Scottie-GNZ Posted June 22, 2001 Share Posted June 22, 2001 I would like to hear some feedback on the comment made in the last sentence on this page. http://www.motormeister.com/suz/911_engines/911_engines.htm Quote Link to comment Share on other sites More sharing options...
clint78z Posted June 22, 2001 Share Posted June 22, 2001 I think the early 240z did have crank problems, however I heard that it was correctly within a year. And went on to lay a beating on the odd porsche or two. Good to see the porsche guy still see the L6 as a threat!! Quote Link to comment Share on other sites More sharing options...
pparaska Posted June 22, 2001 Share Posted June 22, 2001 If you search around on Zhome.com, you can read a story about the first BRE Z's having a crank problem. Nissan found out about it on their own and fixed it. I think it was only the first year, if that long that the cranks had a problem. Quote Link to comment Share on other sites More sharing options...
Guest Frank Rich Posted June 22, 2001 Share Posted June 22, 2001 Scottie, years ago I used to pit crew for my brother-in-law in the Southwest Division of the SCCA, and although he raced Formula Fords, one of his closest friends - a gentlemen named Richard Longren - ran a 240Z in what I seem to remember was then (mid 70's) a "production" class - I think it ran in BProd, but I could be wrong (this Alzheimer's is a b*tch) - but I can absolutely assure you that Richard's budget would not have supported replacing the crankshaft after every race weekend! He did pretty well as I remember, winning enough points over the course of the season to qualify for the National Run-offs, and while he may have completely rebuilt the motor for the trip to the run-offs, and I know that he had his cylinder head re-worked more than once a season, he did not do a major tear down and rebuild (and replace the crankshaft)after every race. That statement about Z crankshafts on the Porsche engine builder's site to which you supplied the link was pretty general and vague. You would think that the sentence should continue with a little more detail , such as " ...replaced after every race weekend due to_______ ". You know, something like "...main bearing failure scarring the journals...", or "...the poorly balanced crankshaft ate main seals at a horrible rate...", or some other detail (no matter how ridiculous) to support this claim. The fact that such a bold and broad generalization is thrown out there without any supporting detail makes me think that its just smoke and mirrors...or a little envy! I'd also be really interested to know if anyone out there has different information, since my experience with a Z campaigned for an entire season is limited to one individual. "Lead me not into Temptation, I'm getting there just fine on my own" Frank Quote Link to comment Share on other sites More sharing options...
Drax240z Posted June 22, 2001 Share Posted June 22, 2001 Yeah, what 240Z turbo said. That's what I've read anyway. Quote Link to comment Share on other sites More sharing options...
johnc Posted June 22, 2001 Share Posted June 22, 2001 Also, current L6 cranks have problems when you run 14:1 or higher compression and run consistently over 8,000 rpms. Bearings need to be replaced frequently and the crank needs to be checked often. But, we're talking about full race GT2 NA engines making 350+ horsepower. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted June 22, 2001 Share Posted June 22, 2001 Consider also, that a inline could have more chance for a crank related problem due to its length than say a boxer 6 motor or a V6 which has a much shorter crank. Just an observation, but if I were turning massive RPM's, the shorter the crank the better to keep everything compact and stiff structurally speaking. IMHO. That said, I think the Z's bottom end at least in they're street applications were exemplary, most of the problems encountered were nearly always the heads. Regards, Lone Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted June 22, 2001 Author Share Posted June 22, 2001 I found it odd that a reputable Porsche engine builder would want or have the need to post a statement like that. After all, the customer base of both makes are worlds apart. Well, that accounts for my split personality . Another reason why I love this forum. Not a single response slamming Porsches! Kudos! If this was zcar.com...... Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted June 22, 2001 Share Posted June 22, 2001 I wouldn't bad mouth a Porsche motor. Ever seen one torn down? Looks like a swiss watch inside! Correctly turbocharged they can make 1000HP, who can bitch about that?! A shame they cost so darned much or I'd be much more interested in them. Too many snobby Porshe owners too (sorry Scottie!). Sort of like the Z3 - I was pretty close to buying one till I read some of the truly "tight" postings on one of their boards. No thanks, not a community I'm interested in joining. Quote Link to comment Share on other sites More sharing options...
johnc Posted June 23, 2001 Share Posted June 23, 2001 For racing purposes, Porsche engines generally work out cheaper over the course of a season than most others. A friend who raced a GTS Dodge Viper in the ALMS series last year did some figuring for the GT class this year (where Vipers based on the production car chassis run). He calculated that it would be about $150,000 cheaper over the season to run a Porsche GT3R even though the initial costs were higher. Almost all of those savings were in the cost of engine rebuilds/refreshes. [ June 22, 2001: Message edited by: johnc ] Quote Link to comment Share on other sites More sharing options...
RedNeckZ Posted June 23, 2001 Share Posted June 23, 2001 The first time the BRE racing team used the old crank in c-production, it broke. It happened a few times for them. I think it was the fourth race that year, they had the new crank from Nissan and didn't have any problems after that. They still have small problems with them. But over all, they will last a long time at RPM below 7000. At any higher RPM (i.e. GT-2) above 7000 RPM to 9000 RPM my friends replace the crank after 3 races. For most street driven Z's, they will last almost for ever. Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted June 23, 2001 Share Posted June 23, 2001 This is the crankshaft skinny from what I know. The very 1st production year of the 240z used a crankshaft that was not fully counterbalanced. This lead to cranks snapping and prematurely wearing components. This problem was immediately identified and corrected with the later years and as such, all other cranks are fully counterbalanced. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted June 23, 2001 Share Posted June 23, 2001 I think lone hit it on the head, that the inherant weakness of any inline 6 engine is simply the crank length. The causes more flex, and lowers the 'safe' redline lower than you might see from other designs. I'm wondering how V12's rev so high, I would think that they would see as much or more crank flex as a inline 6. Gotta love the balance of both engines though! Quote Link to comment Share on other sites More sharing options...
clint78z Posted June 25, 2001 Share Posted June 25, 2001 Length is a factor however, the L6 has 7 main bearings to support the load of 6 pistons and keep the crank from twisting. I have rebuilt 2 L6's and both had minimal bearing and cylinder wall wear, of course these were street engines. I wonder why a crank girdle was never develop in it's racing history. I think crank resonance at high rpm was the thing that killed most cranks. Quote Link to comment Share on other sites More sharing options...
DAW Posted June 25, 2001 Share Posted June 25, 2001 "...Early L24 engines (up to L24-003606) have a six counterweight crankshaft and should be upgraded to an eight counterweight unit prior to any high-performance modifications." NISMO Catalog. DAW Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted July 2, 2001 Share Posted July 2, 2001 I'm w/Pete; funny how the Porsche crowd feals threatened by a "Z" inliner (hey, I'm an Inliner!)...where's a Porsche-let me at'em, rip/snort & roar! If Nissan would have put as much into the Z as Porsche has in its past racing history-there's no telling where the little Z would have ended up. As Scottie said earlier (and IMHO) the Porsche & Z owners are usually worlds apart; especially now that our Z's have V8's & turbo powered V6's...all you can do when you see one coming in your rear view mirror-is get out of the way! I also agree w/another previous response-if the comment is being made-then it needs to be put in context; otherwise its a useless statement! The builder makes a comment on a crank problem Nissan had in the first year of the 240z(?) and the Porsche builder has to slam the Z as a result...that's fear! Yes fear, possibly jealousy, at work; definately insecurity. Why insecure-I've always respected the power of the porsche. I've never owned one but did drive a 911 once; a friend had one & I incredibly enjoyed shifting into "2nd" gear at 40-50mph! Anyways-that's my .02c's worth. Kevin, (Yea,Still a "Porsche Threatening" Inliner) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 2, 2001 Share Posted July 2, 2001 I've always like the power and sound of the porsche boxer 6. A guy across the street used to have one and his wife would take us to school in it. It was cool, 911T had a pair of weber 3 bbls on it and when it came on the cam, it just sounded the business. Handled pretty good I guess, he took me for a more serious ride one time and it cornered pretty flat, always wanted one, couldn't (and probably never will) afford one. I understand they understeer pretty bad at the limit (which would only make sense with the weight distribution..). Porsche purists are no different than Datsun purist, sure they'll snipe at each other, thats what brand loyalism does to you, makes you crazy. Glad we don't do that here... (well hardly at all... ). Regards, Lone 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.