rayaapp2 Posted January 2, 2011 Author Share Posted January 2, 2011 My thoughts: Start with an L28. Displacement is your friend... No need to spend much on ignition, a good 280Z/ZX electronic distributor or 240Z dist with Pertronix Ignitor in place of points, a good coil and you're set for what you're doing (performance street build). You might modify the mechanical advance mechanism to allow more initial advance without overadvancing. I partially filled in the advance slots in my 240Z distributor to limit mechanical advance to ~18degrees. No need for forged pistons, stock will be fine for what you're doing. 10:1 shouldn't be a problem with a stock cam, 10.5+ with a hotter cam. In the ~10.5:1 CR range with a <.5" lift cam, you shouldn't need valve reliefs machined into the pistons. My .02... Hey Dan, Thanks for the input. More displacement has been a thought in the back of my mind during this design thought process. I actually have a full L28 rotating assembly. I need to have it magnafluxed, checked for true, polished, and checked for balance though. I figured I already have a good block so why buy another when its going to be the same amount of work. I like the idea of being able to program in my timing curve so Im stepping away from the old distributor. ~$400 for a new ignition system isnt to bad in the grand scheme of things. Higher compression = more resistance over the air gap. With a MSD Blaster 2 coil and pertronix ignitor my plug gap is pretty much limited to the stock gap size which leads me to think its just not a strong ignitor as the blaster 2 coil has been tested and preforms very well on other systems. Im sure with the MSD6A on there I could open the gap up a bit. Maybe .040"-.045" instead of .036". I am running split fires now as that is all they had in stock at the local stores. I will probably get std old copper cores when I do anything. Im ready for a stable, precise, high powered, programmable ignition even if I give up some stock look and have to mount ugly coil packs to my firewall and live with a waste spark system. As for forged pistons, I know I dont need them. They will be more hassle than cast pistons as I will have to let the car burn fuel away every cold start just to get them to expand properly so I dont cause excessive wear by loading the engine while cold. It makes more sense to run cast. That said I havent ever found a cast piston for the price and reputation that I can get in forged. You have OE which isnt worth the price from the dealer(I checked in 03 and they were still available), then there is ITM pistons which sound good in theory but have no reputation that Ive ever been able to find and they are pretty much out of STD sizes and they are limited on oversize sizes so finding 85, 85.5, or 86 in a flat top may not even be possible if I could get a reputable user saying "YES", and well that pretty much concludes all that I can find in new. Full float wrist pins, custom pin height, ring thickness and placement are all custom definable with forged slugs. How else would I get higher compression? Not needing valve reliefs would be nice. Ive been busy with the holidays and family so I still havent called Isky. Its on my list. In fact I havent made time to call anyone about anything since before the holidays. Its the Holidays anyway so they were probably a closed til tomorrow anyway. Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 2, 2011 Share Posted January 2, 2011 so you missed my post on 87mm VW Forged pistons with rings and 22mm full floater pins for $238 a set of four? Might be worth checking into... Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted January 2, 2011 Author Share Posted January 2, 2011 (edited) Limiting myself to the L24 block Tony. 85.5mm bores are pushing it from what I understand. 86mm is pretty much the limit. The block in my car is the original block and its what I already have so Im going with it. Whats the point in using cheap pistons if I have to spend $$$ for sleeves... I guess I could use an F54 block and go out to 87 with no issues, but I was really hoping to use the block that came with the car... Its the one thing that people say when faced with my 260Z, Oh you beat me because your using that engine under the hood... This time it will be, I did it with the original engine... See the numbers... lol That and the L24 is usually the first thing to get plucked out of a 240Z for an L28 so its just fun to say Ive got an L24 in there still. I did email them and ask if they could do an 85-85.5mm diameter piston in either cast or forged with the same specs as the VW. Edited January 2, 2011 by rayaapp2 Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 2, 2011 Share Posted January 2, 2011 87mm is 1641, stock VW bores are 77, 83, and 85.5mm. Hmmmmm.... Usually two variations are available, those for use with strokes below 78mm, and those meant for strokes longer than 78 mm. If you could fit an 83mm piston in there...stock VW pistons cast are DIRT cheap---under $100 for a set! Forged probably incrementally more since 'stock class' off road racing drives that business and there are forged pistons out there. Did I mention 83mm pistons with flat tops are a stock VW piston setup? And they have dished pistons in that same bore size for the Mexican Beetles that ran on crap Pemex gas. The 40HP and 1500CC Type 1's were 83mm stock bore. 85.5mm is stock Type1 1600CC (85.5X69) Like I said, I've thought about it, just not had the time to do the last bits of checking on the particulars. Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted January 2, 2011 Author Share Posted January 2, 2011 (edited) 87mm is 1641, stock VW bores are 77, 83, and 85.5mm. Hmmmmm.... Usually two variations are available, those for use with strokes below 78mm, and those meant for strokes longer than 78 mm. If you could fit an 83mm piston in there...stock VW pistons cast are DIRT cheap---under $100 for a set! Forged probably incrementally more since 'stock class' off road racing drives that business and there are forged pistons out there. Did I mention 83mm pistons with flat tops are a stock VW piston setup? And they have dished pistons in that same bore size for the Mexican Beetles that ran on crap Pemex gas. The 40HP and 1500CC Type 1's were 83mm stock bore. 85.5mm is stock Type1 1600CC (85.5X69) Like I said, I've thought about it, just not had the time to do the last bits of checking on the particulars. Ah, so 85.5mm is a std 1600 bore. That is very good news! Im glad I emailed them. 87mm seemed like a big bore kit and I knew there might be something smaller. ... Due to the aircooled temperatures, they should be high-silicon for lower expansion in the jugs. I've got over 65K miles on my engine without a hiccup, and I have overheated it for one reason or another several times... Those be Hypereutectic pistons. "Hypereutectic aluminum has a lower coefficient of thermal expansion, which allows engine designers to specify much tighter tolerances." Hell Yeah! Well hopefully I get an email back from AA Performance Products tomorrow or Ill make some time to call them as well! Those would be SWEET! I would just have make sure the machine shop knows how to setup the tolerances for them. I forgot to mention pin height, darn. Well you got me excited about it so Im going to star doing the research. I have been looking for a set of these for years. I wanted a set for my L28et for a long time, but eventually gave up. And you have been saying VW pistons for years... why didnt I listen? Thanks! 85.5mm Bore Set Just need to find out about full float options and pin height. Edited January 3, 2011 by rayaapp2 Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 3, 2011 Share Posted January 3, 2011 Mine are forged at 87 mm and it's a '1641' kit...I don't buy the cast kits. Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted January 3, 2011 Author Share Posted January 3, 2011 I don't buy the cast kits. Why? Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 3, 2011 Share Posted January 3, 2011 (edited) Do you see the price difference? Why buy cast for less than $300 a set? Or for that frame of reference: for less than $100 more, why not get the forged items. Also leaves it open at any time to split the case, slap in a big cam space the barrels and blow 25psi into it while twisting 8000rpms. Especially if you had the forethought to spend the $69.95 for the counterweighted crank that will allow you to go over 5500rpms without pounding the hell out of #3 Crank Web. There is a reason they dubbed me 'turbotony' back in Michigan. Take a 2liter (1915cc or 2110cc) twist the thing to 8000-8500 rpms with a 7:1 CR and pump 25psi into it sucking through a Holley 650 and see what you get...in a car that weighs 1200# (or a Bus that weighs 2315#. Somewhere around 300-350HP...more or less.) Anyway, air cooled engines traditionally had forged internals. My Corvair TRW slugs, every VW I ever built. Frankly I was shocked to see cast piston kits being offered these days for sizes other than stock. Oil control is more an issue based on jug wall thickness and going out-of-round when overheated. I never had oil consumption issues with forged pistons in a VW...they warm up pretty quickly compared to water cooled lumps. Stockers are limited to 5500 for the above reasons, but once you put that counterweighted crank in there, even a small set of Kadrons or ICTs, and have the ubiquitous Engle 110 cam in there, you quickly kick yourself if you didn't put that CW crank in there the way they start revving with even slight increases in carburetion. They are like an old 2.8 German Capri with that small carb on there...derestrict that intake and they start whizzing up in the RPM range. Far too easily... Oh, and there are apparently newer VW Water-Cooled engines that run an 83mm bore... but the pistons are priced accordingly to the water-cooled market. From Gene Berg.com: 85.5mm forged aluminum Cima pistons. For stock replacement, or use with our counterweighted and stroker cranks. (39.6mm pin height), case 90mm, head 93.8mm. (POTL) RW: 2/2/5. See Note A. approximately 7.3:1. SW 28# Yes, this is where I learned detonation blows cylinder heads off VW's and that is why they came up with 'case savers'... Yes, this is where I learned that boost and carburettors work juuuuuust fine if you can live with some quirks... Yes, this is where I learned that an 18 year old kid with an NIASE Patch and Cert can make decent money working on "Import" Engines in Michigan... Yes, I blew things up. Thank god the parts were cheap! (And, comparatively still are!) I'd suggest you look to the Berg set, they are cut/clearanced for counterweighted throws...and aren't the boring 'cylinder' style pistons like stock. Though doing this is pretty easy if you have access to a mill. I digress.... Edited January 3, 2011 by Tony D Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 3, 2011 Share Posted January 3, 2011 (edited) I believe the standard 'stroker' pistons are slipper skirted and have a 34mm pin height if the information on the Berg site is representative of the current industry trends. 87, 88, 90.5, 92, and 94mm pistons with a flat top and 34mm pin height and 22mm piston pin (full floater with circlips or teflon buttons.) I know the CIMA 90.5's are good for 100+ HP a hole and 8500rpms... Circlips retain the gudgeon pin: Gene's Thoughts on Pin Retention by Circlips Edited January 3, 2011 by Tony D Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted January 3, 2011 Author Share Posted January 3, 2011 (edited) I can get 8 for around $250 to my door for a set of high-silicon content casts. The forged ones on the site you provided were $285 for 4 plus shipping and possibly tax(I didnt check). So 2 sets is comparable to ROSS custom slugs at $550 plus shipping and tax. 85.5mm FORGED SLUGS from Pacific Customs Four vs Six prices or am I missing something here? I dont have access to a mill as of now. Edited January 3, 2011 by rayaapp2 Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 3, 2011 Share Posted January 3, 2011 Do the Ross Pistons come with Rings? Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted January 3, 2011 Author Share Posted January 3, 2011 (edited) Do the Ross Pistons come with Rings? I think I have missed something here: Unless the pin height is usable as is(34mm and 39.6mm do not work well with any L6 combo Ive tried so far) and then there is the 22mm wrist pin. Going to a full float requires a hone anyway though. "The Book" says and I quote: "Regardless of which way you go, the small-end bores must be honed to acheive the correct pin-to-bore clearance, not interference as with the pressed pins. Mike the piston pins, the hone the pin bores 0.0008-0.0011 in. (0.020-0.025mm) larger to give this clearance." How to Modify Your Nissan & Datsun What is interesting is the Nissan Sports rod. 23.5mm brass bushing with 2 oiling holes on top. ~$100 set std style rings vs ~$100-$? for 6 fly cuts. These are rough numbers, but it just seems like the cost of your own time(or gas to the machine shop if you work for free) with dealing with the VW ones is still more than the ROSS set. What have I overlooked? Dont get me wrong, Id be in business for my 510 right about now, but Im 2 pistons short of an L6. hehehe pun intended Edited January 4, 2011 by rayaapp2 Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted January 3, 2011 Author Share Posted January 3, 2011 Tony, Back to the Mikuni intake manifold for a moment. It seems the throttle linkage has an issue. The stock throttle linkage mounted to the firewall does not align to the Mikuni Throttle shaft? What is missing? Was it not designed at all for the Z? I may have to call wolfcreekracing and see what Im missing. More phone calls. The phone call list is getting long. Quote Link to comment Share on other sites More sharing options...
madkaw Posted January 3, 2011 Share Posted January 3, 2011 I am looking at my instruction book that came with my Mikuni set-up for the L24-L28 and it shows the wall mounted part of the linkage needing to be 'raised above the seam'. Now my set-up is using the Mikuni manifold with the short runners. Don't know if that helps, but I haven't tried to install my Mikuni's yet since I am still working on my top secret cold air box. Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 3, 2011 Share Posted January 3, 2011 The stock linkage for the mikuinis went to a pivot that mounted to the jet cover/float cover of the #3 carb. There was a short transfer linkage that connected these togehter to the crossbar. This is why I went throttle cable. Actually, it's not, i tried to braze the stock throttle linkage into the hole on the Mikuini piece, at which point I realized they had also made it from chrome plated brass. I discovered this as I poked the brazing rod into the 'red hot' linkage bit and promptly collapsed the arm of the damn thing. At THAT point I decided to use a quadrant I had and convert to a throttle cable. Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted January 4, 2011 Author Share Posted January 4, 2011 Hello Ray First thing is they are all full floating pin's I can't change the pin height on the cast pistons Right now we are only selling 85.5 kits we don't have parts too break them up If you got JE pistons we can chant the pin height and sell you only 6 but they are about 99.00 dollars a piston. Jonathan Beats the crap out of Robello's ~$850 for all 6 for JE... Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 4, 2011 Share Posted January 4, 2011 (edited) See what you get when you go through 'alternative channels'? Call it a Chevy and it's $5.00 Call it a VW and it's $5.50 Call it a Nissan, and it's $500! Remember the advice given here in the past: Call it a Chevy, pay the $50 'custom charge' and then specify ring sizes, pin height, and dome thickness....and get a wholesale cost of about $40 a piston. Call it a Nissan, and the wholesale cost goes up over double that! Damn, and you have two extra pistons when you order the Chevy part... Bummer. Nobody ever breaks a piston skirt or holes just one piston. You always need a whole set of six... Edited January 4, 2011 by Tony D Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted January 10, 2011 Author Share Posted January 10, 2011 (edited) Another issue has arisen. The Mikuni Intake Manifold doesnt appear to clear the stock air injection stuff. It appears I will have to modify or indeed delete my air injection if I install this manifold. Is this the general consensus? I have the Trust/Greddy/Nissan Sport/etc header I can use that deletes the air injection ports I could use instead of my current header with air injection. Someone want to save me the time of test fitting all this stuff together. My build could be much easier without the air injection, but I was hoping to keep the AB valve as well as reduce the extra smell of the exhaust without the air. Without the air pump my crank trigger situation becomes a no-brainer install as I can use the later balancer and still retain my AC system as well as free up that extra 1.5-2hp the air pump uses. The only other downside to all this is that I will have to re-engineer my exhaust system for the new header. Mikuni Manifold Porting Info... Good Stuff I found while looking for fittment info. Ive got a breakdown of the build. I have $3800-4000 to spend on this max so Ive got to spend it wisely. Building an L series to make power isnt cheap. The process could take 3 or 4 months and I might be able to inject more money into this, but right now this is the amount I have to work with and Id like to get it running with that. Headwork ~$1250-$1500 includes -valve grind -valve seat R&R if needed -surfacing -street porting -camshaft setup -includes cam wipe pattern, stem heights, and spring installed heights -new lash pads -port matching intake manifold Camshaft ~$250 Valve stem seals viton "A" series $TBD Radiator $210 N42 valves $0 should have a set around that is usable Head Gasket $180 Bottom End machine work $TBD Piston Set $TBD Complete gasket & seal kit $0 Have one already Timing chain & tensioner set $120 Rod and Main bearings $140 Tomei Adj Cam gear $200 Ignition system -Ford COP set $60-$80 -dereks EDIS mount $200 -EDIS-6 module, sensor, wiring all used $25 -Megajolt $180 -Crank pulley $0 already have one ~$3000 so far That leaves very little for the machine work, pistons, and valve stem seals. Little to say about any problems that may arise during the whole thing. Little things have not been accounted for yet either. Hoses, fittings, etc So the plan has evolved to this setup: Bottom End L24 P30 Block 2.5mm overbore L28 Crank L28 Rods 85.5mm flat top pistons 81 turbo oil pump already have Clevett 77 main bearings & rod bearing ARP rod bolts ARP head studs Nismo .6mm head gasket MSL Timing chain and tensioner set Top End Tomei timing gear adjuster Isky regrind cam Lash pads for new cam N42 I and E valves replace felpro valve stem seals with Datsun "A" series viton engine valve stem seals for cam lift clearance polish combustion chambers light porting around seats Mikuni intake manifold dowel intake manifold for port fit Nissan Sport/HKS/Trust/Greddy/who ever else sold this header for use with Mikuni manifold Mikuni Solex Carbs 40PHH 2.721L displacement 10.6:1 static compression redline set at 7500 power building from 3000rpm to 7200rpm Premium fuel requirement probably dyno tuned on 110octane Edited January 12, 2011 by rayaapp2 Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted January 11, 2011 Author Share Posted January 11, 2011 Mocking it up on a spare E30 head and a saw horse. Lots of room between the headers and the mikunis Here are my clearance issues. The Air injection system will not fit with the Mikuni manifold. The Check Valve on the air injection tube will not clear the manifold or linkage rod tower. So then I decided to use option #2 header. As you can see with this header my AC compressor will have clearance issues as well. So I have to relocate the AC pump stuff down to the later L series location. Its not that big of an issue as I was going to go to a newer rotary pump anyway. Quote Link to comment Share on other sites More sharing options...
madkaw Posted June 25, 2011 Share Posted June 25, 2011 any updates on the L24 build? Quote Link to comment Share on other sites More sharing options...
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