|
weird timing issue????somewhat resolved and new dyno #'
#967474
04/06/11 01:32 AM
04/06/11 01:32 AM
|
Joined: Nov 2006
Posts: 1,090
north cakalaky
instigator
OP
super stock
|
OP
super stock
Joined: Nov 2006
Posts: 1,090
north cakalaky
|
Took the car to the chasis dyno today to tune a setup for the new megasquirt fuel injection/timing computer.....
We set timing with a light...got the compter and light to match on the timing marks at 35 degrees...
now at 3000+ rpms it would break up real bad..after trying everthing in the book..new msd 6al, coil, plugs, indexing distributor, and many other things, then we started backing down timing at 3000 rpms and things started to clean up....we had to pull roughly 20 deg timing to get it clean....just seems real weird....now we have a breakup from 5500 rpms...going to pull the plugs out tomorrow and put some more gap in them (had them down to .012 to check for a weak ignition)....any ideas why it wants so little timing???...this a a 408ci smallblock with indy 230cc heads and twin turbos....BTW it made 650 rwhp at 10psi at 5500 rpm's...got atleast another 1000rpms to go.
Last edited by instigator; 04/07/11 12:15 AM.
65 Barracuda
All aluminum Indy HEMI with some boost!
COMING TO A TRACK NEAR YOU!
|
|
|
Re: weird timing issue????
[Re: instigator]
#967475
04/06/11 01:41 AM
04/06/11 01:41 AM
|
Joined: Feb 2007
Posts: 1,025
Las Vegas, NV
dodgeboy11
super stock
|
super stock
Joined: Feb 2007
Posts: 1,025
Las Vegas, NV
|
First, are you sure the timing is staying constant at higher RPM? Something doesn't seem quite right there. If you have sufficient octane in your fuel then the timing should not need to be retarded so much. That's not good for exhaust pieces, too much fuel burning out the exhaust. At only 10 lbs of boost, even with the 230 cc heads, the mixture shouldn't be so dense it's only wanting 15 degrees of timing. I'm scratching my head, I admit. Wish I was there to do some diagnosing myself, I find it hard to articulate what I'm thinking in writing. Regardless, since it's breaking up at higher RPM, I'd like to know what the timing is doing at that RPM. Since changing the timing is making it run better, I suspect the timing isn't staying constant. Did you build the motor? Was TDC verified? 
|
|
|
Re: weird timing issue????
[Re: instigator]
#967477
04/06/11 07:11 AM
04/06/11 07:11 AM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Quote:
Yes, TDC was verified when I degreed the cam in It was dead on....I know it is very weird...we are using e-85 which can tolerate lots of timing and boost....we had 3-4 very verse minds there scratching our heads....we are going to do some more timing verifying tomorrow..cops showed up about 10pm so we stopped  ......3000 rpm is where we verified timing yesterday...should have been correct there....
Whats the A/F ratio when it starts breaking up
|
|
|
Re: weird timing issue????
[Re: MR_P_BODY]
#967478
04/06/11 08:37 AM
04/06/11 08:37 AM
|
Joined: Jul 2010
Posts: 1,491
Oologah, Oklahoma
Big Squeeze
pro stock
|
pro stock
Joined: Jul 2010
Posts: 1,491
Oologah, Oklahoma
|
What does the timing light show while checking the timing? Is it nice and steady, or is it erratic or does it move around? I've had three situations with an MSD where I had an alternator with a bad diode that caused the timing to move a LOT....With a bad diode, the alternator over charges the battery and messes with the MSD.......To verify that, just unhook one of the field wires and the timing will be rock steady..... I've also heard where one of the magnets in the crank trigger wheel was installed backwards from the other three at the factory and that caused issues..... Just something to keep in mind....  
If you can't handle the truth, you're living a lie.......
|
|
|
Re: weird timing issue????
[Re: Big Squeeze]
#967479
04/06/11 08:45 AM
04/06/11 08:45 AM
|
Joined: Nov 2006
Posts: 1,090
north cakalaky
instigator
OP
super stock
|
OP
super stock
Joined: Nov 2006
Posts: 1,090
north cakalaky
|
A/F was about12 to 1.....fine in our eyes......have a 1 wire alternator...unhooked it and still same problem,
What is weird was with the timing light hooked up we could see the eratic timing, so why did less timing fix it....maybe less cylinder pressure(due to firing later with less timing) could fire or mask a problem that is still there...going to see if the timing light is still erratic today.
65 Barracuda
All aluminum Indy HEMI with some boost!
COMING TO A TRACK NEAR YOU!
|
|
|
Re: weird timing issue????
[Re: CHAPPER]
#967482
04/06/11 10:38 AM
04/06/11 10:38 AM
|
Joined: Nov 2004
Posts: 7,274
s.w.fl
bonefish
master
|
master
Joined: Nov 2004
Posts: 7,274
s.w.fl
|
Quote:
Polarity on MSD wires correct....? I have seen this as one of many problems when the polarity is crossed in the wiring harness some where, be it at the box, the harness itself, or at the distributor connector.
|
|
|
Re: weird timing issue????New Dyno #'s
[Re: 340Bird]
#967485
04/06/11 11:40 PM
04/06/11 11:40 PM
|
Joined: Nov 2006
Posts: 1,090
north cakalaky
instigator
OP
super stock
|
OP
super stock
Joined: Nov 2006
Posts: 1,090
north cakalaky
|
we rechecked timing again today and found it was actually off from where we thought it was yesterday....still a timing issue, so we just set the whole map for 24 degrees and verified with the light.....finally get to do some pulls....oh yea, changed out the MSD cap and button....cleaned everything up......made some power pulls...things were looking up here.....
Mustang dyno (usually 10-15% less than a dynojet)
11psi----710hp 6100 rpms , 764 torque 4400rpms unloaded dyno pull(670 loaded)
17psi----846hp loaded dyno
23 psi----980hp 6500 rpm, 900 torque 5200rpm (loaded pull)
basically picked up 200hp than from before at about 3 pounds less boost.....I was going to add just a tad to see 4-digits but a little water spurted from the radiator spout on the 980 pull... (no overflow yet) so want to re-torque heads first before pushing it any harder.
All on e-85 ,possible still winter blend, so I was a little hesistant to keep pushing....
Last edited by instigator; 04/07/11 12:09 AM.
65 Barracuda
All aluminum Indy HEMI with some boost!
COMING TO A TRACK NEAR YOU!
|
|
|
Re: weird timing issue????New Dyno #'s
[Re: RonP]
#967490
04/07/11 10:08 AM
04/07/11 10:08 AM
|
Joined: Jan 2003
Posts: 13,375
Marion, South Carolina [><]
an8sec70cuda
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 13,375
Marion, South Carolina [><]
|
Quote:
Don't have anything to add that hasn't already been mentioned, but are you taking that bad boy to Rockingham in a couple weeks?
Would love to see that car run again. 
CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
|
|
|
Re: weird timing issue????New Dyno #'s
[Re: RonP]
#967492
04/07/11 08:38 PM
04/07/11 08:38 PM
|
Joined: Nov 2006
Posts: 1,090
north cakalaky
instigator
OP
super stock
|
OP
super stock
Joined: Nov 2006
Posts: 1,090
north cakalaky
|
As long as it ain't the weekend of the 17th on sunday...sons weekend....but just took it around the block and it ran great...couldn't lay it down cause in the neighborhood...called about insurance today...hope to get some tags next week....
Would be glad to get out to the rock....
and yes I checked the cap alignment.....what's happening now is the timing is going up as I rev it about 6-8 degrees, even though the computer is not telling it to.....istributor is locked out and a tensioner on the timing chain....just real weird.
Hope to see all yall guys at the rock.
65 Barracuda
All aluminum Indy HEMI with some boost!
COMING TO A TRACK NEAR YOU!
|
|
|
|
|
