B&M 144 Roots Blower 200 Planning

K

kjacobson351

New member
Hi, first post here but I've been lurking here for years. I've got a unique situation and I'm in the early stages of planning a blown 200 build and would like to work out some details.

First I am located in Japan, there are no junk yards or anything to pull parts from over here. Everything must be imported.

The application is a 1961 Econoline that I imported last year. I imported and installed a long block that I intend to keep stock and I am going to build the block I removed specifically for this application. Both blocks are 7 main 200s.

I have a 1968 Mustang back home with a B&M 144 Roots blower. I plan on robbing the blower for this build.

I am going to import a 250 2v head and get the manifold to run the blower on from Aussie Speed.

I shot some quick emails to Aussie Speed and I am pretty sure that they custom make the crank pulleys for this application so hopefully I can find a way to get the ratio close to 1:1 - 1:2 overdriven instead of nearly 2:1 like the v8 pulleys are set up for. My goals are not to have huge power or to win any drag races. I just want to reliably run the huffer and have a unique build. I am trying to see how low my compression ratio will go using stock dish type pistons with the 250 2v head. My goal is to have a static compression ratio of 7.5 to 8 and to run about 6 pounds of boost (If the proper pulleys can be made).

Can anyone tell me what kind of compression ill be looking at with stock type pistons and an iron 2v head swap?

does the 2v head require 2v specific headers / manifolds?

Is there anything I am missing here? Assuming there is overlap in my cam could I get away with running (and wasting) more boost if I cant find a proper pulley setup?

Thanks for hearing me out, I am definitely still in the planning stages and am picking up the parts I need for the build as I find them. These questions are starting to keep me up at night so I figured I would get them off my chest. Help me not be a laughing stock, I get laughed out of my shop on a regular basis due to the baby 1 barrel, when all the other inlines nissans over here have triple weber setups. lol
 
kjacobson351":rp26sz1q said:
Hi, first post here but I've been lurking here for years. I've got a unique situation and I'm in the early stages of planning a blown 200 build and would like to work out some details.

First I am located in Japan, there are no junk yards or anything to pull parts from over here. Everything must be imported.

The application is a 1961 Econoline that I imported last year. I imported and installed a long block that I intend to keep stock and I am going to build the block I removed specifically for this application. Both blocks are 7 main 200s.

I have a 1968 Mustang back home with a B&M 144 Roots blower. I plan on robbing the blower for this build.

I am going to import a 250 2v head and get the manifold to run the blower on from Aussie Speed.

I shot some quick emails to Aussie Speed and I am pretty sure that they custom make the crank pulleys for this application so hopefully I can find a way to get the ratio close to 1:1 - 1:2 overdriven instead of nearly 2:1 like the v8 pulleys are set up for. My goals are not to have huge power or to win any drag races. I just want to reliably run the huffer and have a unique build. I am trying to see how low my compression ratio will go using stock dish type pistons with the 250 2v head. My goal is to have a static compression ratio of 7.5 to 8 and to run about 6 pounds of boost (If the proper pulleys can be made).

Can anyone tell me what kind of compression ill be looking at with stock type pistons and an iron 2v head swap?

does the 2v head require 2v specific headers / manifolds?

Is there anything I am missing here? Assuming there is overlap in my cam could I get away with running (and wasting) more boost if I cant find a proper pulley setup?

Thanks for hearing me out, I am definitely still in the planning stages and am picking up the parts I need for the build as I find them. These questions are starting to keep me up at night so I figured I would get them off my chest. Help me not be a laughing stock, I get laughed out of my shop on a regular basis due to the baby 1 barrel, when all the other inlines nissans over here have triple weber setups. lol
Click to expand...

Welcome to the Ford Six forums Kjacobson351, okay here is a few starting specs for your proposed B&M 144 Roots Blown 200 build up.
This is for an early 1966 to 1969 200 7 main stock short block.
3.680 Bore Size
3.126 Stroke
1.511 Piston Compression Height
6.5 CC's Piston Dish
.019 Deck Height (Down the hole)
.022 Thickness of a Ford steel shim head gasket
.041 Quench Distance
3.810 Aprox. Ford Gasket Bore Diameter
52 CC's Chamber on stock Ford Head.
8.7 to 1 stock Compression Ratio

I don't remember what the Australian 2V Combustion Cambers measured at but looking at a picture of them my best guess is that they are about 62 CC's this would also be like what the 1970 and up USA made 200 heads measured. Update by pmuller (thank you Paul) says he thinks they were 58 CC's so I will recalculate using those numbers. So now when we swap the 2V head and newer FelPro head gasket this is what you would get.

All specs above except for now a
58 CC's Combustion Chamber with a Australian 2V Head Swapped on
.050 Thickness of the Head Gasket
.069 Quench Distance
8.06 to 1 Compression Ratio

Some other items to note there was another set of stock cast Pistons that Ford used on some of the California Emissions 200 that had a 10 CC's Dish Volume and plus there were the 250 Pistion's which had a 13 CC's Dish Volume. Also note that many of replacement Pistions are a 1.50 Compression Height droping the piston down the bore to.030 or so the block can have a cleanup cut on the deck surface. With mixing and match different parts and machining of the block it should be easy to get the compression ratio to 8 to 1 7.5 to 1 or even down to 7.17 if you wanted.

Tipical Stock 200 Rebuilt Short Block Specs

3.710 Bore Size (.030 over bore)
3.126 Storke
1.50 Pistion Compression Height
6.5 CC's Piston Dish
.030 Deck Height (block not decked / milled)
.050 FelPro Head Gasket
3.810 Gasket Bore Size.
58 CC's Combustion Chamber with an Australian 2V Head Swapped on
.080 Quench Distance
8.00 to 1 Compression Ratio
203 Cubic Inches

Good luck on your Roots Blown 200 build up (y) :nod: Edited Quench Distance
 
I believe the 250 2V head had 58cc combustion chambers.

Some things to consider.
The B&M 144 blower runs best between 5000 and 10K rotor rpm with an absolute max at 14K rpm.
The Volumetric Efficiency (VE) falls off below 4500 rpm.

On your V8 engine where the drive ratio is around 2:1 you may have noticed full boost didn't occur till after 2000 engine rpm. Correct me if I am wrong.
You will need a 1.1 drive ratio for around 6 psi of boost which means it will require over 4000 engine rpm to get full boost.
Below 4000 rpm the boost will be reduced significantly.

There is no need to go below an 8:1 compression ratio on the 200 six with low boost.

You reduce the Dynamic Compression Ratio (DCR) by closing the intake valve later by using a cam profile with a longer advertised duration.
The valve overlap period only affects the combustion process at low rpm but once the engine rpm increases into the power band it is the DCR that determines the tendency for detonation.

I would consider using a set of forged pistons from AutoTec so you can drive the blower faster (closer to a 1.5 drive ratio) to bring the boost in earlier and use a fairly large cam to reduce the DCR while optimizing the power at higher rpm.
Full boost pressure would be around 12 to 13 psi before 3000 rpm providing the carburetor is large enough to handle the airflow.
You would have a fair amount of boost at 2000 rpm in this case.
If need be the maximum boost can be limited by using a smaller carb than required or by throttle stopping a larger carb.

Will you be building this engine in Japan?
 
pmuller9":34ult93f said:
I believe the 250 2V head had 58cc combustion chambers.

Some things to consider.
The B&M 144 blower runs best between 5000 and 10K rotor rpm with an absolute max at 14K rpm.
The Volumetric Efficiency (VE) falls off below 4500 rpm.

On your V8 engine where the drive ratio is around 2:1 you may have noticed full boost didn't occur till after 2000 engine rpm. Correct me if I am wrong.
You will need a 1.1 drive ratio for around 6 psi of boost which means it will require over 4000 engine rpm to get full boost.
Below 4000 rpm the boost will be reduced significantly.

There is no need to go below an 8:1 compression ratio on the 200 six with low boost.

You reduce the Dynamic Compression Ratio (DCR) by closing the intake valve later by using a cam profile with a longer advertised duration.
The valve overlap period only affects the combustion process at low rpm but once the engine rpm increases into the power band it is the DCR that determines the tendency for detonation.

I would consider using a set of forged pistons from AutoTec so you can drive the blower faster (closer to a 1.5 drive ratio) to bring the boost in earlier and use a fairly large cam to reduce the DCR while optimizing the power at higher rpm.
Full boost pressure would be around 12 to 13 psi before 3000 rpm providing the carburetor is large enough to handle the airflow.
You would have a fair amount of boost at 2000 rpm in this case.
If need be the maximum boost can be limited by using a smaller carb than required or by throttle stopping a larger carb.

Will you be building this engine in Japan?
Click to expand...

Yes the engine will be built in Japan, I saw the forged autotec pistons mentioned before while searching this forum and I browsed their site. Are these custom ordered pistons? Do you have any idea how much they run? I understand that the boost really falls off on this blower around 4500rpm but in the case of my 351 it has a lot more volume to feed. When calculating the boost that would be made on my 200 the compression ratios get out of hand quickly with small blower pulley changes. I made this calculation table ill link below to determine boost and the effect on my DCR. I'm still just planning now, I really appreciate your insight. I don't want the blower to be JUST eye candy but I am not concerned about squeezing every ounce of power out of it.

I just want to reliably run the blower with a bit of extra power, repairs (read shipping) is cost prohibitive for me to go through several builds finding what and does not work. I want to error on the side of safe.

Ideally I would like to run a Fitech or Holley throttle body style fuel injection system.

Here is the boost calculation
https://docs.google.com/spreadsheets/d/ ... sp=sharing
 
' Always interested in Forced Induction projects for small block six, any specific reasons for building a 200 cid vs a 250 cid small block six for the SC ?.

thanx
 
The Autotec pistons are custom order. They are forged 4032 alloy aluminum.
They run about $550 for a set of 6 dish pistons.

The Weiand formula gets you close for a good starting place but it doesn't account for different engine Volumetric Efficiencies.
It also doesn't take into account that the supercharger's VE increases with RPM.

The B&M 144 starts with a very low VE at low rpm and doesn't produce the expected boost till close to 5000 rotor rpm.
When working on the 351 it was running twice the engine rpm so target boost was reached around 2500 engine rpm.

If you drop the drive ratio down to 1.2 for the 200 six you may see very little boost at 2000 rpm and will have to wait till after 4000 engine rpm to get your target boost.

Just in case you are thinking that the reduction in drive ratio should still make boost everywhere because you are putting the 144 blower on a smaller engine. Example:
Say both the 351 engine and the 144 blower have the same 80% VE at 2500 rpm and the drive ratio is 2:1
(144 x 2) x 80% divided by (351/2) x 80% x 14.7 -14.7 = 9.42 psi boost.

Now take a 200 six with the 250 2v head, big cam having a 93% VE with a 1.2 drive ratio and the 144 blower at the same 80% VE at 5000 engine rpm.
(144 x 1.2) x 80% divided by (200/2) x 93% x 14.7 - 14.7 = 7.15 psi boost

If you drop the engine rpm to 2000 rpm and the 144 blower's VE drops to 60% the boost drops to 1.68 psi.
At this rpm the 200 six is also being affected by the camshaft overlap period.

What I'm saying is that the B&M 144 is TOO big for a 200 six.
An Eaton M90 would be a much better match where the drive ratio can be kept near 2:1
 
Concerning the spreadsheet calculations for FINAL COMPRESSION RATIO.
It is calculating the effective static compression ratio but the detonation threshold for a specific engine is more of a function of the Dynamic Compression Ratio.

Generally the Ford 300 six operates naturally aspirated with a Dynamic Compression Ratio (DCR) between 7.0 and 7.5 using pump gas with an octane rating between 87 and 93.
The 200 six having a smaller bore diameter can run with a DCR 1/2 point higher between 7.5 and 8.0 with an iron head.
An aluminum head will let you use a higher DCR.

If you have a 200 six with an 8:1 Static Compression Ratio (SCR) and a camshaft profile that closes the intake valve 65 degrees ABDC, the DCR will be 6.5
If you add 7 psi of boost the effective DCR will be 9.6 as far as cylinder pressure is concerned however this doesn't equate to the detonation threshold.
In a boosted engine detonation is controlled by a richer fuel mixture, ignition timing retard, intercooling, ect. so it doesn't compare to the engine when running naturally aspirated.

You will find that the 200 will run with an 8.5 SCR with a moderate size cam and 7 lbs of boost from a roots type supercharger.
If you want additional margin you can go as low as 8.0 just to feel safe and not require as much ignition timing retard.
 
I run a Maverick 250 with a centrifugal supercharger in Blow-Thru Carb config', been reliable for @ 2 yrs (2K m ?) . Working on boost vs RPM curves with pulley 'gearing' and pressure relief 'Blow Off' valve. Has stock pistons, cam, ARP head bolts, 302 springs 2X1 adapter and Holley 2300 . AFR's are good through RPM range. Ignition is advance limited. Un-milled OEM iron head with typical @ 62cc chambers yield SCR @ 8:1.

Runs with no faults with boost up to @ 5-8 lbs. Higher boost significantly increases detonation and blow-by concerns. At @ 3.5 K RPM can easily pass 10 Lbs with current SC ratio's and often does...

.

..


Previous stock 250 in the Mav' had a Draw-thru Turbo and ran well until @ 15-20 lbs boost when severe oil mist and loss of power proved to be cracked off Piston ring lands . 'Recently acquired a set of Forged pistons for 200 or 250 and working up a stage II - Forced Induction build so I watch SC posts intently..

2020 BUILD - HEADS AND COMP. RATIO’S TYPICAL:

200 -- 250

BORE -- 3.68”

STROKE 3.126’ -- 3.910”

DECK HEIGHT @ .019” -- @ .120”

DOME @ 7cc’s @ 7 cc’s

---------------------------------------------------------------------------------------------------

SCRS WITH 54 cc COMPRESSION CHAMBERS & .045 GSKT:

200 -- 250

@ 8.54 : 1 -- @ 8.58:1


W/ 62 cc CHAMBERS:

@7.81 : 1 -- @ 7.97 : 1


haev fun

' fooled around with Eaton M62 SC but never got it past concepts..
 
pmuller9":1eifwuoh said:
The Autotec pistons are custom order. They are forged 4032 alloy aluminum.
They run about $550 for a set of 6 dish pistons.

The Weiand formula gets you close for a good starting place but it doesn't account for different engine Volumetric Efficiencies.
It also doesn't take into account that the supercharger's VE increases with RPM.

The B&M 144 starts with a very low VE at low rpm and doesn't produce the expected boost till close to 5000 rotor rpm.
When working on the 351 it was running twice the engine rpm so target boost was reached around 2500 engine rpm.

If you drop the drive ratio down to 1.2 for the 200 six you may see very little boost at 2000 rpm and will have to wait till after 4000 engine rpm to get your target boost.

Just in case you are thinking that the reduction in drive ratio should still make boost everywhere because you are putting the 144 blower on a smaller engine. Example:
Say both the 351 engine and the 144 blower have the same 80% VE at 2500 rpm and the drive ratio is 2:1
(144 x 2) x 80% divided by (351/2) x 80% x 14.7 -14.7 = 9.42 psi boost.

Now take a 200 six with the 250 2v head, big cam having a 93% VE with a 1.2 drive ratio and the 144 blower at the same 80% VE at 5000 engine rpm.
(144 x 1.2) x 80% divided by (200/2) x 93% x 14.7 - 14.7 = 7.15 psi boost

If you drop the engine rpm to 2000 rpm and the 144 blower's VE drops to 60% the boost drops to 1.68 psi.
At this rpm the 200 six is also being affected by the camshaft overlap period.

What I'm saying is that the B&M 144 is TOO big for a 200 six.
An Eaton M90 would be a much better match where the drive ratio can be kept near 2:1
Click to expand...


I haven't given up on this but it just took me several months for me to finally comprehend what you had said here. I've been looking at this chart

archive/www.classicinlines.com/200Z.html

That explains the dynamic compression ratios of various cam and chamber combos. But for the 200 side of the chart it mentions that it is for a zero decked head. A zero decked head would give more compression so I'm wondering how much dynamic compression a truly stock 200 has.

Im also unsure of the chamber size on my C6 heads although elsewhere on the site a see that this year had 51-53cc chambers.

Ive given up on the 144 due to efficiency problems when under driven and I'm in the process of finding an m90 (not easy in Japan). I've also found a guy who makes custom pulleys for the m90 so i will be able to drive it at whatever speed.

However if you look back at the tables for the M90
https://docs.google.com/spreadsheets/d/ ... edit#gid=0

Even with a dynamic compression ratio of 7.74 or 7.03 and only 5 pounds of boost its bumping up the final compression pretty high. I see guys running more boost than this so I'm wondering why the math seems to put me in the danger zone.

Also I just bought a house so I think the Ozzy head is out of the picture, I probably going to have my log milled off of my spare head in the next month or two and start mocking things up for a custom intake.

If any of you have some new advice regarding the change in project direction I would be happy to try and digest it.

Thanks again for the lesson Pmuller9
 
kjacobson351":mpv1dea4 said:
Even with a dynamic compression ratio of 7.74 or 7.03 and only 5 pounds of boost its bumping up the final compression pretty high. I see guys running more boost than this so I'm wondering why the math seems to put me in the danger zone
Click to expand...
See post #9
 
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