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My jet boat is a 460 pi in a baja hull it has a crane cam 294B-8 . I want to know if I can put a bigger one . I have stock water cooled headers. Inverted dome pistons stealth. Intake and police intercepter head that have been ported to match scj heads . And a 850dp .
 

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What rpm range do you want to run it in? Max rpm and roller cam or hyd or solid flat tappet?

What are the specs on that Crane cam? and what does it spin now?

S CP
 

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650 hp on pump gas

It turns 8000 rpms. Cam solid flattaped . I don't know all the spec on the cam . I just got the boat . And started taking apart the engine. I want to get about 650 hp. Out of it .on pumped gas . Can anyone point me in the right direction. I am new to all of this . Thanks
 

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It turns 8000 rpms. Cam solid flattaped . I don't know all the spec on the cam . I just got the boat . And started taking apart the engine. I want to get about 650 hp. Out of it .on pumped gas . Can anyone point me in the right direction. I am new to all of this . Thanks
Better check out your tachometer. Sounds like it may have a setting for 4/6/8 cylinders, and it's on the 4 cylinder setting, not very likely that you are turning 8000 rpm.
 

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Your numbers do not compute! As said above, check your tach, check the condition of your pump. Give us the size of your impeller. Something is not right here. 460 fords don't turn 8000 rpm and live. (nothing does for long).

Duane HTP
 

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My jet boat is a 460 pi in a baja hull it has a crane cam 294B-8 . I want to know if I can put a bigger one . I have stock water cooled headers. Inverted dome pistons stealth. Intake and police intercepter head that have been ported to match scj heads . And a 850dp .

Here are the specs for your cam :

Adv. Duration I / E:
294 / 304
Basic RPM Range:
3500 - 6500
Dur. @ 0.050 I/E:
256 / 266
Camshaft Series:
Drag Race
Camshaft Type:
Mechanical
Grind Number:
FF 294B-8
Idle Quality:
Rough
Lifters Included:
No
Lobe Seperation Angle:
108
Valve Lash Settings:
.030 / .030
Valve Lift (in.):
.589 / .615


You can probably go bigger but there is not enough information to make that call. You have to check your piston to valve clearance and your cam timing. If your cam timing is advanced or retarded then that will affect piston to valve clearance as well. Also, what is your compression ratio? A bigger cam might make your engine a dog if the CR is too low.
Also how good are your heads? More lift might not do you any good if the heads flow max at .550, more duration would help if you have the compression to handle it.
There are lots of factors to picking the right cam, make sure you gather as much info about the engine as possible.

I'm guessing you have around 8:1 compression with those dished...oops, I mean "inverted dome" pistons lol. I would recommend less cam, something like 240 @ .050" lift, 106 LCA, .550" lift, 4 degrees advance.
 

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Better check out your tachometer. Sounds like it may have a setting for 4/6/8 cylinders, and it's on the 4 cylinder setting, not very likely that you are turning 8000 rpm.

something tells me he is a bored regular having some fun.

If not, he should answer the question about what rpm range we wants to run it in? 650hp at what rpm?

He also needs to remember that bigger isn't always better. The cam specs posted aboe look to be very very good for that engine combo. As an example Comp Cams has a grind for Jet Boats that's 270/276 @ .050 and .649/.642 lift on a 108* lobe center its power range is 4000-7000. But the cam he has is better suited for for his pump gas 650 goal.

" I have stock water cooled headers." are these logs or headers ?


S CP
 

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Ok I looked up your heads and they should have an 88cc combustion chamber, so it's looking like you might have anywhere from 8.5 to 9.5:1 depending on the dish volume, compression height, piston to deck clearance and head gasket thickness.
 

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Ok I looked up your heads and they should have an 88cc combustion chamber, so it's looking like you might have anywhere from 8.5 to 9.5:1 depending on the dish volume, compression height, piston to deck clearance and head gasket thickness.
He could use a compression bump to 10:1 -10.5 to get the benifit out of that cam. 10:1 will do but at 8.5:1 -9:1 it's leaving a bunch on the table.

Did he mention what size CARB ?


S CP
 

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I have a 555ci big chevy, tunnel ram, 750 holleys, aluminum heads, it is a 9:1 motor, pump gas, made 762hp on the dyno, my cam is .777 .731 advertised duration 321 330, 288 290 at .050, and lobe lift .457 .430, lobe speration is 110
 

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I have a 555ci big chevy, tunnel ram, 750 holleys, aluminum heads, it is a 9:1 motor, pump gas, made 762hp on the dyno, my cam is .777 .731 advertised duration 321 330, 288 290 at .050, and lobe lift .457 .430, lobe speration is 110

Curious :)bulb are you recommending your cam for his engine combo? :)bulb

Your cam is bigger than the cam in my 565 that made 935 hp at 7,000 with a single 1,050. ( 12:1 comp)


S CP :)bulb
 

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Curious :)bulb are recommending your cam for his engine combo? :)bulb

Your cam is bigger than the cam in my 565 that made 935 hp at 7,000 with a single 1,050. ( 12:1 comp)


S CP :)bulb
Sleeper, I don't think he has the heads to support anything bigger. It might be a bored member. Not enough info.
 

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Discussion Starter #15
thanks guys

I have pi heads D20E-AB is the casting numbers they are aimost the same as cobra jet head the intake and exhaust value is a little smaller . They are ported and polished. And matching intake. The water cooled headers are logs i think they run level with the engine and go threw the back of the boat. The guy I got the boat from said it has a 11 to 1 compression ratio. The pump is a berkly the impella is a C. I am total re building the engine and pump . My goal is around 650hp and around 85 to 90 mph. On pump gas . Any suggestions please comment. Thanks
 

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Can you please explain why? :)bulb

460 fords don't turn 8000 rpm and live. (nothing does for long).
Taken in contex to the Op's post I'd say that's a fair statement. A Stealth dual plane intake and a single 850 doesn't exactly brim confidence that the engine was built to rev 8,000 rpm, at least not for long. Would you assume otherwise? :)bulb


S CP :D
 

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. My goal is around 650hp and around 85 to 90 mph. On pump gas . Any suggestions please comment. Thanks
Your Baja hull may well be your limitation. Although there is a guy who posts here that put a sub-400 hp 454 out of a Suburban in a jet boat and ran 90 I think. He might be able to help you more than most, he definitely had the right boat for the job. So who know's....................... :)bulb

Just don't tell us your Baja has a bow fuel tank?

You have any pics of the boat?

As far as suggestions...............rebuild your engine with the cam you have, set a goal for approx 10:1 compression, use a set of dry headers, your Stealth Intake is fine, but you might get some top-end benefit with a Victor JR single plane, rebuild the pump with an A/B cut impeller and see where you end-up. Good luck with the project.

Oh yea keep in mind about the cam...bigger isn't always better. Cam the engine for the intended rpm range you plan on running. Somewhere around 6,000 rpm should be a good goal for your engine. But keep in mind; if you have the money and don't mind wrenching on the engine from time to time to set lash, nothing is better ( bang for the buck) than a mech. roller cam. A small to mid- size roller is a 50-75hp gain over a mech. flat tappet and that's mid range to top end power.

Good luck


S CP
 

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My jet boat is a 460 PI in a baja hull it has a crane cam 294B-8 . I want to know if I can put a bigger one . I have stock water cooled headers. Inverted dome pistons stealth. Intake and police intercepter head that have been ported to match scj heads . And a 850dp .
No-one on the this planet can tell you how much camshaft your cylinder heads can accomodate without looking at your heads and the way they've been machined and set up. But if the sky's the limit during a head re-work, then those heads--properly ported--won't taper off in flow curve until valve lift reaches at least 0.800". That being said, taking a bone-stock pair of D20E PI heads and trying to intall a camshaft into them that has any more than ~0.550" lift will risk major engine damage.

I have pi heads D20E-AB is the casting numbers they are aimost the same as cobra jet head the intake and exhaust value is a little smaller . They are ported and polished The guy I got the boat from said it has a 11 to 1 compression ratio. Any suggestions please comment. Thanks
D20E heads with inverted dome 460 pistons does not make 11:1 compression ratio. Even flat top won't get you there. Dome top pistons are required.

LO
 

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460 fords don't turn 8000 rpm and live. (nothing does for long).

Duane HTP
Duane! :D You are in Missouri, aren't you? Go check out some truck pulls where the competitors beat all brands of engines. Two MO guys I know turn their 385 Series Ford engines 9000 rpm or more (one guy's tach records 10,200 at wheel hop). These engines are not all aftermarket non-Ford stuff, they use OEM crankshafts, factory iron block and heads, etc. Pulls are 27 seconds at a time, typical.

Yes, I realize your post is really questioning the tachometer readings, but you know me...... ;)

LO
 
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