5.2 Rover V8 Stroker kit

**DiscoClax** · 22nd July 2015, 10:52 AM

Originally Posted by Pedro_The_Swift

You realise theres probably a market for these,,,

Could be.... Could be...

I developed my engine spec over a couple of years with a Buick/Rover specialist builder in California (at the time it was much cheaper to get the machining and labour in the US due to exchange rates). He also did a second 'kit' of parts based on my build but around a 3.5" stroke P76 crank for another mate (again built into an interim 3.9 block) and that engine we put together over here and had the machining done locally. It develops the same power (head flow limited) but a smidge more torque due to the extra 8ci and 90thou of stroke. He's currently building a 310ci/5.1ltr version for another customer (4.6 based, top-hat linered to 3.80" bore), and the odd Buick here and there. If anyone wants more info on my engine or who built it, feel free to PM me so this thread doesn't go off-topic..

The voice of reason: For a budget build you could get an easy genuine ~300 lb.ft (400Nm) and 250-300BHp+ (185-220kW+) out of an optimised (tight quench, higher-comp, blueprinted) 3.9-based engine, bored to 3.736" with cutting-edge modern camshaft grind. That would end up around 246ci (a true 4.0 litres). BHp would depend on level of head work, cam grind and exhaust, but the torque would be there irrespective. If I had to do it again, I would be more sensible and get 70-80% of the benefit of the stroker at 40-50% or less of the cost (and a quarter the work) by merely carefully optimising an interim 3.9 with modern thinking. Plus my drivetrain wouldn't cower in fear every time I look hard at the loud pedal. The ability to smoke grippy 32" tyres on clean, dry bitumen in high-range is not really a core requirement for comfortable off-roading and touring, so I over-did it somewhat.

MGB3.9 · 17th July 2016, 02:51 PM

Originally Posted by DiscoClax

Could be.... Could be...

I developed my engine spec over a couple of years with a Buick/Rover specialist builder in California (at the time it was much cheaper to get the machining and labour in the US due to exchange rates). He also did a second 'kit' of parts based on my build but around a 3.5" stroke P76 crank for another mate (again built into an interim 3.9 block) and that engine we put together over here and had the machining done locally. It develops the same power (head flow limited) but a smidge more torque due to the extra 8ci and 90thou of stroke. He's currently building a 310ci/5.1ltr version for another customer (4.6 based, top-hat linered to 3.80" bore), and the odd Buick here and there. If anyone wants more info on my engine or who built it, feel free to PM me so this thread doesn't go off-topic..

The voice of reason: For a budget build you could get an easy genuine ~300 lb.ft (400Nm) and 250-300BHp+ (185-220kW+) out of an optimised (tight quench, higher-comp, blueprinted) 3.9-based engine, bored to 3.736" with cutting-edge modern camshaft grind. That would end up around 246ci (a true 4.0 litres). BHp would depend on level of head work, cam grind and exhaust, but the torque would be there irrespective. If I had to do it again, I would be more sensible and get 70-80% of the benefit of the stroker at 40-50% or less of the cost (and a quarter the work) by merely carefully optimising an interim 3.9 with modern thinking. Plus my drivetrain wouldn't cower in fear every time I look hard at the loud pedal. The ability to smoke grippy 32" tyres on clean, dry bitumen in high-range is not really a core requirement for comfortable off-roading and touring, so I over-did it somewhat.

Hello DiscoClax , im interested in the details of using these Chev 305 pistons in a 3.9 interim engine. Cheers Matt

**Tins** · 18th July 2016, 11:17 AM

Originally Posted by DiscoClax

an engine that makes the LS1s look a bit soft, cost me a lot less, involves 0% rego or insurance hassles, and it peaks under 5000rpm.

What sort of torque are you getting? To me that's always been the problem with the LS1, Peak too high and not so good torque down where I would want it in a 4WD.
Can you do this with any 3.9? I have one, but I have no idea what it's out of.

**PAT303** · 18th July 2016, 01:21 PM

DiscoClax,any chance you could do a thread on your engine?,me thinks it'll be popular. Pat

**Tins** · 18th July 2016, 03:03 PM

Originally Posted by PAT303

DiscoClax,any chance you could do a thread on your engine?,me thinks it'll be popular. Pat

Seconded.

**ozscott** · 18th July 2016, 03:50 PM

Originally Posted by loanrangie

That kit can only be fitted to a cross bolted block which means 4/4.6, and if you use one of them you are kidding yourself if you think its going to last.
They fail without being stroked let alone nearly doubling the HP.

I have read the Des Hammill book and heavily researched the subject. I have come to the conclusion that the 4.6 X-Bolt was the best block to use in terms of thickness on the cylinder walls and providing you run the motor at lower temps (like an average of 85 degrees C like mine runs at) and do regular oil changes and keep the cooling system in check, the stock engine is a winner. Having said that as soon as the heads are removed for say a blown head gasket from an overheat (eg leaving the overflow tank lid mis-threaded...) then you might be on borrowed time (but not necessarily) and you should definately use a head stud kit when putting it all back together.

Top hatted liners give piece of mind, but the stock liners are not necessarily a drama.

Cheers

**PhilipA** · 18th July 2016, 04:29 PM

I often wonder why someone has not used a Buick 300 as the basis f a build.
They are a cast iron block version of a 255 and use alloy heads AFAIR.
They are old engines now like P76 but surely there must be some in wreckers in the USA .
They have the same bell housing bolt pattern as the RV8.
Knowing the yanks there is probably lots of gear available such as stroker kits etc.
Regards Philip A

**350RRC** · 19th July 2016, 07:49 PM

Cast iron blocks (and heads for that matter) are so 'forgiving' and incredibly long lasting.

The only thing that will corrode is the thermostat housing, which is probably designed to act as a sacrificial anode anyway.

The only gripe with my recoed 600,000+km thing is that the valve stem seals need doing, but that hasn't got any worse for the last 350,000.

99.9% on lpg. DL

**ozscott** · 20th July 2016, 05:45 AM

I agree mate. Cast iron can withstand more heat and keep trucking. Some of the magic of coil spring LR is their light weight. I prefer alloy for that reason . Cheers

**Traco** · 20th July 2016, 12:03 PM

The iron block Buick 300/340 engines have found their way into some sports cars in the States. There's a range of opportunities for transplanting Buick parts into other Rover applications, crankshafts, water pumps, cylinder heads, etc, see http://www.aluminumv8.com/

The 300 sported alloy heads for 1964 only, after that they went cast iron. They flow better than all the Rover heads on account of their bigger ports and can be fitted with much larger valves.

There's been quite a few stroker kits available over the years, including the local Adelaide made one that TRS ? and also Real Steel in the UK - were selling. These produced tremendous torque but also used a tremendous amount of fuel. And not all proved reliable or durable, Graham Cooper once told me they had to deal with some kits that had pulled liners down bores.

Personally, I'd feel much more comfortable with a top hat 4.6 block over a stroker. If you want a lot of power V8 Developments do a range of large capacity RV8s including a nice 5.5 that produced 398 bhp/438ftlb in a road going TVR. They have a good reputation for high quality workmanship. Not exactly cheap but extremely well built, durable and bolt straight in. Probably not quite what you want in a LR but it could easily be "detuned" for that purpose. How long your tranny would last is another matter, but note in the above link that D&D are now offering a new bellhousing to allow the mating of a range of US muscle car manual and auto trannys to the RV8.
V8 Developments

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