A14 Engine rebuild advice?

[Kitch]

Hi guys looking for some advice, regarding my A14 I am building up.

Looking to make a strong revving A14, EFI, quad throttle bodies, for street and maybe a bit of track use.

1) COMPRESSION RATIO
Looking at targeting around 10.5-10.8, and running on 98 octane - does anyone have any advice on what the best C/R is for my application.
This should get my cam / throttle bodies singing I hope.

2) CAM
Looking at going to a "rally" type grind 238-248° @ 0.050". 108° lobe separation, and cam lift of 0.280"

3) PISTONS
Looking at going to around 78mm, to increase capacity, and also lift the C/R, I am looking for small dish that equates to around 5cc, I am concerned that standard A14 dish of 4.16mm (equating to 9.9cc may mean my C/R suffers) some options I am considering:
>Nissan A14 oversize (dependent on whether I can get 60' or 80' o/size, and whether they don't have too big a dish in them)
>Mazda UC Pistons (Part #ACL 2699), with tops slightly machined off
>MX5 pistons (78.5mm) has anyone fitted these, or is this pushing the boundaries of the block? (unsure of dish and whether heights OK, need to some more homework)
> Mazda E5 pistons
> Mitzi 4G32 (76.9mm standard + o/sizing avaiable) same dimensions as A series, but need 1.1mm taken off crown. this will leave a pocket of 1.9mm, meaning approximately 4.5cc of volume in the dish - which should be very good for compression ratio

4) CRANKSHAFT
Any advice here? I was just going to get clearances checked, and replace bearings, and machine journals as necessary. Should I be balancing or doing any other work to it, that is cost effective or good insurance for motor longevity?

5)OTHER
Any other advice? or recommendations?
Found some yummy yella terra roller rockers, but they are obvioiusly worth their weight in gold?!


Cheers
Kitch

[Kitch]

Oh also, I forgot to ask about head gaskets.

1) what is the finished thickness of a head gasket I use for calculating C/R? I assumed 1.0mm equating to a little under 5cc, but does anyone have a more accurate figure?

2) If I am running 10.5 or higher compression, do I need to use a better head gasket than over the counter monotorque one o rwhatever I usually use? ie do I need a Nismo one or the likes? any help, idea of cost, part number would be appreciated.


Cheers
Kitch

[Bartman]

I'll offer up my 2c.
Wayne murdoch builds race engines using the mazda pistons, (Not 100% sure which ones exactly) and nissan CA16de rods. The CA16de rods are heavier than the A14/15 rods, but lighter than the CA18de/det rods. They use the 20mm gudgeon pin, and have a 9mm rod bolt too. That said, lots of people have used standard rods in some prety high winding motors. If you go down that route, then ARP rod bolts are a must. I think Noddy likes the CA rods when the pin bore has been enlarged to 20mm. Probably not such an issue on a street motor, (My engine runs A15 rods with the pin bores opened up) but for a screaming race engine, (that buzzes to 8000-8500 often) the reduced strength of the modified pin bore may become an issue. (Dunno if you've met him, but Dave Hudson with the imaculate b110 sss told my noddy told him that he's seen stock rods fail in these circumstances) At any rate, if you're using a used rod, you'd really want to have them fitted with new rod bolts,resized, polished, balanced, and shot peened. Another rod option, (Although not a cheap one) would be to use the spool H beam rods for the CA18det.

As for your compression ratio, something to bear in mind is regardless of how high your final (static) CR ends up, the fitment of a big nasty camshaft with lead to a marqued drop in the dynamic compression ratio.

With the crankshaft, balancing is a must. I have a factory nissan rally/race prep guide for the A12, and it tells how to increase the size of the oil galleries in the crank to increase the oiling. The other thing you should do is have your flywheel doweled onto the crank. It also wants to be held on with 12.9 tensile capscrews, held in with loctite. Due to a few shortcomings in the design, these motors can shake the flywheels loose a BIG rpms.

For the caliber of your build, I think a nismo head gasket should be used. I'm fairly sure they are thinner than your run-of-the-mill ones, and I've heard many speak of their improves sealing abilities.

With those yella terra roller rockers, they require custom pushrods. Another thing about higher ratio rockers is pistons to valve clearances will need to be tripple checked. Also your head will require a clever port job, to get any more flow above around 450(ish) valve lift. Although the cam you're looking at using isn't a monster lift cam anyway, so you mightn't have a problem there. Other thing with the yella terra rockers is I hear they're quite heavy. There is another brand, (US made maybe?) which are a bit lighter.

I've never met wayne murdoch, so I don't know how approachable he is. But given he's your local A series guru, It can't hurt to ask his opinion. I'm pretty sure Dave Hudson followed his advise when building his latest engine. He might have got pistons off a bloke from Aussie. (Username "Dundee1000", at http://www.datsun1200.com" onclick="window.open(this.href);return false;)

[nick_m]

I ran 11:1 on 96 (days before 98/95) on my shitty old mini motor. An A series would handle 11:1 all day long i'd say. Especially with EFI. And like Bart says, a big cam helps this.
I can't give any info on head gasket thickness, but you'd be pretty damn close with 1mm
A good machine shop should be able to lighten the crank a little. I'd talk to them about how much you want to spend vs work they can do. Any weight removed is better than nothing. Again using my mini motor as an example (sorry ) me and my step dad, who's a machinist lightened mine over the course of the weekend, maybe 4-6 hours work, I also lightened the rods and flywheel I can't remember the exact weights removed now as it was a quite a number of years ago now but IIRC it was around 5-6kgs from the whole rotating assembly and with balancing that motor used to rev out so quick and smoothly. I'd definitely go to town on lightening the rotating assembly It just really free's up the motor.
I'd even suggest a billet flywheel (stay away from chromoly that crack if the get too hot), then you can get it real light without risking failure

[dirtyleppa]

im not gonna add much here as nick an bart pretty much said everything. just remember to get the whole bottom end balanced together. pistons, rods, crank, clutch, flywheel, front pulley and even the pulley bolt and washer