HakosukaJD Posted December 9, 2005 Share Posted December 9, 2005 So I recently bought a Hakosuka. The shop advertised the car as an L28 with Mikuni (Solex) 44's. So I get the car home and take the silencer out of the tailpipe that was no doubt stuffing the engine. Since I'm new to carb'd cars, a friend of mine assists in balancing them (and we find one of the butterfly posts to be a bit tweaked...fixed now). No matter what he did, he couldn't get the engine to run smooth through the mid-rpms (carb spits, hesitation etc). Power/torque under 2k is pretty good and the car takes off above 4k RPMS. So he assumes the jetting may be a bit off. We pull the head cover to see what kind of CAM its running to possibly get a baseline to start from. The cam has no markings on the end (where, I'm told an aftermarket cam is usually marked), but has L20 stamped in the middle of the cam. Engine looks like it has recently been rebuilt. Looked strange to us...L20 cam in an L28. We look at the block plate, and it also says L20. The head is an N42 (L28, I believe) head. I call the shop. The shop ASSURES me the engine is indeed an L28 and that it is likely the previous owner shaved the block plate and restamped it to pay the lesser road tax (Japan road taxes based partly on displacement). Apart from taking the head off and measuring the cylinders, are there any other definative ways to identify this block as either an L20 or an L28? Block serial code? Appendages? I know somebody here has all these differences memorized! Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted December 9, 2005 Share Posted December 9, 2005 The block should be marked L28 00123456 on the right side at the parting line of the head, right next to the oil filter. Thats the serial number of the block, and the designation ie: L24 L26 L28 Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted December 9, 2005 Share Posted December 9, 2005 Check the other side of the block under the manifolds next to the engine mount bracket, there should be an engine code there (N42, N47, F54, etc) Quote Link to comment Share on other sites More sharing options...
pallnet Posted December 9, 2005 Share Posted December 9, 2005 I would bet that it's an L20 bored and stroked to an L28. Like you said "Japan road taxes based partly on displacement". I know that's what I would do if the block would hold. Your buddy might be right about the roughness. Carbs are such a PITA and even more when you have more then one of them. Quote Link to comment Share on other sites More sharing options...
HakosukaJD Posted December 9, 2005 Author Share Posted December 9, 2005 That's almost a 30% increase in displacement....is that possible? I would bet that it's an L20 bored and stroked to an L28. Like you said "Japan road taxes based partly on displacement". I know that's what I would do if the block would hold. Your buddy might be right about the roughness. Carbs are such a PITA and even more when you have more then one of them. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted December 10, 2005 Share Posted December 10, 2005 So what did you discover when you looked at the numbers on the block as we sugested? Quote Link to comment Share on other sites More sharing options...
NZeder Posted December 10, 2005 Share Posted December 10, 2005 That's almost a 30% increase in displacement....is that possible? Might be possible. L20a = 69.7mm stroke, 79mm bore = 2000cc L20a block with L28 crank and rods = 79mm stroke, 79mm bore = 2300cc L20a block with 0.160 over bore, L28 crank and rods = 79mm stroke, 83mm bore = 2600cc ie a L26. I know the P30 blocks (ie L24 and L26 block) can be bored to 86mm so if the L20 blocks have the same water jackets etc of the L24/L26 blocks then it should be possible. Best way to tell is get the block casting number, ie P30, N42, F54 (does anyone know that a L20 block should be? I can look at Dad's L20 tomorrow when I visit his place (just don't know right now) Quote Link to comment Share on other sites More sharing options...
HakosukaJD Posted December 10, 2005 Author Share Posted December 10, 2005 I will let you know as soon as I get home...had duty last night so unable to check. I'll post pictures of what I find as well.... So what did you discover when you looked at the numbers on the block as we sugested? Quote Link to comment Share on other sites More sharing options...
kcelectronics Posted December 10, 2005 Share Posted December 10, 2005 Are you sure its not a rare 2lt twin cam motor? Chucky:twisted: Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 10, 2005 Share Posted December 10, 2005 Absolutely! Mr. Gasket makes a displacement tester which is basically a plexiglas tube with graduations on the side and a sliding aluminum plate inside that moves when you crank the engine over on a cylinder with the rocker arms disabled. This is how displacement is checked at Bonneville and El Mirage in impound after setting a record (as long as your engine is not within 3% of the class maximum). The shaving of the block and restamping is VERY common in Japan. I had one of those... No 33 plate for you! LOL Quote Link to comment Share on other sites More sharing options...
HakosukaJD Posted December 10, 2005 Author Share Posted December 10, 2005 Are you sure its not a rare 2lt twin cam motor?Chucky:twisted: I guarantee you if I had one of those' date=' you would have seen it by now Z-Gad and N-Zeder win.....although I'm SURE Soileau is right too (I forgot about his suggestion when I was looking...I'll look again:) ) N42 is clearly visible on the left side ~#2 near the oil pan. Obviously molded with the block rather than stamped as the engine ID plate was. http://photobucket.com/albums/c248/hakosuka32/?action=view&currnet=block.gif Funny thing about that ID plate....I WAS registered with a 300 tag! So now the issue is... what the hell cam is it and why can't we get it running right? lol Quote Link to comment Share on other sites More sharing options...
stony Posted December 10, 2005 Share Posted December 10, 2005 As mentioned above you probably have an engine that has had the serial number modded. Lots easier to do that then to get the title changed to reflect L-28. Im kind of an old school guy in japan i had an L-28 that was stamped l-20 in my newman skyline back in the day. Can you take a pic of the serial number area? Its sometimes pretty obvious if you see it next to a block that has not been tampered with. If i remember correctly all teh L series cams are pretty much interchangable and they probably threw whatever they had in it. L-28 parts are getting pretty scarce over there now a days. If it ever needs to be replaced or rebuilt youd be better off going with an rb26. Quote Link to comment Share on other sites More sharing options...
NZeder Posted December 11, 2005 Share Posted December 11, 2005 Cool now you know - re-stamped engine number. I checked Dad L20 Block = M3 or M8 (could not make it out 100%) Quote Link to comment Share on other sites More sharing options...
HakosukaJD Posted December 11, 2005 Author Share Posted December 11, 2005 I tried to get some clean pictures but its difficult as the coolant hose that runs to the heater core is in the way....camera was too close to focus. But this is generally what they look like... So do you think its even possible to get it running decent on an L20 cam with Mik44's? As mentioned above you probably have an engine that has had the serial number modded. Lots easier to do that then to get the title changed to reflect L-28. Im kind of an old school guy in japan i had an L-28 that was stamped l-20 in my newman skyline back in the day. Can you take a pic of the serial number area? Its sometimes pretty obvious if you see it next to a block that has not been tampered with. If i remember correctly all teh L series cams are pretty much interchangable and they probably threw whatever they had in it. L-28 parts are getting pretty scarce over there now a days. If it ever needs to be replaced or rebuilt youd be better off going with an rb26. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted December 11, 2005 Share Posted December 11, 2005 I tried to get some clean pictures but its difficult as the coolant hose that runs to the heater core is in the way....camera was too close to focus. But this is generally what they look like... So do you think its even possible to get it running decent on an L20 cam with Mik44's? If thats the actual pic of the serial number area on the block, you can see that it has a metal head gasket... Quote Link to comment Share on other sites More sharing options...
NZeder Posted December 12, 2005 Share Posted December 12, 2005 I can't recall (who or if I read it somewhere) but I do remember someone telling me once that the L20 cam has a lot more meet and is good to use for putting a grind on to. So maybe this is what has been done to the L20 cam you have in this engine. Quote Link to comment Share on other sites More sharing options...
HakosukaJD Posted December 12, 2005 Author Share Posted December 12, 2005 I already determined that I just wish I knew what else is done..... If thats the actual pic of the serial number area on the block, you can see that it has a metal head gasket... Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted December 12, 2005 Share Posted December 12, 2005 I already determined that I just wish I knew what else is done..... I hear ya..... just pointing out the positives I notice, thats all... Quote Link to comment Share on other sites More sharing options...
evildky Posted December 12, 2005 Share Posted December 12, 2005 well seeing as the pic clearly shows the "N42" it is at the very least a 2.8 block Quote Link to comment Share on other sites More sharing options...
Corzette Posted September 18, 2008 Share Posted September 18, 2008 Cant believe no one said it yet, but if its an L20 there is no mistaking it for an L28 powerwise. Its night and day....L20s are dog slow...ask me how I know...hehe. My Hakosuka has one..... Terry Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.