Tech new Flathead Manifold/Dizzy and crankcase ventilation.

[Mr 42]

I will be traveling all next week, so i have to start to early,Sorry about that ;-)


http://w1.136.telia.com/~u13603243/techweek42/techweek42(1).jpg
I had laid my hands on a Thickstun two carb intake. And a couple of Stromberg carbs. To start with I had to change the original dizzy since it not works together with Stromberg carbs. But this is what I started with



http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(2).jpg
First I found the TDC, its quite easy on The 8BA if its running. First align the pointer to the mark on the pulley.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(3).jpg
Then remove the cap from the distributor, and the rotor should point at the number one post. If not turn the engine another revolution. And it should line up.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(4).jpg
Out with the old and in with the new.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(5).jpg
I got a new MSD Dizzy since I wanted the vacuum functionality. Otherwise a Mallory works ok.First I had to put on and adapter provided, so the mounting height could be defined.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(6).jpg
Then I tried it in the engine and found the right height, end then I only had to tighten the screw, all this is explained in the manual.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(7).jpg
Mounted the gear and put some grease on it.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(8).jpg
After that I mounted the dizzy in the engine, since I haven't turned the engine over the place where the rotor points is the number one post.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(9).jpg
Connect the ignition wires starting with number one (in the right position) and you are done.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(10).jpg
It started up great and I drove it some time, with the vacuum connected to the manifold, I got a ruff idle. And after reading the instruction it said that the vacuum should be connected to an vacuum source above the throttle plate! So that had to be taken care of. After studying my Stromberg carbs, I found these two plugged holes (probably used when drilling holes for the adjustment present on the other side.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(11).jpg
The plugs was removed easily with a pliers and some minor violence.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(12).jpg
Here you can see that the holes are above the throttle plates

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(13).jpg
Then I had to enlarge the holes slightly by drilling, and I used some 6mm copper brake lines.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(14).jpg
I used silver soldering to connect everything (it's a low heat soldering method, hope I got the English words right here).

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(15).jpg
After that it was time to figure out the crankcase ventilation. Mocked up the intake on an spare 8BA I had standing around.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(16).jpg
I capped of the original steel tube that is connected to the road draft tube.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(17).jpg
After some eyeballing I drilled and tapped a hole for a pipe fitting.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(18).jpg
Silver soldered an 8mm copper fuel line to the brass fitting

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(19).jpg
here you can see how the type slip into the steel tube, after id took this picture a made a slip fit steel tube that went over the 8mm copper pipe, so I would not get to much leaks.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(20).jpg
This is what it looks when ready, I put the steel tube into the engine, and the just let the copper pipe slip into it when mounting the manifold.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(21).jpg
Maybe not the best picture, but number one connects to number 3, and number 2 connects to the vacuum wipers and the rubber tube from the carb connects to the vacuum on the distributor.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(26).jpg
Since the hole in the pipe fitting was around 5mm I solder it up and drilled a 1,5 mm hole. After checking the size on my Volvo crankcase ventilation, I guessed to big hole could get the engine to running roughly (and I was right sort off)

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(24).jpg
Then it was time for the Fuel pump, did not bolt on!

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(23).jpg
The lower fuel pump rod id for a 59AB (to thin) The upper is an 8BA rod to long!

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(25).jpg
Had to shorten it around 16mm you have to measure on your own setup to get it right. But unit was quite easy since íts a steel tip sitting it the tube.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(27).jpg
Looking better don't it :-)

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(28).jpg
After i had been driving it for some time I couldn't get the idle right it was bit rough, so I converted the front carb. And used that one as vacuum source for the crankcase ventilation. And i have driven it around 700 miles, and the oil keeps clean and fresh, actually better then with the original setup. The only drawback is that I get some minor smoke at the fuel pump when idling, since the vacuum is not on then.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(29).jpg
Hope ive given you some ideas. Regarding the carbs I ended up with the original size jets 035 in Stromberg 81's. And since my 8BA is original I only got more grunt at 55 mph and above . But I did not loose anything on the mileage (1.3 liter per 100km , figure that one out all you mpg guy's ;-))

[Flat Ernie]

Very cool! However, your mileage figures don't add up for me http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

1.3l = .3434237 US Gallons
100km = 62.13712 Statute Miles

62.13712 / .3434237 = 180.93428 mpg!

I thought maybe I had misplaced a decimal, but I think it was you - you sure that's not 10 km ? Because that would make sense at 18mpg!!

Someone please check my conversion & math!

1 gal = 3.785412 ltr or 1 ltr = 0.2641721
1 mi = 1.609344 km or 1 km = 0.6213712

http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[Mr 42]

you are 100% Right my mistake
1,3 liter per 10km

or as we say 1.3 liter milen.
one mil= 10km

[adzslick]

F*cking Brilliant tech, But my one criticism, i would avoid using copper as a fuel line, it tends to work harden which can be quite dangerous when it splits...... that said, sweet install

[Mr 42]

I agree about the copper as fuel line, and in this application only air is traveling in it.

On another note copper fuel lines are ok if clamped proprtly, to prevent vibrations. Remember its the vibration not the copper as such that is the problem.
I have had steel fuel lines rust on me, and starting to leak.

Clamping is the reason you should not use it in the engine room, you cant clamp it properly.
But clamped every 5" to the frame is ok, in my book.

Thanks for the nice words....

[Flat Ernie]

I think we've visited the copper line issue in the past & come to the conclusion that copper tubing produced in Europe contains a much higher nickel (?) content than that produced in the states and is less prone to work hardening/cracking.

It's legal to use on brake lines over here & several folks have run 'em for years like that. Still freaks me out, but I've heard that even Volvo uses copper in the brake lines as OEM!

That said, it still must be properly supported & given a few good coils to absorb the little vibration over a larger area...

http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[adzslick]

Mr42, i didnt realise that they were air lines, the limited time ive been playing with engines ive only worked on VW's (coz im a poor 17yrold), and lets not go there on this topic, glad you could clarify that for me though.

cheers
Adam


Ps, its not even tech week and it fucking rocks!

[Mr 42]

No problem Adam
You are 17 and know about the copper line problem. I didn't do that at your age. So you are ahead.


Regarding the Volvo brakelines i think its steel lines with copper content to prevent rust. Not pure copper tubes.

And keep a low profile on the vw talk here http://www.jalopyjournal.com/ubbthreads/images/graemlins/crazy.gif
I only have three of them myself, but i dont dare to ventilate it here with all hardcore rodders http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[Digger_Dave]

Mr 42, excellent piece of TECH! The only thing I'm wondering about is; did you use a PCV valve? (the subject of PCV's can be found in the TECH-O-Matic section here on the HAMB)

Now, seeing as how Ryan declared NEXT week as a TECH week; I think you should repost it on Monday!!

EDIT: Opps .. just reread your first line! I think everyone will understand.

Ernie; now you have me REALLY confused! http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[Flat Ernie]

[ QUOTE ]
Ernie; now you have me REALLY confused!

[/ QUOTE ]

Dave, it's really simple to figure mpg - just fill up your tank, keep track of how many miles you drive, fill it up again & note the gallons. Then divide your miles by your gallons & Bob's your uncle!

Sorry, couldn't resist! http://www.jalopyjournal.com/ubbthreads/images/graemlins/wink.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

(I assume you mean the copper line bit, eh?) http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[Mr 42]

I dont use a PCV valve.
1: I dont understand exactly how they work.

2: And most important Volvo engines dont have PCV valves (im a Swede)and Flatheads dont use a PCV valve, it uses the roaddraft tube/Ventilator.
The only thing they have is a sortoff steelfilter put in to prevent backfires to go into the engine i guess.

The Volvo engines have a small hole (around 1.5mm)for thr vacuum source.

And if i understand it right the PCV valve has a much bigger hole.

And my solution have two 2 mm holes into the carb one at each barrel.

Finaly it works for me..

[SnoDawg]

Damn That looks sharp if you will pardon the pun I am glad it is not another Saab story...

[Digger_Dave]

[ QUOTE ]
I dont use a PCV valve.
1: I dont understand exactly how they work.

2: And most important Flatheads dont use a PCV valve, it uses the roaddraft tube/Ventilator.

[/ QUOTE ]

Mr 42, I'm a 50 year fan of flatheads. When Ford designed the "road draft" method of ventilating the cankcase it turned out to NOT be one of their "BEST IDEAS."

PCV valves (Positive Crankcase Ventilation) was introduced after the flathead went out of production.

I mentioned the TECH-O-matic piece on "PCV's for Flatheads" in case you wanted to study how several flathead lovers have incorporated them to their engines simply because no PCV valve showed up in any of your pictures.

Check here .. The Jalopy Journal: Flathead PCV:

[ QUOTE ]
The only thing they have is a sortoff steelfilter put in to prevent backfires to go into the engine i guess.

The Volvo engines have a small hole (around 1.5mm)for thr vacuum source.

And if i understand it right the PCV valve has a much bigger hole.

And my solution have two 2 mm holes into the carb one at each barrel.

Finaly it works for me..

[/ QUOTE ]

My question was not meant to be critical of your solution. As a flathead lover, I was just wondering.

[Mr 42]

Dave i think you have missunderstood my solution.
I have PCV = Positive Crankcase ventilation

I just dont use a PCV Valve.
The valve as such don't do anything (its the manifold vacuum), other then maybe preventing backfires to go into the crankcase (but as i said i dont understand the theory behind the valve as such. Maybe someone can enlighten us).

And thousands of Volvo's Saab's Audi's cars dont have the Valve either.
Sorry that i dont have to much knowledge about American iron except some SBC junk iv worked on (they have the PCV Valve).

But all uses manifold vacuum to get crankcase fumes out of the engine. And so do i now , no more roaddraft

And the main reason for having PCV (positive crankcase ventilation) is to burn unburnt fuel (i dont now the english word for the gases), and contribute to a cleaner environment. PCV was the big aircleanup step before the CAT. Then you get a cleaner engine to as a side effect.

[Digger_Dave]

[ QUOTE ]
Dave i think you have missunderstood my solution.
I have PCV = Positive Crankcase ventilation

I just dont use a PCV Valve.
The valve as such don't do anything (its the manifold vacuum), other then maybe preventing backfires to go into the crankcase (but as i said i dont understand the theory behind the valve as such. Maybe someone can enlighten us).

[/ QUOTE ]

I guess my suggestion of taking a look at some ALTERNATE methods doesn't interest you.
I know how PCV valves work.

[Kevin Lee]

I know how a PCV valve works and I know why it's good to have positive crankcase ventillation - but since Mr 42 mentioned it makes me curious too. What's the advantage of the actual valve if it is pretty much open from the time you start the motor? Meaning, why not just ditch the valve and run it fully open - just like the under the manifold setup in the techomatic minus the valve?

[metalshapes]

I'm just guessing, but could it be that if you switch a Engine with a large intake volume between the Carb and intake valves off, there are a lot of fumes to flow into the crankcase, and over time dilute the Engine Oil?
Cause the PVC Valve closes when the Engine is off, right?

[Mr 42]

I Have read all post's about PCV Valves over the years on multiple boards. Even Fourdys at the hamb (that i think is the latest) and i have even replied to it is that good enough??

And i still cant figure out why you need the valve as such.
I have taken PCV Valves apart and its a spring loaded valve.
And as far as i understand it it dont need much vacuum to open. Making it work more or less as my application, excuse me for my ignorance.

Since some of you have stated that they now how the PCV valve work, could you please share that knowledge with me?(us)

The reason i have chosen to not mount my stuff under the manifold is that i dont like to have rubber hoses running inside the engine, and maybe break and clogg the oilpump some year down tha road. And when i connected it to a vaccum source on the Thickstun manifiold i got a bad idle. so thats the reason i used the carb as a vacuum source.

And i cant see what a PCV Valve could have done to help that since at idle you have a high vacuum situation, so the valve should be open then to and add extra "air" into the manifold.

Nice talking to all off you http://www.jalopyjournal.com/ubbthreads/images/graemlins/wink.gif

[Digger_Dave]

A NEW thread has been started with a DETAILED explanation of how PCV Valves work.

Without the valve, the OPEN port from the intake manifold to the crankcase is the same as having a VERY LARGE Vacumme LEAK!

THAT makes it difficult to get a proper balance on multi carb (and single carb) setups, AS WELL as NOT allowing the distributor ADVANCE to operate to it's full range.

The PCV valve controls the flow of the vacumme to situations (see other thread) that don't upset air/fuel mixtures and the "vac signal" to the distributor.

As far as the "kind of hose" vs. copper line, doesn't have any bearing on the operation of a PVC valve. There are lots of "hard service" types of hose that can be used without any fear of them "gumming up the works." (mine uses stainless braided aircraft hose)

[Mr 42]

Hi Dave

Why are you shouting?

1: I dont have a connection to from the crankcase to the manifold! I use the vacuum source above the throttleplate.

2: That makes it easy to balance the carbs

3: Regarding the vacuum signal to the distributor, it say's in the MSD instruction that the vacuum source should be above the throttle plate (i have that). Shouldn't i trust MSD??
And the advance works fully for me, i have checked ;-)

4: Stainless braided hose should work Ok, in my book to. its the rubber parts i don want to have inside my engine


And finaly Dave, if it makes you feel better i plan to get a PCV Valve and connect it to Manifold vaccum, to see if i can get it to work better then my current solution works. Not that i think i have a big problem with the Current solution. http://www.jalopyjournal.com/ubbthreads/images/graemlins/smirk.gif

[Digger_Dave]

[ QUOTE ]
1: I dont have a connection to from the crankcase to the manifold! I use the vacuum source above the throttleplate.

Regarding the vacuum signal to the distributor, it say's in the MSD instruction that the vacuum source should be above the throttle plate (i have that). Shouldn't i trust MSD??
And the advance works fully for me, i have checked ;-)

Not that i think i have a big problem with the Current solution. http://www.jalopyjournal.com/ubbthreads/images/graemlins/smirk.gif

[/ QUOTE ]

If BOTH (crankcase ventilation and advance) are hooked "above the throttle plate(s)" there is No way your getting full advance.

But, hey, what do I know?

[Mr 42]

yes i get full advance, since the vacuum is taken from two separate carbs (sources).

Rear carb takes care of the dizzy, front carb crankcase
ventilation

If it was from the same source (point), it would affect the vaccum signal.

Maybe you should reread my post?

Anyone else have any questions /opinion's?

[Digger_Dave]

[ QUOTE ]
yes i get full advance, since the vacuum is taken from two separate carbs (sources).

Rear carb takes care of the dizzy, front carb crankcase
ventilation

If it was from the same source (point), it would affect the vaccum signal.

[/ QUOTE ]

One engine, common plennum manifold, two carbs = 1/2 vac signal at each carb. The connections are still drawing from one source.

[Mr 42]

Hi Dave

You are logical, but dont all engines get tha vacuun from one source? The pumping of the pistons?

If PCV and Distributor vacuum was connected thru a T connection im sure we would see your problem description.
But now its not.

And could you explain to me how i should connect it so it would work, remember i dont have a BIG hole for my PCV function im using the small hole compromise. As explained in PCV 101 posting.

And if you look att this picture the "white" line to the left of the pointer is the mark where the original distributor advanced the enging at low rpm (idle). And my setup advances it a bit farther, and it goes to the same position regardless if i have my PCV Connected or if i take the vacuum from manifold or above throttleplate, trust me ive tried both.

http://w1.136.telia.com/~u13603243/techweek42/techweek42%20(2).jpg



Dave im not saying my solution is the best in the world, but i think i have explained why and how it works(with some help from others,Thanks everone).

I will definetly try the Valve route, but the valves i have tried so far have not worked, probably because of the size of the hole in them.

So lets agree to disagree.

[tunglegubbin]

Which brings us to the next class, vacuum sources.

There is ported vacuum which is connected above the throttle plates, and is used for distributor timing control.

And then there is manifold vacuum, below the throttle plates and used for everything else e.g. power brakes, wipers, CRANKCASE VENTILATION etc.

The vacuum signal strength at various speeds, loads, throttle positions, are very different so they should be used appropriately.

And if you have the crankcase ventilation, with your orifice, connected to manifold vacuum, you should reset your idle mixture, this air is leaning out your mixture.
How much? Depends on vacuum strength, orifice size, blow by volume... you get the picture.

[Ryan]

Awesome post.

[Rocket Scientist Chris]

[ QUOTE ]
There is ported vacuum which is connected above the throttle plates, and is used for distributor timing control.


[/ QUOTE ]

I think this is the basis for some of the misunderstandings, here. The Ford flathead and early Y-blocks used a calibrated vacuum source to actuate the advance mechanism in the distributor. I guess that's were the "Load-O-matic" term was coined. http://www.jalopyjournal.com/ubbthreads/images/graemlins/smile.gif After 1956, Ford went with the now traditional dual advance distributor with both vacuum and mechanical advance systems. These can easily be run off manifold vacuum sources.
There's really nothing wrong with Mr. 42's PCV system design. It pretty much follows the original fixed orfice designs that were forced upon California residents as retro-fit kits in the early sixties. I'm sure some of the problems associated with understanding how the carb needed to be re-adjusted contributed the negative publicity the new PCV systems received. Not to mention the fact that the installer of the new system actually had to read and understand the installation instructions! http://www.jalopyjournal.com/ubbthreads/images/graemlins/laugh.gif

[flatordead]

The PCV is also a safety thing. Since it is a one way valve it prevents the crankcase from carb backfire. If your engine is old and worn out and your oil has not been changed for years there is a pretty good mix of oil and gasoline in your pan that could explode when a carb backfire gets down in the crankcase.

[Armstrong]

I think that the misunderstanding is related to the size of the "controlled vacuum leak" that a PVC system creates. The PCV valve on US cars is to control the vacuum leak so the engine only uses it when required by the operating condition of the engine. The solution here on the flathead is to meter the size of the vacuum leak by using a small orifice and a ported vacuum source. The only problem I can see with the orificed system is the amount of flow is restricted in a situation where there may be large amounts of blow-by to contend with ,possibly resulting in escaping gases. Just my 2cents worth. The real proof is that it works!

[Digger_Dave]

[ QUOTE ]
So lets agree to disagree.

[/ QUOTE ]

Mr 42, first, let me apologize for being a bit of an "ass." Language differences (you speak a hell of a lot better English than I do Swedish!!) and the possible misinterprutations on both sides got the better of me.
Sorry.

Now, a couple of questions. Is the MSD distributor Part Number 8573?

I have been considering that paticular one for my latest project.

If yours is the above number, does it have the mechanical advance as well as the vacuum advance?

[Mr 42]

Apology accepted.
No Harm done :-)

Yes my Distributor is the 8573 Ready to run Flathead distributor.

And it has both Mechanical and Vacuum advance. The Vacuum advance was the reason i bought it. Since it saves gas at part throttle driving. There is three sets of spring's in the box so you can tune the mechanical advance curve.

And its fully electronic, i would have prefered breakers Im an old guy and breaker's you can get working out on the road most of the time. but you cant get a distributor with the vacuum can and breakers as far as i know.

So i will have my old 8BA dizzy in the back if i travel on long trips.

I just connected it and the engine fired up directly, did some minor adjustment and checking.

Anyway i was thinking i should have be flamed on the Hamb for mounting a Billet part on my Flathead http://www.jalopyjournal.com/ubbthreads/images/graemlins/smirk.gif

PS: Dont worry about the Swedish it only 9 million on the globe speaks it, its not worth learning http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

[Flat Ernie]

Great stuff! Us flathead guys gotta stick together, right?!

I've been considering the MSD unit for my next project as well - let us know how you like it.

I've always had good luck with Mallory Unilites in other engines, but I know they are plagued by burnt modules in generator equipped flatties. I have a theory that it's the mechanical voltage regulators causing spikes in the field, but it's just a theory at this point (of the 7 I know that have failed, all were running mechanical regulators - I know of 2 folks running Unilites for several trouble-free years & they're both running solid state regulators) & Mallory does sell a filter, but the Mallory advance curve needs a lot of work for a flatty.

How did that MSD advance work for you out of the box?

http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[Digger_Dave]

Mr 42, time for a little experiment. Because of your use of a combination mechanical and vaccum advance distributor and the fact that your crankcase ventilation could be easily BLOCKED OFF for this test.

Now, I would like to see IF the crankcase ventilation tubes were plugged; WOULD (and this has been the "root" of my "bull headedness") this cause a change in the vacuum advance?

In other words; would the vac adv on the dist. PULL MORE advance?

What do you think? Worth a try?

[Flatdog]

Ernie,my MSD dizzy did not come set up for flathead.The centrifacial advance was not done till 3,500, WAY too slow. You want all your advance by 2,000. , about 22 degrees will do you fine.Mine is a early unit with out VA I really like it .I also need big spark because of way I cut plug gap for valve clearance.Your plugs will never foul either.

[Digger_Dave]

[ QUOTE ]
Ernie,my MSD dizzy did not come set up for flathead.The centrifacial advance was not done till 3,500, WAY too slow. You want all your advance by 2,000. , about 22 degrees will do you fine.Mine is a early unit with out VA I really like it .I also need big spark because of way I cut plug gap for valve clearance.Your plugs will never foul either.

[/ QUOTE ]

Hey Flatdog, I seem to be following you all over the HAMB tonight! http://www.jalopyjournal.com/ubbthreads/images/graemlins/smile.gif

The model of MSD that Mr 42 is using (and I plan to use) comes with three pairs of centrifical advance springs. Did yours?

Reading the tech material from MSD, the rate of advance (mechanical) can be made to be "all in" at as little as 1800 RPM using the "softest" (weaker?) springs. Then with the vac advance it could pull the advance up to around (or as much as) 25 + deg.

[Mr 42]

Dave
I have done this test. But will do it with photes this time on Sunday OK :-)

[Flatdog]

Dave ,my setup include a vari-cruve unit that I can set up a addishinal timing cruve .I start backing off advance at 3,000 rpm 2 degrees every 1,000 rpm .When we orginally set it up the advance was sill climing when it should have been retarting.The mech advance was still coming in till 3500 .All I amy saying is to check it do not trust anything to be right. I run a lot more retart with the blower set up.

[Digger_Dave]

[ QUOTE ]
Dave ,my setup include a vari-cruve unit that I can set up a addishinal timing cruve .I start backing off advance at 3,000 rpm 2 degrees every 1,000 rpm

... I run a lot more retart with the blower set up.

[/ QUOTE ]

Oh Ho.. a blown flathead guy to "tap" for some information. (experience)

On the engine (C8BA) that I ran in my '41 with a SCoT blower; I started with a stock dizzy. (no good for me) Then went to a Chryco dist. modified to fit and had Jacobs electronic ignition inside.

In addition to the electronic ignition, I had/have a Jacobs "Boost Control" that allows for a variable rate of advance as well as retard when the boost sensor (at the base of the blower) sensed that "retard was needed."

I never was able to get the exact combination (advance - retard) but the "Boost Control" had a knob that allowed "fine tunning" when on the fly.

What distributor are you using?

[Elrod]

Great post!!

I'm suprised you are running those 81s on that 8BA. I'm also freaking out that you drilled those base plates. You know that 81s sell for 3 times what 97s sell for, don't you? And the reason people seak out those rare 81s is for the smaller venturis that you drilled out! hahahaha! That's hot rodding!

[Flat Ernie]

This needs to be in Tech-O-Matic - appended to the Flathead 101 stuff!

http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[Mr 42]

Funny thing Elrod the 81's are more common in my neck off the woods. Since they came on the 60hpr engine, and i guess they sold us a lot of them before WW2.
And since my 8Ba is more or less original two 81's work ok

And i havent drilled any hole that wasnt there from the start, i just removed two plugs on each carb that was there from the begining.

Anyway i have done some testing today , and to my dispare i found out that my above vaccum throttle source does not work for the distributor vacuum :-( Need to do some more investigation here since im pretty sure it worked on day one?!

The PCV thing seams to move enough air to work, but i think i must have a rethink here to.

Sorry about that boys, i had no intention to spread any faulty information.

So now i have to figure out how to get an above throttle plate that gives enough vacuum. Or i need some sort of valve that open when i press the throttle.

I did not have the right things to verify the if there is enough vacuum both for dizzy and PCV function straight from the manifold. But I will give i a try later and let you know...

[Flat Ernie]

Mr42 - gut reaction tells me you should only take your vacuum advance from above the throttle (ported vacuum) & only take your PCV vacuum from below the throttle (manifold vacuum).

http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[Mr 42]

Hi Ernie
I think you have a point.
I woke up at one a clock this night, and i think i figured it out. And i had to go up and check out three of my Simca Vedette Stromberg 81's carbs and all of them have an Vacuum source for a distributor, so i guess i have to fix one of those.
I will post pictures of what im talking about later tonight.

anyway here is a picture explaining why my setup doesn't work good.

[klazurfer]

Maybe one of these could be of help ?

[Mr 42]

Not really since i have the manifold vacuum sources on the manifold. I have to connect my PCV to the manifold and try to find a good PCV valve or tune my old type with a small hole ( i get a rough idle with the curren hole i tried). But this is not the big problem since the PCVs eams to work with the setup i am using now.
The thing i need is a carb with a above throttle vacuum source. And there is actually one Stromberg that have that (that i know about). Its the Simca Vedette Stromberg 81, see the picture.




Now i only have to renovate the iron cast part for my 42.

[Digger_Dave]

42, at this point, it sounds like a vac source for the distributor is the first step to solving this problem.

In your drawing, you show the ports your using for advance (the ones you removed) as possibly not being in the right location.

Can you look down the barrels and see if the ports are above, or below the throttle blades when they are closed? (idle)

If they are above, then they should work for advance. But I can't say for sure that being on the "up side" of the blade (when it opens) could cause a different effect.

How about a vacuum gauge hooked to the distributor ports to see if the "signal" is being modified being on the opposite side of the venturi?

I'm just "shooting in the dark" here. I have never run into this problem before. All the early carbs that I have used, always had an "above throttle blades" port for distributor advance.