rdaum Posted November 15 Share Posted November 15 Gday team My GT40 replica has a rover v8 3.5 in it, high compression version. Its got quite a few leaks which would be easier solved out of the car. However I have no idea what the engine has in it and it may be better to do another engine and put it in. Does anyone know if there are any dimensional differences between the 4.6 and 3.5 engines? I have heard the 4.6 crank snout is longer, but can't find an accurate figure. There is only a gnats dick hairs gap between the chassis and the crank pulley with the 3.5 and I dont want to go down the route of new engine mounts etc if possible. Any help much appreciated. Cheers Quote Link to comment Share on other sites More sharing options...
ajg193 Posted November 15 Share Posted November 15 @kws Quote Link to comment Share on other sites More sharing options...
Sunbeam Posted November 15 Share Posted November 15 Complicated by the fact there are short and long nose versions of the 3.5 as well iirc. Often dizzy/waterpump style ie front cover version has greater influence on installed length. Quote Link to comment Share on other sites More sharing options...
440bbm Posted November 15 Share Posted November 15 i had thought the blocks and i think some of the heads were the same... but the differences are with the extra mains bolts on crank and then theres stuff to do with it being distributorless. you may need to have a decent googlefest. there's probably a decent bunch of disco nerds around that will know it all around. ytou may want to check the bore while your sump is off..... check they havent already fucked with that! Quote Link to comment Share on other sites More sharing options...
nzstato Posted November 15 Share Posted November 15 In going to EFI, and the 'long' engine they changed the oil pump to crank driven which I believe changes the front cover. The above should be your 3.5 dimensions A quick read, the 3.5 could interchange to a 3.9, but not 4.0 or 4.6 with snout length https://www.gomog.com/allmorgan/40difference.htm This gives you the engine codes to look for https://rimmerbros.com/Images/PDFs/V8Engine.pdf?srsltid=AfmBOor_I3tL7xS6UYiylAxSk9bzs2zCuvbc74FOr7DgacdEnW6D0L_h Best bet would go look for a 3.9 EFI out of a D1/D2 - plenty around for cheap, do fresh head gaskets + studs and you are away... 2 Quote Link to comment Share on other sites More sharing options...
rdaum Posted November 15 Author Share Posted November 15 Sick prompt responses thanks gents! Quote Link to comment Share on other sites More sharing options...
kws Posted November 15 Share Posted November 15 I can't be 100% sure on the 4.6 because I haven't had one, but the crank snout differences on 3.5 and late 3.9 is all inside the timing cover due to the oil pump differences. The actual length was the same. There is a spacer to use the old pulley on a newer engine and keep belt alignment. The blocks are all the same dimensions, just with different bore and stroke. Quote Link to comment Share on other sites More sharing options...
Unclejake Posted November 15 Share Posted November 15 I had a 4.6 in a $50,000 vehicle 20 years ago and it was nothing but trouble - even back then when it wasn't very old. Eventually the cylinder liners and block separated so I happily walked away The 3.9 has shown far greater longevity and can see pretty good performance (using American carburettors and a few other tricks). Based on the above dimensions a 3.9 sounds like a much better choice, but I do know you need to be careful with at least oil viscosity vs. the hydraulic lifters if you're pushing those motors hard 1 Quote Link to comment Share on other sites More sharing options...
locost_bryan Posted November 15 Share Posted November 15 3 hours ago, Sunbeam said: Complicated by the fact there are short and long nose versions of the 3.5 as well iirc. Often dizzy/waterpump style ie front cover version has greater influence on installed length. Water pumps and front covers were discussed here. https://www.fastmarinamagazine.com/viewtopic.php?t=4754&sid=df092dcb2ba3041d363574413bd5e608&start=30 Iirc Rover P6b/MGB V8 and Disco 3.9 serpentine belt had the shortest front-ends. 4.0 and 4.6 have the Iceberg block with 4 bolt mains, strongest block iirc Quote Link to comment Share on other sites More sharing options...
Popular Post ajg193 Posted November 15 Popular Post Share Posted November 15 14 hours ago, locost_bryan said: Water pumps and front covers were discussed here. https://www.fastmarinamagazine.com/viewtopic.php?t=4754&sid=df092dcb2ba3041d363574413bd5e608&start=30 Iirc Rover P6b/MGB V8 and Disco 3.9 serpentine belt had the shortest front-ends. 4.0 and 4.6 have the Iceberg block with 4 bolt mains, strongest block iirc Are they called iceberg because you can only see 10% of the problems at first glance? 3 7 Quote Link to comment Share on other sites More sharing options...
Muncie Posted November 17 Share Posted November 17 I had a 2000 year 4.6 gave me no problems nick named the ramshorn due to the funky inlet manifold way more punchy than a 3.9. I tried both when car shopping. supposedly last of series had issues sorted. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.