575SCi cam question
05-20-2005, 11:44 AM
#1
Registered
Thread Starter
575SCi cam question
After adding the AZ Speed and Marine boost kit, a Whipple intercooler, and an even smaller 3" (4" stock, 3.5" AZSM) pulley to get my boost back, I'm really 
happy with the way my 575 is running. I estimate it's in the 725 bobtail/700 PSHP neighborhood. I've picked up 9 MPH with these mods, and some propeller and gearcase work.
But like all hotrodders, I'm always wondering if there isn't something else on this package that can be improved.
What I'm wondering about obviously is the cam. The HP500EFI, 525EFI, and 600SCi, ALL have roller cams. The 575SCi has a flat tappet.
Has anyone used one of these Merc roller cams in a 575SCi? What were the results? How about an aftermarket roller cam? Give it up cam gurus!
Regards,
Steve
happy with the way my 575 is running. I estimate it's in the 725 bobtail/700 PSHP neighborhood. I've picked up 9 MPH with these mods, and some propeller and gearcase work.But like all hotrodders, I'm always wondering if there isn't something else on this package that can be improved.
What I'm wondering about obviously is the cam. The HP500EFI, 525EFI, and 600SCi, ALL have roller cams. The 575SCi has a flat tappet.
Has anyone used one of these Merc roller cams in a 575SCi? What were the results? How about an aftermarket roller cam? Give it up cam gurus!
Regards,
Steve
Last edited by Steve Zuckerman; 05-20-2005 at 12:06 PM.
05-22-2005, 09:16 AM
#3
Re: 575SCi cam question
Last winter, I was heavily involved in a freshen up project. The boat is a 2002 30' Lip Ship Edition Mystique T/S with 575's that had been tweaked by Richie Zul.
We were looking for a few more ponies without spinning the blowers any faster. Zul had bumped the compression up a bit by swapping out the dished pistons for a set of flat-tops. This upped the static compression to 8.2:1. Still nice and safe for the stock blower pulleys. The heads received some mild port work.
As far as cam selection, we went with a custom ground hyd roller cam by Ultradyne, stock GM roller lifters/dog bone style retainers. The cam grind is very similar to the HP500 EFI cam. The end result was very impressive to say the least.
These motors are basically stock 575 SCI's with flat top pistons and a decent (fairly mild) roller cam. The rev limiters were upped to 5450 rpm and stock 4 lb blower pulleys. In fully dressed trim, complete with wet exhaust, sea pumps, all accessories, we consistantly made 685 hp/655 tq. at 5400. The combination sure works sweet and they idle cleaner than stock 575's.
I had the boat out yesterday for the maiden voyage and this little Mystique runs like a bear.
Kurt
We were looking for a few more ponies without spinning the blowers any faster. Zul had bumped the compression up a bit by swapping out the dished pistons for a set of flat-tops. This upped the static compression to 8.2:1. Still nice and safe for the stock blower pulleys. The heads received some mild port work.
As far as cam selection, we went with a custom ground hyd roller cam by Ultradyne, stock GM roller lifters/dog bone style retainers. The cam grind is very similar to the HP500 EFI cam. The end result was very impressive to say the least.
These motors are basically stock 575 SCI's with flat top pistons and a decent (fairly mild) roller cam. The rev limiters were upped to 5450 rpm and stock 4 lb blower pulleys. In fully dressed trim, complete with wet exhaust, sea pumps, all accessories, we consistantly made 685 hp/655 tq. at 5400. The combination sure works sweet and they idle cleaner than stock 575's.
I had the boat out yesterday for the maiden voyage and this little Mystique runs like a bear.
Kurt
Last edited by Biggus; 05-22-2005 at 09:21 AM.
05-22-2005, 09:43 AM
#4
Registered
Re: 575SCi cam question
Originally Posted by Biggus
Last winter, I was heavily involved in a freshen up project. The boat is a 2002 30' Lip Ship Edition Mystique T/S with 575's that had been tweaked by Richie Zul.
We were looking for a few more ponies without spinning the blowers any faster. Zul had bumped the compression up a bit by swapping out the dished pistons for a set of flat-tops. This upped the static compression to 8.2:1. Still nice and safe for the stock blower pulleys. The heads received some mild port work.
As far as cam selection, we went with a custom ground hyd roller cam by Ultradyne, stock GM roller lifters/dog bone style retainers. The cam grind is very similar to the HP500 EFI cam. The end result was very impressive to say the least.
These motors are basically stock 575 SCI's with flat top pistons and a decent (fairly mild) roller cam. The rev limiters were upped to 5450 rpm and stock 4 lb blower pulleys. In fully dressed trim, complete with wet exhaust, sea pumps, all accessories, we consistantly made 685 hp/655 tq. at 5400. The combination sure works sweet and they idle cleaner than stock 575's.
I had the boat out yesterday for the maiden voyage and this little Mystique runs like a bear.
Kurt
We were looking for a few more ponies without spinning the blowers any faster. Zul had bumped the compression up a bit by swapping out the dished pistons for a set of flat-tops. This upped the static compression to 8.2:1. Still nice and safe for the stock blower pulleys. The heads received some mild port work.
As far as cam selection, we went with a custom ground hyd roller cam by Ultradyne, stock GM roller lifters/dog bone style retainers. The cam grind is very similar to the HP500 EFI cam. The end result was very impressive to say the least.
These motors are basically stock 575 SCI's with flat top pistons and a decent (fairly mild) roller cam. The rev limiters were upped to 5450 rpm and stock 4 lb blower pulleys. In fully dressed trim, complete with wet exhaust, sea pumps, all accessories, we consistantly made 685 hp/655 tq. at 5400. The combination sure works sweet and they idle cleaner than stock 575's.
I had the boat out yesterday for the maiden voyage and this little Mystique runs like a bear.
Kurt
05-22-2005, 09:58 AM
#5
Registered
Re: 575SCi cam question
Originally Posted by Steve Zuckerman
After adding the AZ Speed and Marine boost kit, a Whipple intercooler, and an even smaller 3" (4" stock, 3.5" AZSM) pulley to get my boost back, I'm really happy with the way my 575 is running. I estimate it's in the 725 bobtail/700 PSHP neighborhood. I've picked up 9 MPH with these mods, and some propeller and gearcase work.
But like all hotrodders, I'm always wondering if there isn't something else on this package that can be improved.
What I'm wondering about obviously is the cam. The HP500EFI, 525EFI, and 600SCi, ALL have roller cams. The 575SCi has a flat tappet.
Has anyone used one of these Merc roller cams in a 575SCi? What were the results? How about an aftermarket roller cam? Give it up cam gurus!
Regards,
Steve
happy with the way my 575 is running. I estimate it's in the 725 bobtail/700 PSHP neighborhood. I've picked up 9 MPH with these mods, and some propeller and gearcase work.But like all hotrodders, I'm always wondering if there isn't something else on this package that can be improved.
What I'm wondering about obviously is the cam. The HP500EFI, 525EFI, and 600SCi, ALL have roller cams. The 575SCi has a flat tappet.
Has anyone used one of these Merc roller cams in a 575SCi? What were the results? How about an aftermarket roller cam? Give it up cam gurus!
Regards,
Steve
05-25-2005, 10:28 AM
#6
Registered
Thread Starter
Re: 575SCi cam question
Originally Posted by Biggus
Last winter, I was heavily involved in a freshen up project. The boat is a 2002 30' Lip Ship Edition Mystique T/S with 575's that had been tweaked by Richie Zul.
We were looking for a few more ponies without spinning the blowers any faster. Zul had bumped the compression up a bit by swapping out the dished pistons for a set of flat-tops. This upped the static compression to 8.2:1. Still nice and safe for the stock blower pulleys. The heads received some mild port work.
As far as cam selection, we went with a custom ground hyd roller cam by Ultradyne, stock GM roller lifters/dog bone style retainers. The cam grind is very similar to the HP500 EFI cam. The end result was very impressive to say the least.
These motors are basically stock 575 SCI's with flat top pistons and a decent (fairly mild) roller cam. The rev limiters were upped to 5450 rpm and stock 4 lb blower pulleys. In fully dressed trim, complete with wet exhaust, sea pumps, all accessories, we consistantly made 685 hp/655 tq. at 5400. The combination sure works sweet and they idle cleaner than stock 575's.
I had the boat out yesterday for the maiden voyage and this little Mystique runs like a bear.
Kurt
We were looking for a few more ponies without spinning the blowers any faster. Zul had bumped the compression up a bit by swapping out the dished pistons for a set of flat-tops. This upped the static compression to 8.2:1. Still nice and safe for the stock blower pulleys. The heads received some mild port work.
As far as cam selection, we went with a custom ground hyd roller cam by Ultradyne, stock GM roller lifters/dog bone style retainers. The cam grind is very similar to the HP500 EFI cam. The end result was very impressive to say the least.
These motors are basically stock 575 SCI's with flat top pistons and a decent (fairly mild) roller cam. The rev limiters were upped to 5450 rpm and stock 4 lb blower pulleys. In fully dressed trim, complete with wet exhaust, sea pumps, all accessories, we consistantly made 685 hp/655 tq. at 5400. The combination sure works sweet and they idle cleaner than stock 575's.
I had the boat out yesterday for the maiden voyage and this little Mystique runs like a bear.
Kurt
Thanks for the input. Do you have a part # for the Ultradyne?
You should try an intercooler on your 575s. I think you'll really be impressed with the results. I'm using the whipple, and even with less boost (same pulley, 3.5") taking my boost back to 5 lbs., the power increase was strong. I'm now back to 6.5 lbs with a 3", and it feels like a drag boat with a light load.
Regards,
Steve
05-25-2005, 10:34 AM
#7
Registered
Thread Starter
Re: 575SCi cam question
Originally Posted by JCPERF
The 525 cam would work pretty good in that application.The crane 741 cam always works good in stuff like that.The bigger the cam the more power, but you sacrifice idle quality
I was thinking about using one of the Merc Cams, since I figured they would work with the Merc electronics/ECU with minimal trouble. I sure would line to see the specs on the three cams (500/525/600). I wonder if they are different, or the same? I'm thinking the 600 cam would be the way to go since it's a blower/intercooled motor like mine. What do you think?
Regards,
Steve
05-25-2005, 05:03 PM
#8
MarineKinetics
Platinum Member
Re: 575SCi cam question
Steve,
Here are the specs for the 500 EFI:
292*/298* @ .004"
230*/236* @ .050"
.352"/.359" lobe
.598"/.610" valve
109 ICL
114 LSA
525 EFI
298*/306* @ .004"
236*/244*
.610"/.632" Valve
114* LSA
The 600 SCI is quite different from these two. You can email me for the specs.
Bob
Here are the specs for the 500 EFI:
292*/298* @ .004"
230*/236* @ .050"
.352"/.359" lobe
.598"/.610" valve
109 ICL
114 LSA
525 EFI
298*/306* @ .004"
236*/244*
.610"/.632" Valve
114* LSA
The 600 SCI is quite different from these two. You can email me for the specs.
Bob
05-25-2005, 10:45 PM
#9
Registered
Thread Starter
Re: 575SCi cam question
Originally Posted by rmbuilder
Steve,
Here are the specs for the 500 EFI:
292*/298* @ .004"
230*/236* @ .050"
.352"/.359" lobe
.598"/.610" valve
109 ICL
114 LSA
525 EFI
298*/306* @ .004"
236*/244*
.610"/.632" Valve
114* LSA
The 600 SCI is quite different from these two. You can email me for the specs.
Bob
Here are the specs for the 500 EFI:
292*/298* @ .004"
230*/236* @ .050"
.352"/.359" lobe
.598"/.610" valve
109 ICL
114 LSA
525 EFI
298*/306* @ .004"
236*/244*
.610"/.632" Valve
114* LSA
The 600 SCI is quite different from these two. You can email me for the specs.
Bob
Thanks for the info. I've sent you a PM as requested.
Regards,
Steve
09-06-2007, 07:34 PM
#10
Registered
Join Date: Oct 2006
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
intercooler
Steve how tall is the wipple intercooler [inches] whats the part # if you have it .. I'm running a 2002 38 topgun ts With twin 575 sci and AZSM 3.5 pulleys, MSD ,and reprogramed ecms @ about 4.5lbs boost at 5350rpms XR drives 32'' lab bravos it runs 92mph on GPS 500 ft aboue sea level fresh water. Im limeted with space above my stock air cleaners to about 3inches without cuting into the hatch and mirrors above. Thanks for any info Alan Doherty GIVA$UM
