Boring a flathead

[Tim Ayers]

Originally Posted by Ol' Ron

PS use a 52-3 block

Ron:

Curious why you suggest using a '52-'53 block? I thought I read somewhere the metal/material used in these blocks wasn't as good as previous blocks.

Is that yet just another flathead myth? If not, I'm glad I have a primo standard bore '53 block then.

Tim

[Tim Ayers]

Originally Posted by HotRodmicky

Winfield cams??? They are only good for four bangers....

I follow Petes school of Flathead cams ...... Winfield are lame cams

Read Pete statements on the HAMB about cams.




BTW I love this thread!!!!!!!!!

Can't say I agree with you. Some of the fastest drag engines ran/run Winfield's SU-1A.

Just because a cam is "wild" doesn't mean it's good. Take some time to really think about the theory and timing of some of the cams that are out there.

Winfield was a genius and knew what he was doing.

Always remember this: Opinions about flathead cams can be like dirty socks. We all have them and some stink worse than others.

[Ol' Ron]

I like the late blocks because they don't have any hardened valve seats and you can do wonders with the valve pockets.

Yes Winfield was a genius, I think he was responsible for the nOVu 183 ci and 700 hp on 3 main bearings.All this in 1939. However if I were to go racing, I can't think of a Winfield cam I would use .

[Tim Ayers]

Ah, got it. So, for street, don't use this block for it would needs atleast exhaust seats. But for a block to modify the valve train & ports, it would be a good candidate.

[Ol' Ron]

Yes, the late 49 to early 51 blocks usually come with hardened seats in the exhaust and a 1.72 chevy valve can be used in the intake. Keep the 1.5 in the exhause. This is about max for a street engine. I would even undercut the valve and maybe use a 30 deg seat. Back in the 50's we used De Sota and Chrysler valves. Often wondered how well they worked.??

[Henry Floored]

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I think the center main bearing cap on those Novi V8's was water cooled. That's how they made that center main live I think. I wonder why that was a 3 main brg engine in the first place? Is it possible that even the mighty Novi has roots in the Flathead Ford? The OHC Riley V8 used in Argentinian road races was rooted in the Flathead Ford.

[Tim Ayers]

Originally Posted by Henry Floored

I think the center main bearing cap on those Novi V8's was water cooled. That's how they made that center main live I think. I wonder why that was a 3 main brg engine in the first place? Is it possible that even the mighty Novi has roots in the Flathead Ford? The OHC Riley V8 used in Argentinian road races was rooted in the Flathead Ford.

Harry:

If you havent yet, I think you'd enjoy reading this book.
The Golden Age of the American Racing by Griffith Borgeson


It is an incredible look back at the racing technology and the men who engineered, built and raced this stuff from the 1900's until the late '30's.

According to Borgeson's research, one reason the Novi still only had 3 bearings is the level of the U.S.'s machining and casting skills were so poor when compared to Europes, these early pioneers made a lot of consessions were taking this into account.

It wasn't until after WWI did America start to be considered the leader in maching and casting techniques.

Also, you kind of get the impression a lot these guys were stuck in there ways. If 3 bearings on a hopped-up Model T engine held together, no reason it would work for the Novi. Also, if I remember correctly, Winfield was the main engineer for this motor. He was considered the King of the Model T & A.

Important to note as well, Bugati and Alfa-Romeo already had in production their own OHV 4 cly. hemis prior to WWI. European cars were the ones to beat.

I'm leaving a lot out, but the book is just incredible. I believe their is a picture of Miller hand filing the prop. for one of this superchargers.

Plus, the stories regarding what the drivers went through is simply awe inspiring.

[Bruce Lancaster]

The Novi shared at least its bellhousing flange pattern with Ford, not because of any engineering connection but because the engine was first used with elderly chassis parts from the 1935 Ford Millers, or so I have been told.
Engine swap, anyone??

[Bruce Lancaster]

Let's get away from Indianapolis and roll back to flatheads...we have some serious experts spilling beans here, and we don't want to get in the way!!
Maybe the best thread yet on the new Barn??

[Tim Ayers]

Leaving it to the educator to get the kids back into line...

[Tim Ayers]

OK, let's get back to it.

Ol' Ron: You have tried hogging out the end exhaust ports (I know others as well) and made inserts to go in there place.

Did you ever get to flow test these designs? Did removing that much of the casting weaken the block at all?

[Kahuna]

There has always been great discussion/arguement re the exhaust ports on a flathead. Are they restrictive? Do center dividers work? Etc. Here's my opinion: On End Exhaust Ports, the best fix is to relocate them to the very end of the block to straighten the path (a lot of work, welding, etc). The Center Ports, while not being restrictive in a mild engine, can be improved greatly with dividers. The trick is getting the right dividers in the right place. Once this is done, one of the center ports will actually draw a vacuum on the adjacent one, kinda like a header does. This means that an engine with anything more than a stock cam (overlap) will benefit. The bigger the cam, the bigger the benefit. Will it be a noticeable improvement? Doubt it, but it's another peice of the combination that is so important to the overall engine effort.

[Tim Ayers]

Originally Posted by Kahuna

There has always been great discussion/arguement re the exhaust ports on a flathead. Are they restrictive? Do center dividers work? Etc. Here's my opinion: On End Exhaust Ports, the best fix is to relocate them to the very end of the block to straighten the path (a lot of work, welding, etc). The Center Ports, while not being restrictive in a mild engine, can be improved greatly with dividers. The trick is getting the right dividers in the right place. Once this is done, one of the center ports will actually draw a vacuum on the adjacent one, kinda like a header does. This means that an engine with anything more than a stock cam (overlap) will benefit. The bigger the cam, the bigger the benefit. Will it be a noticeable improvement? Doubt it, but it's another peice of the combination that is so important to the overall engine effort.

Kahuna:

Great explanation and I agree about little things all being part of the bigger equation.

Would you happen to have any pictures? I know a lot of guys make center dividers out of sheet steel since the cast ones need to be whittled down so much to be of any use.

[Kahuna]

I'm sorry Tim, I don't. It's very difficult to explain. Look up 36tird on the Hamb and find his post on exhaust dividers. He's got a picture there that might be of help.
Jim

[Kahuna]

S/B 36tbird. Sorry, not enough coffee yet

[Tim Ayers]

Originally Posted by Kahuna

S/B 36tbird. Sorry, not enough coffee yet

Cool, will do. I know exactly what you are talking about. Just like to see all of the different ways of tackling the issue.

[Bruce Lancaster]

We have at least two schools of thought to look over:
Ron's book (MANDATORY READING) details his efforts to straighten that last bit of exhaust tunnel by shifting the end ports toward the ends of the block.
Flatdog ended up going with the stock routing, and drastically slanted the front and rear of each port to match the tunnel, slanted toward center of block, with headers made to follow that path before turning.
Both obviously require fully custom headers built for the individual engine.
Vergel posted excellent cutaway pictures of the exhaust system on the HAMB recently, showing the path to be more smoothly curved than seems possible from external observation.
It seems to me that the high level of power increase flatheads can show with a big blower exonerate the design of the exhaust passages...if they are the engine's choke point, big increases driven by the intake side would not be possible. The engine would simply choke on its own exhaust.
Ever see the heads from a highly developed high-pressure turbocharged SBC??
Exhaust valves are offset and increased in size to the absolute limit and X ports are hogged out almost beyond belief to allow the engine to accept really radical increases on the intake side.

[Tim Ayers]

Originally Posted by Bruce Lancaster

We have at least two schools of thought to look over:
Ron's book (MANDATORY READING) details his efforts to straighten that last bit of exhaust tunnel by shifting the end ports toward the ends of the block.
Flatdog ended up going with the stock routing, and drastically slanted the front and rear of each port to match the tunnel, slanted toward center of block, with headers made to follow that path before turning.
Both obviously require fully custom headers built for the individual engine.
Vergel posted excellent cutaway pictures of the exhaust system on the HAMB recently, showing the path to be more smoothly curved than seems possible from external observation.
It seems to me that the high level of power increase flatheads can show with a big blower exonerate the design of the exhaust passages...if they are the engine's choke point, big increases driven by the intake side would not be possible. The engine would simply choke on its own exhaust.
Ever see the heads from a highly developed high-pressure turbocharged SBC??
Exhaust valves are offset and increased in size to the absolute limit and X ports are hogged out almost beyond belief to allow the engine to accept really radical increases on the intake side.

Bruce:

I am currently doing it like Flatdog minus custom built headers. Maybe later on down the road.

I've ground a heck of a lot out of material out of those end ports to the point I'm worried how thin it got after taking out the "hump" casting flash & wire and what ever other crud was lurking around in there. I had to also open up the exhaust flanges on the my headers to extreme as well.

When I run my fingers in there it seems like it is certainly a much better path.

I am concerned that I may have increased the possible volume too much and therefore reduce the amount of back pressure. Not sure if this is even a problem, but I'm sticking with top of line 1.5 SBC hi-flow valves for both I & E and a Potvin 3/8ths cam (well- Potvin for know- On deck are also Clay Smith 272-2 & 284-2 cams, Crane 352-2 and/or Melling A-400 short track full race if the 3/8ths doesn't work out.)

I'm hoping the duration/overlap of all these cams (except the Crane which has more duration and lift on the exhaust side) will also help get some of that bad stuff out of those ports when needed.

[Vergil]

Here is one picture of the rear exhaust port. The block is not as thick as it looks in the picture because the cut was made close to the roof of the port. If wanted I can cut in the middle of the port to get an idea of the wall thickness. I still have the piece of block laying around here.

Vergil

[Tim Ayers]

Originally Posted by Vergil

Here is one picture of the rear exhaust port. The block is not as thick as it looks in the picture because the cut was made close to the roof of the port. If wanted I can cut in the middle of the port to get an idea of the wall thickness. I still have the piece of block laying around here.

Vergil

Vergil:

Thanks. I had this picture right along side my Mike Bishop porting article and my calipers to get an idea of how much more I can grind away. Just look at that dog leg jambing up an already crowded port.


I was amazed at how much casting wire was still in both sides of my end exhaust ports.



If you have the time and are willing to cut open a center exhaust port, I'd for one would love to see it. I have a feeling I may have gotten a little carried away with my grinder in these as well.

If I can get off my lazy behind, I'll try to snap some pictures of the porting on the block vs. a stock block.


Don't count on it, things seem to have a way of not getting done at my house.