "2010 L6 R&D" :P *small progress update* I started grinding the flanges to size today... took me all my time just to do one... this is gonna take a while. still have to do the other 6 and grind the ports out to the 37x 38.5mm oval flange... ugh. on the plus side... for any of you suckers paying $15 a pop for drain-o, you can make it using $2 worth of sodium hydroxide crystals and mixing it with aluminium shavings; just saved you 13 bucks Cheers 'gents, -Pete

hmmm... i dont have one of those at the moment... tempting impulse buy :-\ Yes i've read that article before.. great thread . also keep your eyes peeled on the l6 section, i'm about to dump some auto-porn from a visit to the nissan engine museum in yokohama. Bunch of stuff happening this weekend; finally finished rail repairs and put wheels and suspension on the cedric w0000 big moment cylinder head came back from welding and machining.. it loooks purdy, i'll post some photos in the next few days once i find a new camera. As a result not too much happening on the ITB front, i'll try to find some time for it tomorrow. Maybe I should put up a build thread so everyone can criticize my dodgey worksmanship?? DatZed, are you in sydney at all? Postage on that head would rival cost i expect? let me know how the n47 hunt goes? i'm very curious about that one. -pete

Arg!!! this is why I was so tentative to post anything looking like a build blog... everyone always wants more info and progress!!! Thanks for the encouragement guys; I havent got a huge lump of time atm - this is a weekend project for me and its a whole vehicle thing atm so progress is understandably slow as a whole (but still there!!) Some more machining has been done to clean things up and get better fit. I will not be adding lenth between the butterflies and experiment with velocity stacks. Previously I have run MSnS-E but am open to suggestions (please consider budget and feasability constraints guys!!!) I was certain injector staging was a doable option with that setup but have never needed to attempt it... given the higher rpm goals for this build i would consider putting injectors in front of the bellmouths via the plenum. This can be added after i get some O2 data and dyno time methinks. Exhaust.... I totally agree and I'm not even started on that yet, I'm hesitant to comment too much due to the unknown area that exists in future budget and timing constraints (I'm doing almost 50 hours of classes alone a week at the moment)... I've considered upsizing the exaust valves but i suspect the greatest bang-for-buck gains can be made from aggressive portwork and a decent-flowing home-fabbed steam-pipe turbo manifold. (no i havent had the time to start on that, nor will I untill this is completed) i'll try to post some pictures of the cylinder head when it gets back from machining on the weekend. At current the cam i have has a .490 lift and 248 duration 'though i suspect that by the time the build is complete this will be "too conservative"... we'll see. An n47 might be a cool move. I went with the carved mr30 e88 for the longer valves (compared with the p90) and my inability to afford a good cont. japspec welded n42 or source the elusive "mn47" domestically... The culture over there really seems to indicate the n42 as the way to go with really aggressive port and valve modification and they do have the numbers to back it up. Personally I encourage you to try the tounge idea, partly from selfish curiosity and partly because it seems novel and could yeild some ponies for you and add to the volume of L-series knowledge... but I digress Thank you for your input and the slipper-fitting tip. I'm sorry I dont have the numbers and figures at my disposal to answer your questions concisely- as a scientist that frustrates me, I cannot predict the outcome of the build untill dyno day which is very far off but if nothing else the manifold alone will be an awesome conversation peice!! consider this build "an experiment" and I am very grateful and willing to take on any further suggestions thoughts and ideas -pete

Everything is at machining atm so no photos sorry However, when everything is mocked up on the head and you look down the barrels you can see straight past the valve seat into the combustion chamber ... I'll take photos next week when i have everything back home. Honestly i'm tempted to leave the length as is, i like the straight shot and the DCOE manifold would affect that and i'd have to do some milling and redrilling on the DCOE manifold to maintain the downward loading angle acheived with the current setup. the TBs were actually designed for an engine of similar displacemnt to the L-series with an extra few cm of lenght incorporated into the plenum... I'm still curious about the velocity stack idea?

Oh yeah... definately. =)

I'd considered it but guess again... I turned over these for nothing and they worked out to be just the ticket. Think more wheels and older. Because of the way the runner and head ports are shaped there shouldnt be too much opportunity for pooling except behind the intake valve so touch wood this shouldnt be too much of an issue given some careful portmatching... I think Correct... this setup is not in any eventuality intended to be economy/emissions. As a whole the direction of the build indicates a "screamer" application. Regarding the runner length - we recognised early on that using these TB's the throttles would be very close to the head... adding additional length post TB would be preferable however the fabrication involved would be significantly more extensive... I would love some more discussion on this point - our intention was to add extra length via sleaving the plenum end of the runners with velocity stacks... how much detriment to flow do you guys think this approach might cause when compared to adding the same length post-TB? The runnners are taperred at 2.5 degrees.

Hey guys, Since everyone was so kind and helpful to me with an earlier post seeking advice on valvetrain components I decided to post the first pictures of my ITB manifold fabrication in process Any advice comments and suggestions are highly appreciated but keep in mind this is just an early mock up and that further work is ongoing. I'll be very interested to see if anyone can recognise where the throttle bodies came from Cheers!, Pete

I think some of the n42s in nissan patrols had non-EFI heads as they were set up for 2bbl carbs. And yes the injector notches can be cut in easily with a dremel either when the head is off or on... make sure you stuff the ports with foam and vacuum them out thoroughly to prevent shavings getting in the head. use the EFI gasket as a guide I think there's an EFI head on ebay at the moment, might be an easier ticket than than working on an engine inside the bay. if you want to go turbo you might be better off starting a whole new engine rather than trying to alter your existing setup. cheers, Pete

there's a video out there by big phil on converting hydraulic to solid lifters, also I'm not certain because i havent had any n47 heads but the p90's have shorter valves than other heads so this probably applies to the n47 as well. -Cheers, Pete *edit* by that i mean that the n47 valves are probably too long for the p90a... FYI i'd be interested in that n47 if you decide to unload it.. i havent got one so im curious... if theres any parts you need let me know i might be able to find something worth trading

Yeah actaully I'm not too suprised by that - Part of the reason I went for the e88 was the difference in short side radius between e88, n42 etc and the p90... I felt that the the use of the p90 would be a step backwards from what i am trying to achieve with an angular loading and tappered manifold... the combination of a desirable short side radius and fast-burn head made the e88 the choice for me. With unshrounding and mild reshaping i feel i can safely bring the compression down to 8.1-1 using this head-piston-block combination. If worst comes to worst I do have a 3mm HG from japan which will easily drop the CR, however I'd prefer not to do things that way and loose the fast-burn properties of the head. I think that with sufficient intercooling, EFI, and preparation this should a managable CR. and reasonably responsive off the line Incidentally I do have a p90 at home... I just chose not to use it for the above reasons. I know it's a bit of an unusual approach but I wanted to do something outside the box for a car that deserves a bit of originality. The cedrics are pretty heavy cars too so the extra lower end torque may not be a bad thing. Since I have heaps of patrol exausts lying around I was going to have a go at chopping one of those up and fabricating an exaust manifold in a similar method to wax a while ago... i'm not so obsessed with eqaul length piping though so mine will be a little less excentric. I have heaps of fabricating left to do in so many departments and am so busy i dont expect it to be done anytime soon by have a goal of a running vehicle for registration come august... so far things seem to be on target though I doubt i'll have all the paint and trimming ready by then My goals dont involve ludicrus horsepower... I just want a strong fun motor which a bit of a naughty streak- so alot of the work i've done is more for engineering efficiency purposes where cranking the boost up would acheive greater increases more cheaply. I picked up a buzz line from someone at hybridz about flow being flow regardless of boosted or NA and its stuck with me somewhat - I like the idea of a boosted engine where air is chaparoned gently into the cylinders and fills with greatest volumetric efficiency - it reduces the load on the turbo by reducing the required level of manifold boost to achieve a given cylinder pressure and thus reduces the turbo manifold pressure and exaust stroke load. I see many diverse advantages to this, most of which relate to an engine which should last a good long time. I am really loving the feedback. I'm still very young and have alot to learn. I hope I havent exceeded the territory of the original post by too much :S Cheers, Pete

Ahhh yes... believe me there is plenty going on in other departments...do you have any specific suggestions? I'm tempted to put up a build log but tentative since its not a zed and at the moment there is so much work in separate departments it would be very chaotic! Previously I was running a ported cammed N/A l26 with OS valves and MS which actually pulled very well. Unfortunately I had the front end smashed up by a wayward yaris... the l26 was unharmed but since the car was taken off the road I have decided to repair all the rusted sections bogged over by previous owners and drop in some devious ponies... I have been working from the "power starts at the head" concept though I may get some debate...? Said head is a fresh MR30 e88 with l28 valves and 38mm intake ports... I'm in the process of fabbing up some very tricky-dick 45mm ITB's which load both at a 2.5 degree taper and with a slight upwards slant to assist the angle of intake loading and compliment the porting method. The end of these has mounting bolts for an as-yet unfabricated plenum... I'm a very busy boy at the moment!! I have almost all the parts I need, machining costs are the only thing slowing me down these days. Anyway, a good friend has very kindly volunteered an Ivan Tighe 462C cam(&accessories) with .490" lift and 248 duration so unless there are any objections to the use of this cam all I need now is springs and polished valves

Ahh yes I'm aware of the old mantra, I was just hoping someone might have some parts lying around from an abandoned direction... wishful thinking perhaps. Basically for me it's find it at an affordable price or I can't afford to do it - once you take rent and shopping out of the scholarship penance there isnt much left and study is a full-time activity so working extra hours isnt an option... If I had the money I would buy everything schmick new from japan but don't and thus cant. Thanks for all the genuine help guys I'll follow up on those numbers

yes i know! Just finishing rail repairs at the moment, alot of rust to cut in panels... had to kill a donor sedan... If it werent so rare I would never put soo much work in... lots of zeros in the serial number I am prepared to be shot down in flames but i was thinking 0.440 to 0.460inch lift or more if I can get it with very short exaust duration and minimal overlap... To be honest my circumstances dont allow me to be too picky *sorry guys, im in sydney but of course can work something out with postage I'll update my location... "Local" as in within this country- I've looked at some japan s30 parts and SI US valves and packages... my apologies for the communication failures ***I hope this inst in the wrong place, I was considering writing a "wanted" but since I'm after advice primarily this seemed the more appropriate place. -pete