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  #31 (permalink)  
Old 11-11-2008, 02:51 PM
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Quote:
Originally Posted by ap72
Get a set of AFR 195's, cam with short duration, and compression at about 9.7:1. It should run real well on 87. You can choose other head options too, and some may work better. 195's are pretty much a failsafe head though, they work pretty well in just about every application.
Once again, I am in disagreement with you mon ami. 195 heads won't support a short duration cam. And they are not a good match for a 305 motor on the street. Now, if this was a race only motor buzzed to 7500-8000, then fine. And 9.7:1 won't support a short duration cam either. Too much cylinder pressure for anything this side of E85 or race gas.

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  #32 (permalink)  
Old 11-11-2008, 02:58 PM
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Someone mentioned to me this before, and I had a carburated engine Ford Crown Vic. before this Mercury. I always got a smoother ride and better mpgs with high octane gas. I am a techie and a gear head, please have the patience to teach me, how is it low octane gives better mpg and less knocking ? It's dirty gasoline basically, requiring higher detonation points, not lower comp..
Make me understand, give me all the details.

15 - 23 mpgs is the best this vehicle ever seen, or at least at 17y.o. and if I could get or wanted to get an econo car, I wouldn't be here asking questions.
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  #33 (permalink)  
Old 11-11-2008, 03:01 PM
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I run a short duration cam in my Cutlass with 9.8:1 compression... So there's not really an argument there, not to mention what the factory is churning out...

You are right about the 195'2 being over kill for a 305 though. I was thinking of something more like a 350 with a hyd. roller cam and 1.6:1 rockers- which even with 210ish duration the AFR's would work on.

For a super cheap milage miser 305 I'd just use factory 305 Vortec's with cleaned up runners, maybe larger exhaust valves, long tube headers, a single pattern cam, 1.6 rockers, and a 600 cfm or smaller carb. Still shoot for about 9.7:1 compression, unless you have a unusually heavy car or super low gearing.
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  #34 (permalink)  
Old 11-11-2008, 03:07 PM
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Wait, a Ford 305?! well if its a ford you're on your own, I'm not into them really. From what I do know I'd just pull a 5.0 from a late model Explorer and swap the intake to a carb setup. But other's may have more to say.

As far as octane goes, higher octane reduces detonation, higher compression usually leads to higher octane- but there is a LOT more to it besides compression.

LT1's ran on 87 octane with 10.5:1- they were kind of the turning point on V8 design. more compression means more efficent, that's why you want it to go up, but there a lot of limiting factors on how high you can go.
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  #35 (permalink)  
Old 11-11-2008, 03:10 PM
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Thanks again, I know I didn't post my vehicle specs. so it's my fault but it's a 1991 Mercury Grand Marquis LS, heavy four door sedan.
Vortec is 4valve per cyl. heads ? Does Ford make anything similar ?
OK at least I got some idea where my compression should be.

Ah! if only I had my own JunkYard for cars
Given unlimited funds, yeah I'd swap engine and intakes, change transmission and rear gears to positronic. That's just mildly upgrading for not much performance, but I bet it would.

Last edited by Cyberats; 11-11-2008 at 03:19 PM.
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  #36 (permalink)  
Old 11-11-2008, 03:15 PM
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Quote:
Originally Posted by Cyberats
Thanks again, I know I didn't post my vehicle specs. so it's my fault but it's a 1991 Mercury Grand Marquis LS, heavy four door sedan.
Vortec is 4valve per cyl. heads ? Does Ford make anything similar ?
OK at least I got some idea where my compression should be.

Vortec is not 4 valves per cylinder, I have no idea where you got that idea. And if you are doing this to save money stop right now- it's not gonna happen. Hotroddng costs money, it doesn't save it. We all do this knowing that we will never recooperate our costs.

Sure you can make a living off of it, but then you're not building it for yourself, you're building someone elses car, and they are the ones who once again will never get all of their investment out of it.
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  #37 (permalink)  
Old 11-11-2008, 03:19 PM
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Let's begin again. You said "how is it low octane gives better mpg and less knocking ?" Who said this?

"It's dirty gasoline basically, requiring higher detonation points, not lower comp.." Could you explain what you mean please. I don't know what a "higher detonation point" means to you.

Fuel is formulated to match up with a certain limit of cylinder pressure/heat. At 8.5, you could run just about any gasoline that is available to you at the pump. At 10.0, you'd have to be more selective. A lower octane fuel may not tolerate the cylinder pressure at 10.0. The motor could encounter pre-ignition and/or detonation and destroy itself within seconds.
Of course, there are different limits to the fuel based on ignition timing, combustion chamber shape and size, fuel injection as opposed to carburetion, etc., etc. There are new vehicles on the road with static compression ratios at near 11.0 and they are using pump fuels that would be intolerable to an 11.0 older motor of a design that is inferior to the state of the art designs available today.
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  #38 (permalink)  
Old 11-11-2008, 03:28 PM
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The Vortec

Many years back, was it 1996/1998 ?, GM introduced the "Vortec" engine in Cadillacs and some luxury cars and they DID come with 4 valve per cylinder.

Do you think overall that 4 valves would make for a more economical engine ?

My daily driver is both too old and way into too many replacements to be sold for any reasonable sum of money. I never kept a car for resale value. But you know what ? Owning the car in the next 3 years making it about $15K investment in 10yrs., driving a comfortable, powerful and near luxury car with no glitches = cheaper than replacing a 4-banger every 3 years. Even cheaper than most econo cars you can buy today, baring Kia, Saturn and Hyundai, but I highly doubt any of them will last you 10yrs. with NO investment.
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  #39 (permalink)  
Old 11-11-2008, 03:31 PM
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"Do you think overall that 4 valves would make for a more economical engine ?"

Possibly, but I have no experience with them upon which to base a decision.
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  #40 (permalink)  
Old 11-11-2008, 03:38 PM
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techinspector1

Higher Detonation = more pressure, heat and higher spark to detonate fuel.

Now you are trying to tell me 87 octane detonates before 91 octane ?
I thought a more purified gasoline ignites faster with less heat and pressure.

Every time I use 87, I get knocks in my engine and my Mpgs drop a few points. This was true not only in my EFI but my carb. vehicle I owned before. I owned a carb. GM too, same deal. I maintained the vehicles and did timely tune-ups.

I need details, the why & the who, call me SPOCK, but this is inverted to me, does not make any sense.
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  #41 (permalink)  
Old 11-11-2008, 03:45 PM
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Quote:
Originally Posted by Cyberats
Many years back, was it 1996/1998 ?, GM introduced the "Vortec" engine in Cadillacs and some luxury cars and they DID come with 4 valve per cylinder.

Do you think overall that 4 valves would make for a more economical engine ?

My daily driver is both too old and way into too many replacements to be sold for any reasonable sum of money. I never kept a car for resale value. But you know what ? Owning the car in the next 3 years making it about $15K investment in 10yrs., driving a comfortable, powerful and near luxury car with no glitches = cheaper than replacing a 4-banger every 3 years. Even cheaper than most econo cars you can buy today, baring Kia, Saturn and Hyundai, but I highly doubt any of them will last you 10yrs. with NO investment.
No investment? No car can last 10 years with no investment, not even one that just sits in a garage for 10 years. And today's cars in many ways are manufactured much better than the cars of 10 years ago, and they are lasting longer and longer. When you look at a car's true lifecycle cost you can't beat the econo-boxes. In all reality it would save me money to go out and buy a brand new Cobalt rather than fixing up my Cutlass, yet I still put money into the Cutlass because of personal preferance. But it is impossible to justify it financially.
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  #42 (permalink)  
Old 11-11-2008, 03:57 PM
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Financially

I reached the estimated $15K in 10yrs. with pre-emptive repairs made Before it's broken, including the original $4.6K paid at the dealer (rebuilt the transmission otherwise I would've moved on, no Chevy Caprice to be found in the time I had). So my sum includes repairs made and original price.

What I am trying to say I guess is that any used car you buy, big or small, will save you money over buying a new car, keeping in mind maintainance and preventive repairs will not cost more. In the last 20 years the price for new cars have doubled, while my salary has been halved.

Yes I do need a good job first, open to suggestions.
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  #43 (permalink)  
Old 11-11-2008, 04:01 PM
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I'm an engineer, its not the greatest paying gig, but the job security is really good as long as you know what you're doing. If you're good at what you do in this field it seems everyone knows about it.

As far as your car goes, it sound slike you need a $500 ugly beater special. Try looking at pre-94 s10's, they usally go for less than a G and the 4.3L auto versions seem to last forever, I've seen several over 300K miles on them.
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  #44 (permalink)  
Old 11-11-2008, 04:53 PM
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I guess it's the Greed of Petroleum-Car USA that gets me

Fed up with being ripped off by every stupid millionare in the country.
I love my car only problem is the gas, wouldn't trade it unless a pickup or an suv, why, cause all the millionares buy them for the people in the family who CANNOT or should not drive, thus endangering my life so I need to step up arms . Otherwise yeah, would be nice entering and exiting without breaking my back. Yes, pickups also seem to last a lifetime too, problem is I keep staring after the ones I can't afford nor do I need, like the new F-450.

Are you a mechanical engineer ? I am a computer programmer, ended up doing things incredibly far from my profession, my career never took off, long story, ended up with 16yrs. of consulting and basic techie jobs.

Do you have any interest in designing an ALL hydrogen engine ???
Using only hydrolitic converters no gas storage, pour water in tank.
Would be the biggest kick in the nuts to petroleum-tricar inc. and I would love to have one. My favorite hotrod would be the 1970 Judge, but the Olds would be a close second. I like the designs more, maybe the dual lights, but it's the only detail that matters when you can replace everything inside it.
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Old 11-11-2008, 06:13 PM
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Love all this high tech talk guys, but I believe F-Bird'88 hit it on the head. What do you want from an engine? What I wanted in my street rod was to launch and be the first to the end of the next block! What I have is a 4000# 2wd Willys Wagon powered by a 350 sbc bored 40 over with 69-70 64cc 041 heads and dome pistons to keep the compression at around 9:1, Th400 2 stage shift kit w standard stall converter. I like the buck board ride from leaf spring suspension and a 54 GM 1/2tn PU straight axle w 11" discs and power steering. I told my engine builder what I wanted from my motor and he suggested the Elgin P1120 Pro stock cam which is barely above stock. I am running an open gear 10 bolt 373 ratio that will skid my front tires rather than burn a rear due to the weight factor on the *** end! I love the way it launches! So as it is important to have the sound effects of a lumpy engine for some guys, look out for the fellow with the right combination! Kinda makes you want to pull up and try me docent it? I guarantee that while you're giving a noisy smoke show I will be gone!!! However I do shut down at 100mph so I wont break the original speedo. All this on pump gas. For daily driving I run 87 but always have the option for 91 or higher if I want to mix or run at the track. My daily driver tires are 275x60x15 on 10" Cragars. For a little more squirrel I can run 295x50x15's. The best I'll ever get for mileage is about 10mpg HWY but not normally because I am a serious lead foot at every opportunity, especially in and around town. That's why I built this thing is to have fun. Now days they take your ride for street racing that takes all the old school fun out of Hot Roddin and Constructive Cruisin! The main thing is to learn and enjoy what you're doing and you'll never be disappointed! Imports have come along way, but there is nothing like building and driving your very own American Muscle Machine!!!
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