Old Skool 4 bolt mains
Moderator: Team
Old Skool 4 bolt mains
https://www.flickr.com/photos/27666849@ ... otostream/
The first generation of WW2 era Ford V8 tank engines retained Van Ranst's main bearing
design that originated with the V12 highly supercharged aircraft engine. But instead of a
2000HP+ V-12 the GAA/GAF V-8 was de-rated at 450-500HP. The second design of this
series reverted to 2bolt mains, although the triangulated block reinforcement remained.
Anyway, what are the potential advantages of this design? Ease of mfr is surely not one
of the advantages. But Van Ranst and the Chevrolet brothers had quite a bit of experience
designing HP engines, so he must have seen advantages beyond the the 2 bolt and
double tie-bolted main bearing supports used in the Merlin etc.
The first generation of WW2 era Ford V8 tank engines retained Van Ranst's main bearing
design that originated with the V12 highly supercharged aircraft engine. But instead of a
2000HP+ V-12 the GAA/GAF V-8 was de-rated at 450-500HP. The second design of this
series reverted to 2bolt mains, although the triangulated block reinforcement remained.
Anyway, what are the potential advantages of this design? Ease of mfr is surely not one
of the advantages. But Van Ranst and the Chevrolet brothers had quite a bit of experience
designing HP engines, so he must have seen advantages beyond the the 2 bolt and
double tie-bolted main bearing supports used in the Merlin etc.
Re: Old Skool 4 bolt mains
I have little idea what I seeing here, so as a bump I ask, are those slots on both sides to insure the corresponding cap bosses prevent any movement by each set of 4 angled studs ,as they are torqued? Interesting , i never seen this design, and curious what others have to share on the matter.
-
- Guru
- Posts: 3661
- Joined: Tue Aug 19, 2008 7:20 am
- Location: South Australia
Re: Old Skool 4 bolt mains
I like how the studs go thru holes in the block and screw into the horizontal steel dowels. Looks like they were trying to give linear cap support in reference to each bank of cylinders. You would need to torque that setup in stages to avoid very uneven main cap loading.
Craig.
Re: Old Skool 4 bolt mains
Looks like a typical Kraut difficult solution instead of taking an easy route to solve a problem.
-
- Guru
- Posts: 1141
- Joined: Tue Feb 05, 2013 6:56 am
- Location: Melbourne, Australia
Re: Old Skool 4 bolt mains
Being a 60 deg V8 the balance would not have been all that flash, and with a flat crank as well...numboltz wrote:But instead of a 2000HP+ V-12 the GAA/GAF V-8 was de-rated at 450-500HP. The second design of this
series reverted to 2bolt mains, although the triangulated block reinforcement remained.
I wonder how much of the de-rating was needed after losing the balance advantages of a 60 deg V12?
-
- Guru
- Posts: 5566
- Joined: Sun Feb 19, 2006 10:19 am
- Location: MA
Re: Old Skool 4 bolt mains
The Cat 3208 V8 diesel had angled main cap bolts. I see other "vee" diesels with angled bolts too, but the 3208 had them more inline with the bank angle, this was supposed to take the cylinder load better, but I would see fretting on the cap mating surfaces.
You do not have the required permissions to view the files attached to this post.
Automotive Machining, cylinder head rebuilding, engine building. Can't seem to quit
Re: Old Skool 4 bolt mains
The higher angle (compared to say a splayed 4 bolt SBC cap) would provide more horizontal resistance to the cap 'pulling in' and ovalizing as the crank thrusts more or less straight down. The resulting shorter 'arc' of cap material between fasteners might also be a plus.
Felix, qui potuit rerum cognscere causas.
Happy is he who can discover the cause of things.
Happy is he who can discover the cause of things.
Re: Old Skool 4 bolt mains
"Being a 60 deg V8 the balance would not have been all that flash, and with a flat crank as well...
I wonder how much of the de-rating was needed after losing the balance advantages of a 60 deg V12?"
The R-R Merlin also served as a derated tank engine, although it retained all 12 cylinders.
I know a guy that had extensive experience with the GAA as a boat engine and he was pretty
positive about them and never mentioned any vibrations. With a flat crank and only 4 counterweights
[2 in the center] that is interesting. Cast iron crank, BTW. It had a heavy flywheel, maybe to help
with vibrations? The rods look like flathead rods at the bigend and even had the floating rod bearing
design of a flathead. 1/2 rodbolts. I think those changes were made to take advantage of the de-rating.
There was so much pressure on to get a decent tank engine it was a quick hack, which is maybe why they
kept the aluminum block and heads. Block was the largest aluminum casting in the world, at the
time.
I wonder how much of the de-rating was needed after losing the balance advantages of a 60 deg V12?"
The R-R Merlin also served as a derated tank engine, although it retained all 12 cylinders.
I know a guy that had extensive experience with the GAA as a boat engine and he was pretty
positive about them and never mentioned any vibrations. With a flat crank and only 4 counterweights
[2 in the center] that is interesting. Cast iron crank, BTW. It had a heavy flywheel, maybe to help
with vibrations? The rods look like flathead rods at the bigend and even had the floating rod bearing
design of a flathead. 1/2 rodbolts. I think those changes were made to take advantage of the de-rating.
There was so much pressure on to get a decent tank engine it was a quick hack, which is maybe why they
kept the aluminum block and heads. Block was the largest aluminum casting in the world, at the
time.
Re: Old Skool 4 bolt mains
When I was researching for my patent, it was amazing how much of basic engine development
had been done before the 1920s. One of the things complicating digging for early patents was that
so much was done before common terms and names had been created and agreed on. Thus
"explosion engine" "puppet valves" etc appear in the early days. And, of course, the French seemed
to dream up almost everything first.
had been done before the 1920s. One of the things complicating digging for early patents was that
so much was done before common terms and names had been created and agreed on. Thus
"explosion engine" "puppet valves" etc appear in the early days. And, of course, the French seemed
to dream up almost everything first.
Re: Old Skool 4 bolt mains
Ironic, since it was an American design intended to power the machines needed to destroy the German military offensive.ZEOHSIX wrote:Looks like a typical Kraut difficult solution instead of taking an easy route to solve a problem.
NACA (NASA's prececessor) sponsored a lot of basic research, as in "test it to destruction" vs. "mathematical modeling." Most of those papers are available at https://ntrs.nasa.gov/. You see a lot of the same names over and over; those are the guys that Heywood and the rest cite as sources, often in support of the exact opposite of what the report says...numboltz wrote:done before the 1920s
NASA changed their search interface some years ago and it's much harder to find things than it used to be. The Brits have a copy of the old NACA archive and interface up at http://naca.central.cranfield.ac.uk/.
HM Government sponsored its own research, mostly done by the Admiralty and much by Harry Ricardo. Unfortunately very little of that is online; mostly post-WWII rocketry and aerodynamics stuff.
After WWII government research on pistons engines essentially stopped; jets and rockets were where the interest was. But most of the old stuff is up there for anyone to see, in grotty low-resolution images wrapped in PDFs; multi-strike and multi-plug ignitions, stratified charge stuff, hybrid combustion like HCCI, closed loop O2-sensor fuel injection (with vacuum tubes!), high pressure supercharging, balancing and vibration, camshaft profiles, piston rings, valve steels, oiling systems, lubricants, intercooling, exotic fuels... it's the real deal, from the guys who led the way.
Boeing and General Motors used to do their own research and publish papers that seldom circulated outside the company. I've seen reference to a few and was able to get them via Inter-Library Loan; both companies are quite cooperative. Apparently Boeing doesn't have an index to tell what they have; if a request goes in, a company librarian digs through filing cabinets until they find what you asked for. GM almost certainly does have an index, but it isn't available outside the company.
Curtiss-Wright once had a vast amount of primary research papers, but when I contacted them they told me it had all been discarded decades ago. "Bit rot" isn't just for web pages going 404...
Re: Old Skool 4 bolt mains
Yes, it is ironic........The Ford V12 aircraft engine was never used in actual combat aircraft ....So it's potential was unknown...Consider the years of development by Roll Royce and the much smaller Allison company before their engines were reliable in real life situations..peejay wrote:Ironic, since it was an American design intended to power the machines needed to destroy the German military offensive.ZEOHSIX wrote:Looks like a typical Kraut difficult solution instead of taking an easy route to solve a problem.
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire
Re: Old Skool 4 bolt mains
Considering when these engines were designed and developed in a very "short" development window, without today's computers and specialty methods these engines were really some great innovation and look into the future of where automotive engines would go 25 to 50 years in that future. Thanks for sharing the pictures and information!
The Older I Get, The Dumber I Get
-
- HotPass
- Posts: 9391
- Joined: Tue Nov 22, 2005 5:41 am
- Location:
Re:
Many interesting things were removed from the documents put online after some sane reflection.dwilliams wrote:NACA (NASA's prececessor) sponsored a lot of basic research, as in "test it to destruction" vs. "mathematical modeling." Most of those papers are available at https://ntrs.nasa.gov/. You see a lot of the same names over and over; those are the guys that Heywood and the rest cite as sources, often in support of the exact opposite of what the report says...numboltz wrote:done before the 1920s
NASA changed their search interface some years ago and it's much harder to find things than it used to be. The Brits have a copy of the old NACA archive and interface up at http://naca.central.cranfield.ac.uk/. ...
Driving Force Online: BREAKING NEWS—Ohio Governor Signs SEMA-Supported Vehicle Freedom Bill Into Law!