Topic: have to reduce CR (Read 3780 times)

lair116 · « **on:** June 02, 2006, 07:01:38 PM »

I have a 116" motor in my Deuce with close to 12:1 cr and it will only run on 110 race gas so I am liminted to 90 miles one way till have to turn around,I have S&S .640 gear drive cams, was thinking of replacing the head .30k gaskets to maybe .50k to bring my cr down to 9.8 or 10:to1 what cams should I use to keep the Tq the same and all around performance with this cr? any suggestions? I think it's time to go back to 94 gas but don't want to loose the hp or tq

Larry.

AUSSIE_FLSTFSE · « **Reply #1 on:** June 02, 2006, 07:21:38 PM »

Larry,
Changing your head gaskets to ones 20 thou thicker won't do very much to your CR especially if your want to drop from 12 to 10. I would suggest you need to change your pistons.

PS: over here we have a product called octane booster (you must have it in the US) you add a measured amount to every tank full of pump gas to reach your desired octane. The only down side is you need to carry a small bottle of it with you.

Cheers
Aussie

lair116 · « **Reply #2 on:** June 02, 2006, 07:57:32 PM »

Aussie: how I got this high cr was milled the heads and took off .50k so if I replace that .50k with the same size gasket plus .30k I think there's a .60 gasket ofered by James gaskets it will bring my cr back to I believe 9.8... the pistons that came with the 116" Jims kit are 6.5cc dished pistons so I think the pistions are ok

Larry. [smiley=drink.gif]

syclone · « **Reply #3 on:** June 02, 2006, 10:28:24 PM »

You need to change the pistons or the heads....when you add that much chamber volume by raising the head with a gasket, you lose all your squish area. Not a real concern on a low compression motor like a CVO 103 to have little or no squish as we are only at about a true 8.7:1. But if you manage to get that motor down to 10:1 with a gasket ...you will not have enough turbulence in the chamber for good mixture distribution...lean areas and rich areas....now add a cam with lots shorter duration to gain some of the lost torque back...raising the cylinder pressures ...and you end up with the perfect combination for a "ping monster" .
What heads with what chamber volume are you currently using...??

lair116 · « **Reply #4 on:** June 03, 2006, 12:13:07 PM »

The heads are from R&R racing out of New England, 1.97 intake and 1.65 exhaust they flow 300cmf and 97cc total chamber Vol.

HUBBARD · « **Reply #5 on:** June 03, 2006, 12:38:38 PM »

Quote

The heads are from R&R racing out of New England, 1.97 intake and 1.65 exhaust they flow [highlight]300cmf[/highlight] and 97cc total chamber Vol.

I'm sure you meant CFM there, lair, but DAMN! Most HTCC Heads flow around 150-160, I've been told. My Zipper's Heads flowed 174. You talkin' collectively, or individually? Please advise. Later--HUBBARD

freebird · « **Reply #6 on:** June 03, 2006, 03:16:45 PM »

Lair send me a PM with some contact info. I will steer you in the right direction. BTW you are thinking out of the box.

lair116 · « **Reply #7 on:** June 04, 2006, 11:17:58 AM »

Hey guys I will call Randy at Hyperformance he is the one that opened them up and the info I need check out his heads and motors at www.kingofcubes.com his stuff will blow your mind [smiley=huepfenjump3.gif]

lair116 · « **Reply #8 on:** June 05, 2006, 07:01:12 PM »

Hubbard, Ok I just got off the phone with Randy from Hyperformance he said that these heads flow 300 CFM each!! at 28 inches of water maybe the heads you were talking about were flowed at 10 inches of water? any way he also said that with these heasd they reached 6000 rip 3 to 4 seconds faster then the Htcc heads or head quators, I manage to wear out a 240 rear tire every year [smiley=drink.gif]

HUBBARD · « **Reply #9 on:** June 05, 2006, 07:24:55 PM »

You've got my curosity up, there lair! :-? I'll do some research, and then post my findings.

Later--HUBBARD

DCFIREMANN · « **Reply #10 on:** June 05, 2006, 09:39:43 PM »

Quote

Hubbard, Ok I just got off the phone with Randy from Hyperformance he said that these heads flow 300 CFM each!! at 28 inches of water maybe the heads you were talking about were flowed at 10 inches of water? any way he also said that with these heasd they reached 6000 rip 3 to 4 seconds faster then the Htcc heads or head quators, I manage to wear out a 240 rear tire every year [smiley=drink.gif]

Industry standard for heads is 10 inches of water colume. I don't think your problem is the compression ratio. As a matter of fact I KNOW THAT IS NOT THE PROBLEM. I am running a set of heads cut 85 thou with 10.5 to 1 pistons and running a set of cams comparble to the S&S 640 with no ping running in the mountains. Look at your timing and look at your fuel and look at your tuning.

Be Safe

THE DAWG

DCFIREMANN · « **Reply #11 on:** June 05, 2006, 09:41:31 PM »

Quote

You've got my curosity up, there lair! :-? I'll do some research, and then post my findings. Later--HUBBARD

Mr Hubbard I await your findings. Your heads flowing 174 cfm is just about right!!!!!

Be Safe

THE DAWG

lair116 · « **Reply #12 on:** June 06, 2006, 10:01:35 AM »

DCFIREMANN, the info I gave you guys came stright from the horses mouth, did any of you look up Hyperformance web site? www.kingofcubes.com or you could speek to him your self at 515-266-6381 and ask for Randy he an old fart like me and has been building big motors for ever

You took 85k off your heads and are useing 10.5 to 1 domed pistons? you must have 15:1 cr.... I took a compression test when my motor was warm and I get 235 lbs static thats with the .640 cams ..Randy suggested that I go to a .620 cam that he has with a longer duration that will lower my cr by 3/4s of a point that will increase my TQ he also said to check my timming like you said but how can you do this on a twin cam motor? I have the new Dyna ing. any suggestings thanks

Lair. [smiley=nixweiss.gif]

lair116 · « **Reply #13 on:** June 06, 2006, 10:25:42 AM »

DCFIREMANN I talked to Randy one more time and you are right!!! he said to make sure the LED is on the top stoke on number 1 piston then faten up my jets till the pipes are light black ( right now they are almost white) and then fine tune the the ing. timming, when they want to sell you something new, it's the best thing to white on bread but when you ask them to help you with the unit they forget who you are [smiley=soapbox.gif] I'm not sure what he ment to make sure that the LED is on at top dead center on the #1 piston can you help thanks

Lair.

lair116 · « **Reply #14 on:** June 06, 2006, 11:25:51 AM »

DCFIREMANN, I'm doing what you said to do timming is done, a few questions, you said check fuel, right now I running 110 race gas with a S&S carb that has a 80 main jet and a 29.5 second jet and my pipes are almost white should I switch over to 93 octain and see it the pipes change back to black and then jet from there? thanks seems to make sence sofar

lair

Michael · « **Reply #15 on:** June 06, 2006, 04:40:30 PM »

Is the race fuel leaded?

If the race fuel has lead the pipe color can and will be misleading. The lead in the fuel, while acting as a lubricant leaves a grayish, not so much white, but gray film.

lair116 · « **Reply #16 on:** June 06, 2006, 05:38:56 PM »

Michael, yes in matter fact the race gas is leaded, you know last year I tried using 93 gas with the same timming settings and it had no power compaed to the race gas and it also started pinging and over heated

DCFIREMANN · « **Reply #17 on:** June 06, 2006, 07:45:19 PM »

Quote

Is the race fuel leaded?

If the race fuel has lead the pipe color can and will be misleading. The lead in the fuel, while acting as a lubricant leaves a grayish, not so much white, but gray film.

Yep they sure are full of lead!!!!

Liar switch to 93 octane unleaded and start from there. The dyna ignition came with an instruction sheet that will tell you how to change your timing. It will also show you different timing curves. You need to find that sheet or go to Dyna's web site and download one.

I am not sure about your jetting on your S&S carb. I would think you have a super "G" and does it have a Thunder Jet?

? The 29.5 is always a good starting point but in a big motor I am not sure that is enough. You need to get this motor tuned before you grenade it. Running tooo much timing and not enough fuel can blow a piston apart even fordged pistons will blow it just takes a little more to do it.

I am going to send you a PM on this subject. I will also try to find my old S&S jetting sheet. It has a lot of Evo jetting but I am not sure about a big inch two cammer.

Be Safe

THE DAWG

Michael · « **Reply #18 on:** June 06, 2006, 08:17:32 PM »

Take a look at the VP fuel site. There are a number of blends available now that are leaded or unleaded. Actually there are some really cool blends out there. VP has some greatly and heavily oxygenated blends too.

They are lots of fun to ecxperiment with. The U2 & U4 were my favorite.

Not too high of an octane rating, as we know octane robs power, if it isnt needed, dont use it. If I recall the U-series fuels are 97 or 98 octane, leaded and heavily oxygenated.

lair116 · « **Reply #19 on:** June 06, 2006, 10:18:32 PM »

Firemann & Mike,
thanks for the info so far, I do have the Dyna instructions and it states to set the first two settings at 2 which I did, I had an HQ ing, before which was programed for this motor with 93 gas, It had low power and after a long ride it would over head and ping like crazy and started to smoke a bit, so I found a gas station with 100 OCT unleaded, and the motor liked it so then I found a station next to my house with 110 leaded??? race gas and the motor came alive and have been running it for two years now, last summer we had the heads taken off for a vale job and there was no damage to the pistons so we put in a new set of rings and bolted it back togeather tomorrow I'm going to ask the owner one more time if his 110 gas is leaded or unleaded I have seen brand new corvetts put this gas in but also seen old 454's chevelle's stop and also fill up, I'll wait for your PM mike thanks alot I hope I can get the same performance with the 93 oct, [smiley=xyxthumbs.gif]

lair116 · « **Reply #20 on:** June 06, 2006, 10:26:47 PM »

DCFIREMANN, I have a DaVinci 48mm S&S carb with 29.5 pilot and a 80 main jet it came with a 29.5 pilot and a 78 main jet I just hope I can get this all strighten out before I gernad, maybe I'll just bite my toung and take to a super tunner [smiley=nixweiss.gif]

DCFIREMANN · « **Reply #21 on:** June 07, 2006, 06:55:58 AM »

Quote

DCFIREMANN, I have a DaVinci 48mm S&S carb with 29.5 pilot and a 80 main jet it came with a 29.5 pilot and a 78 main jet I just hope I can get this all strighten out before I gernad, maybe I'll just bite my toung and take to a super tunner [smiley=nixweiss.gif]

Liar PM sent. If you need anything just give me a yell.

Be Safe

THE DAWG

lair116 · « **Reply #22 on:** June 07, 2006, 10:02:56 PM »

DCFIREMANN, In talked to Bill at zippers today and he said he could build me a S&S G with a thunderjet that will work better then the one I got for $466.50 and since I have 235lbs static cranking pressure that to continue to use the 110 race gas he new nothing the new Dyna ing, but the Head Quarters that I had on there before was just as good, the new Dyna has a built in program to let the motor turn over 3 times till it fires on top dead center which helps a lot, I could install my own thunder jet and go from there what ya think thanks

Lair.

475wildey · « **Reply #23 on:** June 07, 2006, 10:26:12 PM »

Quote

I'm sure you meant CFM there, lair, but DAMN! Most HTCC Heads flow around 150-160, I've been told. My Zipper's Heads flowed 174. You talkin' collectively, or individually? Please advise. Later--HUBBARD

Hubb,
174 cfm at 10 inches water works out to 291 cfm at 28 inches

DCFIREMANN · « **Reply #24 on:** June 08, 2006, 05:52:23 AM »

Quote

DCFIREMANN, In talked to Bill at zippers today and he said he could build me a S&S G with a thunderjet that will work better then the one I got for $466.50 and since I have 235lbs static cranking pressure that to continue to use the 110 race gas he new nothing the new Dyna ing, but the Head Quarters that I had on there before was just as good, the new Dyna has a built in program to let the motor turn over 3 times till it fires on top dead center which helps a lot, I could install my own thunder jet and go from there what ya think thanks

Lair.

Go with the S&S with the jet it is great for power and it gives you another circuit to tune with. I am very surprised that your static pressure is so high with that set of cams. I will static mine tomorrow night but if I remember correctly it was just around 190. And I am guessing because I really don't remember. Did you actually check yours or did some one else do it?

Do you have compression releases in your heads?

Be Safe

THE DAWG

lair116 · « **Reply #25 on:** June 08, 2006, 10:05:00 AM »

DAWG,Yes I have compression valves is as matter fact I drilled them out to release more pressure during start up, and I did my own compression test some time back when it was hot so today I'll try it again and see were it is at while the motor is cold come to think of it I cant remeber if was before or after the .640's were put in, I guess I'll go do it right now, Ok I justed ran the static psi with the motor cold... I must be getting old or something because some time last summer I sware I had 235 [smiley=nixweiss.gif] but now with the cv's closed and the throttle wide open I get 190 psi static I must be loosing my mind or maybe to much [smiley=drink.gif] any way it is what it is, now what can we do DAWG?? [smiley=nixweiss.gif]

DCFIREMANN · « **Reply #26 on:** June 08, 2006, 10:57:10 AM »

At 190 like mine WE CAN WORK WITH THAT!!!!!! We can start with your timing. You need to cut your timing BACK some. If you had a Daytona Twin Tec or the Zippers ignition I could PM you with your settings. I would do the carb from Zippers before you tune the bike. I know I can get this thing to run on pump gas, mine does and it does it like a RAPED APE!!!!!!

Be Safe

THE DAWG

lair116 · « **Reply #27 on:** June 08, 2006, 01:00:52 PM »

DAWG, I do have the Daytona twin Tec ignition!! I just bought it and it's on the bike right now, I have the first dile, (intial timming set at #2 and the advance slope set at #2) and the rev limiter set @ 6200 and it runs like a divorced man to his new girl friend [smiley=huepfenjump3.gif] now what do we do?

DCFIREMANN · « **Reply #28 on:** June 08, 2006, 01:03:23 PM »

I am at the fire house today, so we will have to wait till I get home tomorrow night. We will get this thing straight.

Be Safe

THE DAWG

lair116 · « **Reply #29 on:** June 08, 2006, 01:19:52 PM »

I work nights my self from 9:00 pm to 7:30 am, I'm looking forward to get this motor on pump gas, oh hears a side shot of my little muel with a 4'' stack

Author Topic: have to reduce CR (Read 3780 times)