supra5677
Pro
Posts: 1279
|
posted April 04, 2007 03:57 PM
unplugged the powercommander and the bike ran fine without it.. Couldn't find correct adapter do do compression test.. have to get some more things organized before I jump back on it.. By the way Doug, if your close to Oakland I could use your help 
   
|
dougmeyer
Needs a job
moderated
Posts: 2713
|
posted April 04, 2007 07:27 PM
You don't need to check the C/R any more. You apparently found the problem.
Sorry, I'm a little far away for a house call......
|
ninja12
Needs a job
Posts: 3310
|
posted April 05, 2007 07:30 AM
Reload the map and try your PC again.
Sometimes they will corrupt the map with a low battery condition.
|
stef12rr
Expert Class
Posts: 144
|
posted April 07, 2007 07:07 AM
the intake cam is install and adjust on ex side on my zx12 04 everythink look good 105 /105
|
supra5677
Pro
Posts: 1279
|
posted April 21, 2007 06:58 PM
did a spark test.. no spark.. Took my bike to shop..he says he turned the motor at the crank and got resistance.. He claims bent valves... The bike has never fired with the new cam only spins the motor.. I asked him if he checked the cam timing and he said no.. Bottom line picking my bike back up from shop.. Only 1 hour labor.I think he's just trying to get my engine apart..
Can you bend the valves if the motor spins and doesnt start?
|
zx12mark
Pro
Posts: 1654
|
posted April 21, 2007 09:15 PM
you would hear the valves banging the pistons
|
tcchin
Zone Head
Posts: 867
|
posted April 21, 2007 09:55 PM
Do a leakdown test - that should confirm valve sealing, as well as gross valve timing. Anything greater than 10% leakage at 100psi would warrant further review. Leakdown testers can be purchased from Summit, Jegs, even HFT. Just be sure the kit includes a 10mm adapter.
|
dougmeyer
Needs a job
moderated
Posts: 2713
|
posted April 22, 2007 02:28 AM
 Edited By: dougmeyer on 22 Apr 2007 03:38
Yes, you can bend the valves and not realize it.
In the second post on this topic almost a month ago Entropy asked about the compression.
This is the easiest thing to check , will absolutely answer the question and still hasn't been done. Give in and borrow or buy a compression tester. Everbody who actually makes mechanical changes to their engines should have a compression tester or a leak rate tester or both. They are essential tools.
For those of you that are really into cam timing changes you'll be able to directly see the results of your changes with the compression pressure tester. You can spend hours at it in the comfort of your garage if you want and actually gather some empirical data.
Doug
|
Y2KZX12R
Needs a job
CompetitionCNC.com
Posts: 3762
|
posted April 22, 2007 02:43 AM
Edited By: Y2KZX12R on 22 Apr 2007 03:51
quote:
unplugged the powercommander and the bike ran fine without it.. Couldn't find correct adapter do do compression test.. have to get some more things organized before I jump back on it.. By the way Doug, if your close to Oakland I could use your help
quote:
did a spark test.. no spark.. Took my bike to shop..he says he turned the motor at the crank and got resistance.. He claims bent valves... The bike has never fired with the new cam only spins the motor.. I asked him if he checked the cam timing and he said no.. Bottom line picking my bike back up from shop.. Only 1 hour labor.I think he's just trying to get my engine apart..
Can you bend the valves if the motor spins and doesnt start?
you disconnected the pc-III and the bike ran fine without it.... but it hasnt run sence you put the new cam in... ???
You need to start with the basics and trouble shoot this thing.
ck fuel
ck spark
ck compression
Once you know what one is missing then you can move on and do a leak down test.
You can bend valves when checking cam timing and not even know it.
There are different degrees of bent valves. valves can be slightly bent and cause compression losses and idle problems, or they can be very bent and not alow any compression.
What cam timings are you running?
What is your intake valve to piston clearance?
____________
Y2KZX12R
CompetitionCNC.com
|
supra5677
Pro
Posts: 1279
|
posted April 22, 2007 06:47 AM
bought compression tester but didnt have proper adapter to use it..
cam timingi is 105/103 intake cam calls for 103.. running .018 thin head gasket stock is .030.. Tried to compensate.. don't trust the shop around the corner from my house so Im just gonna go get it.. he offered to do a leak down test but hes a f**ck*n a******.
1. tuesday get the bike home
2. find proper adapter for compression test
3. if intake valves are bent will replace them
looks like I'll be stuck on wifes bike for a minute..
|
tcchin
Zone Head
Posts: 867
|
posted April 22, 2007 01:47 PM
Slightly off topic: cylinder pressure measured at 300 rpm with a compression tester would be difficult to extrapolate to normal operating conditions and engine speeds because of the thermo- and fluid dynamics at work inside the ports, combustion chamber, airbox and exhaust system. It is interesting to see how cam timing drives cylinder pressure around, though. However, I'm not sure you could use it to predict output vs. RPM very accurately.
|
tcchin
Zone Head
Posts: 867
|
posted April 22, 2007 01:54 PM
Supra,
The compression tester I bought at Autozone included the 10mm adapter. That adapter works with the HFT leakdown tester (94190-2VGA) that I bought some time later, which only came with 14mm and 12mm adapters. BTW, I replaced the gauges on the leakdown tester with 1A-certified, 200-psi Ashcroft gauges to be sure that my readings were accurate and repeatable. (Gauges are most accurate at mid-scale.)
|
dougmeyer
Needs a job
moderated
Posts: 2713
|
posted April 23, 2007 03:07 AM
tcchin,
Oh but you can. It extrapolates well if you test and verify. I have seen repeatable power changes that correlate to cylinder cranking pressure variations made by cam timing changes both on the little dyno and the big salt one.
During engine development on V-8s (single cam) cam centerline a changes clearly change cranking pressure, with lower pressure decreasing bottom end.
It certainly predicts trends.
I was a tech inspector consultant when I was racing mini sprints (GSXR 1000 powered winged midgets), the rules required a stock compression ratio which was verified by a post race compression pressure check.. When pressures started coming up low, we suspected altered cam timing to mask cheater engines. When we did teardowns we found big bores and higher compression engines. Interestingly these guys were better on longer tracks- no bottom end.
Y2? Have you see this?
Doug
|
Y2KZX12R
Needs a job
CompetitionCNC.com
Posts: 3762
|
posted April 23, 2007 07:15 AM
Edited By: Y2KZX12R on 23 Apr 2007 08:25
Doug, i did find that on my 12r back in 2000-2001 when I was trying several cam timings that advancing the intake cam increased cranking compression as expected and increased low and midrange power even thou it increased overlap. so i guess what you are saying is basically the reverse application. using retarded intake cam timing to lower cranking pressure. Its also what I did on my 1375 to make it easier to start hot and cost me quite a bit of peak hp also, so that would indicate a need for more overlap. So aparantly with stock cams the 1375 likes overlap and cranking compression. I would guess because of the short stroke.
Most of my expierience is with single cam v8 engines. Up untill 10 years ago we were building long duration cammed, moderate lift(compared to now), big port, higher cranking compression cam-timed engines for the super comp and comp eliminator classes.
These heads were using full valve circumfrence flow based heads. Now with the smaller port, high valve lift, window based flow heads on the market, cam duration is less, lift is much higher and cranking compression is much lower. This style engine can make more power in the upper midrange where shift recovery rpms are and actually more top end power as well. Low end is very poor untill the port velocity gets up there. but these engines arnt street engines.
Prostock started this trend 10 years ago.
I'm developing a Busa head right now on the flow bench that is heavily reliant on a large window and lots of lift. Taking a page from these engines and the prostock 500 inch play book and seeing if it can be applied to 4 valve 1600cc+ busa engines. The software shows some strange results. We'll see what happens when this head gets on the dyno and real world top speed testing hopefully later this summer.
____________
Y2KZX12R
CompetitionCNC.com
|
tcchin
Zone Head
Posts: 867
|
posted April 23, 2007 09:09 AM
Doug,
I'm not saying that you can't use cranking pressure to generalize about the power delivery, I'm saying that predicting the specific topology of the torque curve would be difficult, particularly at high RPM, particularly without testing. Maybe I'm reading too much into your statement about "directly see[ing] the results of your changes with the compression pressure tester."
|
dougmeyer
Needs a job
moderated
Posts: 2713
|
posted April 23, 2007 06:55 PM
You may have- I was about learing what cam timing yields what cranking pressures in your particular engine. The trends are pretty consistent.
I had particularly good luck playing around at Bonneville one year just changing the cam timing to find the highest cranking pressure. The results on the track were gratifying. It wasn't until I returned home and stuck a degree wheel on it that I actually knew what I was running!
|
supra5677
Pro
Posts: 1279
|
posted May 03, 2007 08:48 AM
got bike out of bad shop, and into reputable shop.. Good news VALVES NOT BENT!! now we go from there..
|
kllrvet
Expert Class
Posts: 148
|
posted May 12, 2007 06:04 PM
what about the friggin compression? Is it making any?
____________
ZX14 cam chain tensioner making noise? I have the set it and forget it fix. PM me if I can help.
|
supra5677
Pro
Posts: 1279
|
posted June 01, 2007 01:59 PM
compression is 175 psi all the way across.. Got bike running sounds nasty
Mods BMC race
extended rev limiter 700 rpms
thin head gasket
Akrapovic full system
Kleen Air Removed
web cam .383 lift intake came 253 degrees of duration at .050.. cam timing 105/103
hoping to get 200 RWHP STD after tuning
|
|
|
HOME
NEW TOPIC