Reply With QuoteWOW! A fellow small block owner. I run a 383 in my jet. Not near the torque of a big block. I have a Beachcomber for sell in the Spam section....Check it out
Zach
Toasted my motor a couple of weeks back. Broke #2 cylinder exhaust valve. It's now jammed into the top of the piston. Cylinder walls are scored and I'm already .060 over.
This is the motor I'm thinking about Blue Print Engines (http://www.blueprintengines.com/popu...specs&pc_id=36)
I figure with a different intake, demon carb, port & polish, 3 angle valve job, and port matching, I should be able to get upwards of 450 hp. They'll also give me a 12 month warranty (gm crate engines are not warrantied in marine apps.) I'm hoping to get my boat up to the upper 70's (80 would be great). 1995 15' Jetcraft Sprint (made by Eagle) Legend drive with place diverter.
Learning more about this hull all the time. Looks like chine walking will be a pretty big issue. Since this is my first jet boat got a couple of questions in regard to chine walking. My boat is a 15' v-hull with a delta pad. I've had some outboard high performance boats and the best fixes for chine walking were to balance the boat side to side and get the motor mounted as rigidly as possible. My jet drive has a fair amount of play. Would changing the steering system to some type of dual cable arrangment and removing the play have as large an impact as on an outboard boat? Does anyone else have any suggestions to keep chine walking to a minimum?
WOW! A fellow small block owner. I run a 383 in my jet. Not near the torque of a big block. I have a Beachcomber for sell in the Spam section....Check it out
Zach
Don't know if a dual-cable exists without a lot of self-invention. I found the worst looseness to be in the rack assy itself. If it's old, replace it and the cable. Spring extra for the Stainless cable. Total arround $150. There's not the slop or flex/movement in a jet there is in a strap-on so you are ahead of the game there.
I think rexone has a calgo steering setup like on steelcomps boat.Roy
Might want to PM Bottom feeder (http://www.***boat.com/forums/member.php?u=7885) . He's got a boat like yours. (I think)
FW, sorry I didn't get back to you via PM, its been a very busy week. Sorry to hear about the motor, what your looking at sounds like a good combo. I just picked up some Vortec heads so with a little luck, maybe this winter I can buy a ZZ4 short block and get back to racing next season. I'm hoping for over 355HP with the Vortec heads. Dam race rules, I'd like to see what it'd do with 450 HP but I can't afford one engine, much less a play engine after I've built the race engine. There are many here on the boards with way more knowledge than my little pee brain has about motor building, combo's, HP etc.
Are you already having a chine walking issue or are you predicting them with more HP? That's odd, I have the same exact hull and I've had a little porpusing but never a chine walk. I'm running a Legend bowl but I have a steel race nozzle. I'd say my roost is about 10' off the water at the highest point and that seems to run pretty well. I'll probably be able to run a degree or two of up-wedge and carry the nose a little more with the ZZ4(couple more HP than my current set up).Of course its not adjustable so off the line my sleds a dog but once I'm on plane it does just fine. Our whitewater races are rolling starts so it doesn't matter.
Look at where your strakes are and hold a straight edge on there. My hull is terrible, it looks like there is a slight warp at every spot weld that holds the strakes on, maybe yours is a little more extreme than mine, who knows? Most of it is out of the wtare at WOT but maybe some of your pad is messed up. Maybe mine is so messed up from all the rock dings that it doesn't porpuse anymore? :boxed: Mess with your PD and see if there is a setting that lessens the chine walk. I'd also look at how you are balanced side to side and front to rear. Jesse over at jetboatracing.com started out racing the exact hull we have and he had good luck moving his CG to the rear quite a bit. Unfortunately, I've built a jumbo gas tank so my seats can't move back anymore. Make sure your battery is mounted on the passenger side or your passenger weighs 40-50 lbs more than you, that may throw off the balance. Also what motor mounts and roll cage are you using? I have full plate motor mounts and a chrome-moly 6 point cage in mine, that may have thrown my CG one way or the other so it rides differently, or it could be a hull stiffness issue? FYI, that aluminum hoop that is bolted on from the factory is for looks only, don't expect to to do much if you roll it over on the beach or in the rocks. Just some thoughts, the chine walk has me a little baffled. Jesse is one of the best sources of knowledge in general but specifically with this hull and you won't come accross a nicer guy, hit him up for some info. Some of these glass guys are pretty dam smart, they probably have a thing or two to say about chine walking-Aluminum Squirt
Thanks Jeff. No I haven't had any problems yet but I would anticipate my hull to start chine walking somewhere in the 70 mph range. Just trying to get a head start.
Speaking of heads have you seen the new vortec iron heads. They wouldn't be legal for the FX class, but they sure do seem to put up some pretty good flow numbers. Check this out Vortec Heads Article (http://www.superchevy.com/technical/...0511sc_vortec/). I'd love to see the numbers I could get off this 383 with those heads and some port & polish work. Might have to change pistons to keep the compression down.
I am still running the stock mounts. I'll try to do something with them this winter. Previous owner had a nitrous setup on this boat and the engine was producing so much torque that the right stringer is bent in some. I 'll beef up the stringers with some type of rail arrangement. Dont know if I will go to a plate mount. That would bring up a couple of other issues. I would need to change my alternator mount. Shouldn't be to bad. Longer bolts for the mount and a spacer for the cranshaft pulley. The oither issue is that right now I can have the engine out and on a stand in around thirty minutes if I've got someone helping.
One other thing. Got the hot ticket for a starter mount. Get rid of your low mount starter. It's down low in a bad place, hard to change with the motor installed and weighs 2 to 3 times as much as a high torque. It does require some modification to the flywheel.
Hey great to see another tin boat on the forum. There are some good guys here that can offer alot of expereince etc I think you've already found one of them. Did I miss what hull you're running? Pics are always great
Cheers
FW, sorry I didn't get back to you via PM, its been a very busy week. Sorry to hear about the motor, what your looking at sounds like a good combo. I just picked up some Vortec heads so with a little luck, maybe this winter I can buy a ZZ4 short block and get back to racing next season. I'm hoping for over 355HP with the Vortec heads. Dam race rules, I'd like to see what it'd do with 450 HP but I can't afford one engine, much less a play engine after I've built the race engine. There are many here on the boards with way more knowledge than my little pee brain has about motor building, combo's, HP etc.
Are you already having a chine walking issue or are you predicting them with more HP? That's odd, I have the same exact hull and I've had a little porpusing but never a chine walk. I'm running a Legend bowl but I have a steel race nozzle. I'd say my roost is about 10' off the water at the highest point and that seems to run pretty well. I'll probably be able to run a degree or two of up-wedge and carry the nose a little more with the ZZ4(couple more HP than my current set up).Of course its not adjustable so off the line my sleds a dog but once I'm on plane it does just fine. Our whitewater races are rolling starts so it doesn't matter.
Look at where your strakes are and hold a straight edge on there. My hull is terrible, it looks like there is a slight warp at every spot weld that holds the strakes on, maybe yours is a little more extreme than mine, who knows? Most of it is out of the wtare at WOT but maybe some of your pad is messed up. Maybe mine is so messed up from all the rock dings that it doesn't porpuse anymore? :boxed: Mess with your PD and see if there is a setting that lessens the chine walk. I'd also look at how you are balanced side to side and front to rear. Jesse over at jetboatracing.com started out racing the exact hull we have and he had good luck moving his CG to the rear quite a bit. Unfortunately, I've built a jumbo gas tank so my seats can't move back anymore. Make sure your battery is mounted on the passenger side or your passenger weighs 40-50 lbs more than you, that may throw off the balance. Also what motor mounts and roll cage are you using? I have full plate motor mounts and a chrome-moly 6 point cage in mine, that may have thrown my CG one way or the other so it rides differently, or it could be a hull stiffness issue? FYI, that aluminum hoop that is bolted on from the factory is for looks only, don't expect to to do much if you roll it over on the beach or in the rocks. Just some thoughts, the chine walk has me a little baffled. Jesse is one of the best sources of knowledge in general but specifically with this hull and you won't come accross a nicer guy, hit him up for some info. Some of these glass guys are pretty dam smart, they probably have a thing or two to say about chine walking-Aluminum Squirt
squirt, i have a good vortec short block that needs freshening up, all you have to do is buy a vortec style intake and a gm hotcam kit to make it a zz4.shipping cost with be a mofo though! be cheaper to buy one local.
Rampager. There are some pics of the boat on this site. Just look under the first couple of posts I made. You replied back when I first got on the site.
My hull is the same as Aluminum Squirts, 1995 Jetcraft Sprint (made by Eagle), 15' long, v-hull with a delta pad.
Talked to Jesse at the Whitewater Jetboat Racing site. He raced the same hull a few years ago. Rule changes have made it where it's not that competitve anymore. He has given me the setup they were using to get the most out of their hull. They were down quite a bit on horse power compared to what I hope to end up with, so my setup might end up being quite a bit different. At least it gives me a direction to go.
I also talked to Bob at double barrell marine. Those guys are big into sprints. He is also familiar with my hull. Same thing, it's not very competitive any more. The newer hulls are much shorter and they're running a different style pump. He did say it would still make a great lake boat. I guess I've got a little of both worlds with my boat. I think I'll eventually see 80, but should still turn like a slot car.
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