The cylinder will not crash into a valve...I think you mean piston. Unless your timing belt jumps/breaks, it would be very difficult to have piston-to-valve contact at a high rpm, even with stock springs. (downshifting from 5 to 2 can do this

You do need to take valve float into consideration though. I would not rev past 8500rpm on stock springs and retainers. Also, when using high domed pistons, it is very important to clay the motor. Claying will allow you to measure the distance from the piston to the valve. (make sure you use your largest lobe...VTEC lobe)

If you are using a stock LS block, the next weakest link are the rod bolts. They tend not to hold on when revving past 8.5k.

 

LS/VTEC's can be any compression that you want. You are correct. High compression and boost can be dangerous. I know a guy with 11.0:1 compression with a turbo...he made over 300hp with a VERY GOOD TUNE.

I know another guy running an LS/VTEC with lower compression that made over 450hp.

It all depends on how you set up the engine, and how good your tuner is.

 

If the stock LS engine can take 8.5K rpm then why is the stock fuel cutoff at 6.8K? Is it safe to manually raise the rpms on a healty LS using hondata/uberdata or some other engine management while still using a stock block? Obviously it is there for a reason...i just can't think of why it would be so low if the engine can take that much abuse...

 

Honda did not intend to put race engines in all of their vehicles. They designed engines that would last 100-200,000 miles, sip gas, and that was it. When you start modify an engine, you are taking away from the life of the engine. Have you ever heard this little saying"

R-uins
P-eoples
M-otors

Will the engine handle 10,000rpm??? Probably, but not for 100,000 miles.

Raising your redline is not something you should do unless you take the correct steps to "re-inforce" your engine. (larger rod bolts, block brace, dual valve springs, Ti retainers, etc)

Does this help you any?

 

YES, thanks a ton dude. I read in one of your previous posts you mentioned not revving past 8.5 without upgrading stock valve springs, retainers, and rod bolts. I would like to build a high revving engine (redline at 8Krpm-fuel cutoff @ 8.5Krpm); is upgrading these parts the best place to start? Reliability and engine longevity are of utmost importance to me as well... What kind of investment would i be looking at to make all this happen?

 

my second favorite choice high compression turbo

 

i am running import builder dual valve springs and titatanium retainers, the head can handle plenty of rpm, and i have no headwork done at the moment, i should be ableto make my goal of 190 with no headwork with my compression,the intake manifold im using, the cams im using, with my header and hondata its quite possible to make 200............



my ls vtec is going to be around 12:1 compression,and it will not be boosted......

 

The springs and retainers will cost anywhere from $200-400. Most aftermarket rods come with larger/better rod bolts. Cost--$300-1000+

If you are building a daily driven LS/VTEC, and reliability and engine longevity are your top priorities, I would make sure to purchase the aftermarket springs/retainers, and strong rods. I have stock springs on my Type R, but I've been known to take the occasional dip to 10,000rpm.(I don't advise doing this regularly)

If you need any help finding this stuff let me know, I am a dealer for Rocket Motorsports.

 

my set-up is 200 to the wheels with no turbo, my compression is 12:1.