I'm looking in the long-term to build a bulletproof ALH bottom end to use with an ALH head and a Bosch VE mechanical pump from a Land Rover 2.5L 300TDI. I have one running 196k mile engine right now for the project, but want to build a very stout, fresh & upgraded version of it for long term use at some point before the final stages of the project.
This will be going into a 2400lb Suzuki Samurai 4x4 with the aerodynamics of a brick wall, pushing 31x10.5 tires, that may see somewhat regular use pulling a 4x8 trailer and 2-3 dirtbikes up steep mountain grades etc, & occasionally some 330-450lb street bikes, hauling firewood & misc etc.
Eventually the Samurai will be stretched to Canadian LWB (long-wheelbase) body specs with an Aqualu aftermarket marine grade corrosion-resistant 5/32" plate aluminum body tub, so it'll gain more cargo/towing capability - 55" cargo bed vs 32" stock US SWB version, 90" wheelbase vs stock, & will be thursty for more engine.
Aqualu body:
I am trying to keep this build plan as durable as I possibly can while still making plenty adequate power & lower end torque, and keeping the fuel economy very respectable. Honestly I am hoping this may be a semi-daily driver from now until they revoke my license in another 40 years due to old age! If it works out to suit my needs, I will be stockpiling another spare engine or two even.
Onto the engine bottom end...
I would say my maximum horsepower goals would be 130hp or 140hp minimum, but no more than 175hp in order to keep it durable, this is not a hot rod but I do want something that is fun to drive still. Torque output I am hoping is 225-275ft-lbs.
The Land Rover Defender 90 (who's injection pump I am using) weighs 1000lbs more, & has a 2.5L 300TDI 110hp/195ft-lbs Land Rover engine, gets 30-35mpg highway, & will pull the heavier Defender 90 up big hills just fine. I figured 1000lbs less and 130-140hp with more torque yet would without a doubt be A LOT more fun to drive still.I currently have a brand new GT2052 turbo that came with this engine, & will swap on whatever injectors that I can in order to keep the smoke to a minimum or non-existent, and keep efficiency up, while still making great power, with emphasis on low-mid torque. This turbo is rated at 140hp to 220hp, and maybe a slight bit on the larger side than what I needed, but it is a brand new $800 turbo and is a highly efficient more modern design oh, so I will probably just run with it for now and see how it does on the low end and turbo lag. I originally planned to find an old Volkswagen KKK K14 turbo and rebuild it. That would definitely have more bottom-end but would be lacking in top-end and really is best to run at no more than 15 psi (I was hoping for just a touch more than that, perhaps 17 or 18psi).
Due to the emphasis on low-end torque, I was especially concerned about the durability of the bottom end, and especially the big end rod bearings, as when you are building more power at low RPM, the oil pump is not spinning faster, so you have less oil pressure. Sputter bearings at minimum will be necessary. I have also heard of people bending rods in engines that did not have substantially more high-end horsepower, but rather just boosted the low end torque more.
I would like to keep the piston size as close to stock as possible, only over boring to get a fresh cylinder bore surface if the cylinders are worn or damaged.
I was intrigued by converting a BHW 2.0 block to work with the ALH front main seal housing and timing belt idlers, BSM delete/ALH oil pump, but not sure I want to go that drilling & tapping route for the missing idler.
Nor do I want to run significantly heavier 2.0L BHW pistons (slightly more vibes) until I need to bore the block that large of oversize in another 500,000+ miles, nor do I want to bore 1.5mm worth of meat out of the ALH cylinders to run the 2.0 pistons just for the extra 0.1L displacement.
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This leaves me with 2 main options & a few others:1.) BHW/PD150 crank and rods (larger big end rod bearings than the rest, stronger cracked rods) & possibly BRM pistons or similar?
Sputter bearings on the big ends as well for longevity.
Disadvantage - BHW are a bit harder to find here in the USA.
2a.) Keep the ALH crank, run slightly stronger factory PD100 rods and Euro-spec ASV 19.0:1 c.r. pistons are the same compression and basically same height & layout as ALH pistons, but have the oil cooling passages underneath & a significantly thicker crown, as well as having the benefit of moving the compression rings lower than the ALH, BRM, BHW pistons in order to be able to tolerate a lot more heat under heavy loads.
*ARL pistons are the same but even thicker crown and 18.5:1 c.r., better for more boost/higher rpm power builds, but slightly more smoke on startup, and slightly less low-end torque.
2b.) Same as above but run Rostens H-beam rods or Molnar etc H-Beam rods from Frank's TDI
EDIT - see later post on pistons:
2C.) BLT PISTONS & TRAPEZOIDAL RODS (OEM or H-Beam)
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3.) BEW crank & cracked rods, BRM(?) pistons?
4.) BRM crank, cracked rods, & pistons?
So from what I understand, the ASV pistons that have the lower compression ring position and oil cooling passages, were designed to use the squared parallel top rods?
BUT... you can still mate these pistons to the trapezoidal rods, but just not the other way around (obviously)?
Are there ANY other pistons in any international (non-USA) markets that are designed for the tapered small end aka trapezoidal rods?
(EDIT - FOUND IT! BLT pistons, see later post) It seems that it would be best to match the trapezoidal rods to a trapezoidal piston, and not an older style piston made for the parallel topped rods, it seems that many people do to PD100 rod + ASV (or ARL) piston upgrade to ALH's.
Comments?
I recognize that the BHW/PD150 crank/rods are definitely going to be more stout on the big ends, but how crucial is this for my goals if I am running high quality sputter bearings especially. Should this be a must-do for my application goals?
If I cannot locate a BHW crank here, how difficult is it to import a PD150 crank?
Thanks,
Chuck in Ohio