disturbing find today/motor ready to blow
11-05-2004, 04:49 PM
#122
Registered User
Originally Posted by Sharp Chuter,Nov 5 2004, 02:07 PM
Seems like anyone who races the car on a track or drives aggressively on twisty roads COULD be risking an over-rev even without missing a shift (getting 1st when trying for 3rd or getting 2nd when trying for fourth). Here's my worry:
Approaching a corner on the track, I'm standing on the brake while trying to double-clutch, rev-match a downshift to the next lower gear to give me good power coming out of the corner. When you let the clutch out is CRITICAL! The car is decelerating rapidly as you brake... You get it into the lower gear and try to guess when your speed is low enough to be safe for the lower gear. Let the clutch out too early and you're over-revving. Not by much, probably, (not like shifting to second from a red-lined third) but over-revving none the less.
I'm going to check my retainers tomorrow. There's some great information in this thread. Thanks to everyone who has contributed.
Approaching a corner on the track, I'm standing on the brake while trying to double-clutch, rev-match a downshift to the next lower gear to give me good power coming out of the corner. When you let the clutch out is CRITICAL! The car is decelerating rapidly as you brake... You get it into the lower gear and try to guess when your speed is low enough to be safe for the lower gear. Let the clutch out too early and you're over-revving. Not by much, probably, (not like shifting to second from a red-lined third) but over-revving none the less.
I'm going to check my retainers tomorrow. There's some great information in this thread. Thanks to everyone who has contributed.
11-05-2004, 04:55 PM
#123
Registered User
Originally Posted by billman250,Nov 5 2004, 03:48 PM
More titbits...
-The engine I'm working on now has 8 bent exhaust valves, and broken intake retainers. So the intakes never made contact with the piston, but broke the retainers like the original car in this thread.
-The engine I'm working on now has 8 bent exhaust valves, and broken intake retainers. So the intakes never made contact with the piston, but broke the retainers like the original car in this thread.
However, the intake valve closes when the piston is near the bottom of its stroke. It would have to float for almost 1/2 of a crankshaft revolution to get hit by the piston. If the engine were over-revved that badly, I suspect that all kinds of failures would be cropping up and it would be hard to determine what broke first.
11-06-2004, 05:21 AM
#126
Registered User
Originally Posted by RedY2KS2k,Nov 5 2004, 09:49 PM
This scenario highlights why the digital speedometer SUCKS. IT'S A SECOND-RATE PIECE OF CRAP!!!!! The expletive-deleted piece of expletive-deleted tells you how fast you were going a couple of seconds ago, and gives no information about rate of change. Perfectly acceptable on a mini-van...
This even reminds me of the recent "my shifter wiggles" thread...
11-06-2004, 05:27 AM
#127
Registered User
Originally Posted by RT,Nov 6 2004, 02:07 AM
... or you whiners could just learn how to drive ...... maybe? just an idea 
We all make mistakes but up till now a mis-shift at 6-7k RPM wasn't a problem. Add more revs and mistakes get to be more critical. I'd like to see retainers that weren't quite so easy to crack but I don't know at what RPM they start to crack and where it should be moved to. I also don't know if it's a materials problem, a design problem or what.
I do know that I've hit the hard limiter a few times quite solidly and would like to know if there's a problem waiting to happen there. Is it possible to observe all valves without removing anything other than the valve cover? Use of mirrors is very acceptable...
11-06-2004, 07:13 AM
#128
Moderator
Thread Starter
I've found a lot of guys are new to manual transmissions when they got the S2000. I think a deathgrip on the shift knob has a lot to do with it. When attempting 3-4, it's easy to pull into second when you're deathgripping the shifter. I personally go 3-4 with two fingers, even on the track.
11-06-2004, 07:24 AM
#129
Moderator
Thread Starter
jquerdat...If you hit the limiter while on the gas, even hard, I think you'll be fine. IMHO this is all happening beyond 9200, which can only happen mechanically (aided rpm's from the inertia of the car from a "wrong gear" missed shift).
I think there's a big confusion with this subject too....If your wide open in third; atempt to shift to fourth, and find neutral instead; let the clutch out and floor the gas, bouncing off the rev limiter...this is NOT the type of missed shift that causes this over-rev scenario.
I think there's a big confusion with this subject too....If your wide open in third; atempt to shift to fourth, and find neutral instead; let the clutch out and floor the gas, bouncing off the rev limiter...this is NOT the type of missed shift that causes this over-rev scenario.
11-06-2004, 01:52 PM
#130
Registered User
Thanks for the information, Billman 250. It looks like the cams and retainers will be coming off this winter while the car is parked, just in case. If I gotta do the work, I might as well replace them while they're off...