I've been looking for a specific V8 engine to rebuild for a while... a long while: my wanted ad was posted here 6-years ago.
The problem was I was looking for one of the cross-boltable 3.5L RV8s that were produced in the late '90s from the 38A castings. Referred to by Des Hammill as a "service block" and by the Lloyds boys as a military block in their books and these proved to be quite hard to find. These are effectively interim blocks that came with the undrilled crossbolting bosses, the 10-bolt heads, wider main caps, etc, except they were built with standard 3.5l 3.500"/88.9mm bores.
This weekend I finally found one and have it in my garage.
The engine (or at least, the block) is going into a late '60s series IIA land rover which is being built from the ground up around a nice period V8 conversion. I really want to build an interesting engine for it and to have fun in coming up with something unique, but I really don't want to get giddy with the power/torque. The drivetrain would already be on the limit at the 185lbft standard figures for a carb Range Rover Classic V8 and a standard V8 produces more (far more) than enough power for such an agricultural vehicle. So, if I can't geek out on power - why not focus on going way over the top on the actual strength of the engine and try to incorporate every conceivable update that BOP/Rover made to the engine during its 40 year life (except for the 94mm overbore). A bit of a celebration unit
Visually, I want the engine to look like a factory engine, correct to the early '70s Range Rover classics (so 'Rover' valve covers and probably Stromberg 175 carbs/inlets). I could use either SUs or Strombergs - the factory V8 prototypes used SUs, but the odd angles that Land Rovers can run at pushed them towards Strombergs in the production Range Rover.
The one exception that definitely won't look period is the timing cover and belts. I need this engine to be the shortest possible Rv8 possible - this means moving to a distributorless P38 timing cover and serpentine belts. I want to use every trick in the book to save every mm in length I can. I'll be measuring all the cooling fan options to see which is tightest to the block, I'm open to using a traditional steel fixed fan on a custom boss (I have a lathe and milling machine) or the thinnest viscous fan available. One other self-imposed limitation is that I specifically don't want to use an electric fan, as is traditional on Land Rover conversions, I want to have an engine driven fan - which should be possible thanks to the distributorless timing cover and short serp pulley.
Happy to post progress on here, but I could do with some help - the first phase of this project is outlining the plan and identifying and collecting parts.
Here is my rough list (I'm no expert, so happy to be steered-correct on any points I've misunderstood):
Machining work (will be done by one of the V8 specialists, I've already had some advice from V8Developments but happy to consider others):
1) drill to accept crossbolts
2) top hat lining (I know this sounds excessive, but I've already budgeted for it - while early 3.5s didn't suffer from liner slippage, on these late service blocks, while they don't crack and are thermally more resilient, LR changed the machining process which introduced an unrelated slippage issue)
3) Line bore the main bearing tunnel (bear in mind these service blocks have the large caps) to the larger 67.577mm P38 size
4) possibly clearance the block to accept a 4.0 crank (I'm told the P38 blocks, which share the same casting as my engine had clearance for the crank counterweights)
5) (if the threaded holes aren't there already) drill to accept a camshaft retaining plate
Parts I'd like to fit:
a) a 4.0 P38 crank. This obviously is setup for the larger main journals and has the same 71.12mm stroke as the 3.5L engine. Its nose and keyway are also ready-setup for the P38 distributorless timing cover.
b) A P38 distributorless timing cover with Serpentine belt, incorporating crank driven oil pump
c) Rover-branded valve covers from an early engine
d) SU or Stromberg carbs and inlet manifold
e) whichever cast exhaust manifolds are best routed for the installation (I won't know this until I trial it in the chassis), being a 3.5l engine I have access to the full LR/LDV/TVR/MG parts bin without risk of strangling the engine.
f) the problem. I would have wanted to use P38 type conrods and pistons (55.5mm big ends and 24mm small ends)... but these aren't compatible with 3.500" 3.5L pistons, nor do the conrod lengths work. So I think my only option is to have the 4.0 crank big end journals ground down from 55.8mm to 50.8mm and use standard 3.5L rods and pistons. Gutted about this as its the only feature I know of in which a P38 bottom end would have an edge over the little 3.5 I'm building.
g) a very thin/tight engine driven fan to keep the engine as short as possible.
h) a sump. I don't know which one yet - again I'll need to trial the engine in the chassis but I'd be looking for one that have the same clearance as the old 2.25L 4-pot engine after allowing for the longer engine. I believe that the P38 timing cover will dictate which sump(s) I cam use and suspect I'm limited to Discovery II or P38 Range Rover options).
i) some sort of distributorless ignition/trigger wheel system.
j) This engine was from an Auto, so anything I need to convert this back for a manual installation, flywheel etc.
I'm open to either tracking down parts individually or buying a donor engine or two to get the bits I need.
So, quite a long post there - but thought it would be of interest to the forum. If anyone can think of any sort of reliability/strength improvement that was incorporated into the late P38 engines that I've missed (obviously excluding EFI) then please let me know.
