55,000 engines later; everything from the P-51 to the P-38 and on and on. The Packard V-12 V-1650 was a very very good aircraft engine.

http://en.wikipedia.org/wiki/Packard_V-1650

Models are available from Engines and Things, for one,  in 1/32. Armor scale I wouldn't know. Likewise the Merlin at 150,000 examples which powered almost every British aircraft in WW2 you can think of. Named after the bird, not the wizard.

http://en.wikipedia.org/wiki/Rolls-Royce_Merlin

Plans:

http://aviationshoppe.com/rolls-royce-merlin-mk61-p-252.html

Not real ones, but pretty nice looking.

But, the 4M-2500 Packard V12 marine engine that powered the PTs is not the same engine, and really would not be interchangeable in a model.

Check your favourite on-line emporium for:

Allied Coastal Forces of World War II: Vosper MTBs and US ELCOs v. 2 (Conway's naval history after 1850)

by John Lambert & Al Ross (google these names for their PT boat threads & sires as well)

This book has dozen's of drawings of the PT boats, inc engines, which are Packard's btw, & is the essential guide for anyone who wants to modify/scratch Italeri's PT.

The Packard is, if you like the cousin to the RR Merlin, and there is a 'strong family resemblance',  to the Merlin Areo engine with  differences in fittings & gubbins!

enjoy!

When I get home tonight, I'll upload the drawings for the 4M2500.

Al Ross

I have read both that the engines were, and were not, Packard Merlins.

It turns out that Packard had long built V-12 marine engines for patrol boats (and racing boats)  (well before they got involved with the license to build Merlins).  So some of what I have read says that the PT boat engines were an upgrade of their existing line of boat engines.

It would be good to read a really authoritative article on this.

For what little it may be worth, I was a teenager during the WW2 years. Like most of my contemporaries I was avidly interested in things military (towards the end was a volunteer aircraft spotter). I have never heard of other than Packards as engines in PT boats. Specifically, the Rolls Royce information is news to me.

Thank you all for your comments and leads. It's helped to refine my searches and there's plenty of food for thought here.

But, you can see the source of my confusion.

I forgot that I had an unread copy of Norman Friedman's, U.S. Small Combatants, collecting dust in my library (I'm glad I don't have to buy that book today.). I think I need to add some Lambert and Ross material to it.

I do believe you should look up any info published by T.GARTH CONNOLLY on P.T. boats.This man knows his stuff , and , if I am correct , based on what I saw in 1959 at SAN FRANCISCO in a warehouse the P.T. there (undergoing repairs and refit to a civilian use) The engines were indeed the second series of PACKARD MARINE HIGH PERFORMANCE engines.They were having a hard time finding parts for them.The things were so massive looking I imagine those puppies generated lots of noise AND heat at high speed. Pity the engineman that had to play with those babies!!  tankerbuilder

Bore: 6.375". Stroke: 6.5". Cu. In. Displacement: 2,490. Compression ratio: 6.4 to 1 (100 octane avgas). Red line: 3,000 rpm. HP (max) 1,500. Supercharged/intercooled.

Man, that's gotta be loud!

Well, I think I'm beginning to catch up on my Packards. It seems, at first blush, that the Packard V-1650-1 through -25 (odd numbers) were essentially Merlins, but US Models (?, I assume meaning for installation in US aircraft).

The PT 4M-2500 motors only share the "V" configuration with the Merlin, and nothing else. Packard built a V-12 Aero engine during WWI called the Liberty engine (L-12) with a 1,650 cu. in. displacement, like that of the later RR Merlin engine. The L-12 engine was, in large measure, a product of Packard's design people and sponsored by the US Aircraft Production Board.

Let's start an International incident? Let's suggest that the Merlin was a Packard design!

The only US PT with Merlins (Rolls Royce, not Packard) was PT 9, which was built by the British Power Boat Company  and served as the basis for the 70' ELCO design.  From PT 10 on, US PTs were fitted with gthe 4M2500 Packard V12.

These illustrations are from the 4M2500  Operating Manual:

John included a large number of detail drawings of this engine in our ACF V2.

Al Ross

Al, thank you for posting those pics. I see ACF offered on line. Is there a best place to buy copies?

WallyM3

Al, thank you for posting those pics. I see ACF offered on line. Is there a best place to buy copies?

Wherever you can get the cheapest price...  You could probably find a copy through interlibrary loan for free.

Al Ross

Rich

For what little it may be worth, I was a teenager during the WW2 years. Like most of my contemporaries I was avidly interested in things military (towards the end was a volunteer aircraft spotter). I have never heard of other than Packards as engines in PT boats. Specifically, the Rolls Royce information is news to me.

Early in the war, before Pearl Harbor, the brits were having a hard time ramping up production to the levels they felt they needed.  They sent a mission to US to get planes and engines built here to their design.  Packard agreed to build the Merlin aircraft engine, a V-12. Thus, the Packard Merlin, designed by Rolls Royce.

There are two versions about the PT boat engines.  Some references say these engines were used in PT boats. Others say that while both were V-12s, the PT boat engine was an existing Packard boat engine design.  And some say it was a Diesel, not a spark-ignition (gasoline) engine.

I would sure like to know for certain the whole story.

The only reference to a diesel engine for the PT boat (preliminary design work in 1937, with budget submissions for FY 1939) that I've sen s far is to a prototype GM diesel of 1,200 bhp in the blueprint stage. BuEng dropped the idea because the long lead time expected for development would have delayed the whole project. At this time, the proposed hull was 54' and a supercharged Vimalert engine was chosen. All engines considered or adopted thereafter appear to be gasoline.

Various versions of the Packard 4M-2500 Marine engine powered the PT boats in actual service ...

Garth

To further confuse the issue in some people's minds, Packard also made automotive V12 engines.  I was watching a TV show a few weeks ago as the two hosts were discussing  a restored pre-war Packard automobile.  When they opened the hood one said "And this is the famous Packard V12, the engine that powered the PT boats in World War Two."

And the moon is made of green cheese...  Ya gotta love TV. 

The 1937 Packard model 1507 is listed as being fitted with the standard-at-the-time V12 gas motor.  Displacement is listed at 473 cubic inches.  The 4M2500 displaces 2490 cubic inches...

Al Ross

WallyM3

The only reference to a diesel engine for the PT boat (preliminary design work in 1937, with budget submissions for FY 1939) that I've sen s far is to a prototype GM diesel of 1,200 bhp in the blueprint stage. BuEng dropped the idea because the long lead time expected for development would have delayed the whole project. At this time, the proposed hull was 54' and a supercharged Vimalert engine was chosen. All engines considered or adopted thereafter appear to be gasoline.

Interestingly, Packard was the only major US effort to develop a diesel aircraft engine (for range).  They built a prototype, and installed it in a plane ( I think a Curtiss Robin).  But the sparkplug (Oh, bad pun!) behind the effort was killed in a crash of the plane and Packard scrapped the effort. I suspect that also may have killed any thought of Diesels for the high speed marine use.

I was at a stoplight yesterday down by Moscone Center. There was a beautifully restored "Straight 8" next to me, and a Buick Special too.

Hi,

In New Orlease we are blessed with the PT-305 as part of the D-Day Museum complex, (boat is at the LAke and you can ride on her)  I have 43 pictures of the boat as well as the engine on my facebook account here.

 https://www.facebook.com/search/top/?q=PT%20305&epa=SEARCH_BOX

Weren't Allison engines used, too?

So welcome to the forum, tractor. Jump on a ten year old post and start insulting people.

I happen to know that at least one of the ignorant people in the earlier thread is "no longer with us".

Good information though in  your salvo.

Bill

GMorrison

So welcome to the forum, tractor. Jump on a ten year old post and start insulting people.

I happen to know that at least one of the ignorant people in the earlier thread is "no longer with us".

Good information though in  your salvo.

Bill

   BOOOM!!

And since we are at various ends of necrothreads--I have this memory that the nice people at Packard made a marine diesel to power harbor tugboats, particularly on the west coast.

And, that the design began as the powerplant for a diesel switching locommotive.