ratedZ Posted October 7, 2003 Share Posted October 7, 2003 ...hey guys, it's been a while. How's everyone? Well I've been busy with the Z. Got the rebuilt motor in and the Spec stage4 clutch (which I'm lovin:D) Driving her easy right now and shes been driven for about two weeks. Within those two weeks I've only managed to put less than a 100 miles I did hit it a little to see where my boost sits and it hit 16psi without hesitation. I let off real quick though and I'm having a hard time keeping my foot off the gas...so hard that my wife threatened to take my keys away lol So my question is this, how long is the average break in period? I've gotten mixed numbers from Zcar.com....some say 500 and some say 1000, and others 1500. I just need to make sure so I can plan a trip or something. Thanks all!!! Quote Link to comment Share on other sites More sharing options...
ratedZ Posted October 7, 2003 Author Share Posted October 7, 2003 sorry for the pic size, I'll have to crop it Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 7, 2003 Share Posted October 7, 2003 It really depends on how close you have all of your tolerances set. If you measured everything (ring gap, bearing clearances etc) to a gnats ball hair, then (getting ready to be flamed), break-in of more than 1/2 hour or so is unecessary. FWIW, when my Dad rebuilds his racing motor (sbc spinning to 8grand, at 600+ HP) in circuit racing, he gives it 2 laps to check water temp, oil temp and oil pressure, then hammers it. He has always told me that break in is unnecessary (except if using flat tappet cam, then obviously you need to give it ample oil supply initially). I've rebuilt several motors, SBF, SBC, 4 bangers, V6s, L-6 etc and never blown any of them up. Hell, the 302 ford I built for oval dirttrack, I didn't even give it a chance. Warmed it up and raced it...straight off the trailer. (late getting to the track). I won that heat and the engine never gave up, no matter how badly I valve floated it!! I don't know if boosted applications make any difference to break in, but I would assume not. I think that you are good to go. Tim Quote Link to comment Share on other sites More sharing options...
Guest oldZguy Posted October 7, 2003 Share Posted October 7, 2003 I'm with Tim, usually the engines I've rebuilt have an hour or two of running time on them with looking for leaks, adjusting valves, the usual stuff. After that I break them in like I'm going to be driving them. Never had a failure. Overall engine life reduced because of that?? Considering the way I drive the engine is going to be seeing redline every day, hard to tell. Wasn't ever planning on getting 200K miles out of it anyway... Quote Link to comment Share on other sites More sharing options...
ratedZ Posted October 7, 2003 Author Share Posted October 7, 2003 WOW you guys put a smile on my face that's great news. However, I still should follow the specified break in period for the clutch right? 500 miles for the clutch...better than 1500, it would take me a year to do that Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 7, 2003 Share Posted October 7, 2003 As long as you aren't slipping/overheating the clutch, you should be fine. Tim Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted October 7, 2003 Share Posted October 7, 2003 WOW you guys put a smile on my face that's great news. However, I still should follow the specified break in period for the clutch right? 500 miles for the clutch...better than 1500, it would take me a year to do that Definitely follow the break-in for the clutch. If you get hot spots, the clutch will go bye-bye. If it's broken-in nicely, it'll work very well. Quote Link to comment Share on other sites More sharing options...
fl327 Posted October 7, 2003 Share Posted October 7, 2003 hey rated, what does the stage 4 pedal feel like? I just broke in stage 2 spec clutch, and its softer than the valeo clutch in my 2+2!!! it grabs, but im not completely happy.. Quote Link to comment Share on other sites More sharing options...
ratedZ Posted October 7, 2003 Author Share Posted October 7, 2003 I haven't really had the chance to break her in yet so I'm not sure how much this thing can handle. It does hold boost up to 16psi though no problem. The pedal is pretty stiff but I've gotten used to it and is not that bad at all. The engagement is very tolerable and I've learned to drive it where I barely get the jolt...it is pretty harse though at wide open throttle but I'm ok with it. It came with the 6-puck racing disk but it's got the sprung hub...which makes the disk very streetable. Quote Link to comment Share on other sites More sharing options...
Guest szlash280z Posted October 7, 2003 Share Posted October 7, 2003 I know jack about clutches. with that in mind, heres my question! 8) Do the springs on the clutch disk help to reduce the harshness of the engagement? Quote Link to comment Share on other sites More sharing options...
ratedZ Posted October 7, 2003 Author Share Posted October 7, 2003 Yes, the springs absorb the impact of the engagement. Spec sells the flat disks, I can't even begin to imagine how harsh those engage. Definitely made just for racing apps. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted October 8, 2003 Share Posted October 8, 2003 wow... you know I just asked this question about breaking in the rings like a week ago, and got completely different responses.... the main consensus was at least 500 miles. You might want to read that thread: http://hybridz.org/phpBB2/viewtopic.php?t=26413 now when I suggested to them that the rings were pretty much broken in after the engine had been run for only a brief period, that idea got shot down fast. Now just yesterday I had a problem where I think I might have damaged the rings on one of my pistons... and someone said to me it's because I haven't been going easy on it during the first 500 miles like they TOLD me. I've already put about 200 miles on the motor, and from what I read here, that means it was well broken in. Interesting.... Quote Link to comment Share on other sites More sharing options...
Guest oldZguy Posted October 8, 2003 Share Posted October 8, 2003 Wasn't part of your problem though that you overheated? (if I remember correctly) If you did I would say warped head before rings. I'd say there are as many thoughts as to how to break in an engine as there are to skin cats... I guess it depends upon what your final useage is. If you want an engine that will give you the maximum life, 200K + miles then slow and easy is probably the way to go. I figure 50K or less on my engines is a long life because of the way I drive them. By then I've either gotten rid of the car, broke the engine, or am rebuilding it going bigger better... If you push it to it's limits on a regular basis it's only going to last so long. I'm not saying that the long break in is wrong, just not necessary in my opinion. There are just too many examples of cars that are broken in doing the wrong thing that live long and happy lives. Police cars, rental cars, taxis, delivery vechials, none of them are broken in "right" but all of them log 100K miles or more without an engine rebuild..... Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted October 8, 2003 Share Posted October 8, 2003 yeah it overheated, but it's not the gasket that went out... I did a compression test and all signs point to broken rings on cylinder #5... Quote Link to comment Share on other sites More sharing options...
Tim240z Posted October 8, 2003 Share Posted October 8, 2003 yeah it overheated, but it's not the gasket that went out... I did a compression test and all signs point to broken rings on cylinder #5... You could have blown the gasket at Cyl #5. Tim Quote Link to comment Share on other sites More sharing options...
Guest oldZguy Posted October 8, 2003 Share Posted October 8, 2003 I would suspect something worse myself, not that broken rings wouldn't be really bad. If you reused old pistons, nothing wrong in that, I would be thinking cracked/broken piston. If you had a lot of preignition during the overheat maybe a hole burned through #5. Are you getting excessive blow by out of the crankcase? If you have a mechanical oil pressure gauge you can often see a tick in the needle when you blow a head gasket through to an oil port, with a stock electric gauge you would probably be hard pressed to see the change, if you blow through to a coolent passage you can usually watch the radiator cap do a dance while the engine runs. I guess where I want to go with this is that it probably wasn't a case of inproper break in that got you, it was the overheat. If you built the engine tight, like I do, then the overtemp took you out of spec and you may have lost your ring gap and yes broke a ring. I always build to minimun spec and a moment of lost oil pressure or overtemp can break you faster than you can say... well pick you most favorite 4 letter word! I hope that you blew a head gasket, that would be the easiest fix. Second would be a hole in/cracked a piston, at least you can replace it with the engine in the car. Broke ring, worst case, boring the cylinder, best case, freshing up the hone job. Worst case there being that you will have to pull the engine and pull it apart to get the work done Broke ring best case you can do it in the car if you are very clean about your work. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted October 8, 2003 Share Posted October 8, 2003 yeah I've considered the possibility that it's the piston. I dont think it's the gasket, because there is oil in that cylinder now, and as far as I know the closest oil passage is between the #3 and #4 cylinders... I can't see how the gasket would have blown in a way that oil would get to the #5. I'm not gonna try to do a rebuild with the motor in the car again... I'm either gonna get another block and rebuild it, or just buy a whole long block. Quote Link to comment Share on other sites More sharing options...
Sean73 Posted October 9, 2003 Share Posted October 9, 2003 Just having built a new L28ET, I'm interested in the "proper" break in procedure as well. I've read a lot of break-in information, and some of it I find hard to believe. For one, why does mileage have anything to do with seating the rings properly? Rings don't see mileage - they see RPM and load. So, one could conclude that a low-revving Chevy V8 would have a different break-in period compared to a hi-revving Ducati motorcycle. Secondly, if mileage was the rule of thumb for break-in, then one could conclude that taking a 1500 mile highway trip would complete the break-in. That would be the worst possible method of break-in, because at highway cruising speed, the engine is not under load. Consequently, the rings aren't pressing against the cylinder walls as firmly as possible. The same holds true if you drive around too gently - the rings won't seat that way. If you drive the car too gently during break in- what's going to happen when you turn up the boost? The rings will see a heat and pressure environment that they have not been subjected to before. Will the ring seal provided during the 5 psi break-in be adequate for 15 psi of boost? It doesn't make sense to me to subject the rings to an operating environment that doesn't reflect normal driving. It also does not make sense to me that a motor needs 500 or 1500 miles of driving to be "broken in". By then, the motor has turned over a million times. I highly doubt that the cylinder walls and rings are so hardened that it takes a million revolutions for the microscopic ridges of metal to mate against each other. I believe the first few minutes of driving are the most critical in engine break in (I'm not the only one that believes this), and then it probably drops off exponentially with time (thats my theory atleast). When I first fire up my motor, I'll warm it up and take it for a spin. I'll subject it to a variety of conditions by varying load, rpm and boost in a systematic way. A country road with lots of curves will be perfect. Sean 73 240Z, L28ET, T3/T04E, NPR IC, 84 Z31T ECCS, 3" Exhaust (build in progress) Quote Link to comment Share on other sites More sharing options...
Guest oldZguy Posted October 9, 2003 Share Posted October 9, 2003 I like your way of thinking Quote Link to comment Share on other sites More sharing options...
Guest jt240z Posted October 9, 2003 Share Posted October 9, 2003 I broke my engine in on a chassis dyno when we were doing the initial tuning session on my Haltech. The engine started with 15 miles on it. By the time 3 hours of tuning (and many 16 psi runs) were done, my engine was broke in. The tuner (Matt Hitman from Australia) said he could actually "feel" when the engine broke in completely. After all was done, I asked him what I needed to do to finish the break in, he said "Your done.". Quote Link to comment Share on other sites More sharing options...
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