dumb person
Well-known member
No.
And not just no, but hell no. (as a response to the first post, just fyi)
And not just no, but hell no. (as a response to the first post, just fyi)
Relieving 8BA Block
- Thread starter 1934calkid
- Start date
Pete
BANNED
Everyone is entitled to his opinion and I respect that, no matter what it is, BUT,
I would like to know how many that say "no" have actually built a FAST street engine and tested it with and without a relief?
Remember, for a valid test, you CAN NOT run the 2 tests with the same heads.
The relieved block will win every time.
Vics Stuff
Senior Member
I relieved my block for street use. Used 11:1 Offenhauser heads. 3/4 old school cam , tri power set up and my truck runs well. Been on the road since 1985 and never any engine issues. Just did a lot of reading and felt that was the best thing for this engine.
Do not regret it.
Vic
Do not regret it.
Vic
dumb person
Well-known member
You can't put ardun heads on them very easily.
I talked with 2 flathead giants in my time. One was Stan Lamelino at Cordova Il In 1962 and John Bradley in 1998 I asked each of them if their blocks were relieved and they both replied Yes.
Roger Huntington in his book and Don Francisco in his articles both stated that relieving the flat head motor increased the horse power. We are talking full out racing engines not street cars. Could all of these Giants of the past be wrong or is it because they are not able to take advantage of the modern technology we now have. Maybe some food for thought. Although John Bradly was still racing in the late 90,s and early 2000. Thank You
Roger Huntington in his book and Don Francisco in his articles both stated that relieving the flat head motor increased the horse power. We are talking full out racing engines not street cars. Could all of these Giants of the past be wrong or is it because they are not able to take advantage of the modern technology we now have. Maybe some food for thought. Although John Bradly was still racing in the late 90,s and early 2000. Thank You
Pete
BANNED
The original question was:
“ Should a block for a street car be relieved 286 ci”.
This can NOT be answered accurately without more information.
Static “street” display in a museum?
Daily driver/commuter?
Occasional street driver to the drive-in, parades or car games?
Fast driver to run at weekend drags and driven to work on weekdays?
Built to flip for quick cash.
Budget concerns?
Stock OEM heads?
Modified heads?
Driver driving style and habits.
How much hp can you be satisfied with.
“ Should a block for a street car be relieved 286 ci”.
This can NOT be answered accurately without more information.
Static “street” display in a museum?
Daily driver/commuter?
Occasional street driver to the drive-in, parades or car games?
Fast driver to run at weekend drags and driven to work on weekdays?
Built to flip for quick cash.
Budget concerns?
Stock OEM heads?
Modified heads?
Driver driving style and habits.
How much hp can you be satisfied with.
Since I was the crew chief for Stan Lomelino, up to the time he stopped racing, I feel qualified to respond---It is true in the early days we would spend countless hours porting and relieving our engine blocks. This had to change when we started using 100% nitro and the racing schedule expanded wildly to a minimum of 3 events weekly. Eventually we found that softening the eyebrows combined with "normal" porting worked best and gave us the most power. There are several reasons why that is true which I explained in my book.
As an aside, Ken Kloth, perhaps one of the more well known Flathead racers, learned to avoid relieving the Flathead block in order to get top performance.
The secret (if there are secrets) is in the port, valve pocket, and head. Not the block relief. Doing wet flow studies will help us understand that the area being "relieved" does not play a significant roll in the breathing potential of our Flathead engines.
As an aside, Ken Kloth, perhaps one of the more well known Flathead racers, learned to avoid relieving the Flathead block in order to get top performance.
The secret (if there are secrets) is in the port, valve pocket, and head. Not the block relief. Doing wet flow studies will help us understand that the area being "relieved" does not play a significant roll in the breathing potential of our Flathead engines.
Ol' Ron
Well-known member
I modified a junk aluminum head to determine the affect of the transfer area had on flow. I sterted with a 4 deg angle and went up to a 12 deg angle. After 8 degs no improvement in flow took place with the port valvr combination i had in the block. Although this did increase flow, it also reduced the CR drastically. I then got as piece of wood and made up a bunch of combustion chamber designs t find the one that flowed the best with the highest CRr This was a wedge chamber the same as the Chevy 348/409 style. I waanted to have Egge make a set oof blanks for me so I could machine the heads and pistons to match, but the cost was much too high. Later i discovered that this chamber had already been used in a Bonneville engine. This is probably the best design so far, untill some one comes uo with a better one.
When it comes to running a fast car I believe the normally aspirated ones require th highest degree of engineering. Stuffing an engine with fuel or a blower is a lazy way to make power. However, I repect those that do, because they have to hold them together.
When it comes to running a fast car I believe the normally aspirated ones require th highest degree of engineering. Stuffing an engine with fuel or a blower is a lazy way to make power. However, I repect those that do, because they have to hold them together.
Pete
BANNED
You are sure right about that.
Not sure what you mean when using the term "engineering"? There are many little problems to be overcome to get maximum performance from any set of components. Mistakes in component selection or status are more readily exposed with boosted or boosted and fueled engines. There is something to be said for the level of refinement in engines of the Pro-Stock or Competition Eliminator categories where a gain of 5HP on a 1200HP engine is considered a great achievement. But the amount of work. study, engineering, and problems is present in all the full competition classes.
cadillac512
Well-known member
The KR comparison is a bit misleading. The engine has a low bore to stroke ratio, which gives good compression (compared to the reverse): 2.745" bore by 3.8125" stroke.
However, the valve seats (which in the Ford are angled toward the bore) are angled away and flow badly due to the cam positions, true of all H-D flathead 4-cam engines: 1929-73 D, R, W, G, V, & U).
A useful feature is that in the KR (and any race-prepared H-D flathead) is to relieve the deck surface directly adjacent to the high edge of each valve seat so that the valve curtain appears instantly when the valve opens; it's not shrouded or sunken.
A light radius can be added to the deep end of the seat as well.
However, the valve seats (which in the Ford are angled toward the bore) are angled away and flow badly due to the cam positions, true of all H-D flathead 4-cam engines: 1929-73 D, R, W, G, V, & U).
A useful feature is that in the KR (and any race-prepared H-D flathead) is to relieve the deck surface directly adjacent to the high edge of each valve seat so that the valve curtain appears instantly when the valve opens; it's not shrouded or sunken.
A light radius can be added to the deep end of the seat as well.
Bored&Stroked
Well-known member
Here is what a typical Harley KR barrel looks like - this is from a 100% race engine. Notice the heavy relief that comes right to the edge of the valve seat. Also, a picture of a KR head and a diagram form the Harley KR Racing manual.
Enjoy!
Enjoy!
