Blowthrough carb systems - getting closer to an answer.
01-14-2002, 02:08 PM
#41
Registered
I went thru the soot, black transom & fouling problems last spring. I solved it in a very simple way.
*** I sent the carb to Nickerson Performance. One trip, 3 days in the shop & its remachined, rejetted, fuel & air metering is filled & drilled. He runs them on an engine in his shop to test them. When I reinstalled it, everything was Perfect !, I only had to adjust the idle up 100 rpm. I have no more problems & Dean will still microscopically inspect plugs sent to him by his customers. He will find any metal transfer to the plugs caused by a leaning out carb/engine combo. He does stuff to the carb that you or I can never do. Trust me, this guy is GOOD! and fast...carb off on saturday & UPS overnight. In shop by noon on monday & in work....fixed, & run on engine by wednesday, packed & reshipped overnight & in my hands by friday...on the engine saturday a.m. and back in the water. All for $400.00 + shipping. What more could you ask?
Dean Nickerson.... he's "The Man!"
*** I sent the carb to Nickerson Performance. One trip, 3 days in the shop & its remachined, rejetted, fuel & air metering is filled & drilled. He runs them on an engine in his shop to test them. When I reinstalled it, everything was Perfect !, I only had to adjust the idle up 100 rpm. I have no more problems & Dean will still microscopically inspect plugs sent to him by his customers. He will find any metal transfer to the plugs caused by a leaning out carb/engine combo. He does stuff to the carb that you or I can never do. Trust me, this guy is GOOD! and fast...carb off on saturday & UPS overnight. In shop by noon on monday & in work....fixed, & run on engine by wednesday, packed & reshipped overnight & in my hands by friday...on the engine saturday a.m. and back in the water. All for $400.00 + shipping. What more could you ask?
Dean Nickerson.... he's "The Man!"
01-14-2002, 03:22 PM
#42
93formula - Thanks for your comments. Your story is encouraging. Can you tell us more about your boat?
As I said before, good carb tuners can make the best of a bad situation, and Nickerson is one of the best. But not even he can change the fact that carbs don't understand boost (air density). So you must jet the secondaries rich enough to cover full boost, resulting in the unresponsive midrange noted by HPjunkie, quoted below:
"I've got a nickerson carb, about 900 something, 850 baseplate and a so and so body, but the primary jets are 80's. Primary power valve is 4.5. Secondary jets are .144 (I drilled them out according to Dean N.) I'm going to install EGT on the 7&2 cyl.(the ones I melted down) I think those are the lean ones, and record the temps. I've heard they should be 1300- 1350 ish, 1400 tops/borderline. Last year was the first year with that combo. It started and ran well although a little "flat" or unresponsive ( or lean)between 3-4K then secondaries would open and what a rocket!"
HPjunkie's experience is exactly what you would expect with this carb set up. It's safe, (rich) and the best you can do without a third fuel circuit adding metering area as air density goes up.
When you say fill and drill, do you mean the PVCRs, air bleeds or both?
As I said before, good carb tuners can make the best of a bad situation, and Nickerson is one of the best. But not even he can change the fact that carbs don't understand boost (air density). So you must jet the secondaries rich enough to cover full boost, resulting in the unresponsive midrange noted by HPjunkie, quoted below:
"I've got a nickerson carb, about 900 something, 850 baseplate and a so and so body, but the primary jets are 80's. Primary power valve is 4.5. Secondary jets are .144 (I drilled them out according to Dean N.) I'm going to install EGT on the 7&2 cyl.(the ones I melted down) I think those are the lean ones, and record the temps. I've heard they should be 1300- 1350 ish, 1400 tops/borderline. Last year was the first year with that combo. It started and ran well although a little "flat" or unresponsive ( or lean)between 3-4K then secondaries would open and what a rocket!"
HPjunkie's experience is exactly what you would expect with this carb set up. It's safe, (rich) and the best you can do without a third fuel circuit adding metering area as air density goes up.
When you say fill and drill, do you mean the PVCRs, air bleeds or both?
01-14-2002, 03:34 PM
#43
If I remember Procharger recommends a 390 carb. I wonder if it is to keep the signal up in the carb or it is small so that you are allways in the secondaries and never in that mid range/transfer zone - on-off idle or in the secondaries.
01-14-2002, 04:16 PM
#44
Registered
I run a 252 SS Formula with a HP454-450hp roller cam with a Procharger set to 5# boost. My top speed is limited to 75 mph by the hull which starts to chine walk at that speed (scary!)
I added "add on" external steering (Marine Machine) & am adding the full hydraulic helm now. I also pulled my engine to completely refurb the engine compartment. While the engine is out we are going to pull the pan and inspect the bearings for wear & do a leak-down test. If everything checks out, it will go right back in the boat.There were no functional maladies present on winter shut down. This is for peace of mind only!
My carb, unlike the "bastardizied 850" mentioned above, is a Holley 750cfm. Per Dean Nickerson, this carb will actually flow more fuel than an 850. Also, he flow matches all venturi and the carb then gets "squared up", airhorn machined and all fuel passages & airbleeds,also the metering blocks get the "epoxy & machine" treatment.
I, like others had extremely rich secondaries at #144. Now all jets are the same/all four holes. I cannot at this time recall the current size of the jets (as recieved from Dean), I can only attest to the fact that all around performance is rated at more than just top speed. My top speed is still 75mph, but the response through out the rpm range is smoother & I no longer have ANY backfiring problems. Dean will tell you, that any blown motor will only live a short time if it spends it's life at maximum throttle. It's like burning a candle at both ends. Blown is good, maximum blown at full throttle is BAD for any EXTENDED time. Like Dean says, if your not ahead in a half a mile, you aren't going to be in a mile either! I have put many hours on my engine and have experienced no difficulties at all. Dean recommends keeping an eye on things in a "rotational" way. Instead of changing all your plugs and inspecting them, pull #1 & change it after 10 hours (inspect the rest & reinstall), 10 hours more pull #2, replace & inspect the rest & reinstall....and so on. You will then have replaced all your plugs in 80 hours, but you would have inspected then 8 times. Total cost ? = one set of plugs result? a monitored & reliable engine.
My engine ran so clean (plugs) that I was concerned. So I called Dean, he told me to do a couple of hard runs on it, then send him the plugs for inspection. The day he recieved the plugs, he inspected them under the microscope & called me back (on Saturday too!) The plugs were fine, just very clean with no evidence of any aluminum transfer. Dean also told me I could continue to send him plugs, one at a time to inspect. I thought that was an incredible offer. All carbs are also registered by Dean & records kept. So if it goes back, he knows all about it.
I know some(a lot actually) think the Whipple is King. Sorry Charlie !! A Procharger engine & drive (properly installed, tuned & maintained) will outlive a Whipple anyday, driven in a sane manner. Equal engines, hp & torque, same drives...the Procharger will live because of the manner in which hp & torque is gained & applied... smoothly and in an ever increasing manner...not just Wham!! here it is!! Not many of us are drag racers., I BOAT for long distances, run fast (cruise 45-60), 52 mph was the old top speed...now I cruise faster than that!! My fuel consumption is also less for a given distance traveled as I don't have to drive the engine as hard......So really what's a Whipple good for??? Just kidding Whipple Guys!!
I added "add on" external steering (Marine Machine) & am adding the full hydraulic helm now. I also pulled my engine to completely refurb the engine compartment. While the engine is out we are going to pull the pan and inspect the bearings for wear & do a leak-down test. If everything checks out, it will go right back in the boat.There were no functional maladies present on winter shut down. This is for peace of mind only!
My carb, unlike the "bastardizied 850" mentioned above, is a Holley 750cfm. Per Dean Nickerson, this carb will actually flow more fuel than an 850. Also, he flow matches all venturi and the carb then gets "squared up", airhorn machined and all fuel passages & airbleeds,also the metering blocks get the "epoxy & machine" treatment.
I, like others had extremely rich secondaries at #144. Now all jets are the same/all four holes. I cannot at this time recall the current size of the jets (as recieved from Dean), I can only attest to the fact that all around performance is rated at more than just top speed. My top speed is still 75mph, but the response through out the rpm range is smoother & I no longer have ANY backfiring problems. Dean will tell you, that any blown motor will only live a short time if it spends it's life at maximum throttle. It's like burning a candle at both ends. Blown is good, maximum blown at full throttle is BAD for any EXTENDED time. Like Dean says, if your not ahead in a half a mile, you aren't going to be in a mile either! I have put many hours on my engine and have experienced no difficulties at all. Dean recommends keeping an eye on things in a "rotational" way. Instead of changing all your plugs and inspecting them, pull #1 & change it after 10 hours (inspect the rest & reinstall), 10 hours more pull #2, replace & inspect the rest & reinstall....and so on. You will then have replaced all your plugs in 80 hours, but you would have inspected then 8 times. Total cost ? = one set of plugs result? a monitored & reliable engine.
My engine ran so clean (plugs) that I was concerned. So I called Dean, he told me to do a couple of hard runs on it, then send him the plugs for inspection. The day he recieved the plugs, he inspected them under the microscope & called me back (on Saturday too!) The plugs were fine, just very clean with no evidence of any aluminum transfer. Dean also told me I could continue to send him plugs, one at a time to inspect. I thought that was an incredible offer. All carbs are also registered by Dean & records kept. So if it goes back, he knows all about it.
I know some(a lot actually) think the Whipple is King. Sorry Charlie !! A Procharger engine & drive (properly installed, tuned & maintained) will outlive a Whipple anyday, driven in a sane manner. Equal engines, hp & torque, same drives...the Procharger will live because of the manner in which hp & torque is gained & applied... smoothly and in an ever increasing manner...not just Wham!! here it is!! Not many of us are drag racers., I BOAT for long distances, run fast (cruise 45-60), 52 mph was the old top speed...now I cruise faster than that!! My fuel consumption is also less for a given distance traveled as I don't have to drive the engine as hard......So really what's a Whipple good for??? Just kidding Whipple Guys!!
01-14-2002, 04:42 PM
#45
Registered
Oh yeh, I also use a Jacobs Marine Master ignition...awesome!! I am adding Stainless Marine headers now also and have Corsa thru hull exhaust. 26" Bravo four blade or 27" Mirage 3 blade, depending on water temp....Pretty neat boat for a family ski boat!
01-14-2002, 05:04 PM
#46
That's excellent info 93formula. If your jets are indeed the same all round then the extra metering area has to come from the PVCRs. So I would guess there's been some major drilling, and the power valves must be timed to deal with the transition.
When you have the engine out could you do us all a favour and take a look at your carb. Jets, power valve and the PVCR diameter if you have a set of small drill bits to use as a gauge. I have no intention of drilling my new carbs when an expert can do it all for $400.00, but I would like to know what has been done.
Thanks
Tom
P.S. Nice boat!
[ 01-14-2002: Message edited by: tomcat ]
When you have the engine out could you do us all a favour and take a look at your carb. Jets, power valve and the PVCR diameter if you have a set of small drill bits to use as a gauge. I have no intention of drilling my new carbs when an expert can do it all for $400.00, but I would like to know what has been done.
Thanks
Tom
P.S. Nice boat!
[ 01-14-2002: Message edited by: tomcat ]
01-14-2002, 06:18 PM
#47
Registered
I'll make it simple for you...call Nickerson's (Dean @ 215-781-1370) ask about registered carb#395/895.
My boat is 100 miles away, & I won't see it for a week!! Oh, woo is me!!
Sorry I can't give you the info myself, but I'm sure Dean can fill yu in. Just be sure and keep us posted also on what he says. If by some chance you cannot get the info- call me at 918-581-1654 (0800-1630 cst) or email at [email protected] will make the call. Good luck (OSO is great, I like this stuff !! Now if I only had enough time to do this all the time,,,,,but work calls!! and of course, the wife demands time too.
My boat is 100 miles away, & I won't see it for a week!! Oh, woo is me!!
Sorry I can't give you the info myself, but I'm sure Dean can fill yu in. Just be sure and keep us posted also on what he says. If by some chance you cannot get the info- call me at 918-581-1654 (0800-1630 cst) or email at [email protected] will make the call. Good luck (OSO is great, I like this stuff !! Now if I only had enough time to do this all the time,,,,,but work calls!! and of course, the wife demands time too.
01-14-2002, 11:55 PM
#49
Registered
93'
If you ordered it from Dean then its most likely the same mixture of of baseplate and throttle body as mine. A complete scratch built custom carb. This is my second one from him. I also have a friend running the same style from Dean putting 16 psi thru it and running 10 sec. quarter mile times with a smallblock no less. I'm not sure bastardized is the right name for his work. Greg
If you ordered it from Dean then its most likely the same mixture of of baseplate and throttle body as mine. A complete scratch built custom carb. This is my second one from him. I also have a friend running the same style from Dean putting 16 psi thru it and running 10 sec. quarter mile times with a smallblock no less. I'm not sure bastardized is the right name for his work. Greg
01-15-2002, 10:51 AM
#50
Registered
Sorry !! I did not mean anything negative when I used the word "bastardized", I was trying to be descriptive in that the carb in question was made up of components from several carbs: ie body differnt model/cfm from base, etc. Please do not infer I was being nasty! ....he whipple guys will probably attack me now too!!
The carb Dean built for me was my old standard Holley 750. All parts he recieved from me, were used in the remanufacture. I can assure you tho, that each & every part of the carb was different, in that they have now been "flowed"(machined) so each venturi/throat flows equally. I still am using the original 750 base plate. Remember, Dean said the 750 (stock) will flow more fuel than an 850.?.
....he whipple guys will probably attack me now too!! The carb Dean built for me was my old standard Holley 750. All parts he recieved from me, were used in the remanufacture. I can assure you tho, that each & every part of the carb was different, in that they have now been "flowed"(machined) so each venturi/throat flows equally. I still am using the original 750 base plate. Remember, Dean said the 750 (stock) will flow more fuel than an 850.?.
