Dilema. to overbore or not overbore.
03-26-2009 | 08:35 AM
#21
lol.. rookie didnt read the entire comment thats all. but as for the overboring c.p put a stop to the ups package and are sending me the 96.00bore. its only gonna cost me 350$ to machine the block to the piston size. as for the bearings i was told even stock should sufice since they are pretty good from factory. feel free to chime in as to why or why not aftermarket bearings.
03-26-2009 | 11:21 AM
#24
Clearance philosophy varies between engine builders/machinists, most important thing is to find one that knows what they are talking about and ask many questions, it is nice to find one that does race engines as well as street engines so he knows and can do what you need.
03-26-2009 | 11:40 AM
#25
main reason is proper lubrication, the assumption is that a built engine is going to be revving high and hard so increasing the clearances a bit allows for oil to lubricate the journals, but to much clearance is also bad.
Clearance philosophy varies between engine builders/machinists, most important thing is to find one that knows what they are talking about and ask many questions, it is nice to find one that does race engines as well as street engines so he knows and can do what you need.
Clearance philosophy varies between engine builders/machinists, most important thing is to find one that knows what they are talking about and ask many questions, it is nice to find one that does race engines as well as street engines so he knows and can do what you need.
So then would it be fair to say that you might be more prone to see problems if someone were to build your forged motor to stock tolerances? Where as it is less likely to see problems with slightly "looser" tolerances??? All for the sake of lubrication. Hmmm. Interesting. How much difference are we talking about? .001-.003?
03-26-2009 | 12:20 PM
#26
it would depend how hard you drive it, like with any other possible issue
the difference is not huge, and you may not have problems, like I said it depends on how hard you plan to drive it. Again it is best to not let forum experts tell you what to do, find a good builder/machinist and take their advise, that is what I did and I am very happy with the result.
the difference is not huge, and you may not have problems, like I said it depends on how hard you plan to drive it. Again it is best to not let forum experts tell you what to do, find a good builder/machinist and take their advise, that is what I did and I am very happy with the result.
03-26-2009 | 02:06 PM
#27
Bearing clearances will vary from builder to builder, and components to components. The rev range of the engine, where it's torque is made (and sustained), whether the engine will see constant high rpm use, vs a constant sweeping of rpm, all comes into play as far as bearing clearances. Components matter as well, as the amount of "swell" vary from rod to rod, piston to piston as alloys differ. It can get mindnumbing to try to understand, and as westpak mentioned, this is where a good machinist is absolutely invaluable. Putting the engine together is one thing...the machining though is critical
The stock Nissan bearings certainly work well - deciphering what is needed takes some patience, a good machinist, and a factory service manual as there are many variances. Rather than talking to the shop who may put the engine in the car, I'd personally try to talk to the person who does the machine work. Aftermarket bearings can make things easier, as there are just less sizes to choose from. The flipside is that means having to pay a bit more for machining costs as you clearance your components to match the bearings.
There are plenty of places that literally drop a set of pistons into an otherwise stock engine and let it go (without even checking the bore consistency..scary stuff). Sometimes it works, sometimes it doesn't. Given the cost of honing being relatively low vs the potential cost of having to do everything over again should a piston or rod decide it needs to see what the sunshine looks like, I'd never suggest to anyone they merely drop pistons into a block, even one that is brand new from Nissan, without at least having it checked. It's not uncommon to find stock bores that aren't 100% uniform even from new.
The stock Nissan bearings certainly work well - deciphering what is needed takes some patience, a good machinist, and a factory service manual as there are many variances. Rather than talking to the shop who may put the engine in the car, I'd personally try to talk to the person who does the machine work. Aftermarket bearings can make things easier, as there are just less sizes to choose from. The flipside is that means having to pay a bit more for machining costs as you clearance your components to match the bearings.
There are plenty of places that literally drop a set of pistons into an otherwise stock engine and let it go (without even checking the bore consistency..scary stuff). Sometimes it works, sometimes it doesn't. Given the cost of honing being relatively low vs the potential cost of having to do everything over again should a piston or rod decide it needs to see what the sunshine looks like, I'd never suggest to anyone they merely drop pistons into a block, even one that is brand new from Nissan, without at least having it checked. It's not uncommon to find stock bores that aren't 100% uniform even from new.
Last edited by Z1 Performance; 03-28-2009 at 08:58 AM.
03-26-2009 | 03:07 PM
#28
So then would it be fair to say that you might be more prone to see problems if someone were to build your forged motor to stock tolerances? Where as it is less likely to see problems with slightly "looser" tolerances??? All for the sake of lubrication. Hmmm. Interesting. How much difference are we talking about? .001-.003?
03-28-2009 | 06:19 PM
#29
Whats the status of your motor now? Actively being rebuilt or already done? Did BuiltZ motors accept any culpability in their machining flaw? This is what gets me...no one stands behind their work. They are all too quick to point fingers and deny any responsibility.
Many motor assembly company lure you in with warranty promises, but when push comes to shove the warranty only covers machining defects. Do you have any idea how hard it is to prove "machining defects". They might as well say "We will cover you motor loss if its raining chickens outside in the middle of summer and then pigs fly..." or some nonsense like that. In my opinion motor warranties are useless. Why bother having them? Nothing race oriented is guaranteed. Period!
03-29-2009 | 08:37 AM
#30
I did end up shipping my stock bore Arias pistons back this week and swapping them for .020 overbore. I have decided that Sound Performance is the place that I am going to get everything done. Not only because they are somewhat local, but because both Sound Performance and AMS use the same machinest. Obviously both these shops have a ton of different builds under their wings including the EVO that whopped us last year at Pikes Peak Hillclimb 
03-29-2009 | 08:42 PM
#31
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From: under the hood
primer: http://www.mahleclevite.com/it_bearinginstall.asp
bearing style is more important then "extra" clearance,under load stock style bearings tend to squeeze the crank.performance bearings are often not concentric and allow the rod to stretch without the squeeze.......but what do i know....
P Series:
Clevite's P series are the original staple bearing. Recommended for stock rebuilds up to medium performance use, these tri metal bearings are made from TM-77 material. They start with a hardened steel back for strength and support. Over that is a cast copper lead lining to provide the durability and support to withstand the loads of engine operation. Then a nickel plating is applied to prevent interaction between the copper lead and the final layer, a strong, extra thin (.001" or less) electroplated overlay of babbitt. Babbitt is a tin or lead based alloy with varying amounts of antimony, copper or arsenic which is designed to resist flaking and is very soft by nature. This helps to give the bearing embedability (the ability for stray particles to be "absorbed" by the bearing so they don't rip the crank journal to shreds), conformability (the ability of the bearing to "conform" or adapt to any out of spec surfaces or distortion) and resistance to both seizure and corrosion while still withstanding the high loads a performance engine can generate. Finally they are flash plated with a lead/tin mixture to help protect them and mostly make them look better, (yes this step is mostly cosmetic.) These bearings have high crush for better retention and their high eccentricity helps to accommodate any housing bore distortion. These are a good quality line of bearings, however if you are building an engine that is highly modified, such as aftermarket cylinder heads, etc, you will probably want to think about upgrading to one of the performance bearings listed below. P series are not clearanced for aftermarket cranks with larger crankshaft fillets, although they will usually still work correctly, and any competent shop should be able to easily perform this operation to them if needed. (See below for more details on this)
H Series:
Originally developed for Nascar racing, H series are made of the same TM-77 material as the P series, and include most of the features described above, however they are not flash plated with the lead/tin apparently in an effort to help them seat better. They also have enlarged champhers to help them clear bigger crankshaft fillets. In rod bearings, these are available in .001" oversize, standard (.000") and .001" undersize, making them an ideal choice for those who want more flexibility in setting their clearances. they also have a medium level of eccentricity. A good overall performance bearing, especially if you need the precision sizes.
M Series:
"M" stands for Micro Babbitt, and these bearings are made of Clevite's B-2 material. This consists of a hardened steel backing, to which a .006" thick layer of babitt material is bonded. Because babbitt is very soft, these bearings have an outstanding level of conformability, (the ability of the bearing to "conform" or adapt to any out of spec surfaces or distortion) for applications where the crankshaft may be subjected to severe deflection under load. However, the downside of this is that the life of these bearings can be very short, and these are generally considered a "race only" item. Although some engine builders are familiar with and prefer this style of bearing, it is generally accepted that the V series will do just as good a job without the short lifespan, making the M series in our opinion, not the best choice for all but the most specialized of applications.
V Series:
The "V" series were originally manufactured by the Vandervell company in England, Clevite bought Vandervell and is now distributing their bearings under the Clevite name as the "V" series. We feel the "V" series are a great choice for performance bearings. "V" series have found their way into nearly every form of motorsports with virtually no problems. Nearly 100% of 8000+ horsepower top fuel drag racing teams use them. They are almost universally used in Pro Stock and Winston Cup. Cosworth Formula one engines that turn 11,000 RPM for extended periods of time use them with great success. These bearings are still a tri metal bearing, however they use a lead indium overlay instead of the babitt in the above bearings. Lead Indium has amazing properties. It has a super low surface friction coefficient or lubricity, meaning wear at startup before the engine can develop oil pressure is greatly reduced. It can withstand and operate at higher temperatures for longer periods of time. It will resist flaking and peeling under extreme loads better than any other bearing. It has the highest resistance to corrosion of any bearing material, and it does all this while still having unsurpassed properties of embeddability, conformability and fatigue strength. And the best part is just because these perform so exceptionally in a racing environment, there is no reason they can't be used with equal success in a street car or in milder performance engines as well.These have a low to medium level of eccentricity, and also are usually narrowed to help them clear bigger crankshaft fillets (see details below.). These are a very nice choice for nearly all performance applications.
bearing style is more important then "extra" clearance,under load stock style bearings tend to squeeze the crank.performance bearings are often not concentric and allow the rod to stretch without the squeeze.......but what do i know....
P Series:
Clevite's P series are the original staple bearing. Recommended for stock rebuilds up to medium performance use, these tri metal bearings are made from TM-77 material. They start with a hardened steel back for strength and support. Over that is a cast copper lead lining to provide the durability and support to withstand the loads of engine operation. Then a nickel plating is applied to prevent interaction between the copper lead and the final layer, a strong, extra thin (.001" or less) electroplated overlay of babbitt. Babbitt is a tin or lead based alloy with varying amounts of antimony, copper or arsenic which is designed to resist flaking and is very soft by nature. This helps to give the bearing embedability (the ability for stray particles to be "absorbed" by the bearing so they don't rip the crank journal to shreds), conformability (the ability of the bearing to "conform" or adapt to any out of spec surfaces or distortion) and resistance to both seizure and corrosion while still withstanding the high loads a performance engine can generate. Finally they are flash plated with a lead/tin mixture to help protect them and mostly make them look better, (yes this step is mostly cosmetic.) These bearings have high crush for better retention and their high eccentricity helps to accommodate any housing bore distortion. These are a good quality line of bearings, however if you are building an engine that is highly modified, such as aftermarket cylinder heads, etc, you will probably want to think about upgrading to one of the performance bearings listed below. P series are not clearanced for aftermarket cranks with larger crankshaft fillets, although they will usually still work correctly, and any competent shop should be able to easily perform this operation to them if needed. (See below for more details on this)
H Series:
Originally developed for Nascar racing, H series are made of the same TM-77 material as the P series, and include most of the features described above, however they are not flash plated with the lead/tin apparently in an effort to help them seat better. They also have enlarged champhers to help them clear bigger crankshaft fillets. In rod bearings, these are available in .001" oversize, standard (.000") and .001" undersize, making them an ideal choice for those who want more flexibility in setting their clearances. they also have a medium level of eccentricity. A good overall performance bearing, especially if you need the precision sizes.
M Series:
"M" stands for Micro Babbitt, and these bearings are made of Clevite's B-2 material. This consists of a hardened steel backing, to which a .006" thick layer of babitt material is bonded. Because babbitt is very soft, these bearings have an outstanding level of conformability, (the ability of the bearing to "conform" or adapt to any out of spec surfaces or distortion) for applications where the crankshaft may be subjected to severe deflection under load. However, the downside of this is that the life of these bearings can be very short, and these are generally considered a "race only" item. Although some engine builders are familiar with and prefer this style of bearing, it is generally accepted that the V series will do just as good a job without the short lifespan, making the M series in our opinion, not the best choice for all but the most specialized of applications.
V Series:
The "V" series were originally manufactured by the Vandervell company in England, Clevite bought Vandervell and is now distributing their bearings under the Clevite name as the "V" series. We feel the "V" series are a great choice for performance bearings. "V" series have found their way into nearly every form of motorsports with virtually no problems. Nearly 100% of 8000+ horsepower top fuel drag racing teams use them. They are almost universally used in Pro Stock and Winston Cup. Cosworth Formula one engines that turn 11,000 RPM for extended periods of time use them with great success. These bearings are still a tri metal bearing, however they use a lead indium overlay instead of the babitt in the above bearings. Lead Indium has amazing properties. It has a super low surface friction coefficient or lubricity, meaning wear at startup before the engine can develop oil pressure is greatly reduced. It can withstand and operate at higher temperatures for longer periods of time. It will resist flaking and peeling under extreme loads better than any other bearing. It has the highest resistance to corrosion of any bearing material, and it does all this while still having unsurpassed properties of embeddability, conformability and fatigue strength. And the best part is just because these perform so exceptionally in a racing environment, there is no reason they can't be used with equal success in a street car or in milder performance engines as well.These have a low to medium level of eccentricity, and also are usually narrowed to help them clear bigger crankshaft fillets (see details below.). These are a very nice choice for nearly all performance applications.
Last edited by go-fast; 03-29-2009 at 09:07 PM.
03-29-2009 | 09:00 PM
#32
Was the tapering done to match the piston design? I personally don't know of any piston that is designed that way, but I am no expert.
Whats the status of your motor now? Actively being rebuilt or already done? Did BuiltZ motors accept any culpability in their machining flaw? This is what gets me...no one stands behind their work. They are all too quick to point fingers and deny any responsibility.
Many motor assembly company lure you in with warranty promises, but when push comes to shove the warranty only covers machining defects. Do you have any idea how hard it is to prove "machining defects". They might as well say "We will cover you motor loss if its raining chickens outside in the middle of summer and then pigs fly..." or some nonsense like that. In my opinion motor warranties are useless. Why bother having them? Nothing race oriented is guaranteed. Period!
Whats the status of your motor now? Actively being rebuilt or already done? Did BuiltZ motors accept any culpability in their machining flaw? This is what gets me...no one stands behind their work. They are all too quick to point fingers and deny any responsibility.
Many motor assembly company lure you in with warranty promises, but when push comes to shove the warranty only covers machining defects. Do you have any idea how hard it is to prove "machining defects". They might as well say "We will cover you motor loss if its raining chickens outside in the middle of summer and then pigs fly..." or some nonsense like that. In my opinion motor warranties are useless. Why bother having them? Nothing race oriented is guaranteed. Period!
On the bright side, I finally got the new short block back on Friday and hopefully the motor will be put together by next week.
03-31-2009 | 06:28 PM
#35
Banned
Joined: Jun 2007
Posts: 1,342
Likes: 0
From: under the hood
acl bearing info at bottom of page
http://www.acl.co.nz/Tech/ACL%20Race%20Series.pdf
they seem to be steel backs,copper and lead,eccentric race bearing.not bad,but not leading the pack either.
http://www.acl.co.nz/Tech/ACL%20Race%20Series.pdf
they seem to be steel backs,copper and lead,eccentric race bearing.not bad,but not leading the pack either.
Last edited by go-fast; 03-31-2009 at 07:26 PM.
03-31-2009 | 06:44 PM
#36
primer: http://www.mahleclevite.com/it_bearinginstall.asp
bearing style is more important then "extra" clearance,under load stock style bearings tend to squeeze the crank.performance bearings are often not concentric and allow the rod to stretch without the squeeze.......but what do i know....
V Series:
The "V" series were originally manufactured by the Vandervell company in England, Clevite bought Vandervell and is now distributing their bearings under the Clevite name as the "V" series. We feel the "V" series are a great choice for performance bearings. "V" series have found their way into nearly every form of motorsports with virtually no problems. Nearly 100% of 8000+ horsepower top fuel drag racing teams use them. They are almost universally used in Pro Stock and Winston Cup. Cosworth Formula one engines that turn 11,000 RPM for extended periods of time use them with great success. These bearings are still a tri metal bearing, however they use a lead indium overlay instead of the babitt in the above bearings. Lead Indium has amazing properties. It has a super low surface friction coefficient or lubricity, meaning wear at startup before the engine can develop oil pressure is greatly reduced. It can withstand and operate at higher temperatures for longer periods of time. It will resist flaking and peeling under extreme loads better than any other bearing. It has the highest resistance to corrosion of any bearing material, and it does all this while still having unsurpassed properties of embeddability, conformability and fatigue strength. And the best part is just because these perform so exceptionally in a racing environment, there is no reason they can't be used with equal success in a street car or in milder performance engines as well.These have a low to medium level of eccentricity, and also are usually narrowed to help them clear bigger crankshaft fillets (see details below.). These are a very nice choice for nearly all performance applications.
bearing style is more important then "extra" clearance,under load stock style bearings tend to squeeze the crank.performance bearings are often not concentric and allow the rod to stretch without the squeeze.......but what do i know....
V Series:
The "V" series were originally manufactured by the Vandervell company in England, Clevite bought Vandervell and is now distributing their bearings under the Clevite name as the "V" series. We feel the "V" series are a great choice for performance bearings. "V" series have found their way into nearly every form of motorsports with virtually no problems. Nearly 100% of 8000+ horsepower top fuel drag racing teams use them. They are almost universally used in Pro Stock and Winston Cup. Cosworth Formula one engines that turn 11,000 RPM for extended periods of time use them with great success. These bearings are still a tri metal bearing, however they use a lead indium overlay instead of the babitt in the above bearings. Lead Indium has amazing properties. It has a super low surface friction coefficient or lubricity, meaning wear at startup before the engine can develop oil pressure is greatly reduced. It can withstand and operate at higher temperatures for longer periods of time. It will resist flaking and peeling under extreme loads better than any other bearing. It has the highest resistance to corrosion of any bearing material, and it does all this while still having unsurpassed properties of embeddability, conformability and fatigue strength. And the best part is just because these perform so exceptionally in a racing environment, there is no reason they can't be used with equal success in a street car or in milder performance engines as well.These have a low to medium level of eccentricity, and also are usually narrowed to help them clear bigger crankshaft fillets (see details below.). These are a very nice choice for nearly all performance applications.
04-01-2009 | 06:40 PM
#38
Banned
Joined: Jun 2007
Posts: 1,342
Likes: 0
From: under the hood
i only used clevite website as an example of styles available,there are far more styles than what's listed on that link.....i was trying to keep it 101
04-01-2009 | 06:59 PM
#40
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From: under the hood
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