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Thats true.

I couldnt find the photo of the clutch that went bang I'm just thankful I wasnt driving.

Someone else might have more luck.

My first a12 was held at 6000rpms for the best part of a day. It had no T/stat, and was stone cold.

IMO the less than perfect aspect of the A series would be,
The rod bolts as discussed
The stock cast pistons have the limitations that go with casties
The springs on the rockershaft need to be replaced with bushes. This imptoves lubrication, and prevents the rockers migrating resulting in bent push rods.
The PCD of the flywheel is too small.

aside from big ends bols breaking, I've never heard of the rods failing.

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YIKES makes me happy to have an auto! but I have fitted some cool datsun floor mats just in case!

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This is an abberation, not a weakness, but even A15's can have a problem sometimes.
This one had a camshaft problem. [The rod took a lobe clean out of the middle of it]

Hang on a minute .......
all these traitors slinging off at the mighty datto Any and ALL items of mechanical nature will fail with age, fatigue, misuse, or stretched to their design limit I agree that the PCD of the flywheel bolts is too small and the lack of positive location can cause heartache with a missed shift But really, for the HP we squeeze out of them, their age, simplistic design and compact nature, they are a really awesome little engine!! Despite the swap to L-series, I still love the hard revving little A
Cheers

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My feet will be fine
As the engine is mid mounted the flywheel is infact inline with my testicles
I have already had a flywheel spin off in the racecar and we think we have fixed that issue
It hasn't come loose since and we are starting to turn it harder and harder
The new steel flywheel goes in with the replacement Daiken cushioned ceramic clutch this week.

Well looks like I have all the issues covered then
I already have ARP rod bolts
I already have cured the flywheel issue
I already have roller rockers
I will have an oil cooler inplace soon
New pistons will be sourced for the end of the year freshen up
The new efi system with Motec has a rev limiter so covered that too.

Looks like I'm indestructable......as I knew I was...... lol

On to racing

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Do either of you care to show pics of your datsun engine bays? Please mainly focus on your modified engine mounts that sit your engines back.
Both 1200's and 1000's in stock form, mount the engine in a position as that the flywheel is about 2 inches forward of the firewall. 120Y's have even more distance. Well atleast all the ones I have owned or worked on have.
Whats that? Textbooks dont teach you this? Maybe its time to actually work on a datsun and not pay people to do it and then just bring parts home to sit beside your computer.
The pics of the flywheel that came loose, will clearly show that Stirlingmac's engine was well and truely recessed into the firewall.
But what would I know? I cant read.

yeah..
so far i not seen any broke down stock A-series engine before

and i wish it wont happen to my engine also.. :) no money to go for repair


weakness..? i think only weakness is lack of power in stock form, and the revs hard to climbs up.. maybe cause OHV setting? i dono...

Well, here's my two-bobs... I agree with a lot of whats been said already, and disagree in some instances. My experiences have been with a race prep A15 and as such only relate to that - not a street or stock motor!

We have broken quite a few head bolts - we were using NEW nissan bolts over tensioned to avoid blowing head gaskets. We've moved to new class 12.9 cap screws for all head bolts except the unusual bolt for the oil flow. For this one we use a new nissan bolt but don't use it for any more than two head bolting applications.

We've broken one crankshaft. We got four years of racing out of that one and expect to replace cranks now every two years.

We've always used old rod bolts with standard tension and (touchwood) haven't yet had a failure. But I feel we've been very lucky although we don't use them more than two applications in race use or two years.

We've also never thrown a flywheel. Other people we race with have thrown them on more than one occation. We over tighten them as well and use new class 12.9 cap screws. Same on the clutch, but I think thats overkill.

the main pulley seems to be cracked every time we pull a motor apart. The key that drives it actually widens the keyway in the crank and causes a local increase in diameter in that region which cracks the pulley through a corner of the keyway. None have come off completely but they don't last long. I'm going to make a new one from a tougher material than the original cast iron.

Hope my experieces can help in someway!

Daniel.

EDIT: Oh yeah, pistons don't have a real long life either in our engines. But they have traditionally been machined down mazda pistons. I'm currently trialing a different idea at the moment!

We had an oil starvation issue to the main bearings in a dry sumped race engine, but we never worked out if it was a problem with the design or an error by the engine builder. Either way, not somthing you hear about on street engines.