HELP! massive HP loss above 4000 rpm, D1SC forged 347
02-18-2016, 04:14 PM
#21
If a 7.300" gave you 1 and 1/4 turns, you're going to need shorter push rods. I would let the cylinder you're checking sit at max lift for a least a few minutes before putting the cam on the base circle to measure for zero lash push rod length.
I hope the information I provided helps in alleviating the issues you're having.
Glad I could be of some help and I hope that my help fixes your problems.
I hope the information I provided helps in alleviating the issues you're having.
Glad I could be of some help and I hope that my help fixes your problems.
Last edited by Martin Smallwood; 02-19-2016 at 03:29 AM.
02-21-2016, 05:47 PM
#22
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If a 7.300" gave you 1 and 1/4 turns, you're going to need shorter push rods. I would let the cylinder you're checking sit at max lift for a least a few minutes before putting the cam on the base circle to measure for zero lash push rod length.
I hope the information I provided helps in alleviating the issues you're having.
Glad I could be of some help and I hope that my help fixes your problems.
I hope the information I provided helps in alleviating the issues you're having.
Glad I could be of some help and I hope that my help fixes your problems.
Okay, so we took the heads apart and inspected all the rockers, valves, and springs. No damage to any of that. Next we measured the preload with the currently installed 7.300 pushrods using the method you explained. With a dial indicator we got a measurement of between .030 and .031 for all 16 pushrods. So with you suggestion of between .010 and .020 we figure on a new pushrod length of 7.285. We checked 7.285 with a pushrod length checker and got a measurement on the dial indicator of .011 preload on 4 different cylinders. Does this sound okay to you? Secondly, where the hell do I get that size pushrod? Everywhere I look sells by .025 increments. I did actually originally order my pushrods from you at tick performance, we have a lenghty email chain discussing my valve train setup I purchased. Any further help you can provide would be greatly appreciated!
02-22-2016, 10:54 AM
#25
Back to my original thoughts.......are you confident in the boost gauge accuracy?
What type of belt are you running on the procharger?
Martin apparantly knows the build which I don't but, .030" of lifter preload is not going to drop off like that.
Manton is the company to buy your incremental sized pushrods.
I'm still thinking belt slippage.
Possibly of the clutch slipping as well.
What type of belt are you running on the procharger?
Martin apparantly knows the build which I don't but, .030" of lifter preload is not going to drop off like that.
Manton is the company to buy your incremental sized pushrods.
I'm still thinking belt slippage.
Possibly of the clutch slipping as well.
02-22-2016, 11:00 AM
#26
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Back to my original thoughts.......are you confident in the boost gauge accuracy?
What type of belt are you running on the procharger?
Martin apparantly knows the build which I don't but, .030" of lifter preload is not going to drop off like that.
Manton is the company to buy your incremental sized pushrods.
I'm still thinking belt slippage.
Possibly of the clutch slipping as well.
What type of belt are you running on the procharger?
Martin apparantly knows the build which I don't but, .030" of lifter preload is not going to drop off like that.
Manton is the company to buy your incremental sized pushrods.
I'm still thinking belt slippage.
Possibly of the clutch slipping as well.
02-22-2016, 06:33 PM
#28
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There is 0 degrees of timing in all of these runs, at least I'm pretty sure that is what the tuner told me. He added no timing in the tune yet
02-22-2016, 07:47 PM
#29
0 degrees of timing? Or 0 degrees of knock retard?
The lifters you're using have .060" internal travel with no oil. With oil they will have roughly .040-.045". .030" pre-load will most likely not cause the issues you're having, but those lifters prefer right around .010" for best performance and I've run them as light as .005" pre-load. They also prefer lighter viscosity oil such as 5w-30.
As for the plugs, I would have at least a NGK 5672-7 spark plug which is a projected tip 7 heat range plug. Gap them to .026".
I can't tell for sure since there is what seems to be a lot of idle time on those plugs, but it doesn't even look like the cadium is burnt off of the strap yet indicating that there is very little heat in the chamber.
If it truly has 0* of ignition timing in it, then that is the reason the graph looks like that. With 0* of timing it is not making any cylinder pressure at higher engine speeds(or really anywhere in the RPM range) causing the power to fall off like it is.
The lifters you're using have .060" internal travel with no oil. With oil they will have roughly .040-.045". .030" pre-load will most likely not cause the issues you're having, but those lifters prefer right around .010" for best performance and I've run them as light as .005" pre-load. They also prefer lighter viscosity oil such as 5w-30.
As for the plugs, I would have at least a NGK 5672-7 spark plug which is a projected tip 7 heat range plug. Gap them to .026".
I can't tell for sure since there is what seems to be a lot of idle time on those plugs, but it doesn't even look like the cadium is burnt off of the strap yet indicating that there is very little heat in the chamber.
If it truly has 0* of ignition timing in it, then that is the reason the graph looks like that. With 0* of timing it is not making any cylinder pressure at higher engine speeds(or really anywhere in the RPM range) causing the power to fall off like it is.
02-22-2016, 07:53 PM
#30
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0 degrees of timing? Or 0 degrees of knock retard?
The lifters you're using have .060" internal travel with no oil. With oil they will have roughly .040-.045". .030" pre-load will most likely not cause the issues you're having, but those lifters prefer right around .010" for best performance and I've run them as light as .005" pre-load. They also prefer lighter viscosity oil such as 5w-30.
As for the plugs, I would have at least a NGK 5672-7 spark plug which is a projected tip 7 heat range plug. Gap them to .026".
I can't tell for sure since there is what seems to be a lot of idle time on those plugs, but it doesn't even look like the cadium is burnt off of the strap yet indicating that there is very little heat in the chamber.
If it truly has 0* of ignition timing in it, then that is the reason the graph looks like that. With 0* of timing it is not making any cylinder pressure at higher engine speeds(or really anywhere in the RPM range) causing the power to fall off like it is.
The lifters you're using have .060" internal travel with no oil. With oil they will have roughly .040-.045". .030" pre-load will most likely not cause the issues you're having, but those lifters prefer right around .010" for best performance and I've run them as light as .005" pre-load. They also prefer lighter viscosity oil such as 5w-30.
As for the plugs, I would have at least a NGK 5672-7 spark plug which is a projected tip 7 heat range plug. Gap them to .026".
I can't tell for sure since there is what seems to be a lot of idle time on those plugs, but it doesn't even look like the cadium is burnt off of the strap yet indicating that there is very little heat in the chamber.
If it truly has 0* of ignition timing in it, then that is the reason the graph looks like that. With 0* of timing it is not making any cylinder pressure at higher engine speeds(or really anywhere in the RPM range) causing the power to fall off like it is.
02-28-2016, 09:38 AM
#32
Mech. everything seems OK, and I don't think the plugs are causing it-are you running an air cleaner? I have seen them with tubing kind of suck inward if thin tubing, and just the air cleaner itself cause a restriction
Are you picking up a lot of dust from the belt (slip)
Did you pull a plug right after a pull, ck the timing on the strap
Be nice if there was a datalog with everything on it
Are you picking up a lot of dust from the belt (slip)
Did you pull a plug right after a pull, ck the timing on the strap
Be nice if there was a datalog with everything on it
02-28-2016, 08:28 PM
#34
My car had this same problem in a turbo application a couple years ago. It was an ignition issue.
Have you physically verified fuel pressure during the pull?
Verified timing with a timing light during pull?
Are you on gas or e85 because unless I'm missing something that afr looks dangerously lean except the 3rd pull. I'd shoot for 10.7-10.8 afr. It appears the fuel is there the 3rd run but it was worse. I'm guessing ignition issue
You really need to post a screenshot of the log when it ***** the bed or get the file so we can look at it in HP tuners
http://www.yellowbullet.com/forum/sh...098&highlight=
Have you physically verified fuel pressure during the pull?
Verified timing with a timing light during pull?
Are you on gas or e85 because unless I'm missing something that afr looks dangerously lean except the 3rd pull. I'd shoot for 10.7-10.8 afr. It appears the fuel is there the 3rd run but it was worse. I'm guessing ignition issue
You really need to post a screenshot of the log when it ***** the bed or get the file so we can look at it in HP tuners
http://www.yellowbullet.com/forum/sh...098&highlight=
Last edited by AutomagicLS1; 02-28-2016 at 08:33 PM.
02-28-2016, 08:32 PM
#35
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My car had this same problem in a turbo application a couple years ago. It was an ignition issue.
Have you physically verified fuel pressure during the pull?
Verified timing with a timing light during pull?
Are you on gas or e85 because unless I'm missing something that afr looks dangerously lean. I'd shoot for 10.7-10.8 afr
You really need to post a screenshot of the log when it ***** the bed or get the file so we can look at it in HP tuners
http://www.yellowbullet.com/forum/sh...098&highlight=
Have you physically verified fuel pressure during the pull?
Verified timing with a timing light during pull?
Are you on gas or e85 because unless I'm missing something that afr looks dangerously lean. I'd shoot for 10.7-10.8 afr
You really need to post a screenshot of the log when it ***** the bed or get the file so we can look at it in HP tuners
http://www.yellowbullet.com/forum/sh...098&highlight=
02-28-2016, 08:37 PM
#36
Yes had mechanical fuel pressure gauge hooked up to regulator and physically watched it during pull. 58lbs idle and rose 1:1 with boost. Using 93 octane. Yes the AFR was slightly high but these were the first runs the car ever had. The tune was no where near complete since we stopped due to this issue. I have not checked timing with timing light. Haven't used one of them since owning non-dristribted engine lol.