Crossflow CFM

[StarDiero75]

Howdy Guys,

3rd and final post of the night. I am hopefully getting a complete 84DA 250 crossflow and am looking to make as much power NA as almost possible (If I'm not happy with it I'll supercharge). This requires some serious porting. Does anyone have a flow bench data table (0.100, 0.200, etc) of the CFM flow rate for the intake and exhaust? research online has led me with a max of 213 CFM @ 0.500-0.600 lift and some other person stated 340 CFM @ an unlabeled lift. Id be in the 0.543" lift range using 1.8 roller rockers on a 14650 Crow cam (292 ADV). I have yet to find exhaust numbers for CFM.

I am trying to use these to help develop a theoretical HP that the motor will make. I know valve choice will make a difference too. I'll likely try to use the largest I can ,reasonably, like the 1.94" (I even saw using a Cleveland 2.02"). what would you all recommend here as well?

Thanks!

 

[aussie7mains]

340, is way high, the 213 is more in the ballpark. As to power a guy here, XRglen claimed he had 365bhp NA"-https://fordsix.com/threads/realistic-hp-for-250-xflow-xe.64767/

 

[StarDiero75]

340, is way high, the 213 is more in the ballpark. As to power a guy here, XRglen claimed he had 365bhp NA"-https://fordsix.com/threads/realistic-hp-for-250-xflow-xe.64767/

Even with porting and a large valve? The highest more normal value I saw was 240cfm, but again, no lift spec. How big a valve would yoy run?

 

[StarDiero75]

And thanks for that link. It had a great list like i was looking for. I'm pretty dead set on 300+hp out of this motor NA.

 

[StarDiero75]

Based on those numbers, the most hp those flow values support is around 232hp at the crank. The exhaust flow is fairly disappointing

 

[aussie7mains]

And thanks for that link. It had a great list like i was looking for. I'm pretty dead set on 300+hp out of this motor NA.

I think you will find you cant get much bigger in the chamber than the 1.84 1.54 they have, Ive got a couple of heads here so Ill have a look tomorrow, And getting valves the correct length might be an issue. I would not touch the exhaust ports they are really good as is, and the inlets are a nice shape from the factory, do a google search im sure you find something. 215 CFM accord to superflow rule of thumb is good for about 320bhp when fully developed, you would need more cam than your suggesting for this level of power, and probably a big 4 barrel of preferable triple webers. You did mention a blower, this is the far easier route to get that power, and it would be a much more civilised engine, you dont need big cams etc to do it. I have a blown 200ci crossflow and I estimate Ive got around 200kw and 500nm, its like driving a 6 litre engine. If you havent seen it already here it is again:-

 

[StarDiero75]

I think you will find you cant get much bigger in the chamber than the 1.84 1.54 they have, Ive got a couple of heads here so Ill have a look tomorrow, And getting valves the correct length might be an issue. I would touch the exhaust ports they are really good as is, and the inlets are a nice shape from the factory, do a google search im sure you find something. 215 CFM accord to superflow rule of thumb is good for about 320bhp when fully developed, you would need more cam than your suggesting for this level of power, and probably a big 4 barrel of preferable triple webers. You did mention a blower, this is the far easier route to get that power, and it would be a much more civilised engine, you dont need big cams etc to do it. I have a blown 200ci crossflow and I estimate Ive got around 200kw and 500nm, its like driving a 6 litre engine. If you havent seen it already here it is again:-

Ok so I'm gonna be limited on valve size then, now does this come from the bore size or the valves are too close together in the head? I'll definitely have to see once i get it. Are the valves inherently short like the log heads where they aren't designed for much lift? I'd really like to keep the multiport efi it has on it. This will give me the best fuel distribution. To make this easy to drive with my power goals, its definitely going to have to be boosted, ok thats alright. The cam i have, would that be bad for a blower?

Thats perty impressive any other mods like a cam or anything? Or is it just a blower? I remember yoy showed me this engine and told me to get a 200 or a 250 aussie, thats why im in this mess now hahaha.

 

[pmuller9]

Ok so I'm gonna be limited on valve size then, now does this come from the bore size or the valves are too close together in the head? I'll definitely have to see once i get it. Are the valves inherently short like the log heads where they aren't designed for much lift? I'd really like to keep the multiport efi it has on it. This will give me the best fuel distribution. To make this easy to drive with my power goals, its definitely going to have to be boosted, ok thats alright. The cam i have, would that be bad for a blower?

Whichever way you decide to go, the connecting rod and piston combination for a bullet proof bottom is still the 6.21" Molnar rods with a Autotec/Racetec piston. That hasn't changed.
You end up with a lightweight piston with a 1.300" CH

Use the rods with the full floating pin.

Ford 300 Inline 6 Rods | Molnar Ford 300 Power Adder Rods

300 Inline 6 connecting rods for high performance and racing Ford 300 engines. Molnar billet H beam Ford 300 Power Adder rods for press fit and floating pin

molnarrods.com

If you use a positive displacement supercharger, cam the engine as you would if it was naturally aspirated for peak torque and horsepower higher in the rpm range.
This will allow the supercharger to operate cooler and more efficiently at the torque and power peaks in the higher rpm range of the power band.
The supercharger will take care of the low rpm power below cam naturally.

What cam do you have?

 

[pmuller9]

As far as 300 hp N/A,
The Promaxx head flows between 215 and 220 CFM at .600" lift and will border line produce 300 hp with a 232 degree .050" duration, 530" valve lift hydraulic cam. (240/300 six)
If you can get near that flow in a XF head you would need something like a Crow 14626 solid lifter cam.
Advertised duration 278°288°, .050" duration 238°244°, Valve lift with 1.73 rockers 0.560" 0.570", 109 LSA, Valve lash .012".014"

Yes, you would have to carefully examine valve travel.

 

[pmuller9]

Install a 36-1 trigger wheel on the balancer hub and modify the distributor to supply the single cam sync pulse.
Then use an aftermarket EFI system of your choice.
I would recommend the Holley Terminator X.

What type of distributor comes on the 250 XF engine you will be getting?

 

[StarDiero75]

Whichever way you decide to go, the connecting rod and piston combination for a bullet proof bottom is still the 6.21" Molnar rods with a Autotec/Racetec piston. That hasn't changed.
You end up with a lightweight piston with a 1.300" CH

Use the rods with the full floating pin.

Ford 300 Inline 6 Rods | Molnar Ford 300 Power Adder Rods

300 Inline 6 connecting rods for high performance and racing Ford 300 engines. Molnar billet H beam Ford 300 Power Adder rods for press fit and floating pin

molnarrods.com

If you use a positive displacement supercharger, cam the engine as you would if it was naturally aspirated for peak torque and horsepower higher in the rpm range.
This will allow the supercharger to operate cooler and more efficiently at the torque and power peaks in the higher rpm range of the power band.
The supercharger will take care of the low rpm power below cam naturally.

What cam do you have?

So this is Rocklord's 250 crossflow. It comes with the 200 rods and ACL pistons. I'd really not like to have to not use those as I kn they are extremely hard to get, as well as allows the 250 to scream, which is nice. Is this not a good combo for this kind of build? If using these, do I just need to accept being NA?

Ok good, thats great to know. The cam that will come with the motor is the Crow cam 14650, 230 @ 0.050", .5225" lift with 1.73 rockers, and 113 LSA. I was thinking on looking for 1.8 rollers to get a little more lift and push the top end a hair out. I think this cam puts me in a 2500-6000 or 3000-6500 rev range. But it is hydraulic, so maybe I should look for a solid?

 

[StarDiero75]

As far as 300 hp N/A,
The Promaxx head flows between 215 and 220 CFM at .600" lift and will border line produce 300 hp with a 232 degree .050" duration, 530" valve lift hydraulic cam. (240/300 six)
If you can get near that flow in a XF head you would need something like a Crow 14626 solid lifter cam.
Advertised duration 278°288°, .050" duration 238°244°, Valve lift with 1.73 rockers 0.560" 0.570", 109 LSA, Valve lash .012".014"

Yes, you would have to carefully examine valve travel.

Thats not aluminum or anything, right> I've never seen a 300 with an aluminum. that will all be in the port work to get that to happen. The exhaust is the problem, right? And can a 1.94" valve be used instead of the 1.80 to get some more flow?

I assume we start getting into the valve kissing the piston territory here? or valve seat hitting the seal?

 

[StarDiero75]

Install a 36-1 trigger wheel on the balancer hub and modify the distributor to supply the single cam sync pulse.
Then use an aftermarket EFI system of your choice.
I would recommend the Holley Terminator X.

What type of distributor comes on the 250 XF engine you will be getting?

Ok so we are still on course for a terminator x, cool. Same as the 2V. I saw MSD offers a trigger wheel that I just need to make fit to the balancer. The distributor is unknown at the moment. I would assume whatever came factory, bosch? i can hack up the bosch trigger wheel or my duraspark to do this still like the hyperspark, right? The hyperspark is way too tall in this case it looks like.

 

[pmuller9]

So this is Rocklord's 250 crossflow. It comes with the 200 rods and ACL pistons. I'd really not like to have to not use those as I kn they are extremely hard to get, as well as allows the 250 to scream, which is nice. Is this not a good combo for this kind of build? If using these, do I just need to accept being NA?

Ok good, thats great to know. The cam that will come with the motor is the Crow cam 14650, 230 @ 0.050", .5225" lift with 1.73 rockers, and 113 LSA. I was thinking on looking for 1.8 rollers to get a little more lift and push the top end a hair out. I think this cam puts me in a 2500-6000 or 3000-6500 rev range. But it is hydraulic, so maybe I should look for a solid?

I didn't know the engine you are getting came with the long 200 rods and ACL pistons.
How much power does Rocklord’s engine make?

If the compression ratio is around 10:1 then the combination is good for NA.
If you are going to supercharge, the compression ratio should be closer to 9:1

The solid roller cam will have a much more stable valve train at above 5500 rpm and will make more power due to a more aggressive ramp rate and higher valve lift.
You can get solid lifters with the small EDM hole in the lifter face to pressure feed oil to the cam lobes
I'm tired of fighting high rpm valve train stability with hydraulic flat tappet cams.
You need around a 240 degree .050 duration and .550" valve lift cam to make the power you are looking for and that is why I specified the Crow 114626 solid lifter cam.

If the piston has a dish. the piston to valve clearance should be ok but you should still check the clearance using a checker valve spring and dial indicator. The valve is closest to the piston between 10 to 15 degrees after TDC for the intake and before TDC for the exhaust valve.

You will have to check the valve travel with the valve stem seal in place to see if there is enough for the cams valve lift.

The Promaxx CNC ported head for the 240/300 is an iron head based on the EFI 4.9 head.

If you do a 1.94" intake valve, you will have to extend the combustion chamber walls out to the cylinder wall.
That's providing there is enough clearance between it and the exhaust valve.

Is the Hyperspark distributor too tall even without a cap on it?

 

[aussie7mains]

Ok so I'm gonna be limited on valve size then, now does this come from the bore size or the valves are too close together in the head? I'll definitely have to see once i get it. Are the valves inherently short like the log heads where they aren't designed for much lift? I'd really like to keep the multiport efi it has on it. This will give me the best fuel distribution. To make this easy to drive with my power goals, its definitely going to have to be boosted, ok thats alright. The cam i have, would that be bad for a blower?

Thats perty impressive any other mods like a cam or anything? Or is it just a blower? I remember yoy showed me this engine and told me to get a 200 or a 250 aussie, thats why im in this mess now hahaha.

Valves in crossflow are much longer than the log head, more like a cleveland valve, they have multi groove collets to allow valve rotation, but they are ok to use with some grinding. My engine has a small cam 210@0.05, just to give me power to 5000rpm, other than that its a stocker that i bought used, re ringed and new oil pump, timing chain etc. I run factory Ford pistons that must have done 100,000km, my block is standard bore in very good condition, rods etc are factory 200s 6.27 long. Your cam is way more than is needed for a boosted engine. I have 1&5/8 inch headers and single 2.5 inch exhaust system with turbo muffler right to the bumper, its a little loud when given the berries. When blown the size of the blower is mostly what determine the torque output, so the displacement of the engine actually affects when the torque is best, more displacement, lower rpm. As Ive said with mine, it just drives like a much bigger stock engine, no cammieness, graet response, torque eveywhere, great on the street!

 

[StarDiero75]

I didn't know the engine you are getting came with the long 200 rods and ACL pistons.
How much power does Rocklord’s engine make?

If the compression ratio is around 10:1 then the combination is good for NA.
If you are going to supercharge, the compression ratio should be closer to 9:1

The solid roller cam will have a much more stable valve train at above 5500 rpm and will make more power due to a more aggressive ramp rate and higher valve lift.
You can get solid lifters with the small EDM hole in the lifter face to pressure feed oil to the cam lobes
I'm tired of fighting high rpm valve train stability with hydraulic flat tappet cams.
You need around a 240 degree .050 duration and .550" valve lift cam to make the power you are looking for and that is why I specified the Crow 114626 solid lifter cam.

If the piston has a dish. the piston to valve clearance should be ok but you should still check the clearance using a checker valve spring and dial indicator. The valve is closest to the piston between 10 to 15 degrees after TDC for the intake and before TDC for the exhaust valve.

You will have to check the valve travel with the valve stem seal in place to see if there is enough for the cams valve lift.

The Promaxx CNC ported head for the 240/300 is an iron head based on the EFI 4.9 head.

If you do a 1.94" intake valve, you will have to extend the combustion chamber walls out to the cylinder wall.
That's providing there is enough clearance between it and the exhaust valve.

Is the Hyperspark distributor too tall even without a cap on it?

Its pretty sick huh?! Currently it needs a full rebuild, but all the hard parts to get are present. mainly it seems like just machine work and porting is left minus an intake and headers now. So i would say it makes close to 0hp at the moment haha.

With i believe he said the pistons are in the 12cc range, which would help decrease compression to get me to 9.1. He would have to chime in to correct that.

I am completely happy with doing that. Since the motor comes with a cam, can I have it reground to the specs I want by like schneider or someone? I feel like that is cheaper than buying new from crow. Can they turn a hydraulic lifter cam into a solid lifter as well? I'm completely on board with solid. I've had issues with hydraulic.

I can always machine the seal down lower right?

Is enlarging the valve to that size worth it to fit?

I was just talking to Rocklord about that. I am really hoping it will fit with the cap and rotor off with just a cover over the reluctor wheel. That would save some change. Then I'll just need to ream the pilot hole out a hair and use the US oil pump and drive pin.

 

[StarDiero75]

Valves in crossflow are much longer than the log head, more like a cleveland valve, they have multi groove collets to allow valve rotation, but they are ok to use with some grinding. My engine has a small cam 210@0.05, just to give me power to 5000rpm, other than that its a stocker that i bought used, re ringed and new oil pump, timing chain etc. I run factory Ford pistons that must have done 100,000km, my block is standard bore in very good condition, rods etc are factory 200s 6.27 long. Your cam is way more than is needed for a boosted engine. I have 1&5/8 inch headers and single 2.5 inch exhaust system with turbo muffler right to the bumper, its a little loud when given the berries. When blown the size of the blower is mostly what determine the torque output, so the displacement of the engine actually affects when the torque is best, more displacement, lower rpm. As Ive said with mine, it just drives like a much bigger stock engine, no cammieness, graet response, torque eveywhere, great on the street!

With the supercharger you don't really need the massive cam to get that. To me, if I am building a really hot street motor (kinda pro-street), I do want a little camminess. The torque will be there with the 250, and whatever I lost in the low end to gain in the upper, the supercharger will carry it through it. (Thats the plan at least)

 

[pmuller9]

Its pretty sick huh?! Currently it needs a full rebuild, but all the hard parts to get are present. mainly it seems like just machine work and porting is left minus an intake and headers now.

Just so I have a clear picture.
Was the Crow 14650 cam running in the engine along with the 200 rods and ACL pistons.
If the engine needs to be rebuilt, will the cylinders need to be bored to the next oversize?

If the engine was running with those parts already in it, did Rocklord give you any indication of how much power it made?

When you get the engine then measure all of the valvetrain and head components and plan your course of action from there.

 

[StarDiero75]

Just so I have a clear picture.
Was the Crow 14650 cam running in the engine along with the 200 rods and ACL pistons.
If the engine needs to be rebuilt, will the cylinders need to be bored to the next oversize?

If the engine was running with those parts already in it, did Rocklord give you any indication of how much power it made?

When you get the engine then measure all of the valvetrain and head components and plan your course of action from there.

So none of these are in the motor. He collected these in plans on building a 250 xflow. The cam is not in the engine. The whole engine is in factory configuration currently with these speed parts on the side. If it does not need a .040 over, I am not sure what to do. Boring it out to 0.040 when unncecessary is a waste, but those are hard to get components. I would assume he measured the bore and estmated. We'll have more talks about it.

That is probably the best course of action. He offered 3 other cams, but that one was the most radical, but nothing is in stone yet

 

[pmuller9]

If it does not need a .040 over, I am not sure what to do. Boring it out to 0.040 when unnecessary is a waste,

If for some reason you do not need the .040" over ACL pistons and don't want to use them, then you would get another set of pistons from Autotec/Racetec.

It doesn't matter if the 200 rod and ACL pistons are a hard-to-get combination, since the Molnar rods and aftermarket pistons are available.
The Molnar rods are almost as long as the 200 rods and are stronger. (6.21" versus 6.27")

ACL pistons are a high silicon alloy piston that is fine for NA use but not for power adder applications.
Here is a statement from their own publication.

"ACL Performance pistons are NOT intended to replace forged pistons in applications where output isgreater than 100 BHP/litre or in turbocharged and supercharged engines. However they are ideal for engine builders wishing to obtain moderate increases in power and speed from otherwise standard engines for street or off road use."

Autotec/Racetec forged pistons would be far better for supercharger use.