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A12 to A14 - need confrimation |
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Just can't stay away  
Joined:
2006/10/20 4:38
From South Coast NSW - Australia
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Registered Users
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Hi all,
I have had a good read of the tech section and I think I have this right. Can someone please confirm for me.
I can use my existing tricked up A12, with oval port head, bigger valves etc.
Throw in an A14 block, bore it out to say 78mm, get appropriate pistons and I am good to go. No other mods required. (maybe a re-jet the webbers because of the capacity change, currently 73mm pistons)
Have I got this right?
Thanks in advance.
Cheers
Damien
Posted on: 2008/8/30 0:23
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_________________
Datto 1200 Coupe - Rally Car A14
Datto 1200 Coupe - Rally Car - in pieces
Datto 1200 sedan - Khanacross Car
180sx - Rallycar under construction.. yeeha
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Re: A12 to A14 - need confrimation |
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No life (a.k.a. DattoMaster)  
Joined:
2006/5/2 7:51
From Darwin NT
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yes you can use the oval port head on the a14 but the gasket may need to be modified if it is a gx head as the early and late blocks are different. the push rods will need to be changed to accomadate the extra block hieght and while you have the motor apart id be rebuilding the whole lot and get everything balanced etc.
Posted on: 2008/8/30 1:12
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-68 1000 wagon long term project sleeper style with heavily worked a series
-evrything in storage... bugger
current project 4x4 patrol...
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Re: A12 to A14 - need confrimation |
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No life (a.k.a. DattoMaster) 
Joined:
2003/6/27 14:53
From Southern Tablelands N.S.W. Australia
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Registered Users
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What it it that you want to do?
You have a 1974 or later A12 engine & you want to substitute an A14 block & pistons, but use the A12 crank & rods & everything else??? Is that it??
Nah, that won't work.
Posted on: 2008/8/30 1:56
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Love your Datsun.
Treat it well.
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Re: A12 to A14 - need confrimation |
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Home away from home  
Joined:
2005/12/7 4:37
From Bendigo, Victoria, Australia.
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chances are that if you have an oval port head it started out life on an A14/A15 block anyway. so essentially you would just be making a normal a14 again. cylinder diam. will not affect anything.
pushrods: if you use the A14 pushrods then you will not need to modify them. just set clearances as per usual when changing head gasket.
Posted on: 2008/8/30 2:28
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"Like a Rolling Stone"
Bob Dylan
New Daily: <<<<Now For Sale.
1972 B110, 13" Bathurst mags, airbrus
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Re: A12 to A14 - need confrimation |
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Home away from home Joined:
2005/12/7 4:37
From Bendigo, Victoria, Australia.
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Registered Users
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actually i just realised what Dodgeman was saying. if you use a complete A14 bottom end then you will be fine. There is no point in using the A12 crank/ rods and getting pistons made to fit your bored A14 block.
Posted on: 2008/8/30 2:32
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_________________
"Like a Rolling Stone"
Bob Dylan
New Daily: <<<<Now For Sale.
1972 B110, 13" Bathurst mags, airbrus
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Re: A12 to A14 - need confrimation |
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Just can't stay away Joined:
2006/10/20 4:38
From South Coast NSW - Australia
Group:
Registered Users
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Quote:
Dodgeman wrote:
What it it that you want to do?
You have a 1974 or later A12 engine & you want to substitute an A14 block & pistons, but use the A12 crank & rods & everything else??? Is that it??
Nah, that won't work.
OK, I am trying to do a ccouple of things at once. I have two A12 engines for the rally car. Both need a rebuild and the regs have changed to allow A14's. I think one is an old A12 and the other newer. I have a couple of A14 blocks lying around. Not sure about what cranks I have (how can you identify an A14 crank). The older A12 used rev out to 7500 with absolute ease, but I have never pulled it down, so I am not sure what it is. It also has a modified sump (big square bit added to the bottom), so it may have been changed to accomadate an A14 or A15 crank.. maybe. So that's what I am trying to do. I am limited to an A14, but trying to use the oval port head etc. Listening to myself, I guess I need to pull it down to know what I am dealing with, then maybe come back with some questions. 
Posted on: 2008/8/30 3:12
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_________________
Datto 1200 Coupe - Rally Car A14
Datto 1200 Coupe - Rally Car - in pieces
Datto 1200 sedan - Khanacross Car
180sx - Rallycar under construction.. yeeha
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Re: A12 to A14 - need confrimation |
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No life (a.k.a. DattoMaster) Joined:
2003/6/27 14:53
From Southern Tablelands N.S.W. Australia
Group:
Registered Users
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OK, here's the deal.
Later [1974 & newer] cylinder blocks with the rear positioned distributor will not 'drop in' where a front distributor A10 or 1200 engine currently reside, so if you have a front distributor engine in there now, then you will need to either mod the engine mounts [not hard] or switch a later 1200 ute crossmember in there in order to mount a 1400 block.
The oval port head that you have, as has been written, is most likely to be an A14/15 one anyway but it will be desirable to identify it 100% before you complete the rebuild.
The A14 has a 77mm stroke, so it might be necessary to clean up a block & crank & put them together with a couple of correct size bearings [used is OK] Install one rod & piston without rings. [If its a 76mm piston, it will be the right rod for the block.] & simply measure the actual stroke.
All the cranks have the same main bearing size so all cranks will fit into all crankcases but long stroke cranks in short stroke blocks quickly become obvious.
Oh, the A10 has three main bearings, so forget that one.
You do not need a modified sump to use an A14 crank in a 1200 or A12 block & the chances of geting an A15 crank in there are just about nil. The batwings on your sump are usually there for additional oil capacity.
If your 1200/A12 would spin to 7,500 with ease than it's probably a 1200/A12 crank with its shorter 70mm stroke.
ALL A series heads bolt to ALL A series blocks. The only combination that will give some grief is the later [1974 & newer] heads on the earlier 1200 & A10 blocks as there was a change in the method of providing oil to the rockers & a mod is needed to make this combo work.
As an absolute minimum to make up an A14 from a 1200 engine you will need.
A14 or A15 block.
A14 or A15 rods.
A14 crankshaft
A14 pistons. [A15 are different]
1974 or later, twin drive gear A series camshaft, any model.
1974 or later A series oil pan, any model.
A14 or A15 pushrods.
1974 or later distributor mounting plate.
1974 or later alternator mounting bracket.
With this little pile & a spend down at the engine parts store, you can take an early 1200 & make an A14.
It's even easier if you are starting with a 1974 or newer A12.
Posted on: 2008/8/30 9:23
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_________________
Love your Datsun.
Treat it well.
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Re: A12 to A14 - need confrimation |
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Just can't stay away Joined:
2006/10/20 4:38
From South Coast NSW - Australia
Group:
Registered Users
|
Quote:
Dodgeman wrote:
OK, here's the deal.
Later [1974 & newer] cylinder blocks with the rear positioned distributor will not 'drop in' where a front distributor A10 or 1200 engine currently reside, so if you have a front distributor engine in there now, then you will need to either mod the engine mounts [not hard] or switch a later 1200 ute crossmember in there in order to mount a 1400 block.
The oval port head that you have, as has been written, is most likely to be an A14/15 one anyway but it will be desirable to identify it 100% before you complete the rebuild.
The A14 has a 77mm stroke, so it might be necessary to clean up a block & crank & put them together with a couple of correct size bearings [used is OK] Install one rod & piston without rings. [If its a 76mm piston, it will be the right rod for the block.] & simply measure the actual stroke.
All the cranks have the same main bearing size so all cranks will fit into all crankcases but long stroke cranks in short stroke blocks quickly become obvious.
Oh, the A10 has three main bearings, so forget that one.
You do not need a modified sump to use an A14 crank in a 1200 or A12 block & the chances of geting an A15 crank in there are just about nil. The batwings on your sump are usually there for additional oil capacity.
If your 1200/A12 would spin to 7,500 with ease than it's probably a 1200/A12 crank with its shorter 70mm stroke.
ALL A series heads bolt to ALL A series blocks. The only combination that will give some grief is the later [1974 & newer] heads on the earlier 1200 & A10 blocks as there was a change in the method of providing oil to the rockers & a mod is needed to make this combo work.
As an absolute minimum to make up an A14 from a 1200 engine you will need.
A14 or A15 block.
A14 or A15 rods.
A14 crankshaft
A14 pistons. [A15 are different]
1974 or later, twin drive gear A series camshaft, any model.
1974 or later A series oil pan, any model.
A14 or A15 pushrods.
1974 or later distributor mounting plate.
1974 or later alternator mounting bracket.
With this little pile & a spend down at the engine parts store, you can take an early 1200 & make an A14.
It's even easier if you are starting with a 1974 or newer A12.
Thanks so much for the help, that is the most brilliant bit/bits of info. I think I get the picture now. I am up to the shed tomorrow to see what's what. Thanks again. Damien
Posted on: 2008/8/30 11:00
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_________________
Datto 1200 Coupe - Rally Car A14
Datto 1200 Coupe - Rally Car - in pieces
Datto 1200 sedan - Khanacross Car
180sx - Rallycar under construction.. yeeha
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