datsunfreak Posted March 1, 2014 Report Share Posted March 1, 2014 Next up, are rocker shaft collars. Have you heared anything good about them? Used them on the last 3 engines. Definitely a good idea. :thumbup: Quote Link to comment
ggzilla Posted March 1, 2014 Report Share Posted March 1, 2014 Rocker shaft spacers are needed at sustained RPMs above 7500 rpm. The stock setup is good for lower speeds. Quote Link to comment
prophet1012 Posted March 1, 2014 Author Report Share Posted March 1, 2014 haha i bought them too, altough i don't tjink my engine can rev up to 7500rpm, also bought a digital tacho as i don't know how much am i revving (fail) Quote Link to comment
prophet1012 Posted March 9, 2014 Author Report Share Posted March 9, 2014 Hi guys big update haha, i got my self an a14 suppositely from a 140j, now after looking through the wiki i got worried that the a14 i bought may be weaker than the a14 since some of them are 63hp. How am i to identify which varient of a14 i got Quote Link to comment
ggzilla Posted March 9, 2014 Report Share Posted March 9, 2014 The low power A14 is superior in fuel economy at makes more HP below 5000 rpm. Best way to identify is to remove the valve cover and read the two casting numbers. You need to retorque the head gasket anyways, and adjust the valves too. Quote Link to comment
prophet1012 Posted March 9, 2014 Author Report Share Posted March 9, 2014 The low power A14 is superior in fuel economy at makes more HP below 5000 rpm. Thats not as bad i guess, the most thing i am interested in is the difference between a12 and 14 when it comes to low rpm torque and acceleration :D Best way to identify is to remove the valve cover and read the two casting numbers. You need to retorque the head gasket anyways, and adjust the valves too. By valve covers are you referring to the top cover? If that is the case it can be done in no time hopefully. I will post some pictures of the lot i bought and an inventory of some sort xD Quote Link to comment
prophet1012 Posted March 16, 2014 Author Report Share Posted March 16, 2014 I got an h75 head which is one of thr common a14 witg standard oval ports...ie not the "low power" one. It should be an easy engine swap i suppose...hopefully. Or am i underestimating it? Quote Link to comment
Atomic Posted March 16, 2014 Report Share Posted March 16, 2014 I would say A12 GX head would be a suggestion too, since you have A12 engine? http://datsun1200.com/modules/mediawiki/index.php?title=A12GX_Engine Quote Link to comment
prophet1012 Posted March 16, 2014 Author Report Share Posted March 16, 2014 You understood me wrong lad, i have a complete a14, but it came from a voilet and soem voilets in europe (the gl versions) had economical engine ie wasted less fuel, but also generated less hp. I was worried that i got the less powered engine and asked for z"how to identify which engine i got". They told me to check the head casting, and when i removed the topcover the casting was h75, so i now know it is the "normal" a14 xD. Also a12gx in malta (europe) is unoptainabable i suppose, even a14 is ultrarare, in fact i only know of another a14 powered b310 and he brought it from italy not from malta 1 Quote Link to comment
Atomic Posted March 16, 2014 Report Share Posted March 16, 2014 Alrighty, my bad! :) Quote Link to comment
prophet1012 Posted June 20, 2014 Author Report Share Posted June 20, 2014 hi lads its been a very long time since my last post and a lot of things happened to the project. first thing first, i decided to turbo the a12. already got the small turbo for it, the manifold is being done as i write, bought some insurance with regards to the head (valve rocker collars, gx springs spring, seat and retainers) (haven't decided if i NEED lightweight pushrods, being only 0.5grams lighter than standard). I have low compression head, which a friend of mine told me it is safer to use with a turbo (don't know really why) than high compression head, this week i will have to take it out and face it (re-machine it flat) and install a new headgasket (it overheats i push the throttle a bit more than usual (average of 80km/hr). my target really is 7.5 to 9 psi from this a12 build) I have too many question though and i would REALLY appreciate if somebody can answer them. I have 2 major concerns Do i need to do something to the distributor? while visiting the 1200 forum i read that the mechanical of vacuum advance (not sure) goes hey wire when you are under boost or you let go of the throttle. if that is the case what is there to do Giving enough fuel to the engine for the turbo not to lean out. as i said i won't give more than 9 psi to the engine (i don't want to blow a 32 year old engine to smithereens), is there a fuel pump that you know it is enough for such expectations? i already know that the turbo i bought off a 1ltr diesel charade is capable of such PSI (p.s. i know i have to seal/redirect the oil intended for the use of the turbo on a diesel engine, they refer to them as carbon seal here) I intend to make a blow-through setup not suck-through as i want an intercooler (i'd like the engine no to go too hot) Finally i know i would be better off with a bigger engine but first off of all in Malta there are very strict regulation on change of engines and secondary (i think more important that the first haha) is that there is no other a12 turbo in Malta, and i wish to be the first or only one to do it. having said that until I deal with the two concerns mentioned above it will not be possible, especially the one regarding the distributor Quote Link to comment
ggzilla Posted June 20, 2014 Report Share Posted June 20, 2014 Good on ya. A12 stock turbo'd can make 160HP. With stock block and A14 oval port head. I have low compression head There are no low compression heads for the A-series engine. Compression is controlled by the piston dish -- unlike Datsun L-series engines which have different compression heads. Thre are open chamber and close chambers both have same compression ratio. Quote Link to comment
ggzilla Posted June 20, 2014 Report Share Posted June 20, 2014 * Do i need to do something to the distributor? while visiting the 1200 forum i read that the mechanical of vacuum advance (not sure) goes hey wire when you are under boost or you let go of the throttle. if that is the case what is there to do I believe that is not true. The mechanical advance is a standard governor type, and is not affected by throttle position or vacuum/boost levels. With a turbo, the spark advance needs to be limited. What you can do is simply retard the distributor. Or modify the mechanical advance. Or best yet install a spark retard system (electronic ignition controller). 1 Quote Link to comment
ggzilla Posted June 20, 2014 Report Share Posted June 20, 2014 * Giving enough fuel to the engine for the turbo not to lean out. as i said i won't give more than 9 psi to the engine (i don't want to blow a 32 year old engine to smithereens), is there a fuel pump that you know it is enough for such expectations? ... blow-through setup You will need a fuel pump capable of the standard carburetor fuel pressure (3.5 psi) + the 9 psi of boost. Get a 'rising rate' regulator so at idle it puts out 3.5 psi. The carburetor needs special seats to withstand the high fuel pressure. Quote Link to comment
prophet1012 Posted June 20, 2014 Author Report Share Posted June 20, 2014 thanks for the great help ggzilla. maybe i got it wrong with regards to the mechanical advance. I may have misunderstood the 1200 forum a little. this is a direct quote igot from the forum: Set initial timing at 3 degrees In the distributor, weld the advance slots partially to limit mechanical advance what does this quote suggest apart from the initial timing which is very easy to do. Quote Link to comment
prophet1012 Posted June 20, 2014 Author Report Share Posted June 20, 2014 I believe that is not true. The mechanical advance is a standard governor type, and is not affected by throttle position or vacuum/boost levels. With a turbo, the spark advance needs to be limited. What you can do is simply retard the distributor. Or modify the mechanical advance. Or best yet install a spark retard system (electronic ignition controller). so what i need to do is to retard the mechanical advance to 3 degrees instead of 8 degrees and check if it pings? i'll look into a spark retard system, maybe they are not super expensive. Quote Link to comment
ggzilla Posted June 20, 2014 Report Share Posted June 20, 2014 Set initial timing at 3 degrees In the distributor, weld the advance slots partially to limit mechanical advance what does this quote suggest apart from the initial timing which is very easy to do. It suggests limiting the amount of mechanical advance. Under heavy boost no engine can survive with a lot of advance. Read up on how they modify Chevrolet Small Block mechanical advance as the welding method is identical. Quote Link to comment
prophet1012 Posted June 20, 2014 Author Report Share Posted June 20, 2014 is 9 psi considered as heavy boosting? xD i really don't like messing with the distributor.... i hoped that retrading the initial timing would be enough Quote Link to comment
prophet1012 Posted June 20, 2014 Author Report Share Posted June 20, 2014 i apologize if i ask too many questions, but as i said no one did it malta (as far as i know) and there is no detailed tutorial on how to turbo an a12. So far i came to the conclusion that i need to buy these things: 14 psi fuel pump (stock pump being 3.5 psi and 9 psi of boost i will give to the engine) rising rate fuel regulator ( so i can set up idle and full trottle fuel requirements) another electronic ignition convertion kit, as the first one failed me. a spark retarder (don't really know which one) The carburetor needs special seats to withstand the high fuel pressure. What are these special seats? Quote Link to comment
ggzilla Posted June 21, 2014 Report Share Posted June 21, 2014 Yes, 9 psi is considered more than a light boost. 5 psi is handled by most stock carbs and stock compression and needs no intercooler. The stock A12 including stock head gasket can take 15 psi, but needs limited spark and extra rich fuel. Same as any engine. A spark retard system is not needed. What is needed is to limit the mechanical advance. Same as any engine. Quote Link to comment
ggzilla Posted June 21, 2014 Report Share Posted June 21, 2014 What are these special seats? Most carburetors are rated for about 3.5 psi fuel pressure. Starting around 5psi many Hitachi and Weber fuel inlet seats will start leaking. Some will handle 10 psi fuel pressure. Try yours. Quote Link to comment
prophet1012 Posted June 21, 2014 Author Report Share Posted June 21, 2014 On another note i have a good a14, but has no carbureyor, a new one is 85euro. Can i use the same carburetor i have on my a12? Quote Link to comment
ggzilla Posted June 21, 2014 Report Share Posted June 21, 2014 Yes but it makes significantly less HP. Quote Link to comment
prophet1012 Posted June 21, 2014 Author Report Share Posted June 21, 2014 i'll buy one right now then :( this is getting expensive haha. bought an exedy clutch kit for the a14 today as well Quote Link to comment
prophet1012 Posted June 21, 2014 Author Report Share Posted June 21, 2014 the a12 carb being richer in fuel than an a14 carb, makes an a 14 slower? if i understood you right ggzilla Quote Link to comment
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