B210 120y - More power please!! (Read 728 times)

[dave45]

Okay chaps, so I'm a bit underwhelmed with the supposed 69 bhp of my 120y. I have a Peugeot 304 with 75 bhp and it'll whip the pants of the Datsun. It has a stainless exhaust on it already but that's it. What mods would you recommend to boost my power using tweeks or fitting parts (camshafts etc) also where to source them. The head is coming off soon for a decoke and a skim. That may help a bit. Anyone know the limitations of a skim?

Basically are there any carbs, camshafts, distributors I should get or any adjustment tricks with valve clearances, ignition timing etc I should know about?

Cheers!

Dave

[Al Ramone]

You're always gonna be limited by the small displacement of the engine.

If you can get hold of one, a 1.4 or 1.5 A series will improve performance and be a straight forward fit.

If you start tuning up the 1.2, any decent increase in top end power with camshafts and the like, will mean rougher low rpm running,

You could always turbo charge it, not as outrageous as it sounds, and gives extra power throughout the rev range.

[dave45]

Cheers for that Al. I like the idea of the engine transplant. Would it be an A14 engine I need then? Only say that as mine is an A12 so it makes sense that a 1.4 is an A14. What datsuns have these engines? I like the sound of it!

[Al Ramone]

Yes 1.4 or 1.5

You need to check if your car is a front drop or center drop sump (early or late B210) if it's center drop you'll need to reuse that sump on the new engine.

The center drop sump will need adjusting (careful hammering) to use with a 1.5 engine as the crankshaft throw will hit it, a 1.4 engine won't need it.

The 1.4 comes in some B310 models, the 1.5 comes in some B310 and also early Vanette and is more common.

[Talking Hoarse]

And ..... your old 1200cc engine may find an afterlife with another car? I recall chatting to an Australian chap visiting the Haynes museum who said a lot of 120y's had been scrapped after donating their engine (& gearbox I expect) to Morris Minor's. That's not a conversion I had heard of.
I recall driving a new 120y back in 1975 (I thibk) that was quite spritely but certaainly no ball of fire. Far better than an Escort 1100 and on par or maybe better than a 1300, at least in a straight line. As I recall it the 120y had a twin choke carb (albeit Nikki) - whereas an Escort had to be the GT to get a Weber.
Maybe your car is down on compression, or the carb chokes are not opening fully, or it needs a bit more advance etc? I am sure Al or Will will have a peep at it .....
Ed

[Al Ramone]

the last A14 engine and matching 5 speed gearbox I sold, went in a Morris Minor. The car already had a Nissan A12 engine conversion.

[dave45]

Very interesting! Right I best keep my eyes peeled for one! Sounds like an easy fit! If anyone knows of one going then I'd be grateful if you send me a pm. I'd keep the original engine and do a rebuild on it. The car only has 33k on the clock and is totally original, never been painted etc. I think it's known on this site already.

Thanks all!!

[dave45]

also like the idea of a 5 speed box. Does that go straight in?

[datsfun]

The A series responds well to the usual tweaks ..if you want a moderate increase in power, the bigger displacement A14 or A15 would be easiest. This is also the cheapest option

I have a A12 which powered a very well known rally car...has the usual modifications done and I suspect has been bored out to 1330cc...it will need twin carbs and proper exhaust to breathe so as to fully take benefit of its potential but would be quite lovely to drive. I was planning on selling this and if it's of interest , PM me.

Apr 17, 2015 13:37:35 GMT 1 dave45 said:

also like the idea of a 5 speed box. Does that go straight in?

Yes, just have upwards of £600 and good luck if you can source one

[dave45]

Ouch!!! Thanks for the info. Best get saving my pocket money hadn't I!

[greenclaws]

I would stick with the A12 - the bigger engine really needs at least the 3.7 diff and/or the 5 speed gearbox and these are rare and mega expensive.
I wouldn't want a bigger engine thrashing it's nuts of it would make the car tiring to drive and a heavy drinker in my view..
I always skim 40-60 thou of A12 heads and clean the ports up with a die grinder - the area under the valve seat has some sharp edges that need smoothing off and the casting flash needs removing. That's all you need to do a few extra horsepower makes a big difference. Use 10-14 deg. of static advance with these mods instead of the standard 7 deg that's not enough.
Valve clearances need to be spot on too - 0.35 set hot and always use a dwell meter to set the points...The carb needs to be perfectly clean and set up correctly too as the 120Y was set up a bit on the lean side anyway and is prone to flat spots...
Fitting an electric fan helps too.

[dave45]

Thanks fir that. The head is coming off and I was going to get a light skim on it. Will take your advice though. These are the mods I used to do on my mini years ago. A12 heads are a bit rarer though! Carb is spotless but it feels like fuel starvation. Feels slightly better with air intake on winter setting though. Set points with a dwell Meyer but will tinker with timing too. Is pinking allowed?

I always like setting valve clearances cold but Nissan workshop manual recommends setting when hot. Never like that idea! How hot and within what tolerance?

Will try a a good decoke, a bit of porting and a good skim.

Many thanks for that!!

[dave45]

Just remembered a mod I used to do talking about the cooling fan. Cut about an inch from each blade. Runs slightly hotter but improved acceleration. That was on minis though when spare parts were everywhere. 120y spares are not in most scrap yards these days unfortunately.

[greenclaws]

On my last Sunny I cut two of the plastic blades of flush with the boss to reduce drag -
helps with warm up to. Unless your radiator is silted up or your towing a caravan you won't
get any overheating -
I didn't anyway and the later Sunny's are heavier...

If your using a better flowing exhaust you might find a jet change is needed in the carb to make the
most of it....120Y's run a bit weak anyway - they all seem to have flat spots that I have driven...


Probably teaching to suck eggs here if you have done all this on mini's before so
apologies for that


I never had any issues with pinking over 10,000 miles after the head skim -
that was using standard unleaded and with the timing set at 12 deg.
But you have to remove any sharp edges around the combustion chambers
that might cause hot spots.

The area under the carb in the inlet manifold needs a bit of smoothing with the die grinder and
the alignment of the head/manifolds is quite poor too if you really want to get at it. Think I used
the gasket as a template.
Exhaust ports are very rough and narrow in places I remember buts it's the sharp edges under the valves that
need most attention.

The cold tappet setting is only for setting up after a rebuild - I always found it to be quite a way
out on the hot setting.
Set No 1 cylinder @ TDC (make sure the rotor arm points to No.1) and check 1,2,3 & 5 then rotate
clockwise 1 turn so cy 4 is at tdc and check 4,6,7,& 8.

From memory Haynes say use the rule of nine but this method is much better and more accurate.

I like to take of the carb tamperproof cap..I cut a slot in the screw with a hacksaw
to make it easier to adjust...should run like the proverbial swiss watch if everything is spot on

[dave45]

Great advice! Thanks again! Head has been stripped and skimmed. Took rough sides off the ports. I didn't grind the combustion chambers as I was concerned about lowering the compression. Polished and lapped in valves with new oil seals. Old ones had disintegrated or at the best cracked! Going to rebuild all tomorrow though as I need it for work Monday. It's.y daily driver! I'll play with the timing and see what happens!

Will keep you posted! Thanks again!