Projects Seagrave 531 V12 Special BuiLd Up in Brazil

1935 Dodge Brothers



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My friends and I have just had 3 years of interaction with a seagrave engine like this to get it ready to run at available car and engine shows and I would like to share some interesting things we learned in the process. The engine was donated to our small tractor and engine club it having been already mounted on a small trailer for show by previous owner, and appeared complete but had the crankcase filled with water and was seriously seized.
Much difficulty in carefully dismantling it and found cylinder damage, but crank and main bearing in very nice condition. piston rings were used from Chevy 261 and 265 engines--rod bearing dimensions allowed us to narrow inserts from Perkins diesel--2 valves cut down from F30 Farmall-- 4 cylinder sleeves and Olsons had head gaskets so cleanup and assembly was the slow work.
Delco distributors got cleanup and advance details on the sun machine and lots of plug wire and guide tube work to restore.
The natural bank angle for a v6 or v12 using 2 rods on a common journal is 60deg giving evenly spaced power pulses of 60 deg--for some reason Pierce-Arrow designed this engine with a bank angle of 80 deg producing power pulses of 80 deg -40 deg -80 deg -40 deg etc, etc--so it is an "odd fire " pattern like Harley and John Deere and many others but unlike most v12 engines. They managed ignition by, in each distributor they had a point and coil group firing 1 6 cyl bank , then 40 deg later they had a second group firing the other bank, a double armed, 40 deg offset rotor and a cap with 2 input tracks put the spark where it belonged.
Look at the combustion chamber and you will find the best of Ricardo's design for L head performance. valves angled toward the bore, relieved from valve out to the bore with piston coming close to the head over most of the bore giving "squish" area for turbulence.
You can't see it but the engineers used Eaton patent hydraulic lifters ( I find them being used in early advanced design engines like Cadillac, Packard, and others). These lifters were carried in bronze blocks bolted to the crankcase casting having the oil galleries integral.
Bore was 3 3/4 x 4 inch stroke-- power rating could be as high as 235 at 3800 RPM and no doubt this was a rating for continuous duty because the fire apparatus designers demand staying power.
I have heard these engines may have been available as late as the 70's but the Diesels had finally become userfriendly and reliable enough to totally phase out the old spark ign engines.
I heard testimony from a shop mechanic in a city fire dept, he said when many of these engines were being replaced by Diesels with no gearing change the drivers hated the new engines because of the much lower RPM range --most Diesels were 2000 max and the Seagraves delivered at 3800---fire responders don't like to go slower.
Hope I haven't strayed too far from the subject and Drmalacarne I thank you for sharing your excellent work with us and I assure you there are many others who are appreciative of your efforts.

 

Thanks very much for sharing your expertise with these old fascinating engines!
They are gems that deserve to be restored and cared.
Gui


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Fuel line ready.


Fuel tank with customs supports.



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Fuel tank in place.
We’ll install an electric fuel pump, with an in-line pressure regulator, because the fuel pump refuses to work properly.

Brake and clutch pedals are ready ok too.



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Warm up.


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COOL

 

KABOOM!!! That is freaking unbelievable, sounds like really good time to me. Great job guys.

 

This thing sounds amazing! Much smoother than I would have thought, and spools up fast too. Terrific build.

 

That sounds great! But I'll bet it's a lot quieter than you would have thought. (On the video, it sounded louder in the front views than from right behind those great-lookin' tips.) I had the same situation with my Seagrave when I put the new exhaust system on it. We tried it with just the pipes first, and it sounded so good we forgot about mufflers. Funny, I also had the same problem with the fuel pump. It had an electric on it when I got it, and when I tried to find a replacement or parts for the original, no dice! It always worked fine, however.

Keep it up; I still want to see a video of it tearin' up the track (or street).

 

Eu gosto muito disso

 

On idle the sound is sweet.
But in full acceleration the noise blows our ears!
But nothing like a big V12 Flathead engine with a direct open exhaust system!


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Amazing!!! Great job on everything you have done.

 

Bravo Gui !
The mighty " LEVIATHAN " has a voice that is throaty and deep and powerful ! Automotive music via superior metal crafting !

 

Nice clean exhaust.

 

And before you know it, it will be time to take it outdoors and frighten the women and children.

And the livestock.

 

Searching for a translation of this phrase brought up an interesting video . . .

https://www.viduba.com/video:QVVMHZFWoN0VGpEMRpmTOVFWShlVB1TP

 

Sounds like you folks are like the old G E add. Progress is your most important product.
Ah, the sweet sounds of success !!!!

 

Looks like a great shop with lots of equipment and projects. Business or hobby. Obviously lots of talent and skills. Very impressed with project, timing and execution! Nice exhaust note! What color?

 

The colors will be red for the chassis and drivetrain and lead gray for the body.


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Yay! Sounds good.

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Have you done anything to the gearing to increase the top speed?

 

No.
The 1926 Buick rear differential is 4.56:1.
And the Seagrave gearbox is a 5 speed with 5 overdrive.
The 5 speed is 0.86
With the 700/20 tires I’m using I believe 70/75 mph will be a realistic hypothesis.
Thanks for ask.
Gui


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I would think that you should be able to do a little better than that. My pumper, which weighed 14,000 lbs and had the earlier 468 ci engine saw the far side of 60 a few times if the road was smooth enough. It had a 4 speed with a 1:1 top gear. It also had 700/20 tires, but I have no idea of the rear end ratio. Being a large truck with dual rear wheels, I would expect it to have been lower than 4.56.

 

I like the sound. A shop full of interesting projects from the looks of it.

 

Now, THAT put a smile on my face listening to it run. I can only imagine how you guys must have felt.

 

4 coils installed in the firewall.


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I've never seen a nicer fit between the firewall and bellhousing.

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Steel motor mounts?
Engine won't hit the firewall?

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No. Engine and gearbox are solid mounted in the chassis. We didn’t used rubber.
The engine is so smooth that we thought rubber isn’t necessary.


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