Merc 496 with Whipple SC, ign.problem
03-02-2012, 07:01 PM
#24
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Moneykiller:
Give whipple Industries a call at (559) 442-1261 and ask for Dustin or Dan.
ZP'd, not sure where you get your information from but there are hundreds of stock Merc 496's with Raylar kits running and making big power quite reliably all over the world. There are also many well constructed Merc 496's around the world producing horsepowers between 525HP and 850HP running just fine.
When you consider there are over 80,000 496's -8.1L engines out there in the boating world since just 2001 and maybe only 7,000 -10,000 HP500's , HP500efis and HP525efi's in total combined out there and most are all running reliably just fine your negative comments are unfounded and ill-informed. How many 496's have you owned? I suggest you quit parroting what you read and hear on a few forum posts.
Get the facts and don't let your lack of knowledge be your only determiner. Sorry , but I get tired of all the so called engine experts here on OSO!
Best Regards,
Ray @ Raylar
Give whipple Industries a call at (559) 442-1261 and ask for Dustin or Dan.
ZP'd, not sure where you get your information from but there are hundreds of stock Merc 496's with Raylar kits running and making big power quite reliably all over the world. There are also many well constructed Merc 496's around the world producing horsepowers between 525HP and 850HP running just fine.
When you consider there are over 80,000 496's -8.1L engines out there in the boating world since just 2001 and maybe only 7,000 -10,000 HP500's , HP500efis and HP525efi's in total combined out there and most are all running reliably just fine your negative comments are unfounded and ill-informed. How many 496's have you owned? I suggest you quit parroting what you read and hear on a few forum posts.
Get the facts and don't let your lack of knowledge be your only determiner. Sorry , but I get tired of all the so called engine experts here on OSO!
Best Regards,
Ray @ Raylar
03-04-2012, 06:10 PM
#25
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I like my 496s . Some people are just scared of a sensor or two. Would love to do a raylar package but not in the budget. We do run the balls of them also. havent missed a beat.
07-05-2012, 07:10 AM
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Mikael:
You are now saying that you had a metalic clicking noise coming from the front of the engine?
The stock timing chains on 496 (8.1L) engines built in the GM plant in Tonawanda all had looser than most engine timing chains and it was more noticable in the double roller marine HD chains. This was I have been told due to the robotic installation of the front of the engine and its timing gears and chains and that GM designed the gear with a few thousandths extra smaller diameter to remove the tension on the chain during GM assembly. We have seen this on every 496 we have ever worked on and it has not ever been a problem as far as camshaft timing or noise. If if you install a new chain you will find nearly the same slop in the chain. For this reason I don't think your timing chain and gears are the issue unless they are damaged or improperly installed.
The camshaft sensor is just a simple on-off Hall effect sensor reading a 180 reluctor degree grove in the camshaft gear face. The location of the leading front edge and rear edge of that groove that tells the ECM when cylinders 1 and 6 are at their compression or exhaust TDC. This tells the ECM when the number 1 cylinder is at its compression point for firing and allows the ECM to locate #1 TDC quicker for quicker starts.
If the camshaft sensor circut is not operating properly the ECM will set a camshaft sensor fault code and the engine will either not start or start only after a lot of cranking and the engine will stay in a reduced power mode, not 100% power.
I suspect the metalic noise you describe may be from something else and that if it is big enough it could be setting off the knock sensor which retards timing, limits power and puts the Merc ECM into a reduced power mode.
If you have a scan tool, what is the ECM history file showing on some of these issues?
It sounds like you are saying that you did a camshaft change in this engine to convert it from a Mag to an HO engine?
Did the engine have this problem before you did the HO conversion? If it did not ,then I suspect the crankshaft reluctor was good then and after a camshaft only change the reluctor should still be undamaged or non-defective unless it was exposed to some other potential damage.
I would suggest a mechanics stethoscope with a metal tube to help pinpoint noises on or in the engine.
Try and locate your described engine noise as it may be affecting knock sensors. Also check for an exhaust header or manifold leak at the head to exhaust gaskets as these can sometimes sound almost metalic or like a knocking noise.
Since you have the Whipple supercharger you should also check the belt, lower pulley, tensioner and drive area of the supercharger to make sure you don't have a problem and noise there.
I hope when we get all the input facts and conditions sorted out so you can pinpoint your problem and get it repaired.
Its obviously winter in Sweden, so can you run the engine in the boat out of the water for some of these type of checks?
Best Regards,
Ray @ Raylar
You are now saying that you had a metalic clicking noise coming from the front of the engine?
The stock timing chains on 496 (8.1L) engines built in the GM plant in Tonawanda all had looser than most engine timing chains and it was more noticable in the double roller marine HD chains. This was I have been told due to the robotic installation of the front of the engine and its timing gears and chains and that GM designed the gear with a few thousandths extra smaller diameter to remove the tension on the chain during GM assembly. We have seen this on every 496 we have ever worked on and it has not ever been a problem as far as camshaft timing or noise. If if you install a new chain you will find nearly the same slop in the chain. For this reason I don't think your timing chain and gears are the issue unless they are damaged or improperly installed.
The camshaft sensor is just a simple on-off Hall effect sensor reading a 180 reluctor degree grove in the camshaft gear face. The location of the leading front edge and rear edge of that groove that tells the ECM when cylinders 1 and 6 are at their compression or exhaust TDC. This tells the ECM when the number 1 cylinder is at its compression point for firing and allows the ECM to locate #1 TDC quicker for quicker starts.
If the camshaft sensor circut is not operating properly the ECM will set a camshaft sensor fault code and the engine will either not start or start only after a lot of cranking and the engine will stay in a reduced power mode, not 100% power.
I suspect the metalic noise you describe may be from something else and that if it is big enough it could be setting off the knock sensor which retards timing, limits power and puts the Merc ECM into a reduced power mode.
If you have a scan tool, what is the ECM history file showing on some of these issues?
It sounds like you are saying that you did a camshaft change in this engine to convert it from a Mag to an HO engine?
Did the engine have this problem before you did the HO conversion? If it did not ,then I suspect the crankshaft reluctor was good then and after a camshaft only change the reluctor should still be undamaged or non-defective unless it was exposed to some other potential damage.
I would suggest a mechanics stethoscope with a metal tube to help pinpoint noises on or in the engine.
Try and locate your described engine noise as it may be affecting knock sensors. Also check for an exhaust header or manifold leak at the head to exhaust gaskets as these can sometimes sound almost metalic or like a knocking noise.
Since you have the Whipple supercharger you should also check the belt, lower pulley, tensioner and drive area of the supercharger to make sure you don't have a problem and noise there.
I hope when we get all the input facts and conditions sorted out so you can pinpoint your problem and get it repaired.
Its obviously winter in Sweden, so can you run the engine in the boat out of the water for some of these type of checks?
Best Regards,
Ray @ Raylar
Problem still in place around 4600-4800rpm.
On the 496 there is not anything that sence low fuelpressure and cuts the spark ?
I´m still in for cam chain do engine has not been apart and there is nothing that could get in contact and damaged the reluctor ring.
Mikael, Team MK
07-05-2012, 10:55 AM
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Mikael:
Glad you found your metalic knocking noise in the tensioner as that can cause the knock sensor system to cut power back very easily especially if the system is still on and operating with the Whipple reprogramming. If the knock sensor system is pulling back power it will be recorded in the ECM history file as events and should be viewable with the scanner.
You really need to hook up a scan tool when the boat is underway under load and specifically and read the percentage power readout which should read 100% at all rpms and throttle settings under load. If for some reason it drops to lets say to 90% only under load at the higher rpms that can hold your rpms down by 10% or so and "Guardian" alarm or beep will many times not happen in the rpm ranges you are actually seeing. If this is happening, read the trouble codes on the scanner as this is actually happening in real time and see if you see any reasons that are obvious on the scanner. Pay particular attention to knock retard, exhaust manifold coolant temperature settings, water pressure settings at that rpm, MAP value, ignition timing, throttle position %, etc.
Also remember that the Whipple 3.3 supercharger on a 496 uses a lot more fuel at higher rpms under boost that a naturally aspirated 496 and the fuel system needs to supply a lot more fuel due to bigger injectors, etc. Measure your fuel pressure on the engine under this same load and make sure it's not dropping at higher rpms to much and cutting power production. It should be on the Whipple system I believe about 43-45psi and should not drop to much lower than this to produce enough fuel flow to support the supercharger in boost at these rpms. If fuel pressure drop is an issue be very careful as this can lean burn the engine very quickly and destroy the engine very fast under loads!
Best Regards,
Ray @ Raylar
Glad you found your metalic knocking noise in the tensioner as that can cause the knock sensor system to cut power back very easily especially if the system is still on and operating with the Whipple reprogramming. If the knock sensor system is pulling back power it will be recorded in the ECM history file as events and should be viewable with the scanner.
You really need to hook up a scan tool when the boat is underway under load and specifically and read the percentage power readout which should read 100% at all rpms and throttle settings under load. If for some reason it drops to lets say to 90% only under load at the higher rpms that can hold your rpms down by 10% or so and "Guardian" alarm or beep will many times not happen in the rpm ranges you are actually seeing. If this is happening, read the trouble codes on the scanner as this is actually happening in real time and see if you see any reasons that are obvious on the scanner. Pay particular attention to knock retard, exhaust manifold coolant temperature settings, water pressure settings at that rpm, MAP value, ignition timing, throttle position %, etc.
Also remember that the Whipple 3.3 supercharger on a 496 uses a lot more fuel at higher rpms under boost that a naturally aspirated 496 and the fuel system needs to supply a lot more fuel due to bigger injectors, etc. Measure your fuel pressure on the engine under this same load and make sure it's not dropping at higher rpms to much and cutting power production. It should be on the Whipple system I believe about 43-45psi and should not drop to much lower than this to produce enough fuel flow to support the supercharger in boost at these rpms. If fuel pressure drop is an issue be very careful as this can lean burn the engine very quickly and destroy the engine very fast under loads!
Best Regards,
Ray @ Raylar
Last edited by Raylar; 07-05-2012 at 10:57 AM.
07-05-2012, 02:27 PM
#28
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Mikael:
Glad you found your metalic knocking noise in the tensioner as that can cause the knock sensor system to cut power back very easily especially if the system is still on and operating with the Whipple reprogramming. If the knock sensor system is pulling back power it will be recorded in the ECM history file as events and should be viewable with the scanner.
You really need to hook up a scan tool when the boat is underway under load and specifically and read the percentage power readout which should read 100% at all rpms and throttle settings under load. If for some reason it drops to lets say to 90% only under load at the higher rpms that can hold your rpms down by 10% or so and "Guardian" alarm or beep will many times not happen in the rpm ranges you are actually seeing. If this is happening, read the trouble codes on the scanner as this is actually happening in real time and see if you see any reasons that are obvious on the scanner. Pay particular attention to knock retard, exhaust manifold coolant temperature settings, water pressure settings at that rpm, MAP value, ignition timing, throttle position %, etc.
Also remember that the Whipple 3.3 supercharger on a 496 uses a lot more fuel at higher rpms under boost that a naturally aspirated 496 and the fuel system needs to supply a lot more fuel due to bigger injectors, etc. Measure your fuel pressure on the engine under this same load and make sure it's not dropping at higher rpms to much and cutting power production. It should be on the Whipple system I believe about 43-45psi and should not drop to much lower than this to produce enough fuel flow to support the supercharger in boost at these rpms. If fuel pressure drop is an issue be very careful as this can lean burn the engine very quickly and destroy the engine very fast under loads!
Best Regards,
Ray @ Raylar
Glad you found your metalic knocking noise in the tensioner as that can cause the knock sensor system to cut power back very easily especially if the system is still on and operating with the Whipple reprogramming. If the knock sensor system is pulling back power it will be recorded in the ECM history file as events and should be viewable with the scanner.
You really need to hook up a scan tool when the boat is underway under load and specifically and read the percentage power readout which should read 100% at all rpms and throttle settings under load. If for some reason it drops to lets say to 90% only under load at the higher rpms that can hold your rpms down by 10% or so and "Guardian" alarm or beep will many times not happen in the rpm ranges you are actually seeing. If this is happening, read the trouble codes on the scanner as this is actually happening in real time and see if you see any reasons that are obvious on the scanner. Pay particular attention to knock retard, exhaust manifold coolant temperature settings, water pressure settings at that rpm, MAP value, ignition timing, throttle position %, etc.
Also remember that the Whipple 3.3 supercharger on a 496 uses a lot more fuel at higher rpms under boost that a naturally aspirated 496 and the fuel system needs to supply a lot more fuel due to bigger injectors, etc. Measure your fuel pressure on the engine under this same load and make sure it's not dropping at higher rpms to much and cutting power production. It should be on the Whipple system I believe about 43-45psi and should not drop to much lower than this to produce enough fuel flow to support the supercharger in boost at these rpms. If fuel pressure drop is an issue be very careful as this can lean burn the engine very quickly and destroy the engine very fast under loads!
Best Regards,
Ray @ Raylar
To morrow i will get the boat out uf water and rebuild the fuel system to make shore it works properly...
After that i hook up the scan tool and check every parameter all the way up to issiu rpm.
I also have a friend that will hook up his computer program and se if he can read anything out of this (Professionel mechanic)
Mikael/ Team MK
08-22-2012, 03:40 AM
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