So since my 2022/23 NA BP rebuild has completely **** the bed and also killed my cat cams camshafts in the process it's time for (another) NA VVT rebuild. No point in going for another NA BP rebuild.
Straight up consumed a quart per 1000km oil after run in cycle, at the end after 3 years and 30.000km more like 3-4 quarts per 1000km. Assumption is that either engine builder or machine shop fucked up, some debris remained in the engine. Upon the recent disassembly we found scored cam shaft lobes, lifters, cylinder head contact surfaces front and rear. And it all went downhill from there. Cylinder walls fucked, crank shaft surface and bearings fucked, boundary oil pump scored, and so forth...

Luckily the 12:1 85mm Wössner pistons survived so at least those will get another run. Yay!

So here some initial pics of the carnage


Cat Cams camshafts

Cylinder wall - others also have lots of vertical scoring marks

fucked crank bearing

scored crank

Boundary stage 2 pump opened up

front plate scored

pump wheel scored

bore pressure relieve valve

piston pressure relieve valve


The oil pump should be fine though, I'll smooth the bore a bit at the bottom and I bought a new pressure relieve valve piston and spring from Mazda.

 

So I got a good deal on a crusty complete VVT engine a couple weeks ago and started to disassemble, inspect and clean up stuff. First time im opening a BP engine yay.


The mighty Euro BP6D


Cut open the oil filter for inspection, no debris found



Put it on the engine stand to inspect one or two main cap bearings, looked good. Also cleaned up the oil pan, main bearing support plate and all the sealing surfaces. Installed my skidnation oil pan baffles and put it back together for transport to my mechanic.



She's quite crusty. Before the engine went back into the trunk via my engine crane I also cleaned the block up with a needle scaler attachment on my air hammer. All the threaded bores on the outside were cleaned up with rust remover, a thread chaser and compressed air.



Pulled the cylinder head


Some scored cylinders but nothing major, marks didn't catch my finger nail





Disassembled the valve train. Ran all the neatly organized valve train parts through my ultrasonic cleaner, making sure every valve stays with its corresponding lifter/shim/spring/retainer parts.
Also cleaned up the vvt solenoid with parts cleaner and pulsing via an injector tester, replaced all the seals and o rings.




Also got a fresh set of hardened intake valves


Then the engine got put back together for transport and I dropped it off at my new mechanic for crank inspection, cleanup and prepping for the machine shop.

 

These pictures are from my mechanic who recently did the final crank and head inspection. Some light scoring on the crank - should be able to get those lapped at the machine shop.





And some scored crank bearings






And some pics from the cylinder head and valve guides






And sadly the valve guides are also quite worn and will need to get replaced from the machine shop - I have to short video clips showing the play of the valves inside the guides but dunno how to embed those.

 

A sexy / expensive piece of aluminium - had the machine shop build a BP honing plate which will also get some use by local club members.




Which brings me to the current build plan - feedback always welcome.

• Build will remain naturally aspirated
• Simply no budget for a new set of high lift VVT camshafts, maybe next winter / next year ?
• Intake, Racing Beat headers, high flow cat and 2.5" exhaust from the NA BP build will get reused.
• 85mm bore job, complete head and valve train rebuild by the machine shop
• new Supertech bronze valve guides and hardened Osvat intake valves, reused / reground exhaust valves by the shop
• reuse / reshim the oem shim over bucket lifters
• stock VVT cam gears - no point in using my adjustable cam gear on the exhaust side
• stock 7200 rpm rev limit - torque build lol?
• Boundary stage 2 pump with new oem pressure relieve valve piston/spring and bore cleaned up

Thoughts ?