22 replies to this topic

[Easyrock]

I'm in the process of building a 1380 and am a bit unsure on what will/won't work. I have a new old stocck 12G940 head which has 36m inlets and 30m exhaust valves (roughly, measured with an old tape measure) the head has never been assembled and was just wondering what work I should get done to the head and what cam etc I should get to make a nice fast road motor?

Any advice would be very much appreciated

[mike.]

What do you want from the engine and what will it be used for?

Whats your budget?

[Easyrock]

the car will be used as a daily driver but i don't do a lot of mileage so not too fussed if it's a tad wild, just don't want to have to rev the nuts off it to get any power. Also i'm in no rush to get the engine together so budget doesn't matter too much, but again i'm not gonna go spending thousands on billet cranks etc

[mike.]

Ok well this is just my opinion, but there is no point going for a 1380 in your case unless you've already had the block work done. 1380's are really only the way forward when your trying to get the absolute maximum power out of an engine or planning on running a racey cam, where the extra CC's will help pull the engine when it is off cam. You end up spending more money on a 1380 for a very small gain, and once the bores are worn - Thats it, the block is scrap.

If you stick to a standard rebore such as 1293, you can extend the life of the block massively as it can be still be rebored again and again when required. Remember 1275 blocks aren't being made any more and are getting harder to come by at a decent price. Of course people will say, its you engine do what you want, which is right; but future block life is worth keeping in mind.

Opinion aside, the type of engine you want is similar to what I wanted when I built my engine.

My spec is as follows:

Rebuilt 1275
Stage 3 head - 35.5mm inlets, 29mm exhausts, 185lb double valve springs and a load of porting work.
Morspeed phase 3 cam - Similar to a Kent 276. You could go for a 286, but this would be quite lairy and not give you decent power till around 3000rpm
Kent vernier timing gears
Pre verto clutch, orange clutch cover, AP bonded rally clutch plate, ultralight flywheel
LCB manifold, RC40 exhaust
HIF44 carb, alloy inlet, K&N cone filter
Megajolt mappable ignition - A must for any A series in my opinion.

So far its not been driven but it run nice, idle's not too lumpy at 1000rpm and should pull from around 2000rpm. I'm hoping it'll make close to 85-90bhp.

[Easyrock]

I already have a 1380 block and pistons so thats why I was going to use that, but if its worth the extra money for pistons, rebore etc I can get a bare 1275 block off a mate pretty easily. Would the current valve sizes be ok for say a 1293 or 1380 then? or would a 1380 need larger valves to make the most of the engine?
I've heard a lot of people say how good megajolt is so I think thats definitely the next thing on my list, Thanks for the help by the way, it's appreciated

[Cooperman]

If you already have a newly bored and as-yet unused 1380, then you might as well use it, so long as you know that it's been correctly offset-bored and has been done to suit the pistons. AsMike' says above, once you go to 1380 that is the effective end of life for that block once it is worn.
With regard to valve sizes, a 1380 will need a head which will flow more mixture at maximum power as identified from the cam power graph. This may mean bigger valves, but the 35.6 mm which you seem to have won't be too bad.
As above, a 1380 is really for max power/torque for whatever yu want your car for. With a fairly mild cam it can be nice on the road, although of course it costs more to build and won't really give more noticeable power than, say, a 1330 which can be sleeved back to standard to re-build, whereas a 1380 can't really be sleeved back to 1275 due to the offset of the bores.

[Easyrock]

Thanks for the help :) yeah the bores are offset and what not so that's all good. Think I'm just gona get a bit of work done on the ports then when I send the crank etc to get balanced. Then it's just the cam to sort really, was thinking something like a 276 maybe

[Cooperman]

The MG Metro or Kent 266 are very good in a 1380 unless you want the car for competition and then a 286 is good. Unless you are going for a 286 there is probably not a lot of point in having it all dynamically balanced as it will perform best at 5000 to 6000 rpm with great torque from quite low down.

[oltonlad]

Ok well this is just my opinion, but there is no point going for a 1380 in your case unless you've already had the block work done. 1380's are really only the way forward when your trying to get the absolute maximum power out of an engine or planning on running a racey cam, where the extra CC's will help pull the engine when it is off cam. You end up spending more money on a 1380 for a very small gain, and once the bores are worn - Thats it, the block is scrap.

If you stick to a standard rebore such as 1293, you can extend the life of the block massively as it can be still be rebored again and again when required. Remember 1275 blocks aren't being made any more and are getting harder to come by at a decent price. Of course people will say, its you engine do what you want, which is right; but future block life is worth keeping in mind.

Opinion aside, the type of engine you want is similar to what I wanted when I built my engine.

My spec is as follows:

Rebuilt 1275
Stage 3 head - 35.5mm inlets, 29mm exhausts, 185lb double valve springs and a load of porting work.
Morspeed phase 3 cam - Similar to a Kent 276. You could go for a 286, but this would be quite lairy and not give you decent power till around 3000rpm
Kent vernier timing gears
Pre verto clutch, orange clutch cover, AP bonded rally clutch plate, ultralight flywheel
LCB manifold, RC40 exhaust
HIF44 carb, alloy inlet, K&N cone filter
Megajolt mappable ignition - A must for any A series in my opinion.

So far its not been driven but it run nice, idle's not too lumpy at 1000rpm and should pull from around 2000rpm. I'm hoping it'll make close to 85-90bhp.

i agree with the use of the morspeed PH3 cam, its the same basic profile as the kent 276 but has less overlap lift to increase torque, i had one of these cams in my 1330 and the torque was unbeleivable, the car pulled like a train from really low revs and once it hit around 2100rpm it took off!!
i did a standing 1/4 mile at shakespeare raceway in 16.4 seconds with that engine in the car.

the spec was

A+ block bored +60
lightened and balanced crank,
morspeed stage 3 head,
morspeed PH3 trackday camshaft,
centre main strap
standard A+ gearbox with s/c transfer gears
uprated diff pin
HIF44 carb on minisport manifold
maniflow LCB with 2" single box exhaust

the engine produced 92.6 lbs/ft of torque at 3700rpm

heres an old video of the car, you can see that the cam works well from low revs, the volvo in front was doing 40 mph

Edited by oltonlad, 21 February 2012 - 05:37 PM.

[oltonlad]

if you decide to go for the morspeed PH3 cam and cant get hold of one (as far as i'm aware morspeed are no longer trading) then newman cams will do a regrind on your own cam to that spec as they were the guys that supplied all of morspeeds camshafts.

heres part of an email that i received from ken newman last week

The MSD P3 was our ARA/290/383 PH3. We offer a regrind on your camshaft for£60 + VAT or a new cam £150 + VAT. Delivery is £12.

Best regards,

Ken Newman

[mike.]

Yeah like I say, i've not driven mine yet but did like the sound of its characteristics on paper and it wasn't too expensive either.

If only Morspeed could still be recommended to people now...

[mike.]

Ahh thats great news, will have to remember and recommend them

[Easyrock]

After watching that video I think I know what cam I'm going for think i'll build the rest of the engine to a similar spec as well! I'm pretty sure I have a hif44 around somewhere but I was planning on using a set of twin hs4's I have, what would be the best set up to use? Only reason I was gonna use the twins is that I love the way they look haha

[oltonlad]

if i still had that engine then i would have put twin HS4's on it without a doubt!!, the car was pretty quick as it was but it would have gone a whole load better with the twins......go for it easyrock......you wont regret it.............apart from the fuel consumption!............

[Easyrock]

Twins is it then, I work within walking distance from my house so I don't do a lot of mileage, so I'll convince myself that makes up for the extra fuel consumption :) cheers for the help!