What do you think of this BBC combo?
12-17-2002 | 11:30 AM
#11
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From: Western Michigan
Originally posted by ursus
That is probably just a smidgeon to much cam, with a 454 you will make peak power at about 5500 rpm if you want to prop for 5200 max a slightly smaller duration cam will make more power in the 4500 to 5200 range and more torque from 3500 right on up , that cam would be better suited for a 502
That is probably just a smidgeon to much cam, with a 454 you will make peak power at about 5500 rpm if you want to prop for 5200 max a slightly smaller duration cam will make more power in the 4500 to 5200 range and more torque from 3500 right on up , that cam would be better suited for a 502
12-17-2002 | 01:42 PM
#13
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Whiteknuckle
When I was Teaching for GM we saw a lot of problems with Piston slap with the Hypereutectic ( 91ish 3.1l)after a fair amount of miles.
When we building 450-500 hp BBc with them we had numerous pistons where the pin boss broke off. Thought maybe we where running to tight. So we set them up on the loose side of the tolerance, still had the same problem. I think they just expand and contract to much. I gave up on them after that. Maybe they are better now. After I seen a few Blocks turned to scrap, I will stick with forged in a boat.
Just my opinion
When I was Teaching for GM we saw a lot of problems with Piston slap with the Hypereutectic ( 91ish 3.1l)after a fair amount of miles.
When we building 450-500 hp BBc with them we had numerous pistons where the pin boss broke off. Thought maybe we where running to tight. So we set them up on the loose side of the tolerance, still had the same problem. I think they just expand and contract to much. I gave up on them after that. Maybe they are better now. After I seen a few Blocks turned to scrap, I will stick with forged in a boat.
Just my opinion
Last edited by MikeW; 12-17-2002 at 02:06 PM.
12-17-2002 | 01:57 PM
#14
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Joined: Mar 2001
Posts: 1,620
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From: st. clair shores mi ,us
Hey Larry ,
Looks like we disagree on the piston thing, we might have to solve it over BEERS !!!
Seriously though I wouldn't put those hyperexploding pistons in my lawnmower! Back in the car days I saw many a guy break those pistons in 400-500 hp small blocks.
Looks like we disagree on the piston thing, we might have to solve it over BEERS !!!
Seriously though I wouldn't put those hyperexploding pistons in my lawnmower! Back in the car days I saw many a guy break those pistons in 400-500 hp small blocks.
12-17-2002 | 05:31 PM
#15
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Thanks for the input guys!
There seems to be disagreement on:
1. IGNITION.
I have not purchased one yet, so I may save money by finding a good used Merc set-up.
2. PISTONS.
Haven`t bought those either. Forged aren`t much more, but I`m not making that much power. Will probably get forged, just for the insurance.
3. CAMSHAFT.
I was thinking it might be a tad big. I may look at one a step smaller.
Do you guys really think 425hp?
I would be very pleased!!!!!
There seems to be disagreement on:
1. IGNITION.
I have not purchased one yet, so I may save money by finding a good used Merc set-up.
2. PISTONS.
Haven`t bought those either. Forged aren`t much more, but I`m not making that much power. Will probably get forged, just for the insurance.
3. CAMSHAFT.
I was thinking it might be a tad big. I may look at one a step smaller.
Do you guys really think 425hp?
I would be very pleased!!!!!
12-17-2002 | 06:02 PM
#16
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Joined: Mar 2001
Posts: 1,620
Likes: 2
From: st. clair shores mi ,us
Ignition:
Your choice , some guys made some good comments about not needing it BUT I've never heard anyone say "well I've got an MSD it's overkill so I think I will change it to a stock Tbolt"
If your not on a real tight budget , what is another $325 (might as well get the distributar too !
Pistons:
GO WITH FORGED ! How do you know what is "to much power " for the hyperjunk pistons ?
Camshaft:
People always seem worried about the camshaft thing, " I might go just a tad smaller" I even said that when putting my motor together ( .723" lift 256/264 @.050 on a 112) but I decided to go with what was recomended and haven't been happier. I've just heard " I should have went bigger " way too many times.
These of course are just my opinions and observations, good luck with whatever you choose.
Your choice , some guys made some good comments about not needing it BUT I've never heard anyone say "well I've got an MSD it's overkill so I think I will change it to a stock Tbolt"
If your not on a real tight budget , what is another $325 (might as well get the distributar too !
Pistons:
GO WITH FORGED ! How do you know what is "to much power " for the hyperjunk pistons ?
Camshaft:
People always seem worried about the camshaft thing, " I might go just a tad smaller" I even said that when putting my motor together ( .723" lift 256/264 @.050 on a 112) but I decided to go with what was recomended and haven't been happier. I've just heard " I should have went bigger " way too many times.
These of course are just my opinions and observations, good luck with whatever you choose.
12-17-2002 | 06:51 PM
#17
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Guys,
On the ignition, a good T-Bolt will run the boat but I always try to upgrade to MSD. If you try to tune a T-Bolt ignition, I don't know any adjustments except initial timing. A six cylinder unit has a much better advance curve and rpm limit. An MSD distributor is a joy to work with and the box helps with idle, plug fouling and starting, but not much at 5000-5500 rpm.
Be sure the components (cap, rotor, wires, plugs, etc.) are good
On pistons, I have had problems with hypereutectic pistons EXCEPT Keith Black. I have seen many of these break in boats and in street cars, but it has ALWAYS been installer error.
Follow the instructions that come with the pistons, not the rings,
for end gap-the top ring gap will be huge compared to what you are used to but do it anyway. The skirt clearance can be relatively small-smaller than forged, but, again, FOLLOW DIRECTIONS!!!!
For the camshaft, I strongly recommend you talk to someone at a reputable cam manufacturer who knows boats, not just the person that answers the phone. A small cam will wimp out and a large one will suck fuel and hurt low speed performance
Hope this helps
On the ignition, a good T-Bolt will run the boat but I always try to upgrade to MSD. If you try to tune a T-Bolt ignition, I don't know any adjustments except initial timing. A six cylinder unit has a much better advance curve and rpm limit. An MSD distributor is a joy to work with and the box helps with idle, plug fouling and starting, but not much at 5000-5500 rpm.
Be sure the components (cap, rotor, wires, plugs, etc.) are good
On pistons, I have had problems with hypereutectic pistons EXCEPT Keith Black. I have seen many of these break in boats and in street cars, but it has ALWAYS been installer error.
Follow the instructions that come with the pistons, not the rings,
for end gap-the top ring gap will be huge compared to what you are used to but do it anyway. The skirt clearance can be relatively small-smaller than forged, but, again, FOLLOW DIRECTIONS!!!!
For the camshaft, I strongly recommend you talk to someone at a reputable cam manufacturer who knows boats, not just the person that answers the phone. A small cam will wimp out and a large one will suck fuel and hurt low speed performance
Hope this helps
Last edited by blown1500; 12-17-2002 at 06:59 PM.
12-17-2002 | 07:16 PM
#18
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Joined: Feb 2002
Posts: 1,296
Likes: 1
From: LaPorte IN.
DonMan,
One thing to keep in mind is there is more to cam selection than just the motor specs. The boat type and hull weight all play an important role. A light boat can use more cam than a heavy boat with the same motor combo. I always have people tell me my cam is to large, and for many of their boats it probably is. My boat is very light and pretty efficient so what my motor is lacking down low is barely noticeable, and there are large gains had on the big end. In my opinion the cam you have chosen is still pretty small and getting the motor to idle and take the throttle crisply may take some minor tweaks, but they will be simple adjustments. Only my opinion! Good luck!
One thing to keep in mind is there is more to cam selection than just the motor specs. The boat type and hull weight all play an important role. A light boat can use more cam than a heavy boat with the same motor combo. I always have people tell me my cam is to large, and for many of their boats it probably is. My boat is very light and pretty efficient so what my motor is lacking down low is barely noticeable, and there are large gains had on the big end. In my opinion the cam you have chosen is still pretty small and getting the motor to idle and take the throttle crisply may take some minor tweaks, but they will be simple adjustments. Only my opinion! Good luck!
12-17-2002 | 07:35 PM
#19
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If you really want to gain something worth the money....put these on.
http://www.offshoreonly.com/forums/s...threadid=38575
You will not be disappointed. They will be the best money you can spend.
The heads are pretty well ported and will make 475+ HP easily on a good 454 and unbelievable torque.
Rod
http://www.offshoreonly.com/forums/s...threadid=38575
You will not be disappointed. They will be the best money you can spend.
The heads are pretty well ported and will make 475+ HP easily on a good 454 and unbelievable torque.
Rod
Last edited by rpm; 12-18-2002 at 10:22 AM.
12-17-2002 | 07:36 PM
#20
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Joined: Dec 2000
Posts: 4,939
Likes: 1
From: Holland, Michigan
you guys are a little hard on the Hypers Ive got 2 seasons at 9.5 to 1 no problems to date runs damn good dont it Kaama? I saw your Knuckels turn white!!! and the MSD is worth the money to me any day it starts better, idles better ,and gets better fuel economy my .02
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