duragg Posted May 24, 2011 Share Posted May 24, 2011 1973 240z gets a new motor this summer. Oily plugs, 80psi compression and a tranny that is just plain beat. I have acquired the following ingredients: * L28 F54 Flattop from 1983 ZX * Tall-eared 5 speed from same 1983 ZX. * N42 head with steel seats and a pristine A-grind cam (ready for regrind). * A valve spring kit with tower shims, different lash pads, from the old L24 motor (also had a CWC cam I am throwing away). * Triple DCOE 40 151s which I've been running all along with the tired L24 Ingredients I am NOT Planning on using: * Tired L24 (P30?) block * Interesting E88 head, stainless (small) valves and cam (stealing springs, shims and keeepers and such). * P79 head * Short eared, but single hanger 5 speed. Ingredients I am still researching * A gnarly cam with a LUMPY idle and up to 7000 rpm would be fun. * Lightened flywheel I will cut down on the Lathe * A reasonable clutch Goal is a scrappy sounding old-school Ratty Z. Drivin about 3 times a month. Bottom end buildup first with new bearings and re-hone and Total-seal rings. Tranny then rebuilt with new bearings and syncros. Top end last with the best of the parts I have and decide to buy. Re-install in the car and begin the Weber dance again (with Wideband). I need to post here so I remember what I did 3 years from now... Many hours spent in the archives here. Great forum. TJ Quote Link to comment Share on other sites More sharing options...
duragg Posted May 26, 2011 Author Share Posted May 26, 2011 (edited) Engine torn down. The good: Crank is marked "STD" in yellow paint, cylinders still show x-hatch, rear main seal is blue, rods marked 0.50, bearings all pristine. The bad: Head gasket blown at #3 and #4 with some water intrusion in the head bolt holes and minor corrosion in those holes and cylinder bores near BDC. Engine was partially rebuilt, but they must not have opened the front cover. Water passages were totally 100% blocked (Surprise the HG B?). What is that nasty crusty shart in there? An LD28 Crank would be handy right now... especially with my old L24 block sitting in the corner... here kitty kitty Edited May 26, 2011 by duragg Quote Link to comment Share on other sites More sharing options...
duragg Posted May 27, 2011 Author Share Posted May 27, 2011 Using the FSM specs measured the crank in all dimensions were standard. Time to order bearings. Have to hone cylinder bores next and then figure piston and ring size. These pistons already have "0.50" stamped on them which I assume is +.5mm. Shipped cam to Isky for the "490 Grind" treatment. Tj Quote Link to comment Share on other sites More sharing options...
duragg Posted May 27, 2011 Author Share Posted May 27, 2011 Pistons are +.5mm measuring 3.405" Cylinder bores are 3.409 Piston to wall clearance is supposed to be .001 to .0018. So we are blowing the bores out to the next size and order new pistons. Bigger is better. Quote Link to comment Share on other sites More sharing options...
duragg Posted May 28, 2011 Author Share Posted May 28, 2011 Sitting here realizing I am already buying new pistons, rings and what for an LD28 crank I'd be strokin. But the whole project scope / time and budget gets wonky. Either leave the 87mm bore, or blow out to 89mm? Can an F54 block be safely blown out to 89mm? Since I am getting free machine shop time asking my friend to blow out to 89 may be greedy. Seems with many of these mods you have to go to a VERY expensive head gasket ($300-$400 bucks)? Eh. Next time will do a Stroker. Aint no deals on LD28 cranks out there now anyways. Quote Link to comment Share on other sites More sharing options...
duragg Posted May 28, 2011 Author Share Posted May 28, 2011 ITM RY6134-040 should be the +1mm replacement piston. Total Seal T2416 +.1mm Quote Link to comment Share on other sites More sharing options...
duragg Posted May 29, 2011 Author Share Posted May 29, 2011 Saturday May 28. Got the N42 head cleaned and on the lapping table. Took about 40 minutes in various steps to get the cylinder side perfectly flat. Back-breaking work! Trying to hold that head on the big table even at moderate RPMs. Wants to run off the side. Disassembled my other heads and found more goodies. * P79 head spit out some pefect valves, but they are the shorter kind. Cant be used in N42? * E88 head spit out an MSA spring kit that is going in the new N42.Plus a bunch of different height lash pads. Along with these... Rockers and MSA Stage 1 cam on the E88 are toast. Rockers and stock "K" cam on the P79 are toast. Rockers on the N42 and "A" cam are just pristine. Moving all the good parts to the N42 build box. Monday will order stones and pistons for the F54 block job along with gaskets and such. Stupid question.. but do I order the Head Gasket for the F54 block or the N42 head? I think F54? Quote Link to comment Share on other sites More sharing options...
duragg Posted May 29, 2011 Author Share Posted May 29, 2011 (edited) Head lapped up nicely. A few small scratches I will let Mike look at (www.sf2racing.com) Valves dimensionally are so-so. A few have some thin spots. Replacement SI plain valves maybe at $7 each? Or Replacement SI fancy valves at $15 each? Or just run these biches again. TBD. Let Mike call that too. I was pretty worried about the guides - I hate pulling and replacing guides. It takes time and patience to do it right. Book specs are .3150 to .3157 for both intake and exhaust. I pulled Mikes pin gauge cabinet open and got a .3150 and a.31565 pin. The .3150 is perfectly snug on all of them. One guide is a bit tight at the top so I will have him take a half out of that one. The guides are surprisingly tight. What next. Guess I can lap the side of the N42 head for the intake manifold. But thats a messy job. Port match the Triple Weber intake to the N42. Type random **** on the internet that nobody reads in an Air Conditioned room with an Ice-Tea? Worthy goal for a Sunday. Edited May 29, 2011 by duragg Quote Link to comment Share on other sites More sharing options...
duragg Posted May 29, 2011 Author Share Posted May 29, 2011 Give Tony my flywheel and this handy drawing... http://www.datsport.com/Flywheel.html Quote Link to comment Share on other sites More sharing options...
neotech84 Posted June 2, 2011 Share Posted June 2, 2011 I love reading random stuff in a air conditioned room! And finding goodies you didn't know you had. Great job, love the hard work you have done. Quote Link to comment Share on other sites More sharing options...
duragg Posted June 3, 2011 Author Share Posted June 3, 2011 THanks. Stuck waiting for the hone-tank to open up after some other cylinders are done. Then blow another .030 out of the bores. Pistons here Friday. Total Seal will make the rings next week. Cam shipped to ISky. Credit Card raped (again). Beer cooler empty (again). Time to order my tranny kit and start pushing bearins and lapping syncros. I wanna drive this motor sometime soon. Need to do some port-matching too. What is that exactly, making the transition between intake manifold and head smooth? TJ Quote Link to comment Share on other sites More sharing options...
duragg Posted June 5, 2011 Author Share Posted June 5, 2011 Help - Order or things. Pistons pressed onto rods first before rings installed? Or Rings installed and then pins pressed through? I am thinking that pressing the pins in today and loading the rings just prior to installation (after end gapping) would prevent any damage during assembly. Quote Link to comment Share on other sites More sharing options...
duragg Posted June 6, 2011 Author Share Posted June 6, 2011 (edited) WTH. Mounted the bare pistons on the rods. Its a snug press but all went in good. Reading the instructions prior to pushing the pins will save time from having to redo the ones you put on backwards. THankfully I only had to reverse 2 of the 6 pistons so the oil hole was on the right side. Kluged one of the pistons a little but we cleaned it up and I think its fine now. Parts starting to show up. Have the Main Bearings, Water pump, remaining bearings and seals here tomorrow. Cam is at Isky for regrind. Total Seal made the rings on Friday and they are ready for pickup. Many thanks to Joe and Donna and Kevin at Total Seal for donating the ring pack. Its good to have friends in high places. Cleaned the heck out of the tranny in advance of its teardown next week. Engine hone is now free and the stones arrived so the block can get poked out this week. Ordered a .315 guide for the Sunen valve seat grinder, should be here Wednesday. Making progress. (edit for spelling) Edited June 6, 2011 by duragg Quote Link to comment Share on other sites More sharing options...
duragg Posted June 7, 2011 Author Share Posted June 7, 2011 I try to work all day before walking next door with parts to play engine-shop. I made it till 5pm today then wheeled the F54 next door and setup the hone-tank. WE have about .020 to remove and many thanks to Mike at SF2 racing for letting me take out the first .010. Under close security I didn't fkcu up anything too bad. Measuring: Honing: Mike offered: Hey how about you let me finish these up now that they are close... Ya, that's a good idea. Thanks ET. All that honing made me beer thirsty. Quote Link to comment Share on other sites More sharing options...
duragg Posted June 12, 2011 Author Share Posted June 12, 2011 Cam returned from Isky today. I am impressed so far. THey were a bit of a pain on the phone. Short and not overly helpful. But based on recomendations and some videos of their L490 cam I chose them. Total cost about $138 including the return shipping. The cam was expertly packed and includes pre-lube, Isky stickers, some general cam articles and a grind-sheet with all the final specs. I like the fact that they stamped the regrind details on the tail of the cam to aid identification down the road. That is a nice touch. Quote Link to comment Share on other sites More sharing options...
duragg Posted June 14, 2011 Author Share Posted June 14, 2011 Monday: Back at it today. Mike got the new stones for the hone since the old stones were goofy and cutting a taper into the bore. I can assure you that honing a cylinder straight and true is an art. After I struggled to get the bores true and messed them up worse Mike took the old stones and cut then down to half height but left the shoe guides full height. This allows me to feel the choke better and made an amazing difference. We also stopped using the pneumatic stroke mechanism and began dialing the bores in by hand. Had I just let him do this job it would have been done perfectly. But this is my project and learning the art of honing is fascinating. Patience. Sneak up on it. Not my specialty. I want to hog and chop. It is surprizingly relaxing and "zen". The Datsun spec for taper is no more than .0008". We are shooting for no more than .0001" but will be happy with .0003". Piston to Block clearance of .0015 to .0020 should be fine. The pistons I pulled out where .004". Sunday I port matched the head and unshrouded the valves and tidied up the intake runners. The correct taper pilot for the seat cutters should be here late this week and can finish the head. Once the block is done I will lap the top surface and paint the block then reassemble the beeatch. Working on engines and metal and doing it yourself is an amazing learning experience and provides tremendous satisfaction. Quote Link to comment Share on other sites More sharing options...
duragg Posted June 25, 2011 Author Share Posted June 25, 2011 Voodoo Style! Now for some bearings... Quote Link to comment Share on other sites More sharing options...
duragg Posted June 25, 2011 Author Share Posted June 25, 2011 Main bearings just on the fat side. But I didn't torque the bolts down fully. We're running this. Quote Link to comment Share on other sites More sharing options...
duragg Posted June 26, 2011 Author Share Posted June 26, 2011 Crank is in and toqued, vent grate and baffle in, rear cap sealed (f'er better not leak, those stupid side seals suck). Started to load the rings and realized my ring compressor was no good. You gotta have the correct Total Seal compressor to get the rings in right. With the TS compressor you can watch the rings load into the compressor and then better install into the bore. Stuck until Monday. Quote Link to comment Share on other sites More sharing options...
duragg Posted June 28, 2011 Author Share Posted June 28, 2011 I know what Quagmire would say... Quote Link to comment Share on other sites More sharing options...
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