The perfect "street engine"
- Thread starter Ol' Ron
- Start date
petehoovie
Well-known member
Ol' Ron
Well-known member
I get quite a few questions from some of the readers her about rebuilding their engines, and what to do to make them better. What modifications to make, etc!! I think most of the guys are refering to a stock engine rebuild. If You have an issue of JWLs book, the first thing he does id give the torque and Horsepower of the stock engine. He goes on to make some modifications to the exhaust system. In Any case the engineonly produced 80 HP and 150ft of torque at 2000 roms. Max HP is at 3000rpms with oly 133 ft lbs of torque. This is a very inefficent engine and not much can be done to improve it. my first suggestion is to bore it to 3 5/16. This will increase the CR to 7.7:1 using EAB 74cc Heads. This will add about20ft lbs of torque. Doesn't sound like much, but will be felt in low speed acceleration, but mostly at the gas pump
Tuning th e engine is where most people drop the ball. How many people have an AF meter?? Their not expensive and you need to know this information. An inexpensive intake with a late 1/16 Holley and aload amatic distributor. The expense if a 4bl or 2 ducejust adds $$$$$$ and don't offer much in performance and economy and you'll need one of Charly's disributors, Probably shouldget one anyway.
Now Lets hearsome other suggestiond. This is a bottom line "Street engine" But it will run that old Ford DDR at 70 mPH all day long.
Gramps
Tuning th e engine is where most people drop the ball. How many people have an AF meter?? Their not expensive and you need to know this information. An inexpensive intake with a late 1/16 Holley and aload amatic distributor. The expense if a 4bl or 2 ducejust adds $$$$$$ and don't offer much in performance and economy and you'll need one of Charly's disributors, Probably shouldget one anyway.
Now Lets hearsome other suggestiond. This is a bottom line "Street engine" But it will run that old Ford DDR at 70 mPH all day long.
Gramps
3twinridges
Well-known member
I have an 8BA in our 52 F1. 4” crank, bored 60 over, 1CM cam, and 8ba heads milled. Stock distributor and carb and it pulls strong. Easy to tune and no fancy parts. I did convert the air cleaner to run a K&N filter. Everything looks stock on the outside, but when you crank it, you can tell it has more than the average Joe.
JB
JB
I'd be interested in this and what the final outcome is.
I may have a different mindset than others when rebuilding a motor.
While it's apart (which is the hardest part of the job), why not try to get the most of out if for your application?
Meaning: If it's a truck that's going to be used as a truck, get as much torque out of the motor as you can.
If it's a street car, get as much fun out of it as you can.
There are things you can do that don't cost money. Ex: Porting the exhausts and intakes runners is relatively free. If you don't have a hand grinder, even the cheapie Harbor Freight job will do. Why port it? For the reason Ron mentioned. To help it be more efficient.
It's a fun job to do and you'll learn something along the way.
Doing what you can to get the block prepped for cleaning. Working to get those water jackets surgically clean is another "at home" job. Getting as much gunk out of the water jackets helps before the block goes in for a cleaning. Baked and blasted and chemically dipped or washed.
You will be amazed as to how much crud and, sometimes, casting sand comes out of the water jackets.
This is essential in order to get a cool running motor.
Other things just make sense after knowing what we know today. EX: Using metric rings packs to help with efficiency and reduce wear. You'll need to buy pistons for the rebuild anyway, so why not use modern technology to help get a little more out your engine?
Using three ring pistons instead of four. Why? That fourth oil ring has been proven as not needed on a fresh rebuild and only causes more drag and wear.
Using a torque plate when honing. Why? Getting the bore as perfectly round as possible helps with wear and efficiency.
Like JWL's book mentions, picking up little gains along the way eventually add up to a big gain.
I may have a different mindset than others when rebuilding a motor.
While it's apart (which is the hardest part of the job), why not try to get the most of out if for your application?
Meaning: If it's a truck that's going to be used as a truck, get as much torque out of the motor as you can.
If it's a street car, get as much fun out of it as you can.
There are things you can do that don't cost money. Ex: Porting the exhausts and intakes runners is relatively free. If you don't have a hand grinder, even the cheapie Harbor Freight job will do. Why port it? For the reason Ron mentioned. To help it be more efficient.
It's a fun job to do and you'll learn something along the way.
Doing what you can to get the block prepped for cleaning. Working to get those water jackets surgically clean is another "at home" job. Getting as much gunk out of the water jackets helps before the block goes in for a cleaning. Baked and blasted and chemically dipped or washed.
You will be amazed as to how much crud and, sometimes, casting sand comes out of the water jackets.
This is essential in order to get a cool running motor.
Other things just make sense after knowing what we know today. EX: Using metric rings packs to help with efficiency and reduce wear. You'll need to buy pistons for the rebuild anyway, so why not use modern technology to help get a little more out your engine?
Using three ring pistons instead of four. Why? That fourth oil ring has been proven as not needed on a fresh rebuild and only causes more drag and wear.
Using a torque plate when honing. Why? Getting the bore as perfectly round as possible helps with wear and efficiency.
Like JWL's book mentions, picking up little gains along the way eventually add up to a big gain.
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Love it. That's my kind of motor.
Haha. If one has an aggressive, heavy hand could be. I bet you learned from it though, right?
Ronnieroadster
Well-known member
Certainly true if you don't know what your doing especially when it comes to thinking your going to weld holes in cast iron!
Its like if you don't know how to do plumbing you have a professional do it. Or else your going to need a sump pump. When it comes to porting porting read, learn, ask and practice and then all will be good.
Ronnieroadster
What do you consider small displacement? The proposed 258ci engine?
I'm interested in hearing more about your comment regarding low & mid range.
A few thoughts, what does that entail? Very few cars drive around for any extended period going slow. They generally get up to speed (45-75) for most of the time while driving.
I had the luxury of having a junk block around and I cut open the block at the end ports. I would really like to see some flow test data with a worked over motor that was ported vs. the exact same motor without being ported.
Maybe that information is in John's book. I haven't read it a few years and will go back to look at it again.
I'm really interested in seeing data of how improving the flow out of the end ports has little benefit.
This is a fascinating topic to me and I'm trying to soak up what I learned with my recent build and what to do next for my future 99A build up.
Pete
BANNED
Very true. A MILD street engine only needs port matching and very mild decobbing.
Even an all out engine will not benefit much if any, from a flow bench any more.
Flathead ports flow more the bigger you go and if you go to .090 wall all the way through the port with a sonic gauge, that is about all you can do unless you go to installing steel tubing for ports.
Lawrie
Well-known member
the engine in my 33 is 265 ci. a 99a block .040 with a 4in crank, I used the stock 33 cam and inlet manifold ,a new 97 carb, it will run all day at 50-55 mph with the caravan on the back and is one nice engine,
I know it would be better with a different cam and bigger carb But for my application its really good,
I set up the carb using an O2 meter.
Lawrie
I know it would be better with a different cam and bigger carb But for my application its really good,
I set up the carb using an O2 meter.
Lawrie
Ol' Ron
Well-known member
if, a big IF you consider what moves your car , and how fast it accelerants. You must consider TORQUE, and BIG engines make large amounts of torque. Or do they When you get your dyno sheet with the torque readings, you can see them start to fall off very quickly with a flathead. Yet when you run a sBC the torque curve cintinues along for quite awhild, befor falling off. I had this exolained to me once by the dyno Teck as the breating of the engine had reached it limits. In other words the ports could noe move more air. In johns book he shown that at 2000RPM the engine was recieving all the air it could use, but at 3000 RPN, the port couldn't supply any more air, thus the power was down. But the formula for hP provided more HP
In order for a engine of any kind t make 200 HP it has to cary the torque to a much higer RPM range. OR supply more aqir. It's the only thing thst makes power.
Gramps
I just read this and don't understand a thing I said.
G
In order for a engine of any kind t make 200 HP it has to cary the torque to a much higer RPM range. OR supply more aqir. It's the only thing thst makes power.
Gramps
I just read this and don't understand a thing I said.
G
Brian
Well-known member
The ports and valve sizes remain much the same throughout the entire flathead engine series, irrespective of engine displacement. There is a limit to how much these can flow. Once this limit is reached, with the larger displacement flatheads, you obviously are not going to be able to completely fill the cylinders. Therefore, the smaller displacement engines must be more efficient? I'm talking naturally aspirated.
Ol' Ron
Well-known member
If you think the ports are too small, all you have to do is add a supercharger. % lbs of boost will make more power tham a Bored and stroked L-100, try carbe engine any day.
So drag out those old blowers and bolt hem on. The only thing you need is a timing lite and an AF meter.
Gramps
So drag out those old blowers and bolt hem on. The only thing you need is a timing lite and an AF meter.
Gramps