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Mystery Engine Number
Posted: Mon Mar 07, 2016 7:21 am
by john 215
Hi,
Been asked by a fella over on a TR7 forum I am on to help I.D a engine number for him, it is -
46A00708A
Its a late 3.9 / 3.5 block with cast crossbolts BUT not tapped, fitted with a SD1 type front cover, you can see that the engine number has been machine stamped into the block and has a compression ratio od 8.13:1 -
Any ideas ???
Cheers John
Posted: Mon Mar 07, 2016 8:12 pm
by mgbv8
46A is a new one on me John ??
Maybe an export engine??
if you cant find the number on here try the V8 register or even give Rimmer Brothers a call
Perry
Posted: Mon Mar 07, 2016 8:19 pm
by ChrisJC
Looks unusual. I think 46D is the Range Rover P38 engine....
Chris.
Posted: Tue Mar 08, 2016 5:35 am
by john 215
Hi,
Could be a Range Rover lump with that compression ratio and acquired a SD1 front cover along the way. I did ask ' Google ' and Marcos was mentioned in relation to this number, but really cant see them using a 8.13:1 CR can you ??
Cheers John
Posted: Tue Mar 08, 2016 12:40 pm
by SimpleSimon
ChrisJC wrote:Looks unusual. I think 46D is the Range Rover P38 engine....
Chris.
I think the owner may be in for a nice surprise rather than the 3.5 he expected

Posted: Tue Mar 08, 2016 4:54 pm
by DEVONMAN
SimpleSimon wrote:ChrisJC wrote:Looks unusual. I think 46D is the Range Rover P38 engine....
Chris.
I think the owner may be in for a nice surprise rather than the 3.5 he expected

I would have thought it would have factory drilled and tapped cross bolts if it was a 4.6 but you never know.
Posted: Tue Mar 08, 2016 8:06 pm
by Blown v8
Just out of interest,are most of the engines stamped there !
My engine number is on the n/s but at the back near the bellhousing !
Posted: Tue Mar 08, 2016 9:09 pm
by mgbv8
Blown v8 wrote:Just out of interest,are most of the engines stamped there !
My engine number is on the n/s but at the back near the bellhousing !
Thats where the engine number was stamped on my original 1975 MGB V8 engine which was also 8:1 CR ??
Posted: Tue Mar 08, 2016 9:10 pm
by john 215
Hi,
Looks unusual. I think 46D is the Range Rover P38 engine....
Sorry but looking at the picture it says 46A, I think ?
Cheers John
Posted: Tue Mar 08, 2016 9:11 pm
by mgbv8
Blown v8 wrote:Just out of interest,are most of the engines stamped there !
My engine number is on the n/s but at the back near the bellhousing !
Thats where the engine number was stamped on my original 1975 MGB V8 engine which was also 8:1 CR ??
Posted: Wed Mar 09, 2016 10:18 pm
by ChrisJC
john 215 wrote:Hi,
Looks unusual. I think 46D is the Range Rover P38 engine....
Sorry but looking at the picture it says 46A, I think ?
Cheers John
Yes it does. I was just thinking that maybe it meant it was of a similar age to a P38 engine (the style of the numbers looks to be the same). I would go with the theory that it is a special number sequence for a small sports car manufacturer, as pointed out above. It's a low number too, so clearly not a volume builder.
Chris.
Posted: Thu Mar 10, 2016 6:37 am
by john 215
Hi,
Thanks for the answer,
Was thinking along the same lines myself, just the low compression ratio, unless destined for a foreign market and never made the journey.
Cheers John
Posted: Thu Mar 10, 2016 7:20 am
by Ian Anderson
Could it be for a TVR turbo application?
Or is that too high a static compression fora turbo engine?
Ian
Posted: Thu Mar 10, 2016 8:44 am
by DEVONMAN
8.13 compression ratio is ok for turbo application.
My Son's sierra has a twin turbo 4.6 with this ratio.
The max boost is controlled at 1 Bar.
Posted: Thu Mar 10, 2016 10:54 am
by Darkspeed
Could it be just a number for a spares new short block assembly - hence why no list as being associated with particular car.
There were quite a few of these new short assemblies kicking about a while back and may explain all the secondhand parts bolted to it. SD1 cover 14 bolt heads etc.