good mods while i have the head off
- Thread starter 79granada
- Start date
Gene Fiore
Famous Member
Cam swap.
Howdy Granada and All:
Have the head milled .075". .025" to compensate for the thicker composite type aftermarket head gasket you will be using, and .050" to raise the CR up to about 9:1. Have the intake valves back-cut. Pocket porting (already mentioned) and smoothing the chambers.
Keep us posted on your plan.
adios, David
Have the head milled .075". .025" to compensate for the thicker composite type aftermarket head gasket you will be using, and .050" to raise the CR up to about 9:1. Have the intake valves back-cut. Pocket porting (already mentioned) and smoothing the chambers.
Keep us posted on your plan.
adios, David
Hey everyone... I'm in kind of the same boat. My head was milled already, but no port work or nothing done to the chambers. The chambers look rough... very, "as cast" looking.
For a mild engine, what's the benefit of cleaning up the chambers? (all I got is projects, why not another one!?)
For a mild engine, what's the benefit of cleaning up the chambers? (all I got is projects, why not another one!?)
im going to be doing the machining myself on the carb swap and i think i could pull off milling the head down but i dont know if i could pull off the valve job maybey i could get my machinist buddy to help me (im using his shop.) as for cam what kind of effect would that have on gas milage. also keep in mind i dont want to go with headers cause i am not sure if i can pull that off with the air conditoning.
Benefits to cleaning up the chambers:
1. those cast surfaces contain millions and millions of tiny sharp points. If one of them gets hot enough it could act like a little spark plug and ignite your fuel at the wrong time causing detonation or ping.
2. Unshrouding the valves so more air can get around the big end and either into or out of the cylinder
3. You can guarentee that they are all the same CC
There was also something about the polished surface being more reflective to potentially keep more heat in the cylinder instead of heating up the cylinder head itself.
Sorry, no help on the cam, but more air in and more air out is always good and the stock cam is not very performance oriented.
It sounds like you are building the motor to be used for cruising not high performance (based on your willingess to have AC instead of headers) so you would probably want to pick a cam that builds better low end torque and has a nice power band through the normal RPM of cruising (1500-4000) hopefully somebody with more cam knowledge can help you pick one out.
-ron
1. those cast surfaces contain millions and millions of tiny sharp points. If one of them gets hot enough it could act like a little spark plug and ignite your fuel at the wrong time causing detonation or ping.
2. Unshrouding the valves so more air can get around the big end and either into or out of the cylinder
3. You can guarentee that they are all the same CC
There was also something about the polished surface being more reflective to potentially keep more heat in the cylinder instead of heating up the cylinder head itself.
Sorry, no help on the cam, but more air in and more air out is always good and the stock cam is not very performance oriented.
It sounds like you are building the motor to be used for cruising not high performance (based on your willingess to have AC instead of headers) so you would probably want to pick a cam that builds better low end torque and has a nice power band through the normal RPM of cruising (1500-4000) hopefully somebody with more cam knowledge can help you pick one out.
-ron
Here's what I did when I was in the same situation as you and was very pleased with the results:
*Mod the log for a 2v.
*did some pocket porting on the intakes and ported the entire exhaust ports out out to the gasket.
*Installed 1.75 intake and 1.5 exhaust valves.
*polished the chambers
*milled for 9.5:1 compression
I also installed full roller rockers. (but considering the price of those it makes more sense to install a mild cam.) The end result was an engine that went from falling on it's face at 4200 rpm to pulling hard from 1500 to 4700 rpm. It was also a lot "looser" feeling, willing to rev freely and cruising easily with much less throttle than before. You can read about my experience and see some pics here: http://falconfanatic.blogspot.com/p/engine.html
*Mod the log for a 2v.
*did some pocket porting on the intakes and ported the entire exhaust ports out out to the gasket.
*Installed 1.75 intake and 1.5 exhaust valves.
*polished the chambers
*milled for 9.5:1 compression
I also installed full roller rockers. (but considering the price of those it makes more sense to install a mild cam.) The end result was an engine that went from falling on it's face at 4200 rpm to pulling hard from 1500 to 4700 rpm. It was also a lot "looser" feeling, willing to rev freely and cruising easily with much less throttle than before. You can read about my experience and see some pics here: http://falconfanatic.blogspot.com/p/engine.html
What Gene said. Even a mild cam, like I"m running (Comp Cam 260H) will increase the lift 20% without making the engine tempermental. I ran this cam with a 1V carb and it's a night and day difference. It is the best bang for buck you can get. If you don't pull the engine, it is a bit of work to replace. You'll need a lifter puller, and you'll have to remove the radiator as the I6 cam is so bloody long.
The only effect it will have on your mileage will be the effect caused by your lead foot that may enjoy the power more.
The only effect it will have on your mileage will be the effect caused by your lead foot that may enjoy the power more.
I have AC and headers... I took the AC bracket and had the alt mount extended 1.5 inches, 3/4 inches wasn't enough and was still really close, it did fit but I eventually took it back again and got it the 1.5 inches over from original bolt hole. didn't have to change anything else except that and the welding shop charged me $40 bucks total (20 a trip).
2bbl direct mount
stock valves as for 79 you have decent valves
clean up/smooth the valve bowls (pocket porting)
cam 260/260 .450 112 H
electric fan
IMO, these are the best bang for the buck. these will net a decent 120-130hp or 60hp increase and gas mileage will increase 2-6mpg.
when installing a cam, make sure you degree it, you'll be surprise how easy it is to install and degree a camshaft. even in the engine bay. oh and nice lifter removal tool, a $5 autozone extendable pen magnet.... maybe you can find one cheaper?
2bbl direct mount
stock valves as for 79 you have decent valves
clean up/smooth the valve bowls (pocket porting)
cam 260/260 .450 112 H
electric fan
IMO, these are the best bang for the buck. these will net a decent 120-130hp or 60hp increase and gas mileage will increase 2-6mpg.
when installing a cam, make sure you degree it, you'll be surprise how easy it is to install and degree a camshaft. even in the engine bay. oh and nice lifter removal tool, a $5 autozone extendable pen magnet.... maybe you can find one cheaper?
hey thanks for the sugesstions everyone i do want something to cruise in but with a little more power. cobra six do you know the specs on that cam you was talkin about? id like to have all the info i can on that.
mpg mustang i would love to see some pictures of the AC setup you got going
i think im going to do most of the things mentioned here hopefully i can find a decent machinist to do the valve/porting work, my guy is super slow again thanks all
mpg mustang i would love to see some pictures of the AC setup you got going
i think im going to do most of the things mentioned here hopefully i can find a decent machinist to do the valve/porting work, my guy is super slow again thanks all
The 250 will take a 274 degree Clay Smith cam on the right lobe centre to suit the transmission, and behave well. On a poorly flowing engine, it will not 'come on the cam' like a Twin Cam Supra or GT Corolla. If your effective compression hasn't dropped, then neither will your low end torque suffer.
If your breathing improves in a 250 engine with a cam, it won't get cammy even with 280 degrees duration. I've checked with Kelford Cams, and even the 250 with the much better breathing alloy head is really insensitive to cam duration. The 1987 Falcon 4.1 Litre X-flow with 155 cfm of port flow at 25"H20 was totally happy with a 2.77:1 diff, T5 gearbox, and 280 degree cam on a factory experimental SVO Falcon XF.
Lastly, the 250 is a long stroke, short rod engine with small heads and the info from my sources in the industry say that at 270 degrees, emissions starts to suffer, at 280 with a free breathing head and 50 thou lift durations of 215 degrees and a stock stall converter, you'll still be okay. The point where things start to unrevel are the off idle hole when both valves are open 30 thou, and you have a really stiff 1650 stock stall converterand a cam over 280 degrees at lash, or over 220 degress duration at 50 thou. At that point, air flow can suffer reversion, and low end torque can go away an hide, making the car unstable on off idle.
Power steering and a/c also can hurt idle, but its not an issue on this Ford six.
After you've done the cam, the initial ignition advance and total curve ramp will need reworking downwards. Verification of stock curve needs to happen with a dial back timing light, then I'd use the stock placards 9 degrees measured as per Fords requirements, and then peg the total advance back to no more than 34 degrees. That way, you should be able to run 87 octane, and hopefully not suffer pinking under load. A bigger cam helps blead off compression, and if the cold crank value is around 180 psi with the cam degreed, then you'll have a really nice combination.
If your breathing improves in a 250 engine with a cam, it won't get cammy even with 280 degrees duration. I've checked with Kelford Cams, and even the 250 with the much better breathing alloy head is really insensitive to cam duration. The 1987 Falcon 4.1 Litre X-flow with 155 cfm of port flow at 25"H20 was totally happy with a 2.77:1 diff, T5 gearbox, and 280 degree cam on a factory experimental SVO Falcon XF.
Lastly, the 250 is a long stroke, short rod engine with small heads and the info from my sources in the industry say that at 270 degrees, emissions starts to suffer, at 280 with a free breathing head and 50 thou lift durations of 215 degrees and a stock stall converter, you'll still be okay. The point where things start to unrevel are the off idle hole when both valves are open 30 thou, and you have a really stiff 1650 stock stall converterand a cam over 280 degrees at lash, or over 220 degress duration at 50 thou. At that point, air flow can suffer reversion, and low end torque can go away an hide, making the car unstable on off idle.
Power steering and a/c also can hurt idle, but its not an issue on this Ford six.
After you've done the cam, the initial ignition advance and total curve ramp will need reworking downwards. Verification of stock curve needs to happen with a dial back timing light, then I'd use the stock placards 9 degrees measured as per Fords requirements, and then peg the total advance back to no more than 34 degrees. That way, you should be able to run 87 octane, and hopefully not suffer pinking under load. A bigger cam helps blead off compression, and if the cold crank value is around 180 psi with the cam degreed, then you'll have a really nice combination.
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