z28lt1rocket

ok like the title says I was wondering if there was any special technique or modification you can do on a lt1 engine or a chevy 350 for that matter that will make bearing failure almost impossibel. because no matter how well a motor is built in general the higher the rpms you turn and sustain the more prone to bearing failure you are.

cam bearings are the easiest to modify or fix you can A) you can go with a bigger cam journal which will more evenly distribute load or go to a roller cam bearing but rod and main bearings are the most suseptible to failure and 6000 rpms isnt bad for a few seconds but 7500 rpms and above for 20- 30 seconds or more and your engine is toast even if its broke in in ideal situation with .oo2 clearance and a balanced rotating assembly properly broken in with 5000 or more miles on the motor it still wont last at 7500 where theres f1 and nhra cars turning 11000+

what canm you do to make a chevy 350 sustain higher rpms with out bearing failure. Thanks in advance alex.

ss.slp.ls1

iTrader: (36)

How high do you plan on spinning your motor?
How much power are you planning on making?
FYI you can properly build a motor that can spin higher than your PCM's computing capabilities can handle...

fleetmgr

There's no surefire way to completely prevent a bearing failure from EVER happening. But there's lots of stuff you can do to move in that direction. As has been mentioned, you can easily build an SBC that will exceed the RPM capacity of your computer. Part of that comes from meticulous engine assembly, part of it comes from premium parts. A whole lot of it comes from having the internals of the engine cleaner than you'd want your dishes to eat off of. And so on and so forth.

You're doing a little of the apples and oranges thing in your question, though. F-1 engines get their high revving ability from roller bearing crankshafts and so on, no to mention small displacement and therefore reduced reciprocating weight . The top fuel guys tear the engine down after every round. Both of those examples also have cubic money to play with, so bearings (in top fuel) are considered a consumable the same way you or I would go through paper towels.

My95Z

iTrader: (8)

Like stated above, no sure way, but several areas need to be paid attention to during the build that could prevent spinning a bearing.

First off the oiling system needs to be up to the task, not only do you need good pressure at a given rpm, you need good oil, and the correct thickness. Bearing clearances are also critical, some people get into the way of thinking tighter is better when in reality that is about the worse thing you can do. I have and will never build a Gen 1 or 2 with rod bearing clearances tighter than .002 and about .0025 on the mains with a little more on both the #1 and #5. Balancing is also key, at high rpm's a misbalanced motor will "eat" its bearings causing failure.

You also have to have everything fastened correctly this means good rod/main bolts that are up to the task and won't stretch. Its all a balancing act, an engine built to run at high rpm's for long periods of time won't do well sitting in traffic idling so you have to build it for your use.

speed_demon24

iTrader: (6)

The only thing you need to do is find a competent engine builder. 7500 RPM's is nothing for a properly build SBC.

mdacton

iTrader: (3)

nothing at all......

these are the easiest engine to do it with

96capricemgr

iTrader: (1)

I third the motion.


Problem is people trust shops that build reputations on advertizing or low prices. a "cheap" engine is not inexpensive when it self destructs at 5000miles, spent 5-10% more upfront using better parts and machining and the engine casn see 50,000 miles instead.

There is a guy who used to post on here who has a Lingenfelter 383 from the mid 90s, he updated the heads and cam and it runs low 11s reliably. Other guys buy a cheap engine from one particular board sponsor and have the crank eat the bearings at 5000 miles and only have made 325rwhp. Who got the better deal? Egven if the Lingenfelter motor cost twice as much it was FAR cheaper.

wrd1972

iTrader: (12)

OMG I cant believe I am agreeing with Speed and Cap on something. Next I will be voting Democrat.

mdacton

iTrader: (3)

Thats alan I am pretty sure...he is still using that engine....

I have almost 200 passes on my engine, had it apart 3 times and all bearing are like brand new. reused em everytime..... I spent 12 hours clearancing those bearings. And I have done several since then for my builder I guess so I would learn it.... But it was well worth the time to learn how to do something the right way instead of these fly by night shops that put out crap

z28lt1rocket

thanks guys sounds good I also did some passive research and theres bearing with teflon coatings on them you can get and and a well balanced motor like what was previously said I've found out...


plus once I do turn it past 7000 rpms and it is out of the computers capabilities what can or should I do and I DONT WANT TO GO CARBED the only thing is some aftermarket computer?

ss.slp.ls1

iTrader: (36)

Yes, aftermarket air/fuel management system. Not sure what the popular systems are though...I only shift at 6500 rpm