Recommendations in selecting camshaft
03-11-2005, 11:39 AM
#41
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Re: Recommendations in selecting camshaft
[QUOTE=tomas_wallin
What is the difference between a GM cam and aftermarket ones then? What parts do I need, to be able to use a aftermarket cam?[/QUOTE]
The base circle of after-market cams may be different than a GM cam. You will need "conversion" rocker studs and long slot stamped or roller rockers...
What is the difference between a GM cam and aftermarket ones then? What parts do I need, to be able to use a aftermarket cam?[/QUOTE]
The base circle of after-market cams may be different than a GM cam. You will need "conversion" rocker studs and long slot stamped or roller rockers...
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Patrick
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03-11-2005, 12:53 PM
#42
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Re: Recommendations in selecting camshaft
Stock rockers are made from stamped sheet metal which is them surface hardened thru a carburizing prossess. This hardening is only about .020 thick and it rides directly on the rocker stud and the end of the valve. No bearings. When you increase travel and spring pressure you increase friction and wear. The valve tip can wear through the hardened layer very quickly. They are not as rigid as a roller rocker. I've seen them crack in half at the rocker stud.
03-11-2005, 06:11 PM
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Re: Recommendations in selecting camshaft
Originally Posted by KAAMA
A 236*/246* duration cam is A LOT of cam for a 454cid marine engine. I think you will find yourself being very disappointed with a cam that size for a 454 marine application.
Obviously you can do as you please, but a Comp Cams 218*/226* duration cam would be a much better choice. My cousin ran this cam in his 454's and with 8.6 comp ratio it made 461hp @5100rpm and 510 foot pounds of torque on the dyno.
Obviously you can do as you please, but a Comp Cams 218*/226* duration cam would be a much better choice. My cousin ran this cam in his 454's and with 8.6 comp ratio it made 461hp @5100rpm and 510 foot pounds of torque on the dyno.
03-13-2005, 02:19 AM
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Re: Recommendations in selecting camshaft
Originally Posted by scarabman34
For allot of people that came would be very mild. It all depends on what you are looking for. This topic of cam selection is like black magic, and is the million dollar question it seems. Most boaters I see really don't want a cam that makes docking a grand production. Most have trouble alone handling the boat ,let alone worrying about which motor is running and which one needs to revved before it stalls. Those of you that have radical motors know what I'm talking about. Me personally love the attention when I fire up a radical motor(motors) that sounds like the beginning of VanHalens song Hot for the teacher. But for the motor described in this thread The above mentioned Comp cam would be good and anything bigger would be a waste. Just my 2 cents.
I assume that you mean the
Comp Cams 218*/226* duration cam would be a much better choice. My cousin ran this cam in his 454's and with 8.6 comp ratio it made 461hp @5100rpm and 510 foot pounds of torque on the dyno.
Is that the one you guys mean?
Last edited by tomas_wallin; 03-13-2005 at 02:22 AM.
03-13-2005, 09:32 AM
#45
Re: Recommendations in selecting camshaft
Originally Posted by tomas_wallin
Hi scarabman,
I assume that you mean the The only one I could find was this (Cam 4)
Is that the one you guys mean?
I assume that you mean the The only one I could find was this (Cam 4)
Is that the one you guys mean?
Yep, that looks sure looks like the one! From the link you provided, the cam looks to be ground on 111* lobe seps----my cousin's were on 110*. You could specify that you want 110* lobe seperation when ordering the cams, but 111* is fine too. With the 110* lobe seperation my cousin's engines peaked out @5100rpm. (power was peaked out at that RPM).
You could install a higher RPM running cam of 222*/230*, but there are TWO reasons why I wouldn't recommed it for your engine(s) 1) if you are using CAST PISTONS w/stock rod bolts----AND 2) if you are going to be running the STOCK MERC exhaust manifolds.
Even if you were running a better breathing aftermarket exhaust system and yet still had the cast pistons w/stock rod bolts (such as my cousin) I still would still only run the 218*/226* cam.
If the engines were mine with the same situation, then that is how I would personally do it---but I am just one person.
03-13-2005, 10:13 AM
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Re: Recommendations in selecting camshaft
Originally Posted by KAAMA
Yep, that looks sure looks like the one! From the link you provided, the cam looks to be ground on 111* lobe seps----my cousin's were on 110*. You could specify that you want 110* lobe seperation when ordering the cams, but 111* is fine too. With the 110* lobe seperation my cousin's engines peaked out @5100rpm. (power was peaked out at that RPM).
You could install a higher RPM running cam of 222*/230*, but there are TWO reasons why I wouldn't recommed it for your engine(s) 1) if you are using CAST PISTONS w/stock rod bolts----AND 2) if you are going to be running the STOCK MERC exhaust manifolds.
Even if you were running a better breathing aftermarket exhaust system and yet still had the cast pistons w/stock rod bolts (such as my cousin) I still would still only run the 218*/226* cam.
If the engines were mine with the same situation, then that is how I would personally do it---but I am just one person.
You could install a higher RPM running cam of 222*/230*, but there are TWO reasons why I wouldn't recommed it for your engine(s) 1) if you are using CAST PISTONS w/stock rod bolts----AND 2) if you are going to be running the STOCK MERC exhaust manifolds.
Even if you were running a better breathing aftermarket exhaust system and yet still had the cast pistons w/stock rod bolts (such as my cousin) I still would still only run the 218*/226* cam.
If the engines were mine with the same situation, then that is how I would personally do it---but I am just one person.
What hp do you think I will get with that cam (218*/226*) (with the setup I mentioned from the start)?
Last edited by tomas_wallin; 03-14-2005 at 03:12 AM.
03-13-2005, 11:23 PM
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Re: Recommendations in selecting camshaft
Last winter I freshend up the 2 carbureted 454 mags in my Formula 311. Basically a stock rebuild, bored .030 over,and some pocket porting. I used the Comp cams grind (218/226 on a 111*LSA) that KAAMA mentioned instead of a stock Merc cam.I had planned to use the 218/224 on a 112*LSA but it was out of stock and the one I used was almost identical.Idle is good for docking,boat accelerates much faster than with stock 365's, and I was able to pull a 25" pitch Mirage prop when previously could only pull a 23 inch.Boat also picked up 3 mph which is about 30 horsepower per motor increase.Some of that is from the bowl clean-up but the engines feel much more torquey.I had used a slightly larger cam (224/232* on a 110* LSA) on similar engines previosly , but the idle was a little rough for docking.I agree with KAAMA that this would be a great choice for your application. Sparky.
05-06-2005, 12:28 PM
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Re: Recommendations in selecting camshaft
In about a week I'll get the heads, camshaft and the rest of the stuff shipped from the states.
A decided to go with Cam 1 with some help from Lennart at Autoshop Racing Engines.
Autoshop is also rebuilding the heads with larger Manley valves, other springs, rockers and rockerbolts to take the higher lift.
I have also ordered a new throttle control, new cables, a new trim pump and some other useful stuff.
About a month away from the first run
A decided to go with Cam 1 with some help from Lennart at Autoshop Racing Engines.
Autoshop is also rebuilding the heads with larger Manley valves, other springs, rockers and rockerbolts to take the higher lift.
I have also ordered a new throttle control, new cables, a new trim pump and some other useful stuff.
About a month away from the first run
