| Author |
Message |
Jim Bob
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 2:03 pm: | |
I have an old 6-71. We have not been able to find the serial number in books available to us.
Is there anyone with access to OLD stuff that can look this up & tell age & horsepower? (This is a marine engine, aluminum block!) Serial: *12A5081* |
Geoff (Geoff)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 3:00 pm: | |
"12A" is a serial number for a 12 clyinder, 12-71 engine. What you have is a block that has been converted to a 6-71, instead of two blocks mated together to form a 12-71. The serial number is from the 1960's, and wouldn't tell you anything relevant since it originally was a 12-71.
--Geoff
'82 RTS AZ |
john w. roan (Chessie4905)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 5:06 pm: | |
I thought 12v71's had a one piece v block |
John MC9
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 6:49 pm: | |
His is a 6-71. |
Jim Bob
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 8:47 pm: | |
A very interesting theory Geoff. But I thought a 12V71 was a one piece block while 16 & 24V71s were two piece.
In any case, this is an inline 6-71 that as far as I can tell has always been a marine engine. It was one of a pair of "pancake" (horizontal)engines removed during a repower. It definitely has an aluminum block but a cast iron head.
It's brother is newer, all iron block, 1962 serial nr. I will find out in a day or so which is an opposite rotation engine. One of 'em is.
Come on, where are those old GM insiders when you need 'em? |
Geoff (Geoff)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 10:39 pm: | |
Theory?
Goodbye.
--Geoff
'82 RTS AZ |
Tim Hoskinson (Tdh37514151)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 11, 2005 - 10:53 pm: | |
Hi Jim Bob I have a friend in the antique truck club I belong to that worked many years for detroit diesel. He is retired now but is a wealth of info on detroits and is able to get very reliable iformation. If you would like I can give him a call and see if he can run down your number. As far as 12v71 I have never seen or herd of one that could be separated I do know that I have not seen it all nor done it all but all 12v71 engines I have ever seen are one piece blocks. It is possible it was numbered this way to id the engine as one of a matched pair for marine use. This may be what Geoff was refering to as he did not make referance to a 12v only a 12 71. Well let me know if you are interested and best of luck to you. Tim |
Jim Bob
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 12, 2005 - 10:09 am: | |
Geoff, I didn't mean to disrespect you. I meant that your line of thought was interesting.
If it were a 6V-71 I could agree that it could have been part of a two piece 12V71 block if they were made that way. And someone could have used the block to build another engine.
I also though that I had mentioned that the engine was an inline 6-71N but looking back I see I was a little vague on that.
So, don't be P'd off at me. I didn't mean it like that. |
Jim Bob
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 12, 2005 - 10:50 am: | |
Hi Tim,
Yes, I am interested in any info your friend may be able to turn up. I have spoken to another friend who thinks it might be a Navy engine because he saw these in launches when he was in the service years ago. It may be that it has a non standard type serial number for that reason.
BTW, this is a horizontal "pancake engine".
(I tried to e-mail you directly but neither address in your profile would go through.) |
Tim Hoskinson (Tdh37514151)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 12, 2005 - 7:55 pm: | |
Hi Jim Bob I looked at my profile and I am glad you said something my address was wrong so I corrected it. Thank you. I will call my freind Dan and when I find out something I will e mail you. Tim |
jimmci9 #2
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 12, 2005 - 7:59 pm: | |
geoff didnt say 12v71... he said 12-71.... the 12-71 is commonly called a twin... lots of different configurations.. its 2 6-71's side by side with a common flywheel housing... some are same rotaion, some counter-rotation...there's also a 24-71.its known as a "quad".. 4 6-71's pulling together in a compound.... i saw all this stuff today in a genuine detroit parts book (btw i work for a dd dealership) |
Jim Bob
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, October 13, 2005 - 8:37 am: | |
Jimmci9, my bad again. I assumed that 12V-71 was what Geoff was speaking about. I have seen "compound" engine setups with, say, 2 or 4 inline 6-71s each bolted to a gear housing that then connected to a propeller shaft. 1/2 of the engines counter rotated as they were "butt to butt" so to speak. Heck, the Scenicruiser came with a pair of compounded 4-71s.
But I did not know that they numbered the blocks differently or referred to the compounded rig by the total number of cylinders.
It COULD be that the engine was originally part of something like that. But it came out of a yacht as one of a pair of fully DD marinized pancake engines with Allison marine transmissions.
I can look on the other pads on the block but with the star at the beginning and end of this number it REALLY looks like the serial number. Did you try to research the number? |
jimmci9 #2
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, October 13, 2005 - 11:08 am: | |
didnt take the time to research it much... our parts gut was busy and i was doing it at break time....there are lots of different combinations... but all are bolted side to side with a common flywheel/gear housing... |
FAST FRED
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 14, 2005 - 9:29 am: | |
If there really old engines DD doesnt have the numbers.
Our 1944 6-71 in our boat has ALL the numbers quite readable , but DD draws a blank.
Best is the DD folks in Ronkoncoma NY , who have the most experience with Marine engines.
AS I understand my books the use of 2 3 or 4 DD engines was done by bolting them to a tranny designed for this.
LST's usually had 2 pairs of 6-71 bolted to one tranny , but except for a throttle cable the engines shared nothing.
This was done to reduce replacement times, and with a push of a lever a non functioning engine could be secured off line.
The engines had to be stopped to reconect to the tranny.
The aluminum blocks were most used in mine sweeps to keep the mass of ferrious metal as low as possible.
or....
BOOM!!
FAST FRED |
Jim Bob
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 14, 2005 - 1:45 pm: | |
Hi Fred,
Another reason for compounding the engines was that DD didn't have anything bigger (71 series) than the 6-71 until about 1960.
I thought of the mine sweeper engine idea too. I have seen some big iron Waukesha engines that were also specially made with aluminum blocks (only for Navy) mine sweepers. The Navy version part numbers weren't in the system. (Probably "National Security") |
DMDave
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 14, 2005 - 11:29 pm: | |
Detroit Dealer in Ronkonkoma on Long Island is called Atlantic Detroit/ Allison. |