imco offshore
Competitor / Charter Member
i,m not an engine man of sort,,,, but i would think the carb is a little fat or the power plug is too high
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.060" spark plug gap?
- Thread starter 2112
- Start date
i,m not an engine man of sort,,,, but i would think the carb is a little fat or the power plug is too high
MikeyFIN
Competitor
Offtopic.
Also Deck heights and head deck heights are nothing even close to blueprint standards as there is material left to machine while new.
It´s not a wonder sometimes brand new GM long blocks are off by a a lot in compression.
At 8.9 compression you can run your engine with almost anything, no need to worry there.
Our octane ratings in Europe are higher because we use RON ( Research octane number) on the pump which applies more on idle and low detonation while MON ( Motor octane No) is more applied on High temp/Rpm and on load. The average of these two numbers is AON ( Average ) or PON ( Pump octane # in U.S.).
So actually our fuels like 95 RON is close to your Regular and our 99/98´s are like Super(?) for you.
I guy that writes on another site told that his best numbers with a Vortech X Centrifugal blown 548 was 1025hp with regular 95 RON on a boat motor any higher octane made it worse so I think you´re more than safe...His base comp is 8.33:1
And here´s a pump gas 950hp blown Marine one plus some..
http://www.youtube.com/watch?v=ZtaYdzoCzl8
MikeyFIN
Competitor
Yes of course it is as the velocity at idle is what it is...can´t help that. Engine would be a hell of a engine in a twin engine or a lighter boat...
The plugs pulled from a high rpm run looked just fine before Clearwater while testing, just the way a boat motor should be to be on the safe side IMO at least.
Maybe it would work better with a Tunnel ram and two 600cfm´s
So the only remedy for a racecourse like with a long idle time would be open the gaps as we speak.
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DAREDEVIL
Banned
High compression race fuel engines DON'T like to idle !!!!!!
If i would of known that the idle time in Clearwater was 25 min. i would of ran #7 plugs instead of #9,,,but u lose power that way.
It cleared up as soon as we got on plane.
Also in Sarasota,,,just for the note George,,i had an other issue and only ran on 7 cylinders because of a small hole in the intake runner so oil was pumping on to the valve and fouled up #3 plug so it could not clean out.
Thats why i did not finish Lauderdale & Sarasota,,,it tock me that long to find the problem.
Mika ,,a Tunnelram ,,,u lose exselleration,,thats what i need most.
But this thread is not about ME or my engine. LOL:rofl:
If i would of known that the idle time in Clearwater was 25 min. i would of ran #7 plugs instead of #9,,,but u lose power that way.
It cleared up as soon as we got on plane.
Also in Sarasota,,,just for the note George,,i had an other issue and only ran on 7 cylinders because of a small hole in the intake runner so oil was pumping on to the valve and fouled up #3 plug so it could not clean out.
Thats why i did not finish Lauderdale & Sarasota,,,it tock me that long to find the problem.
Mika ,,a Tunnelram ,,,u lose exselleration,,thats what i need most.
But this thread is not about ME or my engine. LOL:rofl:
MikeyFIN
Competitor
But with small throttle barrels It Might actually work, just a brainstorm.... LOL.
DAREDEVIL
Banned
The farther the carb/s is/are away from the block,,the less tourqe u have !!!!!!!!!!!!!!!!
MikeyFIN
Competitor
No --- the opposite..the longer the runners are the more torque you have down low..but they also have to keep up the velocity to work which tunnels seldom doesn´t as the runners are too big.
Think (Smokey) Crossram for example..works like Gangbusters or Individual runners.
Scotty I´m a Roadracer/oval Tracker at heart... not a Drag racer... and it´s allbout torque there.
also a Big plenum gives a lot of air for the initial throttle opening so the engine doesn´t need to suck thru a straw.
http://www.sporttruck.com/products/0903st_2008_sema_show_top_50_products/photo_27.html
Think (Smokey) Crossram for example..works like Gangbusters or Individual runners.
Scotty I´m a Roadracer/oval Tracker at heart... not a Drag racer... and it´s allbout torque there.
also a Big plenum gives a lot of air for the initial throttle opening so the engine doesn´t need to suck thru a straw.
http://www.sporttruck.com/products/0903st_2008_sema_show_top_50_products/photo_27.html
Geronimo36
Charter Member
have you tried opening up the secondary butterflies or changing the air bleeds? With some work I bet you can get it to idle, probably just take some time to do it right.
MikeyFIN
Competitor
Nickerson ain´t the only one... I can drill too
That´s an old trick bytheway which you necessarily doesn´t need to do with a 4500 Holley.
And Geronimo you´re right. It takes time to get a carb to work good thru the whole powerband a lot more than just doing WOT and High RPM tuning.
That´s an old trick bytheway which you necessarily doesn´t need to do with a 4500 Holley.
And Geronimo you´re right. It takes time to get a carb to work good thru the whole powerband a lot more than just doing WOT and High RPM tuning.
2112
Founding Member / Contributor
Carbs require a special talent. If you have it great! I don't and I sure like bolting on a Carb that has been tuned by someone who does so all I do is set is idle speed and and get boating. :USA:
Nickerson has done me a a great service solving many of the Dominator hassles I just lived with for years.
.
Nickerson has done me a a great service solving many of the Dominator hassles I just lived with for years.
.
2112
Founding Member / Contributor
Mine were way lean up top. When I jetted it to get it right it was so fat at idle it blew soot and fouled plugs.
They were 1250 dominators BTW. Nickerson said that is exactly what they expect out of the box on the 1250.
.
Geronimo36
Charter Member
Worked on a 42' Fountain, triple engine, 600 hp with big solid roller cams and 850 Nickersons (basically an HP Holley with air horns cut off and worked)...
Couldn't get the darn thing to idle worth a damn...shipped it back to him and they came back perfect. He flow benches the carbs. I remember him telling me he works the metering blocks a bit and said that by all means do not attempt to re-set the mixture screws on his carb. Well, that's what got me into that mess to begin with... We put big cams in and I was setting them up and messed with the settings which sent the carb off the deep end.... Even Nickerson told me his stuff has a tendency to do that. :cuss:
As far as Holleys out of the box, it's been my experience that a properly sized holley should be pretty close, it'll pull as much fuel as it needs and 1-2 jet sizes either way to perfect it.
If running too big a carb it'll run lean up top out of the box, too small usually runs fat out of the box...
This has been my experience, yours may vary!
MikeyFIN
Competitor
Well I´ve fiddled all mylife with Holleys. Qjets (love them), Carter AFB´s and Weber DCOE´s.
Gotta Say the Qjet is the best 4 barrel in general. Especially when dialed in.
But no match for a stack of DCOE´s in any 4 Barrel.
MikeyFIN
Competitor
The Power Valves are all up the place where there ain´t no sun...
I don´t trust an out of the box Holley.
Yes they are somewhat rich but when you know which carb is the one for you´re apllication it´s quite ok.
All the double pumpers though are too general to suit any engine...
I once put Qjet on top of a boat engine ...ran out of jets and drilled the jets to the size ( went a tad rich) but on the dyno the dyno operator fiddled 2 hours with jets and timing and couldn´t better more than 3 hp on the top the midrange being equal...
DAREDEVIL
Banned
Mika,,,i know u know alot ,,but stop it .
If u order a new 1050 dominator MARINE carb it is dialed in +2 on the rich side.
End of discussion.:reddevil:
PatriYacht
Charter Member
The air bleeds they use in Dominators now are too large. If you jet to be clean in the midrange, they will be lean at top end. I think it may be to make them run well on near stock 454's and 502's. They don't require the kind of fuel that a 700hp 540 or 598 requires. I went from .038 high speed air bleeds to .027 and it was a huge improvement. I went down 6 jet sizes and it was proper mixture from mid to top end. Sorry for the hijack, now back to the thread.
Blue Thunder
New member
When you say flat thru the mid on up do you mean the a/f ratio stayed at say, 13 at 3000 and 13 at 5500? My dominators are lean in the mid range and fatten up on the top due to the power valves I presume.
Oh yeah, I run .038" gaps, with tbolt ignition and blowers. No misfires I can detect.
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