mrcj280z Posted March 18, 2011 Share Posted March 18, 2011 hey has anybody ever heard of makin this block a 4 bolt main with the 4 bolts at a 45 degree angle instead of the 2 bolts at 90 Quote Link to comment Share on other sites More sharing options...
CamH Posted March 18, 2011 Share Posted March 18, 2011 Why would you need to do that? Quote Link to comment Share on other sites More sharing options...
mrcj280z Posted March 19, 2011 Author Share Posted March 19, 2011 to make the bottom end of the motor stronger come on now why would you want to use arp head bolts over stock they are just stronger and first datsun i had lost a rod dont want his one to when i finish building her Quote Link to comment Share on other sites More sharing options...
stravi757 Posted March 19, 2011 Share Posted March 19, 2011 What kind of power are you looking to get? Quote Link to comment Share on other sites More sharing options...
rossman Posted March 19, 2011 Share Posted March 19, 2011 (edited) Oh, because everybody knows that the L6 bottom end is weak because it only has two main bolts. Nobody does it because it's not needed. Your old engine throwing a rod had nothing to do with the fact that L6's only have two main bolts. Edited March 19, 2011 by rossman Quote Link to comment Share on other sites More sharing options...
ctc Posted March 19, 2011 Share Posted March 19, 2011 (edited) I don't think there is enough material in the main cap to get a two more main bolts installed. Have you opened up your block and looked at the main cap? I know on some V8's they have two additional bolts that splay out at 45 degrees but I have never heard of all 4 main bolt at 45 deg. Take a look at this photo I pulled of one of the stroker build websites, It would take a lot of machining to get more bolts in there. If you machined entirely new main caps and came in at 90 deg to each other like the old chrysler hemi engines it might work. That would take a lot of work, but this is Hybrid Z so have at it. Others have made a lot of power on stock main caps, 800+ hp, so if your's failed I don't think it was because of the main bearing cap unless it was installed wrong. My 2 cents.... Edited March 19, 2011 by ctc Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 19, 2011 Share Posted March 19, 2011 Just because the guy up th' hollow does his sister, doesn't necessarily mean it's the best idea, nor particularly suited to your situation... So goes for splayed main caps. Quote Link to comment Share on other sites More sharing options...
mrcj280z Posted March 20, 2011 Author Share Posted March 20, 2011 thanks for all the responce didnt mean to offend anyone it was an idea tossed at me by a machine shop guy for a strong durable rebuild if it was something more common like porting or messing with oil passages or coolant passages for better flow like how they always put those restrictors in their to boost oil pressure in other areas of the motor on some older designed motors Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 20, 2011 Share Posted March 20, 2011 Get a machine shop familiar with something more than domestic crap. That is Chevy stuff they are talking, not Nissan! That block/cap combination holds over 1000hp AS IS...you plan on making more than that? Quote Link to comment Share on other sites More sharing options...
mrcj280z Posted March 21, 2011 Author Share Posted March 21, 2011 yea i was only planning on using them for baking and if i ever need a bore i dont think ima trust their opinion on such matters and really 1000whp damn go nissan thanks for the info Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 23, 2011 Share Posted March 23, 2011 OVER 1000 Hp. Quote Link to comment Share on other sites More sharing options...
josh817 Posted March 23, 2011 Share Posted March 23, 2011 Do you know how tempted I am to stand up and shout OVER 9000. I'm in the middle of a computer room, people would stare. I don't think he meant yah as in over 1000HP. I don't know anything about V8's but if the 4 bolt main is to prevent a main cap from breaking, I've only seen one broken Nissan main cap on the internets. An easier solution would be to have billet caps machined for you I suppose. I posted the picture in a thread somewhere around here. Just my thought... Tony is more often than not correct though. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted March 23, 2011 Share Posted March 23, 2011 hey has anybody ever heard of makin this block a 4 bolt main with the 4 bolts at a 45 degree angle instead of the 2 bolts at 90 to make the bottom end of the motor stronger come on now why would you want to use arp head bolts over stock they are just stronger and first datsun i had lost a rod dont want his one to when i finish building her thanks for all the responce didnt mean to offend anyone it was an idea tossed at me by a machine shop guy for a strong durable rebuild if it was something more common like porting or messing with oil passages or coolant passages for better flow like how they always put those restrictors in their to boost oil pressure in other areas of the motor on some older designed motors yea i was only planning on using them for baking and if i ever need a bore i dont think ima trust their opinion on such matters and really 1000whp damn go nissan thanks for the info PM sent your way. Please comply. Thanks Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 24, 2011 Share Posted March 24, 2011 I meant exactly what I posted: the L-Block with unaltered stud configuration has run well over 1000HP. The rod you threw, that was #5 right? That's an oiling problem, not a main cap problem. They all let go at #5, and seem to want to spin #1 first. They make stud girdles, but again the question is "How much are you planning on making?" At 780+ to the rear wheels and countless hours on the dyno there were no issues with main or rods in that engine. And all that one has is ARP's. Which seems to be a cheap standard performance build part, not due to any particular 'weakness'---the only weakness (if it is one) is the rod bolts. And that solution has been known since the 70's. Quote Link to comment Share on other sites More sharing options...
ozconnection Posted March 24, 2011 Share Posted March 24, 2011 (edited) I meant exactly what I posted: the L-Block with unaltered stud configuration has run well over 1000HP. The rod you threw, that was #5 right? That's an oiling problem, not a main cap problem. They all let go at #5, and seem to want to spin #1 first. They make stud girdles, but again the question is "How much are you planning on making?" At 780+ to the rear wheels and countless hours on the dyno there were no issues with main or rods in that engine. And all that one has is ARP's. Which seems to be a cheap standard performance build part, not due to any particular 'weakness'---the only weakness (if it is one) is the rod bolts. And that solution has been known since the 70's. There is a thread on an Aussie forum that discusses the fabrication of main cap girdles as a bottom end 'support'. Their arguement is that the guys who are dripping oil from their pans and rear seals are those experiencing block twist. The solution they say is a cap girdle similar to the RB setup. Is this valid or just silly talk Tony? Edited March 25, 2011 by ozconnection Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 26, 2011 Share Posted March 26, 2011 Again, 'how much are you planning on making'? We do have a persistent oil leak at the rear of the engine, but that may be due to using a 160,000 mile rear main seal... Or improper PCV action. There are many variables to take into account. I would think 'block twist' is reaching out there for a reason when no toehr testing has been done. Really, with modern sealants or even old gaskets proper installation is taken for granted, but is rarely the case in practice! E-Motive ran without a stud girdle... So much of this stuff is done 'because the other guy did it' and little thought is put toward the actual engineering basis for it! Quote Link to comment Share on other sites More sharing options...
ozconnection Posted March 26, 2011 Share Posted March 26, 2011 Again, 'how much are you planning on making'? We do have a persistent oil leak at the rear of the engine, but that may be due to using a 160,000 mile rear main seal... Or improper PCV action. There are many variables to take into account. I would think 'block twist' is reaching out there for a reason when no toehr testing has been done. Really, with modern sealants or even old gaskets proper installation is taken for granted, but is rarely the case in practice! E-Motive ran without a stud girdle... So much of this stuff is done 'because the other guy did it' and little thought is put toward the actual engineering basis for it! Maybe I should throw the cat amoungst the pidgeons and remind them of that electramotive L28 turbo! I've heard and read about the PCV issue, that could well be the problem they're experiencing. Would they know about it? Dunno? I'll suggest it and see who says what. Thanks Tony. Quote Link to comment Share on other sites More sharing options...
luvemfast Posted March 28, 2011 Share Posted March 28, 2011 Maybe I should throw the cat amoungst the pidgeons and remind them of that electramotive L28 turbo! I've heard and read about the PCV issue, that could well be the problem they're experiencing. Would they know about it? Dunno? I'll suggest it and see who says what. Thanks Tony. The gentleman who designed and made these years ago was a clever man who raced these with great success and reliability! The issue is not just block flex and reinforcing the rear mains, but also crank flex/whip and harmonics. Then there is the builder who is for these locally, he himself is no dummy. Working with Gibson motorsport here in Australia back in the day, still in the performance tuning industry 20+ years. For me the price of the girdle, compared to the price of a complete performance engine, is negligible. I see it as extra insurance as we all cannot afford a rebuild after events! Quote Link to comment Share on other sites More sharing options...
d3c0y Posted March 29, 2011 Share Posted March 29, 2011 And as stated on the thread on the Aussie forum, the e-motive L28 was running a dry sump which is known to help brace the bottom of the block. Another interesting point is that Nissan switched to running girdles in their straight sixes as early as the RB30 in 1986 which is pretty much on the end of L28 production. I understand that the RB blocks aren't going to be the same exact design as the L-series and the RBs might have used the strength of a girdle to make the block lighter or something. However there must be something in it because all the good performance Nissan engines of the 90's incorporated them: RBXXDET SR20DET VG30DETT I'm no girdle evangelist, but I thought that anything that helps crank flex/whip is a good thing, especially in an L-series that has a high rev limit. Tony D please feel free to shoot down my post so i can learn another engine building lesson! Quote Link to comment Share on other sites More sharing options...
z-ya Posted March 29, 2011 Share Posted March 29, 2011 (edited) I don't know anything about V8's but if the 4 bolt main is to prevent a main cap from breaking, Four bolts on Chevy main caps are to keep the caps from moving, not breaking. The Chevy blocks are not notched like the Nissan blocks. So you need a lot more clamping force on a Chevy block to keep the caps from moving. The Nissan main cap fit snugly into a recess machined in the block. Edited March 29, 2011 by z-ya Quote Link to comment Share on other sites More sharing options...
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