Cam Grind Specs
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Cargo Master
Joined: May 2011
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From: Northern California
Cam Grind Specs
Okay so here the deal... I dont know shít about cam grinds beyond what I saw in a few youtube videos; it is a tather facinating process.. Someone gave me this spec sheet and said to simply take it in with the cam and they will know what to do.
The cam is from a 98 explorer 5.0 roller engine. I also grabbed the gt-40p heads from the same engine. It is going into a boat replacing an old 28oz flat tappet lifter engine. The spec sheet is supposed to offer a reasonably aggressive marine grind. Can anyone confirm? The idea here is trust but verify.
The roller engine will be getting a carburetor on top.
The cam is from a 98 explorer 5.0 roller engine. I also grabbed the gt-40p heads from the same engine. It is going into a boat replacing an old 28oz flat tappet lifter engine. The spec sheet is supposed to offer a reasonably aggressive marine grind. Can anyone confirm? The idea here is trust but verify.
The roller engine will be getting a carburetor on top.
Hotshot
Joined: May 2003
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From: south louisiana
The Explorer cam specs out like this: 256/266 (advertised) duration (your cam specs are the @ .050 figures) Valve lift with 1.6 rockers is .422/.445, LSA is 116.5. You cam is a little bit warmer than the Explorer cam, but not by much. Run the Explorer cam with 1.7 rockers and the lift goes to .445/.473
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Cargo Master
Joined: May 2011
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From: Northern California
So the machine shop didn't look up the numbers but they didn't think the grind would be much of a difference either. They said the stock '98 302 explorer roller cams were already pretty aggressive. So I am going to simply keep it as is and if I find I want a bit more I can swap out the lifters later on without a complete tear down.
I looked up the specs myself and there was about a 0.060 difference on the intake and a 0.050 on the exhaust increase at the valve. I understand the physical difference but I don't know enough about the dynamics of all this to understand the significance but everyone is saying its not much. I will accept that.
So I am going to simply keep it as is and if I find I want a bit more I can swap out the lifters later on without a complete tear down. Even putting in a new cam down the road wouldn't be too bad.
stock cam part number cs1533 / OE number F4TE6250BA
I looked up the specs myself and there was about a 0.060 difference on the intake and a 0.050 on the exhaust increase at the valve. I understand the physical difference but I don't know enough about the dynamics of all this to understand the significance but everyone is saying its not much. I will accept that.
So I am going to simply keep it as is and if I find I want a bit more I can swap out the lifters later on without a complete tear down. Even putting in a new cam down the road wouldn't be too bad.
stock cam part number cs1533 / OE number F4TE6250BA
FTE Legend
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From: Ottawa, Ontario
The cam lobe seperation angle(LSA) which is the difference between the centerline angle of the intake and exhaust lobes is generally 114deg and above for EFI automotive applications due to emissions requirements, while cams for carbed applications typically have 108-110 deg LSA. The difference here is only 4-6 degrees total but even a slight change in this spec produces significant differences in where an engine makes peak TQ.. all else being the same. So the stock Explorer cam won't quite make as much TQ as it could but overall it's not a bad piece and will produce a smooth stable idle.
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Cargo Master
Joined: May 2011
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From: Northern California
The cam lobe seperation angle(LSA) which is the difference between the centerline angle of the intake and exhaust lobes is generally 114deg and above for EFI automotive applications due to emissions requirements, while cams for carbed applications typically have 108-110 deg LSA. The difference here is only 4-6 degrees total but even a slight change in this spec produces significant differences in where an engine makes peak TQ.. all else being the same. So the stock Explorer cam won't quite make as much TQ as it could but overall it's not a bad piece and will produce a smooth stable idle.
I found the 98 5.0L was rated at 215 hp & 288lbs/tq... This is way more than the old motor. Its a family boat that is way lighter (so light that it floats
) than an explorer so it should be good. If I need more I will simply have to deal with that later. As baddad said I can always add rockers later which are pretty easy to help out if needed.
Hotshot
Joined: May 2003
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From: south louisiana
I don't think the difference in the LSA's are that big a deal as far as the narrower making more power. The F4TE runs great with a carb, it's got a smooth powerband from idle to around 5500-6000 when run with 1.7's and an RPM type intake. I seriously doubt a narrower LSA cam would do any better with similar lift/duration specs. The F4TE runs so well with a carb, that there's little if any difference run with a carb as run with EFI. Anyhow, you really need torque down at the bottom end with a boat, that's where it'll shine over a bigger cam. Getting it up out of the hole (i.e: the hull out of the water) is where the torque comes in, once it's up on plane, it doesn't take as much power to accellerate it. I played with a chevy 4.3 in a 19 ft ski boat about ten years ago, I went so far as to replace the 2 bbl intake with an Edelbrock 4 bbl topped with a 600 Holley, that alone gained it 5 mph on the topend, but little else.
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Cargo Master
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From: Northern California
My buddy has a 6 y/o boat with one of those chevy 4.3's in it. My intention is to out do that. If I do I will be happy. I think it was pretty close before with the old motor.
For now though I plan on simply putting it back together with the original intake... Its the cast Iron ford 2bbl with a holley carb. The top end stuff is pretty simple to deal with. I just want to get it reassembled with the explorer cam & gt40p heads and go from there.
It sounds like it will be a pretty nice motor just as so...
For now though I plan on simply putting it back together with the original intake... Its the cast Iron ford 2bbl with a holley carb. The top end stuff is pretty simple to deal with. I just want to get it reassembled with the explorer cam & gt40p heads and go from there.
It sounds like it will be a pretty nice motor just as so...
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And that's with the factory whisper quiet exhaust on it of course, simply uncorking the engine with a free flowing exhaust is good for a 20-30 point gain.
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