'79 Formula 255 Liberator Update
#311
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Hello,
I want to first thank you so much for your posts. I enjoyed following along with you on your restoration. I'm in the process of building almost exactly the same engine combination that you have in you Liberator for my boat. I especially appreciate actual dyno results that I found on your post on another forum! What I'm having difficulty with is how you got 9.4:1 compression ratio with your parts combination. If I have the right part number piston, the ones you used are a +4cc piston. Using the following assumptions I come up with a 10.9:1 CR.
Bore: 4.030"
Stroke: 3.480"
Head Gasket Dia.: 4.125"
Gasket Thk.: 0.039"
Head Vol.: 64cc
Pistons: +4cc
Deck to Piston Clearance: 0.025"
Can you help me understand what I'm doing wrong?
Thanks,
Andy
I want to first thank you so much for your posts. I enjoyed following along with you on your restoration. I'm in the process of building almost exactly the same engine combination that you have in you Liberator for my boat. I especially appreciate actual dyno results that I found on your post on another forum! What I'm having difficulty with is how you got 9.4:1 compression ratio with your parts combination. If I have the right part number piston, the ones you used are a +4cc piston. Using the following assumptions I come up with a 10.9:1 CR.
Bore: 4.030"
Stroke: 3.480"
Head Gasket Dia.: 4.125"
Gasket Thk.: 0.039"
Head Vol.: 64cc
Pistons: +4cc
Deck to Piston Clearance: 0.025"
Can you help me understand what I'm doing wrong?
Thanks,
Andy
Unfortunately with the weather and the fact that I am in the midst of a MAJOR move...I haven't been able to get out to experience the difference the counter rotating props turning out make.
I will say that it became a handfull at about 55-60 both turning CW. My old 272 LS with Alpha SS drives never had that issue. I guess it's true what they say..."Every combination can be totally different"
#313
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I am as you know running DUI Marine Ignition and last week I reset the timing for the first time since I put the motors in the boat. I had started with about 28*-29* for initial break in. It had slipped a bit due in part I think to the distributor /Cam gear settling in and now I have it set at 30* total at 3000 RPM. Tommy Hoffstetter and I were talking about this last week. He mentioned that testing shows that the Vortec Heads like about 32* total at 3200 +/- but no more. They're similar to the fast burn heads that get lean above 32*. The old "Bow Tie" "Slant Plug" heads in the day liked 36* but the Vortecs are so efficient that they lean out badly above 33* and loose power. The plugs looked good...running .055 gap with the 50,000 V DUI coil.
#314
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Join Date: Feb 2014
Location: Newaygo MI
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Awesome Job!!!
I have a question for you about the motor mounts.
Did you have to change them? or relocate them?
On my thread i have a link to pictures of my boat up.
after reading through yours I am excited to start mine, too bad the snow is thigh deep and single digit temps.
Thank you for any help.
I have a question for you about the motor mounts.
Did you have to change them? or relocate them?
On my thread i have a link to pictures of my boat up.
after reading through yours I am excited to start mine, too bad the snow is thigh deep and single digit temps.
Thank you for any help.
#315
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It takes time...I have been working on this one for 3 years. Still have some cockpit-cabin work ahead of me.
I had twin small blocks to begin with so yhe motor mounts were never an isue.
When you have questions we have answers...most of the posters of this forum are very helpful.
I had twin small blocks to begin with so yhe motor mounts were never an isue.
When you have questions we have answers...most of the posters of this forum are very helpful.
#316
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![](http://i705.photobucket.com/albums/ww52/sprink49/255Chief2_zpsddc87a71.jpg)
![](http://i705.photobucket.com/albums/ww52/sprink49/255Chief_zpsf36c41d7.jpg)
The 255 is the guest of my friends at Chief Performance while I am settling in. Couldn;t be in better company LOL!!!
Looks like Saturday might be a great day to get out if the forcast holds..High of 77 with light winds out of the west...seas 2' or less...bay waters smooth to a light chop.
Last edited by sprink58; 02-13-2014 at 09:58 PM.
#317
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Yes we need some pics of that boat in the water, I know your moving and your heart is heavy but a little boating my be good for you.
#318
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#319
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OK...new issue. Got in the wter this am nd idled up to Hillsboro inlet...cldeared the bridge and put the wood to it. I come up on plane nd suddenly the Port engine races away. I backed off and tried again....same result. I limped back to the ramp and called it a day.
History: This same thing happened whe I ws out with Diego and Brian and I assumed it was a spun hub in the port LH prop (23" Mirage). So I had it re hubbed this past week and put it back on this am...obviously this is not the problem.
I rulled out coupler because I smelled no burnt rubber either time and it always worked fine tuning RH. The only thing I think is left is the shift is enough out of adjustment that it's slipping out of gear. I but the port drive in forward and tried to turn the port prop CW against the gear and it would not budge. Bravo I's are Bi Directional drives so if it works in CW it has to work in CCW...at least in theory. Never had any issue turning port drive CW...all my issues have come on since I changed to CCW. Starboard Drive works flawlessly.
I have a one year warranty on the drive so I'm covered if that's it. Any ideas that I haven't thought of?
History: This same thing happened whe I ws out with Diego and Brian and I assumed it was a spun hub in the port LH prop (23" Mirage). So I had it re hubbed this past week and put it back on this am...obviously this is not the problem.
I rulled out coupler because I smelled no burnt rubber either time and it always worked fine tuning RH. The only thing I think is left is the shift is enough out of adjustment that it's slipping out of gear. I but the port drive in forward and tried to turn the port prop CW against the gear and it would not budge. Bravo I's are Bi Directional drives so if it works in CW it has to work in CCW...at least in theory. Never had any issue turning port drive CW...all my issues have come on since I changed to CCW. Starboard Drive works flawlessly.
I have a one year warranty on the drive so I'm covered if that's it. Any ideas that I haven't thought of?
#320
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With bravos, can you just swap the props side to side and put the levers in reverse? That is if you think the reverse is engaging enough? How hard is it to get to the cables to adjust them?
I agree on coupler, if it was that I thought it would happen more under full load of pushing up on plane. The fact that it will get up shows everything is probably solid. Not like the slp comes on slowly, you mentioned it just let's go and spins up.
I agree on coupler, if it was that I thought it would happen more under full load of pushing up on plane. The fact that it will get up shows everything is probably solid. Not like the slp comes on slowly, you mentioned it just let's go and spins up.