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Jamie, you beat me to it! :) Jamie and I are doing an experiment with my motor on the effect of going totally OCD and coating everything to control frictional and combustion related haet. We have coated or will coat:
Ceramic heat coating: Piston crowns Valve faces Combustion chamber Exhaust ports Dry film lubricant: Piston skirts Piston pins valve springs valve shafts camshafts intermediate shaft gears cam chains cam sprockets rod bearings main bearings i-shaft bearing oil pump internals Oil shedding coating: Piston undersides Other trick anti-fricction bits: Craig Garrett's teflon bronze NASCAR rocker bushings The motor will have full EMS w/ data logging, so we'll be able to get per cylinder CHT and EGT in addition to oil temp and wideband O2 data. Jamie has been amazed at the AFRs he's been able to get with his motor and it will be interesting to see what effect going all the way will have. Last note: I recommend everyone with JEs to hand work their pistons to break the sharp edges on the crown and valve pockets to reduce hot spots. My assertion is that with coatings, trick rocker busings and this piston work, a motor can steal an additional half point of CR in terms of knock threshhold and at the very least allow much more aggressive timing. |
If you choose to do your plain bearings (main and rod) make sure you sand any residual off the back side of the bearing. It can add to the total dimension of the bearing thickness and can cause a tight fit when the crank is installed. Also the rods can get tight as well if the back sides of the bearings aren't cleaned up. I have always used a 400 grit wet / dry paper to cross-hatch the back side and the saddle to get a better bite on the case or rod when installed. I have used this method in 1000 cc race motors that see 16000 revs and it works well.
Also, as Kenik points out, any time you can reduce a sharp edge on the piston crown or the head combustion chamber, you increase the reliability by reducing the build up of heat in critical hot spots. A sharp edge will concentrate heat and cause detonation (pre-ignition) that would otherwise not happen without the sharp edge. Lots of little details to look forward to! Lindy |
One more coating tidbt I neglected to mention: oil shed coating rods. I am not doing this as my R&R moly rods came coated out of the box.
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No turning back now!
Try not. Do or do not, there is no try. -- Yoda |
Jamie,
I think that's Henry's line! Har Har I'm a little surprised he hasn't chimed in here. Henry, are you still alive or has that girl friend of yours worn you out? Lindy |
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The very experienced Porsche dyno guy said this could be tuned out using longer intakes or true equal length headers. The wasted spark stopped me from getting a proper torque reading but overall im very happy with the way the engine has turned out so far,it pulls like a train and revs like mad |
Great news! glad to hear you have your tuning issues worked out.
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Need some serious running in miles now at WOT to find some free bhp's :) |
heres my spec ,I have to give a massive thanks to Mike at mbengineering for helping me build this engine hes a legend
DIY boat tailed and flowed C3 alloy case,oil mods DIY mooned original Nikasil barrels 10.5:1 JEs DIY smoothed out edges,CR measured at Mike Bainbridges Camgrinder DC62 cams on a 108 lobe Pauter light weight moly rods and ARP bolts DIY ported c3 heads 41mm in 38mm out,new guides etc race springs ,titanium retainers TRE unequal length ,38mm equal length headers M&K double bass box 48mm taper Jenveys Omex ecu running wasted spark twin plug & crankfire Mapped by a god at Chip Wizards Sachs HD clutch kit,close ratio 1st-4th gearing and heres a short vid of the final runs,god I love 3 litre engines :D Final Dyno runs to 7200 revs on Vimeo |
Fantastic sounding 3L engine you have there. Amazing how close together Porsche and Ferrari are with their bhp numbers with 3L engines with similar mods. A 2v 308 engine with just about equivalent modifications made 317bhp at the flywheel, but at 8400rpm. The conversion to ITB injection really helped driveability compared to Webers. Congratulations to you though. What an engine.
back on topic :) |
46 Webers for sale by MBruns today for $1500 including manifolds and linkage. Killer deal!
Lindy |
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Update - just picked up some 98mm cyclinders. These are 3.2 Carrera's that have been bored and plated.
So for now I have pistons, cylinders, cams, SSI's and dual outlet dansk sport. Just needing PMO 46mm carbs and I'll book it in with my engine builder - he is going to look after all the other stuff (ie. rod bolts, machining, head work, ignition, etc). Cost so far - $4K. Anyone got some carbs for sale let me know. I hear Webers are good but I have my eyes set on some PMO's. |
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I bought a set of pistons from Jamie that had been cer-met coated on the crowns. I have no way of quantifying the effect, but.............. a hot rod 3.0 dynoed at 250hp with no front cooler and it's never gotten over 220. this in a climate where summer temps hang in the 30 degree celsius range daily. I've checked the gauge and sender for calibration and they're dead on. I do run a little rich but not enough to have much of an effect. I boroscoped the piston tops the other day and they look perfect. is it possible that carbon has a tougher time sticking to the coating than bare aluminum? |
Don, Interesting to see a datapoint from the borescope that shows less carbon on the crown. One of the benefits of the ceramic coatings is a reduction in carbon buildup and deposition. I followed your build and am happy you like the results.
yes, the coatings reduce temperature. I have similar results in my warmed over 3.2SS here in triple digit TX heat. |
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great info guys, glad i found this post im on the fence as to what i should do w/ my stock parts (use or sell) and what other parts to mix into the motor. thanks for all the tech info |
Hope you don't mind me digging up my old thread but I am so close to completing my rebuild that I cannot contain my excitement any longer.
PMO 46's and Dansk Sport are yet to go on, but as you can see there is not much more to go. The car itself is ready so in about 1 week's time I should be driving it for the first time in 26 months. http://forums.pelicanparts.com/uploa...1346049495.jpg http://forums.pelicanparts.com/uploa...1346049529.jpg |
Done!
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Very nice looking. I am starting to get that anxious feeling myself on a 3.2 short stroke rebuild. Let us know when she roars to life!
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Looks absolutely fantastic - congrats!
looking forward to the break-in video |
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