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3.9 Engine Build

Harv

Well-known member
Joined
18 Sep 2014
Messages
1,204
Thought I'd throw up a thread detailing my engine build as a thank you to some of the businesses and members on here and it maybe of some use for others contemplating similar works.

I finally have enough parts in hand to make a start and this will be a full refresh at 120k and upgrades that seemed to make sense while the unit was in bits. All new bearings, chains throughout and lots of cleaning, measuring and cleaning again prior to assembly.

Crank, lightweight flywheel, clutch cover and underdrive pulley balanced as a unit to within 1/10th of a gram.

Basic components of the bottom end ready for assembly


Are you sure it clean? Clean it again!


New bearings fitted


Crank in place, bearings pre lubricated


Bolts torqued up, i added a few more reps to the sequence and check for no tight spots as we went. The marks only indicate that that particular bolt has been torqued to final spec


Crank end float checked and bang within spec at 0.15mm


Still waiting on modified engine cases, more next time


:thumb:
 
Excellent, this looks interesting... :thumb:

MC
 
Nice job! I am in awe of your spanners skills.

What sort of state were the bearings/bores/pistons in?
 
Generally the engine was tired and lacked zing...

Top end the valve seat faces were wide and hammered and exhaust valves very shagged and failing



Main bearings, big end bearings and thrust shim all thread bare




Pistons all good but bores becoming oval and quite a lot of blow by going past the rings, though the rings themselves look ok.
 
infrasilver said:
Glad it's coming together now Harv, if you don't feel brave fitting the gudgeon circlips let me know.

Are you using assembly lube, I can't see any?

Thanks for that, though I'm some way from you.

Yes assembly lube used throughout just not seen in these mockups

:thumb:
 
alex yates said:
infrasilver said:
:thumb: I knew you wouldn't mount anything dry.

:eek:


:floor: double :eek: :eek: :D but Harv this looks like it's going to be a thread to watch mate , good luck with the build
 
Nice one, Thanks Harv. Will definately follow this thread. I'd like to do something like this in the future.

What vintage is the engine for reference?

cheers
 
Sorry for late reply the engine is a 3.6 from 2002

Time for an update:

I should finally have my modified crankcases back from Serdi next week which will allow me to build up the bottom end. They have been fitted with custom made fully wet 99.5mm I.D bore liners.

The collection of assorted bits continues but here are a few pics which details parts going into the rebuild

Match weighted and balanced end to end rod set with ARP bolts






Wossner forged piston set, 4032 Ali, low expansion, coated skirts and NPR ring set. Again these are matched in weight as a set to within 1/10th gram.







Lightweight single mass flywheel which is a work of art but was still way off the level of balance I'm looking for out of the box, more TLC.





New IMS and cam drive chains



Underdrive pulley



997 GT3 throttle body, note the difference in size?



Next time hopefully some pics of the bottom end going back together after a lot more cleaning.

One thing I'm quite keen to do is get the IMS tube assy itself onto the machine to see if there's any out of balance in it and if that can be improved. I'm not sure if this is something that other engine builders have done/do but something I worth checking.

:thumb:
 
:stay: :popcorn: :popcorn: :popcorn:

Harv - what a great thread; looking forward to more and seeing the finished project

Good luck


Osh
 
I'm wanting on of them there flywheels!!!! :thumbs:
 
Flywheel is the TTV racing item and I'm impressed at the quality for the price, sourced through Richard at Coordsport

The balancing has been done by David Martin who's a well known Aston Martin engine builder and local to me, they have their own in house developed machine for balancing automotive, marine and aviation engines. He really knows his stuff, not repeatable here is what he thinks of dual mass flywheels :floor:

At the moment I'm trying to find a intake plenum solution for fitting this 997 GT3 throttle body, maybe build something or have a 3D one printed but I don't know anyone off hand :?:
 

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