Technical Marching forward 1-2-4-3, Banger time...

This is what I use:

https://www.summitracing.com/parts/ARP-150-2201

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This is what I was told:

The car is reported to originally have a 4 port Riley head on a B block like the one that is in it now. But that engine had injectors instead of the carbs that are on it now.
The uncle of the guy I bought it from bought it @ 40+ years ago. His uncle raced a roadster at the lakes. He bought this car for the engine. His uncle took the engine out of the dragster and put it in his lakes car.
This car, without the engine, got put up in the rafters. The guy I bought it from got it after his uncle died and restored it @ 5 years ago.
I was told the it ran @ 120 mph. In the 1/4 mile. It has not run since it was restored. This car has a cut down flathead V8 flywheel inside of a fabricated "scatter" shield mated up to a V8 transmission modified for 2 gears, low and high.

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Thank you… ordered and on the way

 

Watching hard to find the link this month

 

Thanks for the back story...
It is way cool and I hope that you get to have fun with it and we get to see more of it!!!!

 

Donovan Head motor in and running...have tuning to do but it runs real strong. Believe it needs more valve spring as it hits the wall at 3400 RPM...

 

What does the combination chamber look like on the Donovan head?

 

Yikes! What comp is that running!

 

Does that head require a zero deck height? I assume if the head was fly cut or at least my understanding of fly cut, that the piston could have a positive deck height?

 

Good point. I didn't give it any consideration in my question.

 

Looks very much like super Winfield head
Not sure about CR but reducing the chamber too much will choke off the airflow
J

 

Another question for you fella's who break A model's, what kind of rpm's can a stock bottom end maintain safe-ish-ly

 

I tend to gear for a 2-2200rpm cruising revs which is 55-60 with my current gearing. 3.27 and 600 x 19 tyres.
An occasional blip up to 2500 gives me 70mph for some overtaking, and on a faraway beach, just over 2700 gets me a class record...
That's on a stock B bottom end.

 

9.4 CR figuring in the gasket thickness

The piston tops were cut down to achieve a deck height that is zero at TDC.

Yes, very similar chamber shape to the Winfield. I have my concern over the lack of airflow and that as to why the thing starts falling on its face around 3300 RPM. A set of stronger valve springs will answer that question. They are stock, no shims now. Thanks for the feedback....I will share the outcome of the spring change. It runs like a scalded ape up to that engine RPM so I have hopes and if not, their is head work. I've got Joe Abbin and his flow bench as a resource.

 

Well, Been playing around, found too heavy of spring in the mallory dist. Cut timing marks into pulley and now getting 5 base with swing to 22, seems to run alot smoother, more power in 3rd for sure.

Decided to upgrade to 2/0 cable for the battery cables. Pulled the starter out to clean the base and noticed the armature shaft was bent so swapped it out with an old one I had here.

Made new plug wires.

Then pulled side cover and adjusted the valves for my annual maintenance thing. Finally did a compression test and found
#1 70
#2 95
#3 90
#4 75

Oil the cylinders with no additional psi, so I think its time to lap the valves into place. So pulling the head, wish me luck.

Going to drop the pan also to fix a leak, and noticed the crank moves forward .04 " Its an inserted motor that was orig built by John Cosper from what I was told. Maybe its worn out a thrust shim is what I am thinking. So once I get the pan down I will pull rear main to see whats going on back there.

Few nice pics before tear down of motor and the cable routing.



replacement armature


2/0 cable made a huge difference in starting and starter motor performance. Big Red is 2/0 and the small one to chassis is 4 gauge...

 

Well did a leakdown and 1 and 4 hold no pressure, seems Intake valve on #1 leaking and exhaust on #4, so Time to pull a head and get to lapping valves....... Should be worth a few HP for sure here.....

 

You guys have all the fun! Hahaha

 

I sent an A motor to Bonneville years ago with a 9.5:1 Super Winfield head that looked just like that Donavan. We used stock valve springs on oversized valves (1.8” in and 1.7” out IIRC) and the owner was shifting at 4500! We never heard any misfiring, just were worried the crank was gonna fall out!

You sure yur not getting too much spark advance at the top end…?

 

@Kevin Pharis thanks for the reply. That's good information.
Interesting...latest run shows a steady vacuum gauge, so valve float may not be the problem. With your comment..ads more credence to that belief. Started with a modified B distributor. Back on the distributor machine it was showing bouncing timing on #3. Changed out for a Mallory dizzy. Timed to 26 degrees total advance. No pre detonation. Going to give it some more total advance...

 

A very much overlooked item is the exhaust.
If you have ability to remove muffler and test or can check the exhaust pressure it might pay off.

John

 

As far as distributors are concerned, I see two choices available presently. FSI or from H&H Flatheads.
Are there other choices? Of the 2 I have listed, is there a preference?

 

search for a Mallory dual point or a mag. I am a fan of points.

 

Found some valves not sealing, went ahead and did them all with some lapping compound.



On a positive note, block is sleeved and is std bore. So that's a good piece of information. Modern valve guides and keepers etc are installed.

Also, found the crank thrust issue, worn thrust washer. Looks to be worn from lack of lube so no one chamfered it nor had oil grooves in it so it was basically wiping the oil from what I can see. So stay tuned. Once the thrust washer is installed the motor starts going back together for sure and will be better than ever.

 

Yes, thanks
The current set up is 2" home fabbed header into 2 1/2" and a Flowmaster muffler... it is set up with O2 sensors so can pull them to check pressure

 

What’s the story on the center punch dimples on the block deck…? Snake oil? I thought they were trying to retain the valve seats at first glance… then noticed they dimpled damn near everything???

 

That was done to help hold the head gasket on higher compression engines. The dot punch disrupts the surface and raises a small spot. I have several Olds heads that were raced that were punch pricked.
After coming and looking at it again, they punched everywhere! A lot of places it wouldn't do any good even if the idea worked!

 

If some is good more is better...
Or, maybe the work being done too close to the still
J

 

Yeah, I have seen it done around combustion chambers before but not to this extent. Yeah I guess someone got over zealous with the punch....

 

Mums burtz powered sport coupe went for its first test drive with dad @phill today, it went fairly well but still needs a bit of tuning, the engine is so smooth, its hard to believe its based on a model a engine, the 32 trans with v8 gears is also a nice addition

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