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loose rockers....?

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#81 ·
cfm said:
Kid - he gave us the Class II automotive specs. Has not given the Class II marine specs. So we don't know really what's in it. :confused1
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AHhhh, ok....I don't think they'd use that cam in the marine version. Too controversial with the 110 LSA...bunch o' puzzies :eek:

Regardless, with 454 CI, smaller intake valve (ZZ has 2.25 Int.) and different heads and smaller carb, is that cam overkill for fivep's 454?

I know you guru type's talk "combination" on a build. That's why I wondering :confused1
 
#83 ·
Kidnova said:
AHhhh, ok....I don't think they'd use that cam in the marine version. Too controversial with the 110 LSA...bunch o' puzzies :eek:

Regardless, with 454 CI, smaller intake valve (ZZ has 2.25 Int.) and different heads and smaller carb, is that cam overkill for fivep's 454?

I know you guru type's talk "combination" on a build. That's why I wondering :confused1
Click to expand...
If the carb, intake, heads don't flow well in a certain perios of time, they need more time to flow more air.

Only way to give them more time is by opening the valves longer which is done thru a bigger camshaft.

To have good power and be able to run a small camshaft you need a goo carb, intake, and cylinder head package.

:bigsmile: :bigsmile: :bigsmile:
 
#85 ·
cfm said:
If the carb, intake, heads don't flow well in a certain perios of time, they need more time to flow more air.

Only way to give them more time is by opening the valves longer which is done thru a bigger camshaft.

To have good power and be able to run a small camshaft you need a goo carb, intake, and cylinder head package.

:bigsmile: :bigsmile: :bigsmile:
Click to expand...

Ok... but if intake, heads, and carb are limited, and you have a big cam, your set up can't take advantage of the cam. In other words, just not enough flow/capacity to handle it.....yes, no??

To take advantage of a bigger cam, ya gotta have heads, intake, and carb that will take the mix that the cam is supplying...right?
 
#86 ·
Yup, it's called 'crutching.'

Example:
400hp 5.7 small block same compression in both

1) Old OEM heads
Holley 650 carb
RPm Air Gap Intake
230+ at .050" cam to reach 400hp at say 6300-6400rpm

2) AFR 180cc heads
Holley 650 carb
RPM Air Gap Intake
218-220 at .050" cam to reach 400hp at say 5600-5700rpm.

--------------------------------------------------------------------

Okay, one more example:

A 2bbl race motor:

360hp at 6800 rpm :shocked:

------------------------------------------------------------------

Remember, hp is a function of rpm. If torque remains the same as rpm increases, the HP goes up. In fact, if torque goes down slowly while rpm goes up, the hp can still go up also. Plug in some numbers:

HP = (torque X rpm / 5252)

---------------------------------------------------------------------

So,

A camshaft duration detemines what rpm the power band is in and how long each cylinder has to breather in/out during each event

To make big power in a lower rpm, the cam of course has to be smaller for this desired low rpm, so it's the cylinder head + intake that must fill the cylinder faster and with more quanitiy in that same time period.

======================================

This is why we speak combination !
 
#87 ·
I think I got the overall picture.

So, there is a point where the carb, intake and heads provide, or, have too much flow/capacity, for a given cam. When close to that point, that would mean the low rpm hp/tq threshold has been met, right? So what happens....the engine must simply cease increasing in rpm's, and hp ?
 
#88 ·
On a very simplistic but meaningful explanation:

The cam determines what rpm band the engine is going to be run at

The top end will determine how much power is made within that rpm

I'm tripping on my tongue - it's Friday. :shocked:

Gotta work on the driveway paperweight this week-end. :confused1
 
Discussion starter · #96 ·
Jasper called me today, they recieved the core motor back and they tore it down and found that cylinder number 3 and 6 were scored and appeared to have overheated, they say it wasnt their fault...........they say it must of been a ignition problem or fuel delivery problem..? I dont know regardless now I am nervous because if this thing blows again im gonna be pissed
 
#98 ·
fiveptohh said:
Jasper called me today, they recieved the core motor back and they tore it down and found that cylinder number 3 and 6 were scored and appeared to have overheated, they say it wasnt their fault...........they say it must of been a ignition problem or fuel delivery problem..? I dont know regardless now I am nervous because if this thing blows again im gonna be pissed
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If it wasn't their fault I'd be nervous that a big bill is coming in the mail. :shocked:
 
#99 ·
fiveptohh said:
Jasper called me today, they recieved the core motor back and they tore it down and found that cylinder number 3 and 6 were scored and appeared to have overheated, they say it wasnt their fault...........they say it must of been a ignition problem or fuel delivery problem..? I dont know regardless now I am nervous because if this thing blows again im gonna be pissed
Click to expand...
Sounds you need to check your cooling system...
 
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MadMike
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