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Below is a drawing of the Jowett four cylinder boxer engine.
Notice the lifters are above the pistons.
The VW is an air cooled, rear boxer engine with the lifters
at the bottom so the lifter tubes could serve as return path
for rocker oil. This design might be the Jowet's problem.
On 10/7/2022 5:39 PM, Scott Davis wrote:
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Jowett migrated to solid lifters on all later engines, factory replacements engines would be the improved design - solid lifters.
I’m sure the Javelins lifters have lots of milage on them, but it is or was running, that’s noteworthy - it hasn’t blown up early like most Jowett motors of that era!
Alloy blocks wear, as they wear they leak oil, as oil leaks grow, oil pressure drops, it can leak past the camshaft journals , lifter bores, let alone worn crankshaft bearings (a known problem) so restoring running clearances is the only fix.
A VW owner can buy a new alloy block for $1000 to replace an old heat cycled old block, or they can think they can restore an old block for the cost of a $100 main bearing line bore, which ignores the worn lifter bores and camshaft bearing bores, so rebuilt VW engines using such a partially remachined block typically have very short lives, do to LOW oil pressure , add bigger cylinders and hotter cams and you have a grenade in 10,000 miles.
The so called fix of putting a BIG oil pump on a tired VW engine was putting a bandaid on the loss of oil pressure that a worn engine case was causing, and not understood as being a sign of a badly heat cycled case needing replacement rather then complete remachining to tighten up all the worn machined surfaces.
Porsche guys remove all the engine care studs, lap the two case half’s, restore crush, then align bore the case for over size main bearings and cam bearings, Porsche 356 lifters are pencil like and break the card when they fail at hi revs - it’s common to weld up broken lifter bores and machine them, or bush if just worn out - you can’t buy new Porsche cases, and if you could, how about $5000 or $10,000 ?
Jowett cases are what they are - tired and high milage - you restore the engine blocks the best you can afford, but low oil pressure is and will be the enemy of the boxer style split case alloy engine block.
On Oct 7, 2022, at 10:00 PM, Lou via groups.io <c1937@...> wrote:
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