Thread: V8 Engine Identification

Originally Posted by 748Rum

Recently managed to pick up an injected 3.9 V8 to rebuild over winter for my MGB project.

4.0 engines are often lying around for a reason and that is that along with the 4.6 they can slip liners when getting a bit hot. Now as you are going to rebuild the engine I would certainly check the liners with a block pressure test. I would even consider replacing the liners with top hat liners to stop them possibly slipping in the future.

However this engine has obviously has some tinkering done as evidenced by the 3.9 injection system and timing cover etc so if you are lucky it may have been top hatted. I acquired a 4.0 a little while back to build a 4.6 and when I pulled the heads the 4.0 had already been top hatted

You also need to learn the differences between the 3.9 and 4.0 (they are the same displacement with same stroke and bore) as lots of internal block parts - are different - eg different sized cranks and bearings. The 4.0 has a crank oil pump where the 3.9 has a cam driven oil pump - but as you have the 3.9 timing cover I assume it uses the 3.9 oil pump.

So just do a bit more research on the 3.9 and 4.0 engines so you know what you are dealing with.

Cheers

Garry

They can crack or slip liners but generally they just do head gaskets even with quite high temp overheats. I am convinced that ARP Head Studs, stock gaskets and lower running temps keep head gaskets happy.

Cheers

Awesome thanks Garry and Ozscott.

I had heard that the liner slipping was an issue but thought it would only be for the larger displacement blocks due to what i presumed would be thinner cylinder walls behind the liners. Looks like I have a heap more reading to do!! I have ordered the “How to Power Tune Rover V8’s” book and am looking around for a D2 (and D1 as well I suppose) manual so hopefully they will have a mass of information in them as well as the forums of course.

Actually really looking forward to stripping the engine and seeing what puzzle awaits inside. Again only going off what was said when i grabbed it but was told that it had a cam and some head work when it was rebuilt so i have my fingers crossed that that is correct and they did the top hat liners at the same time.

Are there particular Rover V8 specialists around north side of Melbourne who are good at doing the machining (including top hat liners) checking the block and doing balancing work etc? Or is this something all should be able to do? Will check out the vendor pages but assume people will have had good experiences with particular ones.

I wont be looking for massive stump pulling torque as the car only weighs 950kg wet but having it happy to rev a little with some good mid range poke would be great. I will sit a Ford XR6 T5 behind it (the LT77/R380 needs firewall and tunnel mods so not interested in that) and not sure what diff but something in the 3.27/3.55 ratio range would be good. Couple of MG aquaintences run earlier 3.9 motors with around 220-240bhp and see sub 6 sec 0-100 times and 13 sec quarters with 3.55 diffs so that would be nice to aim for.

Also engine temp is going to be interesting as there is bugger all room in the bay once everything is stuffed in. I am planning to use a custom radiator to make sure it can control the heat as well as an oil cooler, bonnet vents and header wrap/ceramic coating. Not sure about the value of electric water pumps and the like but will certainly investigate.

Long term project but I have already done all the body and suspension mods to make sure it will cope with the power as well as be able to get it down on to the road. On the hunt for some Volvo 240 4 pot vented calipers as when combined with Peugeot 505 vented discs they give fantastic stopping power for the road and track and all at about 1/5 the price of the equivalent Wilwood kit.

Thanks again for all the great advice.

Originally Posted by 748Rum

I had heard that the liner slipping was an issue but thought it would only be for the larger displacement blocks due to what i presumed would be thinner cylinder walls behind the liners.

You have the largest block that Rover built - it is the same basic block in the 4.0, the 4.6 and the TVR 5.0 - all have the same bore of 94mm. Yes there are larger versions but one offs and by obscure or private builders.

So you need to check this out on your engine - there are youtube videos on how to water pressure test the engine block.

Sounds like a great project always loved the MGBGT. This site has a fantastic Knowledge base and very friendly people. In terms of finding parts for your engine, keep looking on the www. The UK has plenty of Land Rover specialists, Rimmer Brothers for example deal in most things related to Rover, British Leyland, Triumph... also check out TVR enthusiast sites, as they used the Rover V8 too. I'm only a novice, but key things from what I've been told are cooling system, cooling system....cooling system. The general, car services places/mechanics etc, will likely say "Land Rover's / (their engines) are a specialist vehicle" and that's from experience (another story) however, from my research, a fuel injected engine pretty much has the same components bolted to it externally to make it work. Eg MAF sensor, IAC, TPS, injectors! etc. If your in the North of Melb, might be worth you having a chat with Romsey British Automotive & 4x4 (formerly Romsey Land Rover) very friendly, Knowledgable and easy to deal with. good luck with it and would love to see pictures and stories of progress

Thanks again folks for all the advice. I have been working my way through a bunch of YouTube videos and parts websites to see what’s out there and how to do stuff. I am up in Kyneton so ducking over to Romsey will be very easy. I can see a few visits for parts and advice coming up.

My copy of “How to powertune” arrived on Friday. Must say I am a bit underwhelmed by the content. For the MGB 4cyl equivalent book by the same publisher there was a wealth of information in there. Everything from proven engine recipies (with driving characteristics and power output) through to tips, tricks and required specialist tools. On the initial read of the V8 one it just feels like an ad for JDE and Wildcat Engineering and not a great deal else. Will go back through and see what else I can glean from it as my initial assessment may be a bit harsh.

As I start pulling the engine down I will start another thread with that and the car as well.

I am starting with the MGB roadster that I have owned for over 24 years. I imported it from the US and had to do a RH Drive conversion for full rego. At the same time i rebuilt and modified the 4cyl and the suspension and brakes. Then it was my everyday car for 10 years where I clocked up over 180,000 miles. Did a few modifications along the way including MGB race suspension, EBC Pads & liners and slotted&dimpled rotors, wheels and R spec tyres and big valve head. Then when I moved to the Middle East for 10 years it was put in storage waiting for my return.

Came back, dusted it off and gave it a service and then it became a fun weekend car. It’s mostly original paint and panel except the right hand rear corner where some idiot hit it and then did a runner a couple of years ago. I knew that i would need to rebuild the whole driveline in the next few years as well as go through the interior and put in good heat shielding (dynamat or HP Products) but following a small wire fire on the starter-motor figured now was as good a time as any.

Looked at parts and pricing and for rebuilding the 4cyl engine and i’d be looking at over $8k + a few more thousand for gearbox and diff and still would only be about 140bhp and starting to become temperamental below 2000rpm. A V8 conversion had always been in mind but back when I first built the 4cyl I couldn’t have found a V8 for the same price it was to rebuild and modify the 4cyl and it also required significant body mods for the transmission tunnel as there were no gearbox options except for the R380. Now its the other way round and I have the added bonus of a standard 3.9 being 190bhp and completely drivable, a T5 that requires no modification to the bodyshell and lots of resources and information to draw on.

When I stripped the interior i found a little bit of rust in the passenger floor pan. So when i replaced that my good friend, who is also my engineer and teaching me how to weld, designed some chassis components that will link the front half chassis to the front leaf spring hangers that we are stitch welding into the body next weekend. These will then double as mounts for the anti-tramp bars that I am making and all up stiffens the body shell considerably. Enough for 350+bhp and 400+nm torque without twisting the shell according to his calculations. I’m not aiming for that much but makes me comfortable knowing that the bodyshell can put up with a bit of punishment. I have also put in new rollbar mounting plates, new soft top mounting plates and stitch welded the transmission tunnel base board (like a 14 inch long prop shaft loop that is currently spot welded in). Only other body mod required will be welding in new mounts for the radiator but I will leave that till the engine and everything else is in place so I can mount the most efficient radiator i can in the best spot.

Lots of work ahead, was planning for the engine to be finished and car be prepped and ready for the conversion by the end of the year (bloody cold up here during winter which will limit how long I can work in the shed before i can no longer feel my hands). I will then enjoy my last summer with the 4cyl before the transplant next winter.

Anyway, enough of me going on, thanks again for all the info and here is a pic of the car before I started pulling it apart for welding.

Cheers
90FE0BCA-40F5-4CFB-9A06-FD828AA10A48.jpg

Remapped and cammed a hi comp 3.9 MGRV8 a few years back with 14cux. Be prepared for the vehicle to attempt to swap ends when pushed hard😎😃