Max effort stage II with carb

[buickstage II]

I have a 275cu.i off center in Australia and im looking at making the maximum amount of horsepower as possible, ive made 242hp at the wheels and that was only at 6000rpm as the power just drops off on the dyno, would love to have anyones help thats made good power n/a, using 98 octane (may look into race fuel if the benefits are there)

stage II (016) 4.015"
3.625 moldex
6.5 carillos
je 10.8:1
je moly rings
stage II heads jessel rocker
reed roller cam 106 lobe sep, 308/312 adv, 267/274 @ 0.050", 0.667" lift at the valve, intake centerline at 102
balanced to 38 percent
milodon gear drive
stage II heads jessel rocker
ceramic coated extractors 36" long, 1 3/4" into 1 7/8", 3" collector to 2 1/2" merge with single 3" pipe to the back
750 holley hp vac sec
msd 6al, distributor, 18 degrees initial and 36 total @ 4500rpm
sce gaskets
victor junior manifold
moroso 4 stage dry sump, currently running crank case under about 10 in.hg

power glide
3000 stall converter (unknown condition)
9" diff with 3.25, full spool
15 X 10 convo pros



any help, advice or criticism appreciated!

cheers Simon

last but not least a really big thanks to Mike Booher for all his time and help to get this motor together, it would have been extremely hard without him, not to mention all the parts he has freighted here to Australia!
Thanks Simon

 

[J-B Racing]

Hello Simon
Do see that you are not making the HP you would like. I had a look at what you did, and if I was with that Motor! These are the points I would look at..

That 750 VS is not my choice. A double Pumper is a night and day difference.
Not sure how light your Rods are or the Crank! But I would see of making them as light as possible.
You also don't want extreme Huge Intake Runners in the Heads. Natural Aspirated work BEST with smaller but well Ported Runners to get as much Fuel in the Combustion Chamber.
A Hi Rise Manifold would be my choice as well. Now if you are looking to make as much power on Pump Fuel. Not much can happen. But a set of HI Compression Pistons and C-12 or C-16 will get much more HP.

Just a thought from someone who built plenty of Carbed Engines for the past 25 Years...

Cheers Mate...

Joe

 

[Mac in SD]

I don't know his email, but Tim Cole at Comp Cams is extremely knowledgable on NA Buick V6's. He was running 7's in the quarter a few years ago (comp eliminator or altered - I don't know.) I do know he was running something like 9,000 rpm - maybe more. I'd also guess that Mike Booher should be able to help. (Maybe Ohio George Montgomery - Goerge's Speed Shop - but they're big bucks. I get the impression they don't give out free advice.)

Something's not quite right with your HP figure, though. Busch Buicks were making 540+ HP with a single 4v, and ASA 9:1 motors were making 450 HP or so, with a single 4v as well.

One more thing, if I may. See if you can get a copy of the "Buick Stage II V6 Racing Engine" booklet that was written by Dave Emanuel based on Jim Ruggles' development. Only about 30 pages or so. Long out of print, but they come up on Ebay pretty often. It's got more up-to-date info than the Buick Power Source book.


Hope you find that power. It's just hiding somewhere. Good luck.

 

[Alky V6]

The T/C stall and the final gearing looks very conservative for your combination. I would imagine that the V/S holley works better with your present stall and gearing, but if you went a little more wild with the stall and gearing, it should wake up your combination. I think I'd get rid of the single 3" exhaust also.

Camshaft looks bitchin. That thing should be revving like crazy. I'd try 34 total with the timing, unless 36 works better with that CR. I'd be using a bit more compression with that cam. Well, not just a bit. More like a lot. You'd need racing fuel too with the CR I'm thinking about.

Going to a double pumper would work nice if you matched it to a more appropriate gearing and stall combination.

The header dimensions are conservative too. Should be stepped starting with 1 7/8" for 10" to 2 1/8" for a total 46" with a 3 to 3 1/2" collector. The step downs after the collectors are not helping.

With that cam, the valvetrain should be setup for over 9,000 rpm. No wonder your HP level looks so small. That cam is going to be making its HP much higher. You need to figure out why the power is dropping at 6,000. It shouldn't be.

 

[turbodave231]

Floating the valves? Why are you not spinning the engine higher? Even with the lower CR, this setup should make 450HP at the flywheel. Assuming a 20% loss through the drivetrain should put you at 360 RWHP.

I have to ask.......What kind of valve springs are you using? That cam is going to need some really big spring pressure to control the valves even if you are using titanium valves......and that cam should really come alive at the higher RPMs (kinda like an ON/OFF switch with the narrow lobe separation)

Sounds like it ought to be FUN when you get it figured out!!!

Dave

 

[buickstage II]

thanks to those that have chimmed in on this, ive been reading both power source and dave emanuel back to front numerous times, the only real difference i see is that in power source they were running 13.28:1 with 104 octane, 13.65:1 with 108 octane,
i know 10.8:1 is a little conservative but i wouldn't of thought the power would be that low.

your dead right about the cam coming on, but as soon as it does it goes off!
i have PSI 1541ML springs with 250 lb on the seat and about 550 lb open, stainless ferrea valves and titainium retainers so i wouldn't think their floating.

as you said Donnie, i think the V/C is okay for my current setup, but when i change the converter and gears then it will be different, still havn't run it down the track! just want to know where the power is going!!
i have been told by a few reputable people know that double pumper has power advantages over V/C, which im willing to try on the dyno

has anyone ever had a converter slip or something under load? the oil smells like brand new and thats after 3 dyno sessions, although the power curve is dead consistant

last thing i can think is the exhaust system needs redesigning from the collector back? twin 3" with single mufflers at the rear? crossover pipe?

will try and get some photos and dyno posted soon!

Aussie Pride!

Cheers Simon

 

[buickstage II]

Image032.jpg - Image - Photobucket - Video and Image Hosting

 

[turbodave231]

You need better springs. If you hit the power band and then it goes flat, I'll bet you are floating the valves. S2 heads need big spring pressures. I'll assume the cam is a solid roller based on the cam specs. You're not using a rev kit are you??

I'd recommend a minimum of 350# of seat pressure. Call Tim Cole at Comp Cams or talk to Mike Booher.........I'll bet $$$ they will confirm my spring recommendations.

 

[buickstage II]

You need better springs. If you hit the power band and then it goes flat, I'll bet you are floating the valves. S2 heads need big spring pressures. I'll assume the cam is a solid roller based on the cam specs. You're not using a rev kit are you??

I'd recommend a minimum of 350# of seat pressure. Call Tim Cole at Comp Cams or talk to Mike Booher.........I'll bet $$$ they will confirm my spring recommendations.

i hear what your saying, i don't exactly know what valve float should be sounding like because the motor sounds so sweet even after the power comes off, its very consistant on the dyno for numbers. but to think the valves are starting to float at 5500rpm im not convinced
yeah its a solid roller cam, would Tim Cole want to know me if im not running a comp cam? if not what is his number?

im sure someone here on the board has run a motor identical? anyone?

 

[Alky V6]

Ruggles recommends a seat pressure of 220 lbs. with a cam exactly like yours. How did Ruggles get away with such light seat pressures?

 

[BlownV6]

Ruggles recommends a seat pressure of 220 lbs. with a cam exactly like yours. How did Ruggles get away with such light seat pressures?

Titanium valves and rev kits Mike

 

[Alky V6]

Titanium valves and rev kits Mike

I'll have to look again, I don't recall any mention of rev kits being used in his articles.

I use 190 (seasoned spring) on the seat without a rev kit and use a similar .420 lobe lift. I've had the same set of springs in there for well over 150 passes. Still pulls to 7800 without hesitation. I don't understand why you guys need so much pressure. I also use a heavier lifter and thicker pushrod than most. The cam looks good on inspection. No hammering.

 

[unboostedV6]

That 2-1/2" merge looks suspect...my springs are 220# seat. Cam's a little big for the compression. More converter, more gear. Is there soot in the intake?

 

[BlownV6]

Don, Simon and I talked about this a while back and he asked about 250# seat pressure. I told him that I would go a little more but since it was to a street car that it should be fine. However what I did not know was his open pressure would only be 550#. What is your open pressure?? Could it be that by switching to SS valves and 550# open pressure that there is a problem??
Mike

 

[Alky V6]

Don, Simon and I talked about this a while back and he asked about 250# seat pressure. I told him that I would go a little more but since it was to a street car that it should be fine. However what I did not know was his open pressure would only be 550#. What is your open pressure?? Could it be that by switching to SS valves and 550# open pressure that there is a problem??
Mike

That open pressure is way low compared to mine. Stainless valves with that, I would imagine, is a problem. When I get home I'll look up the exact specs of the spring I use. If I recall, the rate is something like 620 lbs per inch.

Keep in mind that I'm only turning to 7800 at the very most. You Stage II guys can easily twist it to over 9,000. So comparing my spring to a redline like that is silly.

 

[Alky V6]

The spring I use, new would have 210 lbs. on the seat at 1.960" installed height. 625-635 lbs. open at .700" lift. The average spring rate is 621 lbs. per inch. This spring works with my setup, max 7800 rpm, and floats at 8100 rpm. I use Ti valves. Intake and exhaust. Valves sizes are also smaller than most. 1.835 int. and 1.5 ex. There's some weight loss from that also.

 

[Alky V6]

A spring for your application would be something like 310# on the seat and 700# per inch rate.

 

[buickstage II]

A spring for your application would be something like 310# on the seat and 700# per inch rate.

i think im definately sold on the springs being the problem, i did the maths
(as i don't have a spring pressure tool)

250lb on the seat
494lb./in spring rate
0.667 lift

250 + (494 x 0.667) = 580lb open

for your recomendation Don,
310 + (700 x 0.667) = 777lb open
- that sounds to be more correct if your factoring SS valves

any spring recomendations?

starting to get that excited feeling again!
Cheers Simon

 

[Chuck Leeper]

Floating the valves? Why are you not spinning the engine higher? Even with the lower CR, this setup should make 450HP at the flywheel. Assuming a 20% loss through the drivetrain should put you at 360 RWHP.

I have to ask.......What kind of valve springs are you using? That cam is going to need some really big spring pressure to control the valves even if you are using titanium valves......and that cam should really come alive at the higher RPMs (kinda like an ON/OFF switch with the narrow lobe separation)

Sounds like it ought to be FUN when you get it figured out!!!

Dave

what the Cobra car made on the engine dyno, prior to install. Totally streetable w/ solid rollers, 750 Holley, dry sump.
Buick Stage2:
I can put you in touch w/ the owner, if you'd like to correspond w/ him....

 

[lazaris]

i think im definately sold on the springs being the problem, i did the maths
(as i don't have a spring pressure tool)

250lb on the seat
494lb./in spring rate
0.667 lift

250 + (494 x 0.667) = 580lb open

for your recomendation Don,
310 + (700 x 0.667) = 777lb open
- that sounds to be more correct if your factoring SS valves

any spring recomendations?

starting to get that excited feeling again!
Cheers Simon

Whats the installed height? Depending on that I would go with a Comp 955 or 26115. These are a Pacaloy material and last long time.