The perfect "street engine"

[pistonbroke]

Ron, I'm trying to build the perfect street engine you speak of. Here is where I'm currently at in the process. 1953 low mile mercury . Cleaned and checked for cracks, board .030 , Three ring pistons ,Crank turned .010 .010 ,had hard seats cut in for the exhausts, running the stock Mercury cam ,stainless valves, Melling oil pump, new aluminum and steel timing gears . The distributor is a old dual point conversion I found ./ I ported the block but opted not to relieve it. I port matched the original Fenton headers to the block and plan on doing the same to the intake when I find one I like. Leaning towards a slingshot and a pair of 1 1/16" Holley's. I'm currently looking for a set of EAB heads and would like to hear more about this angle milling you have spoken of in past threads (what angle and how much) as aftermarket heads have reached the stratosphere in price. One question I have is, are hollow lifters that much better then solid adjustable ? Another one is are any of you running the modern front seal? I will follow this thread as far as it goes thanks guys , Tim

[BUBBAS IGNITION]

ron I have detroit 3-71 blower i would donate just for shipping

[Ol' Ron]

Wow!! That's a good offer Bubba, but ny building days are numbered. Never finish the projects I have started. The 3-71 should work well on a small engine but the intake would be rare.
Angle milling is just another way to remove material from the area that will do the most good. The late heads are limineted in how much you can mill them do to the thincasting near the water outlet. I only mill them about.070" but that's on a stock head. now dwpwnding on the type of milling machine you have determines how difficult this is. The shop near me has a "Brock" with a 12' wheel. Al I have to do is put a shim on one side of the amt I want removed and that's It. I use .060" washers and then a .010" clean up pass. The only thing you have to do is measure the an't of cam lift first. If you need to clearance for the valves, do that at a 4deg angle it will remove less material. Now raising the compression is the only reason we're doing all this and reliving the block is probably the least profitable mofification you can do. The reason they relieve blocks is: When casting an alumonum head they lower the trandfer area th increase the CR. noe relieving the block is supposed to cure that. Stock heads have a better combustion chamber tham most aftermarket heads.
Gramps.. Stop eating books and start reading them>
G

[Pete]

There are two PRIMARY reasons for relieving the block to maximum depth.
One is to shorten the fuel transfer path to the cylinder.
The other is to shorten the flame front travel.
The compression ratio is adjusted to the required value by adjusting the volume of the transfer area in the head. This works equally well on street engines as well as all out race engines.
A couple of NASCAR engine builders figured this out back in the 50's. They were probably the first ones to get over one hp. per cubic inch out of a flathead Ford engine.

[Ronnieroadster]

Adding to the thoughts on the The Perfect Street Engine I would look into a vacuum pump electric operated. Reducing crankcase pressures will increase output and at no cost in power grabbing when a good alternator is used to feed the needed voltage to run the pump.
Ronnieroadster

[40 Deluxe]

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Originally Posted by Ronnieroadster

Adding to the thoughts on the The Perfect Street Engine I would look into a vacuum pump electric operated. Reducing crankcase pressures will increase output and at no cost in power grabbing when a good alternator is used.
Ronnieroadster

Hmmm, I would expect that a BAD alternator would be the one that does not rob power! A "good" alternator is the one that robs engine power to generate electrical power. (No such thing as a free lunch!)

[Ol' Ron]

Pete, One horsepower per cubic inch from a flathead back in the 5's????? At one time back in the 80's I went thrugh the Bville pits looking for a relieved block, and nobody had one and a good way to shorten the flame front would be to put the spark plug in the transfer area where it belongs.;
Gramps Maybe alittle nitro??

[Pete]

Originally Posted by Ol' Ron

Pete, One horsepower per cubic inch from a flathead back in the 5's????? At one time back in the 80's I went thrugh the Bville pits looking for a relieved block, and nobody had one and a good way to shorten the flame front would be to put the spark plug in the transfer area where it belongs.;
Gramps Maybe alittle nitro??

In the early years of Bville I saw the inside top end of more flatheads than I can count, at record impound inspection. ALL were relieved, DEEP. There are a few of those guys still doing engines and they still practice DEEP relief.

By the way, it is just a matter of math which can be found all over the internet.
You have the car weight, frontal area, drag coefficient and speed, plug them in and get hp required.

Putting the plug in the transfer area will cause uncontrollable detonation in a race engine.

[Ol' Ron]

I agree with you on the early days when we all relieved our engines. I spen many hours doing so. However that was then and many of us had no idea what we were doing. Today is a different story,, we have more information. Some where the flow data I have somewhere puts the best transfer angle at around 12 degrees for better flow into the cylinder and that's aprox what the EAB head has. Why would putting the spark plug in the transfer area be a bad idea. That's where Grancore put theres. . now I could be wrong here, however, I have to consider all the information and put some of it to work on this engine. Crank assy is done and I'm working on the ports, and they are different?? Biggest problem is I can't get any compression. I wanted to use a wedge style piston (ALA 409)But couldn't afford it. Running out of time.\Gramps

[Pete]

Originally Posted by Ol' Ron

I agree with you on the early days when we all relieved our engines. I spen many hours doing so. However that was then and many of us had no idea what we were doing. Today is a different story,, we have more information. Some where the flow data I have somewhere puts the best transfer angle at around 12 degrees for better flow into the cylinder and that's aprox what the EAB head has. Why would putting the spark plug in the transfer area be a bad idea. That's where Grancore put theres. . now I could be wrong here, however, I have to consider all the information and put some of it to work on this engine. Crank assy is done and I'm working on the ports, and they are different?? Biggest problem is I can't get any compression. I wanted to use a wedge style piston (ALA 409)But couldn't afford it. Running out of time.\Gramps

Over the years I have followed what you said you put in various engines. If you make this one like the one you ran on the dirt track it should go plenty fast and last forever with modern parts.
Stick with what you know works and stay away from modern all out race stuff. Very few can afford that stuff anyway..

As far as plug location, go with data acquired by people that put millions into research on the subject. Plenty adaquate for street.
Harley Davidson and B&S. Look at hp figures for the KR and the B&S junior dragsters.

[Ol' Ron]

Good information Pete, unfortunately, some of my knowledge is pretty old, but I worked with JWL and we both moved our plugs to the center of the transfer area. He ran several tests with these heads, it in thebook. So I made a set as well, but havent had an engine to try them on. YET!!

[40 Deluxe]

Originally Posted by Pete

In the early years of Bville I saw the inside top end of more flatheads than I can count, at record impound inspection. ALL were relieved, DEEP. There are a few of those guys still doing engines and they still practice DEEP relief.

By the way, it is just a matter of math which can be found all over the internet.
You have the car weight, frontal area, drag coefficient and speed, plug them in and get hp required.

Putting the plug in the transfer area will cause uncontrollable detonation in a race engine.

Hey guys! Check out the October 2022 issue of Hot Rod, pictures on pages 71, 73 and 74. See a Bonneville flathead. All the latest tricks like tunnel ram manifold, .470" lift roller cam, 313 cu. in., etc. 249.4 HP. BUT, notice it is not relieved! I repeat, NO relief!
Also note: In spite of all the modern technology, it is not anywhere one HP per cube!

[tubman]

Like everything else, horsepower was a lot cheaper back in the day.

[Tim Ayers]

Originally Posted by 40 Deluxe

Hey guys! Check out the October 2022 issue of Hot Rod, pictures on pages 71, 73 and 74. See a Bonneville flathead. All the latest tricks like tunnel ram manifold, .470" lift roller cam, 313 cu. in., etc. 249.4 HP. BUT, notice it is not relieved! I repeat, NO relief!
Also note: In spite of all the modern technology, it is not anywhere one HP per cube!

When speaking to the few salt racers I know, they are more tight lipped than a frog’s behind. They don’t give away any secrets at all. I would be really surprised if this article revealed all their tricks. I could be wrong.

[28fordroadster]

Is the 8cm cam a good choice for this build?

[Pete]

Originally Posted by Tim Ayers

When speaking to the few salt racers I know, they are more tight lipped than a frog’s behind. They don’t give away any secrets at all. I would be really surprised if this article revealed all their tricks. I could be wrong.

It is not just salt racers that are tight lipped Tim.
Anyone that spends 40K for a race engine is sure not going to tell anyone what he spent it for.
I have never seen an article or a book on how to build an engine like the 777 had 3 of or what John Bradley, Whitey MacDonald, the Bean Bandits, Speedy Spiers or a dozen others had in their engines. All of those engines were naturally aspirated and got well over one hp per inch. There is a guy with a modern vintage style dragster right now that is getting well over 2 hp per inch from a blown FLATHEAD on fuel.
You sure are not going to see a parts list for that one.

The engine written up in HR is a healthy street engine at 249+ hp. There is another street flathead engine write up in the AERA magazine this month. These are good street engines but are not even in the same universe as a modern flathead all out race engine.

[Ol' Ron]

Not sure what the timing specs of this cam is. But I'd look for a cam with less than 220 duratin and .350 lift. This will keep the torque in the driving range, I used the EAB/EAC cams.
G

[40 Deluxe]

Originally Posted by Ol' Ron

Not sure what the timing specs of this cam is. But I'd look for a cam with less than 220 duratin and .350 lift. This will keep the torque in the driving range, I used the EAB/EAC cams.
G

Ron, the engine in Hot Rod has special oversize cam bearings to give .470" lift. Duration is given as 270/280 deg. at .050 lift. But compression is only 9.2 to 1.

[40 Deluxe]

Originally Posted by Pete

It is not just salt racers that are tight lipped Tim.
Anyone that spends 40K for a race engine is sure not going to tell anyone what he spent it for.
I have never seen an article or a book on how to build an engine like the 777 had 3 of or what John Bradley, Whitey MacDonald, the Bean Bandits, Speedy Spiers or a dozen others had in their engines. All of those engines were naturally aspirated and got well over one hp per inch. There is a guy with a modern vintage style dragster right now that is getting well over 2 hp per inch from a blown FLATHEAD on fuel.
You sure are not going to see a parts list for that one.

The engine written up in HR is a healthy street engine at 249+ hp. There is another street flathead engine write up in the AERA magazine this month. These are good street engines but are not even in the same universe as a modern flathead all out race engine.

Well Pete, this engine has a lot of expensive overkill parts for a street engine! The article says they are going for the "XF/VGC" record (around 135 MPH) with a '39 coupe. What I consider to be non-street parts include: fabricated sheet metal high rise intake with dual 750 Holley carbs, belt drive roller cam with oversize bearings to allow .470" lift, billet main caps, 4 3/8" crank, dry sump pan, belt drive custom distributor with crank trigger ignition, and more. There are pictures of the intake interior, the ports and valves, top and bottom of the block, the cam and belt drive, the oil pan and more. One secret they did not show: the combustion chambers.
I'll bet that those roller cam bearings, the cam and the belt drive alone cost as much as a typical "healthy street engine"!

[Tim Ayers]

I'm going to try and find that HR article. I'm very curious about this motor.