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Motor rebuild: list of items and cost, suggestions?

839 Views 8 Replies 6 Participants Last post by  vigman
I'm resigned to the fact that the motor needs to be rebuilt. The car is a blast to drive and deserves a fresh motor and some new syncro's in the trans.

The motor has N42 block / N47 head motor and is fed by dual 32/36 webers, pertronix disti.

I met with a machine shop that has done a few small block Fords for me and have always done a great job. First question. Is this a decent motor to rebuild? I am reasonably happy with the performance of the current motor, but if there is an easy way to pick ups some performance, without trading reliability, I'm open to that.

Here is a list (from my notes) talking to them about what they would do to rebuild the motor. Thier cost is $1500 and would take a few weeks. Second question: Is there anything missing, is this a reasonable deal?

Complete disassemble and cleaned

Pressure test head
Surface head
Three angle valve job
Cam sent out checked and reground
New valves
New valve guides / seals
New bearings
New timing chain
New timing chain sprocket
Reuse springs/keepers, lash pads, retainers/rockers

Magniflux block
Block checked and honed, bored if required
Crank checked, polished
New bearings
New pistons / rings
New oil pump
Reuse rods

Resurface flywheel
Resurface intake manifold if required
Resurface exhaust manifold if required
Reassembly, adjust valves
Paint color of my choosing
Spin up engine on stand verify compression and oil pressure
No water pump
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It's a great deal if it includes parts. New freeze plugs? No single thing can be done for performance w/o altering everything else, which would triple the cost. Balancing is highly recommended for reliability and maximum enjoyment at high RPM. The ONE thing you might consider would be an aluminum flywheel. No decrease in reliability and it FEELS like an extra hundred horsepower!
If that was my Healy no way I would spend money on that motor. Get a Healy motor and return the classic car and its value to what it should be. I owned a 100-6 Healy. No Datsun engine can replicate that sound. Check around especially British club sites for engine, trans. and swaps.
Second choice, I would install SBC or a SBF.
A Z motor in a car like that adds no value.
That's like telling someone what color to paint their car. To each, his own.
I'm assuming new clutch...
Timing chain guides
You MIGHT want to consider keeping the timing gears unless your getting Nissan parts ( the aftermarket ones are softer metal ) .
New Oil sender
( maybe go back to FI... or make carb plates to accept PVC )
Send carbs out for rebuild
Confused about.... No water pump??

Thank you for the replies. I added them to the list for the engine builder.

It is a fair comment about putting an original motor/trans back in the car and I have looked into it. To purchase and rebuilt an AH drivetrain would be around $10K-$12K and just cannot be economically justified on this car.

SBF, sure it has been done a lot since the 60's. I had a cobra kit car (FFR) for nine years and frankly this car's personality with the Z six cylinder is just fine.

The Z eng/trans is a great soluton and in many ways a better set up than the original. The car is what it is. I got it for a song and it will be a sweet, fun car when it is done. Never a collectable car, just a great looking, vintage feeling, good performing, fun car.

Vig, the rebuild place send the engine rebuild did not include a waterpump. I will certainly put a new one on, but was not included in the $1500 rebuild fee.
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A few points I could add about the head;

Unless totally necessary, I don't believe the valves would need to be replaced, they can be cleaned up just fine with the valve job. I have never really seen a stock cam that needs to be reground, but you can do this with a different performance grind still using the original stock hardened cam. At this time, you may want to deshroud the combustion chambers and ports to improve flow, but don't enlarge them.


Most likely a good hone job will be all that is required (Japan really did thier homework with the metallergy) so stay with the stock pistons or possibly go to the later ZX flat top pistons to kick the compression ratio up to near 10.0-1. I would also replace the stock oil pump with one out of a turbo L-28, it bolts right up and provides higher pressure/flow.


Definately get a new water pump as you mentioned later, and of course, all new gaskets everywhere. I would also cleanup and portmatch the intake and exhaust manifolds to the block. Another really good idea is new ARP head bolts or studs along with new bolts for the manifolds.
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webbers look nice but the z mechanic at a race shop I go to says the SU is better
Ahhhhhhh I get it ..... so you just provide a new Nissan water pump...
What about new harmonic??
Rebush the dizzy?
HEI ignition?

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