HP500 Crane 169611
09-11-2003, 08:29 PM
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HP500 Crane 169611
Am I correct in assuming Merc put the HP500 Crane cam on a 105 intake lobe centerline to increase dynamic compression and build low end torque?
Would the 169611 in a small boat with 9.5 compression and silent choice work better @ 109 intake lobe centerline?
Thanks!
Would the 169611 in a small boat with 9.5 compression and silent choice work better @ 109 intake lobe centerline?
Thanks!
09-11-2003, 10:33 PM
#2
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I believe that Mercruiser installed that camshaft and liked the results as it came from Crane. I would seriously doubt that Mercruiser High Performance knows much about Intake Lobe Centerlines or Lobe Separation Angles.
I have talked to the guys in High Performance and they don't exactly inspire confidence that they know what they are talking about! If you look at some of the engines they have come up with in the past and some of the camshaft selections, most would agree.
I think there are people on this forum that have more knowledge and experience than the Mercruiser HP guys.
Mercruiser has a very firm belief in promoting within the company. Those high performance guys may have been driving forklifts before they were promoted to the high performance dept. (I'm not kidding!).
It is not uncommon to go to Mercruiser service school and meet a new instructor that has been promoted from the warehouse.
Try getting a Mercruiser engineer on the phone. I have been working with that company for 30 years and none of them has ever had the guts to introduce themselves in public. I am sure that instead of boating on the weekends, most Mercruiser engineers are entering their cats in cat shows or Petunias in flower shows.
Any Mercruiser engineers have the guts to respond? I don't think that they have enough interest in the boating industry to log on to a boating forum!
Sincerely
Dennis Moore
Mercruiser Master Technician
I have talked to the guys in High Performance and they don't exactly inspire confidence that they know what they are talking about! If you look at some of the engines they have come up with in the past and some of the camshaft selections, most would agree.
I think there are people on this forum that have more knowledge and experience than the Mercruiser HP guys.
Mercruiser has a very firm belief in promoting within the company. Those high performance guys may have been driving forklifts before they were promoted to the high performance dept. (I'm not kidding!).
It is not uncommon to go to Mercruiser service school and meet a new instructor that has been promoted from the warehouse.
Try getting a Mercruiser engineer on the phone. I have been working with that company for 30 years and none of them has ever had the guts to introduce themselves in public. I am sure that instead of boating on the weekends, most Mercruiser engineers are entering their cats in cat shows or Petunias in flower shows.
Any Mercruiser engineers have the guts to respond? I don't think that they have enough interest in the boating industry to log on to a boating forum!
Sincerely
Dennis Moore
Mercruiser Master Technician
09-12-2003, 09:49 AM
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I was curious about the installed intake centerline on the 611 cam as well. I just rebuilt my HP 500's and replaced the cams with Crane 168731's, which like most Crane catelog cams, are ground with 5 degrees of advance built in.
I was planning on putting a degree wheel and dial indicator on the 611 cams before I removed them from the motors but suffered momentary brain fade and forgot to do it. Oh well.
I can tell you that my 1999 vintage motors had stock GEN VI timing chain sets in them with no provision for altering cam timing. If you can verify from Crane that they ground this cam 5 degrees advanced as usual, then I would assume that the intake centerline would be 105 degrees since the cam has a 110 degree LSA.
This would tend to build a lot of cylinder pressure with 9.5 static compression and likely require premium fuel. Maybe you use premium anyway so no big deal. If you installed it at 109 you should theoretically pick up the top end power a little.
Rich
I was planning on putting a degree wheel and dial indicator on the 611 cams before I removed them from the motors but suffered momentary brain fade and forgot to do it. Oh well.
I can tell you that my 1999 vintage motors had stock GEN VI timing chain sets in them with no provision for altering cam timing. If you can verify from Crane that they ground this cam 5 degrees advanced as usual, then I would assume that the intake centerline would be 105 degrees since the cam has a 110 degree LSA.
This would tend to build a lot of cylinder pressure with 9.5 static compression and likely require premium fuel. Maybe you use premium anyway so no big deal. If you installed it at 109 you should theoretically pick up the top end power a little.
Rich
09-13-2003, 07:44 AM
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Dennis
Too bad Merc Racing is not like BMW M Division. There you have to be an engineer to push a broom
Do you have an opinion to my intake lobe centerline question? 105 or 109?
35/25
The 168731 Crane Cam Card states intake lobe centerline is 107.
Too bad Merc Racing is not like BMW M Division. There you have to be an engineer to push a broom
Do you have an opinion to my intake lobe centerline question? 105 or 109?
35/25
The 168731 Crane Cam Card states intake lobe centerline is 107.
Last edited by RickR; 09-13-2003 at 07:47 AM.
09-13-2003, 09:17 AM
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I think that the camshaft companies have a problem with customers wanting bigger camshafts than fits their application (overcamming). To compensate for this tendency they grind the camshafts with an advanced Intake Lobe Centerline to boost low speed torque. Crane camshafts are also ground on wide Lobe Sep Angles to make these overcamed engines idle a little smoother and increase manifold vacuum. By doing this they have happier customers who can spread word-of-mouth advertising that the big camshaft they installed is designed so well that it didn't effect the engines low speed operation and driveability.
If the correct duration camshaft is selected for the application and the LSA angle is a little tighter than stock (112 LSA is considered ideal for a stock engine) Then a modified engine should need very little camshaft advance to make good power throughout the rpm range. Two degrees advance would be maximum.
Your camshaft has the correct amount of duration and the correct LSA for your application. If you degree your camshaft to have maximum intake valve lift when the piston is at 110 degrees after TDC you will be very close to maximum piston speed and maximum vacuum in the cylinder (most engines reach maximum piston speed around 108 -110 degrees piston position ATDC). In other words, the Intake Lobe Centerline will be at 110 degrees.
Not to beat a dead horse, but Mercruiser has overcammed HP engines in the past and advancing the camshaft worked for them also.
Dennis Moore
If the correct duration camshaft is selected for the application and the LSA angle is a little tighter than stock (112 LSA is considered ideal for a stock engine) Then a modified engine should need very little camshaft advance to make good power throughout the rpm range. Two degrees advance would be maximum.
Your camshaft has the correct amount of duration and the correct LSA for your application. If you degree your camshaft to have maximum intake valve lift when the piston is at 110 degrees after TDC you will be very close to maximum piston speed and maximum vacuum in the cylinder (most engines reach maximum piston speed around 108 -110 degrees piston position ATDC). In other words, the Intake Lobe Centerline will be at 110 degrees.
Not to beat a dead horse, but Mercruiser has overcammed HP engines in the past and advancing the camshaft worked for them also.
Dennis Moore
09-13-2003, 09:03 PM
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Sorry to burst your bubble, I guess we all need heroes. I just hope that you have more sense than to make the guys at Mercruiser yours! They are no heroes!
Are you a Mercruiser engineer? You wouldn't admit it if you were!
You see I happen to be embarrassed when unmotivated American engineers make us look like fools to the rest of the world.
I always buy American made products if at all possible, but I do get a little sick of buying American made products designed buy engineers who have little interest or enthusiasm for their own product. When Mercruiser engineers also become boating enthusiasts, the Mercruiser product will improve.
Talk to any young person about to buy a new car. They think that American cars are a joke! Mercury and Evinrude/Johnson used to dominate the world in outboards. Go overseas and you will see nothing but Japanese outboards now. Not until we get some motivated engineers, designing innovative American products, will that change.
I am as patriotic as the next American, that is why I am upset with shoddy engineering! Every good American should demand better made American products!
Dennis
Are you a Mercruiser engineer? You wouldn't admit it if you were!
You see I happen to be embarrassed when unmotivated American engineers make us look like fools to the rest of the world.
I always buy American made products if at all possible, but I do get a little sick of buying American made products designed buy engineers who have little interest or enthusiasm for their own product. When Mercruiser engineers also become boating enthusiasts, the Mercruiser product will improve.
Talk to any young person about to buy a new car. They think that American cars are a joke! Mercury and Evinrude/Johnson used to dominate the world in outboards. Go overseas and you will see nothing but Japanese outboards now. Not until we get some motivated engineers, designing innovative American products, will that change.
I am as patriotic as the next American, that is why I am upset with shoddy engineering! Every good American should demand better made American products!
Dennis
