The Typhoon Build (Hopped Up F-Head)

Instead of a Hurricane, I am building a Typhoon.

Specs:

F134

Bored .060 OS (18 Hp gain)

Decked .080 & Stroked .040 (~20 HP gain)

End compression ratio; 7.92:1

Ported and polished, 54cc combustion chambers. (~5 hp)

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The plan:

I will be using a dyno to accurately give the results of the power gains all figures now are mathematical guesstimates.

First I will put all stock stuff on, IE. YF, and a point distributor, so on and so forth.

I will then test ignition upgrades, followed my carburetor.

Eventually I will convert the engine to TBI, VIA a donor engine harness, sensors, and so forth from a smiler sized engine (currently looking for a Dodge Daytona 2.2L engine).

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Costs so far:

Pistons____$32 ea.
Rings____$43
Boring of cylinders to .060____$83
Sleeve installed in cyl #2____$94
New cam bearings____$10
Broken stud removal____$5
New freeze plugs____$10
Gasket kit for F134____$56

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What I've done for free:

Port and polish
Disassemblely
Cleaning
Rebuilt the head (valve seats)
Re did valve seats in block installing hardened seats.
Valve grinding and lapping

*it pays to have friends who work at machine shops*

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I got 3 other F134s I am picking up next month (for free), so if I screw up, I got a replacement.

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Some background on the Typhoon:

Out of a 1963 CJ-3b what was bought new be a friend, and mechanist just down the road from where I live. Was then sold to another friend of mine ~1981. That friend had the engine stroked .040, balanced and lightened the crank and rebuilt. The CJ was redone at the same time too. Ran for 8,000 miles then parked in 1989 due to a fuel issue. I bought it in February 2007. Engine stored for 2 years (got back out in January 2009). Water got in cylinders ruining walls and pistons. Rest of the engine is perfect shape. Perfect candidate for what I am doing.

 

Just wondering how you came up with the hp gains for the different mods, boring it and shaving the head? By your calculations your gaining 43hp over stock, naturally aspirated....Thats a 50% increase with a stock rebuild esentially, without a custom ground cam. If I had to guess you might see a 10-15 hp increase at most over a stock engine.

 

Very cool ! Sounds like you are having fun on this build. Do you know someone with a dyno or are you going to have to pay to do dyno runs ?

 

I will test it with the stock cam and then a custom grind one. How whould I have such a little increase? I am not turbocharging it...yet...

I have a friend who owns a High Performance Speed/Engine shop. Has a NICE Dyno.

 

The stock compression ratio is ~7.0:1 right. with every 1 point in compression increase it is almost always about a 5 HP increase per cylinder. 4 cylinders ~20 HP. This theory has been proven for years to be always true. if you add the Decking and stroking, you get a .120 increase, like decking the head that much.

Their is another theory that has been proven true almost always too. For every .010 OS you make a piston, it is a .75 HP increase per cylinder. I went .060 over. thats 6 HP per hole, 18 HP if you add all four.

yes I am just as interested in finding out myself.

 

Should be a learning process. Good luck with those gains!

 

Onyl reason I asked is because when I rebuilt the Lhead I had in gold a while back, I bored it 40 over, and put the supersonic head which changed the compression to ~8.5:1. I could barely tell a difference, but then again that was with the stock cam and a solex carb. I hope yours does gain all that hp but Im trying to warn to not get your hopes up so high.

 

did you advance the timeing slightly? sounds like you could have been getting detonation. And the supersonic head only makes it go to 7.4:1, as far as I have read.

 

You're kinda off. We'll take a SBC 350 with decent heads & intake that delivers good VE numbers as an example. For ever point of compression increase you'll generally see a 3-4 percent increase in power. So, for a 400hp engine, going from 9.5:1 to 10.5:1 should be good for about 12-15hp. That's total for the whole 8-cylinders, not per cylinder.

Boring .060-over is only going to increase the displacement by about 6-cubes or so. Even if you're getting 1hp/cubic inch outta that engine you're not going to see 18hp from the overbore.

I'd also watch the piston deck height if you really do stroke it 0.040. That's not a lot, and I assume you're getting that from offset-grinding the crank a bit. Just make sure you check piston-to-valve clearances and make sure there is enough clearance between the piston skirts and crankshaft counterweights.

Best of luck with the build. Looking forward to seeing what power you're able get outta that little thing.

 

with increased compression, you MUST run a higher octane gas so that the fuel will burn SLOWER. The higher the octane the slower it will burn. As the cylinder is coming up, it is compressing the a/f mix. if you get too much compression, it will cause the gasoline to detonate (pre-ignight, ping) You advance the timing to counteract this so that the a/f mixture will ignite before the compression causes it to explode. Its all about controlled burn.

the information I was told was told by a race engine builder who had been doing it for 40+ years (hes in his 60s, old guy). I would think he would give me good information. and he said that it was 5 HP per cylinder, I wrote that down when he said it so I wouldn't forget it too.

Furthermore, you will see larger butt dyno power in lower HP engines...you will feel it more. Also, your typical stock 350 has a VE of around 82. that's a lot of room for improvement, and thats why so much power can be made from them. That's getting on a different topic now. I need to put the Typhoon on a flow bench to find out the VE. I just might have aanotehr friend that will help me do this. :twisted:

 

yea math isn't my best subject.

 

No I wasnt having any detonation issues. Engine just didnt reflect as much horsepower as I thought it would after all the work. I even smoothed up the intake ports in the block and polished the heads, balanced the rotating assembly to a .1 of a gram. Heres some pics of my rebuild http://s74.photobucket.com/albums/i269/neptco19/L%20head%20build/ I hope you do see some drastic hp increase and Im looking forward to some dyno numbers after the mods, b/c it is a common thread started around wondering how much power is gained from the common rebuild.

 

Guess what? my gasket kit came in today, time to rock and roll...turn up the Chickenfoot!