SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: Legal Chemistry on October 02, 2007, 11:26:23 AM
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I figure with some down time this winter it may be the right time to give the cruiser a little more pep. I figure another 100 hp would be a good target to work for (~500hp). Currently everything works flawless, I'm just kicking the ideas around. I hate to tear down something that works, but more is always better!
The engine is a '96 Marine Power 454 ~390 hp (spinning an A ~4800-4900), forged pistons, new gm hi-perf sq port heads, rpm type intake, q-jet carb (works for now), 9.5:1 compression. Pump gas is a must and not squeezing.
What are the options without tearing though everything? Blower... too much compression? Stroke it to a 496? If so, what are your estimates on the build $ ??? Any help ;D
Thanks!
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A good set of cylinder (aluminum) heads , cam and 850 carb.
-beerjet-
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pro charger ;D
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I like the procharger idea... however I'm already running 9.5 : 1. Too much more and kaaaboom, esp on pump gas. I don't know if I can run much boost safely w/the procharger and my existing compression -anyone know what I can get away with on pump gas? I've seen used kits on the low $ (ahhhhh and the whine of the blower!) Add a set of carbs, larger impeller, and an oil cooler and I'd be in the 550+ range.
The heads are a good idea, but I just spent $ last season on the current ones. Still would need a nice db carb to match.
Maybe cam and carb? I'll try to find out what's in there now.
Keep em coming in you have any ideas!
Thanks
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A good set of cylinder (aluminum) heads , cam and 850 carb.
-beerjet-
::) ;)
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I have to agree with the cam and carb idea!! ;D
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Get your current heads flow benched and optimized, new cam and good set of roller everything, RPM airgap manifold, new carb. Carb is the expensive part. Unless you're really trying to save weight, don't waste your money on the aluminum heads.
As far as the centrifugal supercharger you can probably run 7lbs comfortably and still just run 91. If you put a real supercharger on there, same story 17% underdriven should give you about 6 lbs of boost. That 6 pounds will give you a clean 125HP. Slap two 600 Holley's on there a new cam and roller everything, have your heads reworked and you'll be gold. Probably closer to 550HP conservatively.
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The problem with flowing and porting factory heads is for just a couple hundred more dollars you can get aluminum heads that probably flow the same as ported iron heads, and potentially in the future be ported for more flow.
As I worked on cast iron heads everyday, machineing and porting, I would buy aluminum for barely more money, unless it was a rare motor where aluminum heads aren't available like Y-Blocks :D
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What's the casting # on the heads?
Put a solid roller in it .680 lift with about 260 durration at 50. Instead of a carb, I'd run carbs.
I had a similar combo that made just under 600 hp with a flat tappet cam. Boat ran 83 mph!!
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I would buy aluminum for barely more money, unless it was a rare motor where aluminum heads aren't available like Y-Blocks :D
I bet Dove makes aluminum heads for them Y blocks ;) you are talking ford right?
Rebel
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As far as I know there is still no aluminum Y Block head. I was helping in making one, but it's stilll not available
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Stroke it....496
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I seriously doubt that by only stroking the engine out will it get you 100 HP. He's making less than one HP per cubic inche so by stroking it to a 496 it should theoretically gain him... about 36 more HP. Even if he bumped up the compression a point, which may stop him from using pump gas, he'd still be under his 100 HP more goal.
If you look at the cost of decent aluminum heads, combined with the potential to increase air flow more at a later date, plus they're aluminum which (supposedly) helps control detonation, not to mention they look SIK, why bother with 20 or 30 year old cast iron heads?
It's difficult, at best, to argue with a blower engine. However consider that a blower will reduce the life span of the engine signifantly.
I'm still leaning towards a decent set of aluminum heads, a "bigger" cam, and a Holley DP. If you got the $ definately go roller cam.
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What rod said . Check the flow numbers on new heads these days . Power is made in the heads with the right cam .
-beerjet-
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http://sandiego.craigslist.org/pts/438443461.html
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http://sandiego.craigslist.org/pts/438443461.html
That dude has been trying to get rid of those carbs for over two months, he used to (?) have some tunnel rams he was trying to unload as well. $140 per used vacuum secondary carb, that's about $60 too much (each) for me.
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How much for the aluminum heads? Then you gotta worry about electrolysis. Doesn't really sound like this guy is someone who's is ready to do a lot of tuning and maintenance. You're not gonna want to pass up much more than 500HP. You've got to consider your pump too. Some guys insist on running an aluminum impeller all the way up to 1000HP but you're eventually going to spin the center right out of the impeller. Just can't exactly dump on it at low speeds. You've got to be ready to make the commitment to your pump too, not just the engine...
Easy power, since you're not willing to buy new heads (as you said you just bought these ones) I know two different guys who will both do a great job for $500 or less. Get a Hydro-roller cam and roller everything package from Comp or Crane (preference is up to you), find a used RPM airgap manifold on ebay or something, and an 850 carb. I'm partial to Demon's. Had a 1050 Dominator on my truck and had to adjust it constantly, 950 Demon tweaked it once and it ran great all season.
If you're looking turn key, stick with the single carb.
What kind of boat is this going in?
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350 Chevy bored .060, 6v-71 blower, ported cast iron vortech heads ($900 with porting done), either comp or crane roller setup, forged bottom. 10.5:1 compression, blower runs 17% underdriven at 6lbs of boost. Getting close to 700 HP. Next season it'll be out there with 8:1, blower 17% overdriven @ 15lbs.
Not counting the professional builders fees the parts are relatively cheap (not including the blower).
http://myspacetv.com/index.cfm?fuseaction=vids.individual&videoid=9115630
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Thanks for the feedback. There's tons of info available from this boards' members!
This is going in a big hawaiian... a cruiser (below). "Plug and Play" would be best because of my limited knowledge and experience. I'm not afraid to learn, I'm just doing so as I go along.
As for the heads, I found the part number and info on the net. These were new and fully assembled:
12562920 Cast Iron Gen V & VI Cylinder Head Assembly Gen V and VI cast iron head with 118cc open chambers, rectangular intake ports, and 3/8-inch rocker stud holes. 2.18-inch intake valves, 1.88- inch exhaust valves.
What does a set a Al heads cost? Ah, never mind, probably would have been a better idea to spend the money then -when I didn't have it! So about porting the existing heads, what gains would be see with a mild cam? Cost/labor?
So...
Port existing heads $?
Roller kit + Cam $?
Holley dp 850 $300 to $500
The pump should be in great shape. It was completely gone through last year from a new drive shaft to new impeller (just about end to end!) I'm thinking towards a AA to pull the rpm's down on the long hauls and give a bit more out of the hole. This boat can use a stump puller! I'm finally licking my wounds after buying the boat a year and a half ago, running it for a couple hours, then in the shop for the next few months. I took all the funds away which I was hoping to spend on the fun stuff a year ago...
Thanks
LC
big jet.
(https://www.socaljetboats.com/cpg/albums/userpics/10520/topock.JPG)
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To rebuild a complete set of cast heads, and then have them ported as well it's going to cost around $1500. Theres a lot of services that need to be done to used heads to make them have good longevity.
Blasted and Maged
surfaced
cut for new seats
cut valve guides down, possible resize for different springs
install guideliners
hone guidliners
valve job with bowl blend
new springs, retainers, and keepers
new valves
cut for new style valve seals
fully ported, and polished maybe
all that stuff adds up, that's the only reason why I suggest aluminums. Eldebrock oval port aluminum heads will make great torque and alot more horsepower, not a high RPM head at all.
But if you find a set of iron heads, assembled, and ported already, then that could be a good deal. That's if you trust others machine work. I barely trust eldebrocks machine work alone.
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... These were new and fully assembled:
12562920 Cast Iron Gen V & VI Cylinder Head Assembly Gen V and VI cast iron head with 118cc open chambers, rectangular intake ports, and 3/8-inch rocker stud holes. 2.18-inch intake valves, 1.88- inch exhaust valves.
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(From what I've read) Those are some really good numbers for a Chevrolet stock head. Ditch my suggestion of switching to aluminum heads. The combustion chamber is not too big and not too small, couldn't ask for better flow (stock) than rectangular ports, real good valve sizes... plenty of air flow potential for some real good HP.
An engine is an air pump and with Chevrolet the stock heads are what usually limits the HP, your heads ain't limiting jack sh!t at this point. Much bigger cam (roller preferred), Holley DP (or two), and you'll have your 100 HP addition. I wouldn't even port the heads you have.
You wrote you're thinking of going to a "AA" impellor to lower the RPM's, what RPM are you at W.O.T.? Going to a roller cam will significantly raise your redline thereby not making it nesessary for you to lower the RPM's at W.O.T.
IMO
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Gonna have to agree with Rod. New cam, keep the carb a single (less tweaking), RPM airgap manifold. Good looking boat by the way.
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I dis agree on the carb set up! I have a tunnel with dual 750's on a stock motor and have never had to touch them once since I got them back from the carb guy. Just do yourself a huge favor and make sure you get matched carbs ment to be ran togeather , not just two of the same kind.
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Agreed Marc, once two carbs are tuned you're set. Just gotta jet and adjust twice as much ;D
As long as the cfm of two carbs is the same as the single carb, you should relatively see the same fuel mileage. On my father's Hondo I had taken off his Single 850 and intake to do a tunnel Ram with dual 450's. Honestly couldn't really tell the difference that much, just a little less oomph at low RPM, but not enough to make it swing one way or the other.
I like tunnel rams cause they look cool ;D but I would do a single 4 if that's what's already on it. Big Cam+ big carb= race boat! O0
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I dis agree on the carb set up! I have a tunnel with dual 750's on a stock motor and have never had to touch them once since I got them back from the carb guy. Just do yourself a huge favor and make sure you get matched carbs ment to be ran togeather , not just two of the same kind.
Legal Chemistry may want all of the info on your "never been touched" tunnel ram set-up. Not to jump on your back or throw you under the bus but... I read nothing in the above post that tells the story of 3' flames shooting out of your two carbs! I saw it more than just a few times. Maybe he doesn't want flame thrower's serving as carbs ???
As far as the "matched carbs" and "not just two of the same kind", I'm calling BULLSH!T. If you are refering to the two carbs needing to have the same jet sizes, accelerator pumps, etc... then yes, a matched set is required. BUT if you are refering to "matched set" of carbs built by Holley with different metering blocks and all of that other crap you saw on TV - BULLSH!T.
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Legal Chemistry may want all of the info on your "never been touched" tunnel ram set-up. Not to jump on your back or throw you under the bus but... I read nothing in the above post that tells the story of 3' flames shooting out of your two carbs! I saw it more than just a few times. Maybe he doesn't want flame thrower's serving as carbs ???
As far as the "matched carbs" and "not just two of the same kind", I'm calling BULLSH!T. If you are refering to the two carbs needing to have the same jet sizes, accelerator pumps, etc... then yes, a matched set is required. BUT if you are refering to "matched set" of carbs built by Holley with different metering blocks and all of that other crap you saw on TV - BULLSH!T.
I think he's talking about core shifts straight from Holley, kind like cylinder heads. Maybe?
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Legal Chemistry may want all of the info on your "never been touched" tunnel ram set-up. Not to jump on your back or throw you under the bus but... I read nothing in the above post that tells the story of 3' flames shooting out of your two carbs! I saw it more than just a few times. Maybe he doesn't want flame thrower's serving as carbs ???
As far as the "matched carbs" and "not just two of the same kind", I'm calling BULLSH!T. If you are refering to the two carbs needing to have the same jet sizes, accelerator pumps, etc... then yes, a matched set is required. BUT if you are refering to "matched set" of carbs built by Holley with different metering blocks and all of that other crap you saw on TV - BULLSH!T.
Call holley and ask for yourself if you don't believe me!
And the back fires were my fault not the carbs!
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Yeah... 3' flames are cool, but not on my boat >:D
I'll see if I can find the specs on the cam in there now and would appreciate any suggestions for another (without worry about reversion).
One fatty cam and new carb sounds like a good start to me. Shouldn't break the checkbook too bad. The stock manifolds will have to due with jacketed headers running several k!
gotta keep the engine covered for the dance platform:
(https://www.socaljetboats.com/cpg/albums/userpics/10520/san_v_mar.JPG)
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Call holley and ask for yourself if you don't believe me!
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I don't believe you. Got Holley's number?
Legal Chemistry, what RPM's does your engine have at Wide Open Throttle? W.O.T.
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You don't need Aluminum heads if you already have a set of new Square ports. Go to a bigger roller cam and upgrade to a 950 hp (i think they are called 1000 Hp's now)
The cam and carb change will net you you 100 hp gain....without a problem.
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I don't believe you. Got Holley's number?
Legal Chemistry, what RPM's does your engine have at Wide Open Throttle? W.O.T.
1-866-goholley SORRY FOR THE THREAD JACK!!
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a 950? really with only 500hp? I'm just curious as to what the advantage would be?
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'Rollin... it's a Dom 12s with an "A" ~4800 rpm or so.
Thanks for the compliment UNDONE... not a hot rod but still puts me on the water.
So I'm looking through some paperwork and it may be 8.8 or 9.0:1... more boost friendly than I thought. The only issue with going with a blower is the rear seat will need to be moved. Not really an option.
Any suggestions to cam/carb combo? An 850dp should do the trick up to 500hp?
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a 950? really with only 500hp? I'm just curious as to what the advantage would be?
I've ran a tunnel ram on 500 hp that totaled 1320 cfm. Worked great!!
It's not how much HP you make that dictates what carb to run, it's the carb that dictates how much HP you make. Yes similar power can be made with an 850, but why buy the smaller carb when the need for the larger one will come later down the line. The HP series carbs are far more adjustable than a regular Holley. Better throttle response and more mid range power.
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I have to agree with Quickjet's opinion/posts. He's actually worked with this kind of sh!t and I've only read about this sh!t. :D Makes sense though. Hey Q-jet, how about a cam and intake recomendation from you?
1-866-goholley SORRY FOR THE THREAD JACK!!
Got it. I'll call them late tomorrow afternoon. ;D
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yea...do all that, then add the Procharger
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I have to agree with Quickjet's opinion/posts. He's actually worked with this kind of sh!t and I've only read about this sh!t. :D Makes sense though. Hey Q-jet, how about a cam and intake recomendation from you?
Got it. I'll call them late tomorrow afternoon. ;D
Thanks Hot Rod..... ;)
I'd run the Victor intake, 1000Hp carb, and a .670 roller with 260 durration @ 50 and a set of roller rockers.
The motor will make 550- 575 hp with that combo, possably more.
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QJ , how fast is your boat? ( I am not thread jacking there is a point )
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QJ , how fast is your boat? ( I am not thread jacking there is a point )
122 on motor. .
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122 on motor. .
Now that's the person I would listen to! ;D
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QJ , how fast is your boat? ( I am not thread jacking there is a point )
122 on motor. .
:o
Point well taken!
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dont you have a v-drive too Qjet?
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Thanks Hot Rod..... ;)
I'd run the Victor intake, 1000Hp carb, and a .670 roller with 260 durration @ 50 and a set of roller rockers.
The motor will make 550- 575 hp with that combo, possably more.
Thanks Quickjet... your numbers are impressive. Again, I'm new to most of this stuff. What is involved w/upgrading the cam? New lifters, springs, etc, ???? I have little knowledge about changing hydraulic to solid, so why not stay hydraulic and use the existing parts with a larger cam (or is that not even an option???) What will be the trade off from my current setup, bad idle or ??? With your recommendation you'd guess ~550hp, that's a great number -but will my bottom end hold up? For a relatively simple solution that seems like a big gain!
Again, still learning here -so gathering the information now to set the budget. An idea of what the cost will run? I know I won't do this on own w/my lack of experience.
Thanks!
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Let me clarify a couple things. The 122 is in my V-drive. That's a Dave Riolo engine that I didn't build. I bought the boat turn key. The motor makes roughly 890 hp. I know that may disscredit me in some eyes but I'm being honest.
I would also never reccomend anything that I wouldn't or havn't ran myself.
When I was running my jet boat (which I have sold) I ran a combo similar to the one I reccomended to Legal Chemistry. The only difference wasI used a solid flat tappet cam instead of the roller. That motor made just under 600 hp with a set of 990 square port heads, 11-1 compression and an old TR-2 Edelbrock tunnel ram with 660 center squirters and an Isky Z-89 camshaft ( .636 lift 256 durration @ .50 ground on a 108) That motor ran 85 mph in my Bahner.
That same combo with 8.75 compression in my Bahner jet ran 83.7 mph all day long on pump gas.
I couldn't afford a roller a the time, however it was known that it would most likely pick up another 30- 40 hp with the cam change alone.
The heart of any engine are the heads and camshaft topped off with the right carb(s). The bottom end is along for the ride.
That bottom end should hold up fine. Yes you will be in another RPM range however the pump will keep you safe from catostophic failure.
You will love the power, throttle response and the oohs and ahhs you get everytime you fire it up.
A set of water jacketed headers in the future wouldn't hurt either.... ;)
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Looks like Q-jet just gave up a 550+ HP combination for the Chevrolet big block. ;D
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Quickjet, thanks for your input -it is appreciated. Any downside to this combination? Jacketed headers would be nice but $$$$ :o
I just got back from Havasu... damn it was nice. The weather has cooled down and the speed picked up. Boat ran great, a constant 4900-4950 rpm all day long.
SO with that being said, what is the parts list to get 'er done? The cam above (.636 lift 256 @.50, 108 degree.) and carb? I'll have to send this out to be worked on -so what else should I expect to add to the list? Estimated cost or SoCal
Anyone?
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Of course...you could always do a 100HP shot of funny gas! :D
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Thanks for the feedback... I looked around for some more info and a little feedback led to reversion w/the cam above (636 lift 256 durration @ .50 ground on a 108) Can anyone else comment on this? This will be running on stock Merc manifolds. Also what was the power band for that cam? I'd like to stay below 5500 and keep the A impeller... is that possible?
A bottle of the funny gas would just leave me laughing my arse off all day passed out in the cove!