DatsunZman04 Posted August 15, 2013 Share Posted August 15, 2013 I know everyone bores out a 280z block rather than mess with a L24 (240z) block. I have a friend who needs to rebuild an engine for his stock 71. I have 3 L24 blocks laying around plus 280 cranks to make him a little more power but not a 280 block. So Heres the question. What is the max (sefely) you can bore a stock l24 block?? Can a L24 withstand 89mm overbore. Stock I believe is 83mm and a 280z should be around 86mm. You ask Why go 89mm?? I can get Ka24de pistons cheap at $100 a set forged. some left over from a kids drift project that didn't go anywhere. He bought 2 sets just in case. I can have it bored out and put these piston in cheaper than buying a 280 block and or buying new 240 z pistons. Plus I dont know if any of the used L24 blocks will needed to be bored to clean them up. I figure if I have to bore it I might as well go bigger This car will be mainly a decent modded street car, and not autocross. It will use either a 3100 head or the lower compression 72 model. Any help or advice would be greatful Thanks Quote Link to comment Share on other sites More sharing options...
madkaw Posted August 15, 2013 Share Posted August 15, 2013 This has been covered on a thread before. Not telling you to search, but it was dealt with in detail before and I don't have an accurate answer for you. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted August 15, 2013 Share Posted August 15, 2013 A machine shop will have a tool to measure cylinder wall thickness. That's the only way to tell you how big your bore can go. My machine shop tells me you need a consistant 0.090" wall thickness. Quote Link to comment Share on other sites More sharing options...
Xnke Posted August 15, 2013 Share Posted August 15, 2013 (edited) You can bore the L24 block to 85mm in most cases. The F54 block can usually take an 88mm bore, and so far I haven't found an N42 block that can't take an 88, and many will handle an 89mm bore acceptably. NOT ALL L28 blocks can handle the 89mm bore! Edited August 18, 2013 by Xnke Quote Link to comment Share on other sites More sharing options...
DatsunZman04 Posted August 16, 2013 Author Share Posted August 16, 2013 Thanks for the help, Maybe I just need to have the machine shop check and see what the max is on my best looking block. I just figured someone had to try this just because the abundance of L24 blocks vr L28. I just wanted the 89mm because I can get my hands on a set of pistons cheaply. Quote Link to comment Share on other sites More sharing options...
ctc Posted August 16, 2013 Share Posted August 16, 2013 In all my searching l28 blocks are much more abundant than l24 blocks. i' ve got three in my garage i got free for hauling them away. For around $200 you should be able to get an l28 block that will take the 89mm pistons. Just have to look. Quote Link to comment Share on other sites More sharing options...
roger280zx Posted August 16, 2013 Share Posted August 16, 2013 Am I the only one trying to figure out what a 3100 head is? Quote Link to comment Share on other sites More sharing options...
ctc Posted August 16, 2013 Share Posted August 16, 2013 (edited) I Think he means the e31 head from the 71 l24. Edited August 16, 2013 by ctc Quote Link to comment Share on other sites More sharing options...
Tony D Posted August 16, 2013 Share Posted August 16, 2013 Anything is possible with Wet Liners... Quote Link to comment Share on other sites More sharing options...
DatsunZman04 Posted August 16, 2013 Author Share Posted August 16, 2013 CTC you are correct, The HOW TO MODIFY DATSUN ENGINES book called it a 3100 AKA (E31) High compression head with lilttle valves I take it. Do you need any l24 blocks I would be willing to trade? My problem is I live in Missouri and everyone wants to sell you a rotted out 280 car for 1500 when all I want is a block/ rotating assembly. Everyone thinks their lawn orniments are worth thousands. Quote Link to comment Share on other sites More sharing options...
Josh280z Posted August 16, 2013 Share Posted August 16, 2013 CTC you are correct, The HOW TO MODIFY DATSUN ENGINES book called it a 3100 AKA (E31) High compression head with lilttle valves I take it. Do you need any l24 blocks I would be willing to trade? My problem is I live in Missouri and everyone wants to sell you a rotted out 280 car for 1500 when all I want is a block/ rotating assembly. Everyone thinks their lawn orniments are worth thousands. +1 Quote Link to comment Share on other sites More sharing options...
Xnke Posted August 17, 2013 Share Posted August 17, 2013 Hit the junkyards. I have bought complete runners for 350$, complete with triple sidedrafts that I turned around and sold for 1500$. I like the way TonyD thinks. Quote Link to comment Share on other sites More sharing options...
Gollum Posted August 17, 2013 Share Posted August 17, 2013 Anything is possible with Wet Liners... And boy does that open the door to possibilities! Quote Link to comment Share on other sites More sharing options...
DatsunZman04 Posted August 18, 2013 Author Share Posted August 18, 2013 In Missouri 90% off all junk yards have crushed anything older than a 1985 model car due to the price of steel going up. Like I said my options seem to be stuck with the lawn ornaments or just by luck come across one. I wish I could find a set of triples on a car. I doubt there's a mechanic around here smart enough to rebuild or tune a set. Diesel wet liners? Quote Link to comment Share on other sites More sharing options...
Xnke Posted August 21, 2013 Share Posted August 21, 2013 mmmm....V07 block with 90mm wet liners...machined RB30 crank with 90mm stroke...Awwww Yisss... Quote Link to comment Share on other sites More sharing options...
DatsunZman04 Posted August 21, 2013 Author Share Posted August 21, 2013 xnke, Your suggesting a VO7 block, (which is a 80' maxima diesel block) add sleeves and then bore it out?. RB30 crank from a rb30det? Sorry Ia'm a little confused on the parts list here. Clue me in ohh wise one. Quote Link to comment Share on other sites More sharing options...
Xnke Posted August 22, 2013 Share Posted August 22, 2013 Heh, the RB30 crank can be used to push the stroke way out, if you're up for a 10-15 thousand dollar engine build. The diesel block can't be bored very large, but it's got an extra 19mm of deck height. Combine these with wet liners, a modified gas head, four-banger front cover, and a decent hay-bale sized brick of cash, and 3.6L+ of displacement is obtainable. If you use wet liners (And there are forklift diesel blocks with DRY liners already in them!) you can push the bore to about 90MM, however it's going to be a limited life engine between rebuilds. Unless you have the liners welded in place, wet liners WILL leak at some point in time, so it'll have to be checked often. So, 90MM bores, and a highly modified RB30E crankshaft, small journal connecting rods, and you could run a 90mmx90mm engine... PMC has built 3.6L L28 strokers down in the Southlands, that push close to 400HP flywheel, if not a little over! He uses L28 engine blocks mostly, and has a few photos here in the archives. Quote Link to comment Share on other sites More sharing options...
DatsunZman04 Posted August 22, 2013 Author Share Posted August 22, 2013 Lets say I have a Vo7 inline 6 block (Diesel) and a decent reworked gas Head, All I would have to do Is locate a rb30 crank and have it machined down?? What rods would you use? Obvisouly you would sleeve the block to have a 89mm or 90mm bore. Maybe I need to do some researching on this setup because I know where theres a complete 81 maxima ( diesel) that is just sitting in a driveway. Just trying to put together a build list in my head. Thanks XNKE Quote Link to comment Share on other sites More sharing options...
ctc Posted August 22, 2013 Share Posted August 22, 2013 Curious when this is going to the tool shed, now that we are in fantasy bench racing land. I called a shop specializing in installing wet sleeves and was quoted around $6k for the block work alone, welded like mentioned above. For the coin one would drop on a "hybrid" engine such as this you could get proven power from someone like Rebello or PCM. Some like doing it the hard way, but maybe we should do our thinking in the shed from here on out. Quote Link to comment Share on other sites More sharing options...
johnc Posted August 22, 2013 Share Posted August 22, 2013 For some folks $6K is nothing for the block work on a L6. Your budget is not the same as others. Quote Link to comment Share on other sites More sharing options...
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