Donovan 4 Cylinder

K

Krylon32

Well-known member
Studying the Donovan Aluminum 4 cylinder motor. I'm a rookie and am wondering what do they use for a head? They show both Flathead & Overhead parts. They are priced the same just 2 separate lists. Over the years at the LARS in June I've seen I think H&H? or maybe someone else displaying a variety of over head conversions for the 4 cylinder. There's also Miller High Speed Heads. Since Donovan doesn't show a head I'm curious to know what fits and is available? When I total up their price sheet you gotta be a Griz, not for the faint hear ted.
 
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Donovan makes a flathead but most guys use an OHV head. The Model D (Donovan's name for the banger block) is super strong, and expensive but worth it if you are going to drive it hard. They are not legal in V4 Bonneville classes. I'm not sure they are still in production???

The Burtz is a more economical way to get a good block/crank, they are really nice, but also not legal for Bonneville.
 
The Burtz has 2 intake ports like stock.
The Donavan has 4 of better flow design. It is like adding 4 more cylinders if you develop them.
 
Donovan is no longer offering the D block for sale as far as I'm aware. The block will accept any Model A/B flathead or Overhead valve head made for an A or B block as the cylinder spacing and head bolt layout is the same as a Ford block. Donovan blocks do come up for sale on occasion, but not very often.
 
This was a couple years ago, "D" block and a Arnold Birner head a friend was making.

I did a build on another "D" block made for the Birner head, without intake ports or valve chambers.

J
 

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Chris Haynes said:
Why is it that other classes have no problem using aftermarket heads and blocks but a Four Banger can Not?
Click to expand...

Chris

The V4 classes are Vintage strictly meaning original blocks of pre 1935 manufacture
You can run the Donovan in the displacement classes but the architecture is a disadvantage

J
 
Many years ago I had a friend that was a professional student.
He had inherited money when in high school and did not have to work after he finished 6 years of college in electrical engineering. He had an extremely high IQ and was always seeking knowledge of any kind. I met him at the local ham radio club.
By professional student, I mean after he finished getting a Phd in EE he enrolled in getting a degree in mechanical engineering. He was always going to school. He was always working part time in the trade he was studying and while not always pursuing the work aspect of life with complete interest he figured it was helping to reduce the time required to get the degree. He was always looking forward to more schooling.
Later in middle age and after he had quit going to school with 6 degrees in, I don't remember them all, except that one was law, he got a job teaching high level college mathematics.
He had always been interested in LSR and had been on my pit crew several times.
One time we had been talking over quite a few beers and the discussion got around to building a 4 cylinder engine that would absolutely meet the rules of the vintage class but would be so illegal rules intentwise, it was a joke.
After listening to his idea, I decided it was possible and within cost possibility, I told him I was not interested but we did talk about it for several years after that.
The main reason I was not interested was that while the rules would have to let it run if it showed up, (and it would have absolutely set a record so high it would never be reached unless with a similar engine) the rules for the next meet would have been changed before the current meet was half over.
And after that, it would be REAL boring if you knew you could win every time.
 
Terry,
There have been a lot of discussion about letting your Block kits run in the F.A.S.T.
hill climbs.
The outcome is this year they are going to be allowed to run for time up the hill,
but not be eligible for class wins or King of the Hill.
There was discussion about looking at it next year if enough show up they might have
their own class.

Having fun with your Kits......

Dodge
 
Chris Haynes said:
Why is it that other classes have no problem using aftermarket heads and blocks but a Four Banger can Not?
Click to expand...

Vintage 4 (V4) classes are allowed any OHV or OHC conversion that you want to run, its the block that SCTA limits, to 1934 or earlier, or any block approved by the original manufacturer as a replacement block, so diamond blocks are also permitted. Turbos are not allowed except in Lakester or Streamliner classes. 5-main cranks, etc. are also permitted. V4F classes are for the above but must be of flathead design. The SCTA president says he may try to get the Burtz block allowed, don't hold your breath!

The V4 streamliner record is somewhere North of 200 MPH, even when using gasoline!
 
Dodge said:
Terry,
There have been a lot of discussion about letting your Block kits run in the F.A.S.T. hill climbs.
The outcome is this year they are going to be allowed to run for time up the hill, but not be eligible for class wins or King of the Hill.
Click to expand...


This is logical as a separate class. As Terry says - "It's a modern engine".
There are several original block engines that have been modified for 5 main cranks but they do not have the metallurgy or rigidity of the Burtz block. I've also been curious if the Burtz can be ported beyond what you can do to a stock block.

There are a lot of different groups with different rules. SCTA/Bville limits block age but everything else in the driveline is open.

TROG limits body to pre 34, engine and drivetrain to 1953 and older as well as the "look" - https://www.theraceofgentlemen.com/entry

FAST will even fiberglass bodies. - https://www.hotforhotfours.com/documents/Classes & Rules.pdf

You need to figure out which arena you want to play in and build for that battle.
 
I did some mild porting on the intakes on my Burtz block. Just enough to clean it up. Terry changed the design of the intake area slightly for better flow. There is some thinking around too much porting that changes the flow to the point where it is detrimental. Putting the design in a CAD system with flow simulation would be the way to go if you wanted to do any radical porting.

I approve Terry's block as a replacement. Does that count?
 
Port clean up will not net much improvement in flow, it may remove a shadow in the flow but that's about it.
The Siamese intake port design is the culprit, the Donovan 4 port design is far superior with appropriate manifold.

Here is a pic of what it takes to make a side valve engine to make HP. Individual intake ports and appropriate runners.

Now, many have tried to make reverse port side valve motors to get individual intake port/valve arrangements. This will improve performance quite a bit but the result usually is the original intake port casting failing. (too thin)

It would be very interesting to see how the Burtz casting works, I would think this could be done very nicely and survive.

John
 

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