Although RPi, who have spread the story that every engine will fail sooner or later, always maintain that the 4.6 was affected most. I've always assumed that there were more 4.6 engines made than 4.0 litre so it stands to reason that more would fail.
I agree to that ....
No it isn't. It was a 1960's Buick design that Rover bought from them....
Richard, you missed the romantic take on my words ... lol
I meant it as if the relationship between the P38 and the RV8 is like a loving, but sometimes troubled, marriage :-)
03 & 04 were all 4.6 IIRC.
I'm surprised there was never a bigger market for better flowing heads for the RV8. Also given it was in many ways ahead of it's time being an aluminium V8, with a long span of production, and used by sports car manufacturers, it's surprising there were never 4 valve per cylinder overhead cam heads made (which could use external cam belts).
I once bought 2 'grass track' spec RV8's, one with big cam and valves, the other with standard-ish cam but supposedly stronger bottom end, with the intention of fitting one of them in a Ford Sierra. I eventually bought a 'proper' Ford Sapphire (Sierra) Cosworth with the well known 2L Pinto derived but 16valve and turbo'd Cosworth engine but there were a few RV8 powered Sierra's around.
Yeah its odd, especially given the massive range of heads available for the various other yank V8's
I suspect it comes down to cost and volumes. Massive numbers of chevy/ford/chrysler V8's sold and a thriving tuning/hot-rod scene mean huge aftermarket for them. Heads are available at a massive variety of price points and performance levels.
The Rover in comparison was only ever really fitted to a few niche low volume sports cars back in the 70/80's and spent most of its life powering various 4x4's..
The two heads that do exist (wildcat and TA) are very expensive as a result and both are a bit "weird" requiring many additional parts which drives up the cost further.
V8 Developments do ported heads in 3 stages (http://www.v8developments.co.uk/headporting.htm) but I'm not aware of any 4 valve or OHC aftermarket ones. While checking out the Wildcat heads, I came across this https://www.ebay.co.uk/itm/115732141242, a pre top hatted block for not that much more than the cost of getting top hats fitted to an existing block. A good mod if building an engine is to use the 4.6 crank and con rods with 4.0 litre pistons. As the 4.0 litre pistons have a smaller dish, that ups the compression ratio to around 10.3:1 (ish). Pre-ignition won't be a problem with the knock sensors to back off the ignition timing if it occurs or if running on LPG with the much higher octane rating.
Gilbertd wrote:
V8 Developments do ported heads in 3 stages (http://www.v8developments.co.uk/headporting.htm) but I'm not aware of any 4 valve or OHC aftermarket ones. While checking out the Wildcat heads, I came across this https://www.ebay.co.uk/itm/115732141242, a pre top hatted block for not that much more than the cost of getting top hats fitted to an existing block. A good mod if building an engine is to use the 4.6 crank and con rods with 4.0 litre pistons. As the 4.0 litre pistons have a smaller dish, that ups the compression ratio to around 10.3:1 (ish). Pre-ignition won't be a problem with the knock sensors to back off the ignition timing if it occurs or if running on LPG with the much higher octane rating.
I remember V8 Developments advertising in car mags I read in the early 90's.
Come to think of it, while there are plenty aftermarket heads (especially Chinese made) for SBC and SBF engines (with various chamber volumes so you can pick your compression ratio) there doesn't seem to be any 4 valve per cylinder OHC heads for them either... Again, given the popularity of the engines would've thought there'd be a few firms making them. I quite fancied some big flow heads for my SBF boat engine, just spent over £120 on one of my cast iron heads but I could've bought 2 new big flow aluminium heads for around £700 and gained around 100bhp... but then to use the boat on saltwater I would've needed to fit a closed cooling system with water to water heat exchanger setup. Strange that there are no 4 valve per cylinder OHC heads for SBC and SBF engines when there was at least one firm making 4 valve per cylinder heads for the 4 cylinder Pinto engine (and iIrc it was an American firm) well before Cosworth made their 4V per cylinder Pinto head... Begs the question why they didn't make 4V per cylinder SBF and SBC heads, would only need to fit a toothed cambelt drive (or 2) between the harmonic balancer and front pulley, remove the tappets and plug the tappet oil feeds.
Just finished the L322 LPG conversion, can't believe how long this one took me I've been working on it all week! when 10 years ago I used to rattle them off in a few days! For sure I've done things a bit differently on this conversion compared to those I did 10 years ago, had to relearn some stuff that I used to be extremely familiar with, in fact so familiar it seems I didn't even bother making notes. All good and running great but I haven't quite finished even now, I still have to refit some boot trim, the engine cover, couple of nuts on the heater air intake panel that goes over the engine and recheck calibration from a cold start in the morning. Checked my records, seems it's been 10 years since I last converted an L322 (the last one I did was a supercharged one, this is the 4.4 normally aspirated engine) but I've fixed the LPG system on a great many L322's and other model Land/Rangerovers during that 10 years and converted around 1000 vehicles since then.
I was expecting to get this L322 converted in 3 days leaving Thursday and Friday to work on my boat engine. I've already got all the short block re-assembled (more or less, still need to fit the brass core plugs), the last thing I did was to re-lap the valves on one of the heads. The next thing I'll be doing is to check the other head and re-lap the valves, then I'll be refitting the tappets and refitting the heads. Can't wait to get it all back together and refitted in the boat so I can try it at least on the river once or twice before winter.
4v just isnt needed, as GM discovered with the LS.
Ford went off down the 4v OHC route in the 90's, at the same time GM ran the numbers and realised that a very well designed 2v pushrod engine with all the latest technology could compete favourably at much lower cost and we got the LS, which is now in its third generation and has all the good stuff like cylinder on demand and variable timing, and competes pretty favourably with 4v designs from their competitors.
4v is great when you need to extract every horsepower from a tiny engine, but for a big V8 it tends to matter a lot less, and they can get close enough with a good 2v head.
Not sure if i should try to steer this back on track or just make a new thread. Anyways i had a day off yesterday and after the brake issues i decided to do some more plumbing on the engine.
When i put it all back together i replaced every coolant hose on the engine. That meant that the LPG vapouriser was no longer connected so i've done the last few hundred miles on petrol. MOT is due next month so i need the LPG working as the cats are worn out and it probably wont pass on petrol... I didnt want to hack up my new pipes, and i wanted to try something i've been thinking about for ages.
Some years ago i blanked off the throttle heater loop. So yesterday i removed my blanks and ran new pipework to the LPG vapouriser. Now it comes off the manifold pipe stub that used to feed the throttle heater plate, goes over to the vapouriser in 10mm hose, then from the vapouriser back to the small header tank inlet underneath.
Obviously cant drive it, but i fired it up, initially with the return line just poked in the top of the reservoir so i could see the flow, and once the air purged out, i was getting a nice strong flow from the pipe. win?
Wont know until i fix the brakes and try to drive it, but hopefully it all works nicely and its a LOT neater than the horrible T'ed fittings that were there before.
My only concern is both the manifold and header tank stubs are 8mm, with a 10mm hose cinched down onto them. I'll keep an eye as that might leak, if it does i'll probably get a short length of 8mm and some streight couplers and use those for the final connection. The vapouriser has 10mm stubs so those fit nicely.
I also reinstalled the passengers side exhaust manifold heat-shield, and peered at the drivers side one thinking how the F am i getting that back in there... any tips?
Oh i also found a small leak on the top radiator hose at the manifold. Replaced the factory constant tension clamp with a nice JCS HiGrip to see if that fixes it. It almost looked like it was leaking out of the fabric reinforcement at the radiator end too which is very weird. Will need to keep an eye.
Aragorn wrote:
I also reinstalled the passengers side exhaust manifold heat-shield, and peered at the drivers side one thinking how the F am i getting that back in there... any tips?
Shove it down at the back, then rotate it so the front comes down. It bends easily enough so will go in (if you are brutal enough) but you can always bend it back into shape once it is in place.