needing advice on a performance EFI 300I build

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#16

11-09-2011, 05:43 PM

300ci Legend

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Quote:

Originally Posted by SideWinder4.9l

He has a EFI engine.....SO the lift will upset the 'puter...

Thats all my post was about.....If he has a MAF truck...things would be a tad different...

Guys im not talking about using the SBC rockers. Only the SBC valves for more airflow, and then a cam. Most likely I'll use the comp 260. It is supposed to be compatible with the ECU

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#17

11-09-2011, 09:17 PM

1983F1503004x4

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The other poster is right... a 240 6 is just like the 300 6. It's got a 10.18'' deck height, but the 240 has a smaller crank with a stroke of 3.18''. The 300 has a 3.98'' stroke. That 3.98'' stroke is what makes the 300 such a torquey six.

But heck, now I'm curious. If you swapped a 240 crank rods and pistons into a 300 EFI with MAF, and did some mods and balanced it, I wonder how that'd run with the computer and crap?

Hmm. ^.^

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#18

11-09-2011, 10:37 PM

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Quote:

Originally Posted by 1983F1503004x4

Yes I agree. That would certainly be interesting. In my opinion it would probably run similar to the 4.0 jeep straight six. I would think you could get higher rpm's out of it too.

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#19

11-10-2011, 12:29 AM

F-250 restorer

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The Comp 260 has 212 degrees duration @ .050". That's a lot of duration for a computer rig. I'd make certain it is kosher. I was reading the Isky 262 is 'puter friendly.

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#20

11-10-2011, 12:50 AM

SideWinder4.9l

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Quote:

Originally Posted by F-250 restorer

The Comp 260 has 212 degrees duration @ .050". That's a lot of duration for a computer rig. I'd make certain it is kosher. I was reading the Isky 262 is 'puter friendly.

I was looking into the Isky cams...And on the sheet they have...It seems a 256 cam would suit me moreso, than a 262....

Isky 256 cam Operating range-1,500-4,800 rpm
Isky 262 cam Opertaing range-2,000-5,500 rpm

BUT

It says the 262 camshaft shout be used with 3.08 to 3.70 gears...
and that the 256 cam needs to be used with higher ratio'd gears..(2.73's, etc)...

www.iskycams.com/pdfcatalog/2004-05/page62.pdf

Any thoughts on that?

Because, if at all possible...I'd like a 256 cam, and either 3.73's or 3.55's....

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#21

11-10-2011, 09:56 AM

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oNotPromoteQF/> <w:LidThemeOther>EN-US</w:LidThemeOther> <w:LidThemeAsian>X-NONE</w:LidThemeAsian> <w:LidThemeComplexScript>X-NONE</w:LidThemeComplexScript> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w

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ontVertAlignInTxbx/> <w:Word11KerningPairs/> <w:CachedColBalance/> </w:Compatibility> <m:mathPr> <m:mathFont m:val="Cambria Math"/> <m:brkBin m:val="before"/> <m:brkBinSub m:val="--"/> <m:smallFrac m:val="off"/> <m:dispDef/> <m:lMargin m:val="0"/> <m:rMargin m:val="0"/> <m:defJc m:val="centerGroup"/> <m:wrapIndent m:val="1440"/> <m:intLim m:val="subSup"/> <m:naryLim m:val="undOvr"/> </m:mathPr></w:WordDocument> </xml><![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority

9; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} </style> <![endif]-->Generally, a cam with wider LSA (112-116 degrees) offers less overlap between intake and exhaust opening and closing events. That translates into a wider rpm range, better idle quality, and higher engine vacuum, but at the cost of less torque at low and midrange rpm. A cam with a narrow LSA (104-108 degrees) offers greater low and midrange torque production, but with a narrower operating range, a choppy idle, and less engine vacuum.
For the street, you want a cam that offers a compromise--decent idle quality, respectable vacuum for operating power brakes and such, and good overall power production. separation. Again, much depends on the overall engine combination and intended use, but as a general rule, cams with a 110 to 112 degree LSA offer good power and decent street manners.

Something else to think about that is paramount to the life of your engine and cam: The manufacturers recommended valve spring installed height and pressure. Buy the kit with the cam, lifters, v.springs, retainers, keepers, and have the head set up by a machinist who knows what he is doing.You have to have the required installed height and seat pressure for everything to work together correctly. And don't use the Chinese cheapo crap t. gears that come with a lot of rebuild kits. I did and they knocked!! Spend the $ and get a good set from Comp Cams, or, even better, from Cloyes. They cost IIRC, about $90, and you never have to r&r them again.

I'm thinking. If you go with the Isky cam you'll want to use their kit. But the Isky v.springs are way over the top and produce 134 lbs @ required height. You only need about 110 lbs. I think Comp and Crower offer v.spings of like 80 lbs. Clifford requires 110lbs. I used the Isky springs but removed the inner spring and tested it. I wound up with 117 lbs at the seat (fully closed), which has worked well for me.

Good luck.

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#22

11-10-2011, 10:28 AM

SideWinder4.9l

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Quote:

Originally Posted by F-250 restorer

The higher the gear ratio, 3.50:1, 3.73:1, 4.10:1, which means lower gears, add bottom end to your vehicle, and only improve the starting ability of any engine/cam combo. I use the Isky 256 and have 3.31:1 gears. It drives great all around. The only time I even think about lower gears (higher numbers)is when approaching the long grades of mountain passes, and even then, towing a trailor or hauling, it's not really a problem.

However, with a cam you also need to consider tire size. If, for example, you have 3.50:1 rear gears, and decide to put on 36" tires, then suddenly your gears are behaving like a lower numbered ratio (higher gears). Imagine starting out in second gear and your sort of get the idea.

The big diff. I see between the 256 and 262 Isky is the Lobe Seperation Angle: The 256 has 12*s, and the 262 has 8*s. In terms of how the cam sounds and acts in the engine that is a huge amount. Whereas the 256 idles smooth with great vacuum, the 262 is going to lope at idle and not produce quite as much vacuum.

Let me post something I copied from Summit Racing's site. It might help a bit:

Generally, a cam with wider LSA (112-116 degrees) offers less overlap between intake and exhaust opening and closing events. That translates into a wider rpm range, better idle quality, and higher engine vacuum, but at the cost of less torque at low and midrange rpm. A cam with a narrow LSA (104-108 degrees) offers greater low and midrange torque production, but with a narrower operating range, a choppy idle, and less engine vacuum.
For the street, you want a cam that offers a compromise--decent idle quality, respectable vacuum for operating power brakes and such, and good overall power production. separation. Again, much depends on the overall engine combination and intended use, but as a general rule, cams with a 110 to 112 degree LSA offer good power and decent street manners.

Something else to think about that is paramount to the life of your engine and cam: The manufacturers recommended valve spring installed height and pressure. Buy the kit with the cam, lifters, v.springs, retainers, keepers, and have the head set up by a machinist who knows what he is doing.You have to have the required installed height and seat pressure for everything to work together correctly. And don't use the Chinese cheapo crap t. gears that come with a lot of rebuild kits. I did and they knocked!! Spend the $ and get a good set from Comp Cams, or, even better, from Cloyes. They cost IIRC, about $90, and you never have to r&r them again.

I'm thinking. If you go with the Isky cam you'll want to use their kit. But the Isky v.springs are way over the top and produce 134 lbs @ required height. You only need about 110 lbs. I think Comp and Crower offer v.spings of like 80 lbs. Clifford requires 110lbs. I used the Isky springs but removed the inner spring and tested it. I wound up with 117 lbs at the seat (fully closed), which has worked well for me.

Good luck.

I have 235/75/15's on the truck as of now, and have no intentions of going to a larger tire...Too many issues...

My idea for the build, is one of the Isky cams (Best bang for the buck, and most straightforward #'s I've seen), a Cloyes timing gear set, a GOOD P & P......

Idle doesn't have to lope....I like a lopey idle, but i've seen some cams that makes the 300 sounds like a pissed off Briggs & Stratton 5hp engine...

I basically want a good, firm rpm band from Idle-3,500rpms...

I've driven my truck for almost a year now, taking note of how it drives...And not once have I seen it hit 3,500-4,000 rpms...Never..

It's a DD, and need to be a smooth running unit...MPG/Power CAN go hand in hand, but only if you pay a LOT of attention to whats going on...

As for my rear gear, I currently have a 3.08 open, BUT, I'm wanting to swap to a 3.73/3.55.....Either/or...And keep the factory size tires...

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#23

11-10-2011, 03:49 PM

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Quote:

Originally Posted by F-250 restorer

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Well I recently found out my truck actually has a 3.55 gear. (if my tach is right) So im guessing the ISKY 256 would be my best bet for EFI. I deffinatly want more power. Im guessing that the guy before me ragged the old beast to death. Because it only has launch power in 1st and 2nd gear. After that its a pure slug. It wont even go up the hills in 5th gear going 65. It still loses rpms. Given I live in good old WV. But still my 91 model with a 302 and 3.55's went right up em in 5th. Out of curiousity what happens if you run 134lb springs? Im all new to valvetrain and cam work. Sure I can take it apart and put it back together, but reading all this is like reading chineese to me. Help me out guys.

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#24

11-10-2011, 04:00 PM

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IIRC the comp 260 is supposed to work with EFI, And its within my price budget. Here is the link with more specific details. And could you send me the link on were to buy the isky you were talking about?

66-237-4 - High Energy

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#25

11-10-2011, 05:47 PM

Harte3

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ISKY Racing Cams - Do It Right. Race with the Legend. Camshafts, Connecting Rods, Valve Springs, Lifters

For technical questions it's best to contact the manufacturer direct.

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#26

11-23-2011, 10:31 PM

optikal illushun

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- This cam:
Crane Cams 503901 - Crane Hydraulic Flat Tappet Camshafts - Overview - SummitRacing.com

- These headers:
Hedman Hedders 89300 - Hedman Street Hedders - Overview - SummitRacing.com

- Steel timing gears from a 70s F-Series with a 300
- Lightly clean up the heads, 3 angle valve job, back cut the intake valve 30*, polish the exhaust ports, dont touch the short side radius
- Test valve spring pressure, replace if needed
- Gasket match the intake (upper to lower) only need a little, the few intakes i had were horribly mismatched
- High output coil, Taylor wires, Copper Motorcraft plugs, brass cap n rotor
- Exhaust is ur choice, stick with 2 1/2" though

side note - adding an adjustable fuel pressure regulator and #19 injectors will add more tuneability but may add some driveability issue. Best to get a wideband o2 and guage for tuning. Dont go hog wild on the head, mild work only. EFI heads has a fast burn/swirl combustion chamber. My truck seems to run great, idle at 700 rpms smoothly and pulls good vacuum...this cam was ran (not the same one) in 2 different 300s i built. Dont worry about a larger throttle body, does no good trust me. No idea where my hp or torque numbers are, dont care but i happy with it. I can pull most hills around here around 65-70 at the bottom, top im at 52-53 but im pulled 35s with stock gears.

I also helped a friend build a mean 300 for his 92 F-150 SCSB 2wd with a 5 speed. Pretty much the same specs but a little more block work (we did more for oiling and such), a little more head work and different exhaust. Would keep up with most newer trucks, definatly ran like a *******.

Im running most of those mods, except fuel, on my truck with 35"s and stock 3.55 gears. Truck will see anywhere from 8 mpg when in 4wd/bush wackin to 14-16 on the highway doin 75 mph. General milage is around 12 mpg in town, short trips, some highway.

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#27

12-18-2011, 05:32 PM

JohnMcD348

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Question about the 19lb injectors. Which ones are compatible with our EFI 300's? I have a '92 Bronco and was interested in finding some of the newer style 2 or 4 hole injectors to replace the OEM ones in the hopes of better fuel atomization.

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