11 replies to this topic

[Stu1961]

Posts merged Stu

Edited by KernowCooper, 21 July 2013 - 02:13 PM.

[Stu1961]

Just looking for advice on an engine specs. I have an engine from a 1990 Metro 1275, fitted with a HIF44 with 3.44:1 diff. At present the engine is in a striped down state and generally looks in nice condition. What I want is something with a small to moderate increase in power throughout the range. It must be drivable and not idle like a bag of nails which I believe is what happens with some of these hot camshafts. In its present form the BL/Austin spec states 63bhp at 5650rpm with 72flbs torque at 3100rpm so is 85/90bhp unreasonable? Reliability is paramount.

My spec so far, please feel free to put me right if I’m a long way of the, mark constructive criticism is always welcome.

1. Rebore to + 0.020” (1293)
2. Swiftune SW05-7 camshaft in new bearings with Vernier duplex timing gear.
3. Pistons? Looking for help here.
4. LCB manifold with RC40 exhaust
5. HIF44 with K&N cone type air filter on a separate inlet manifold.
6. Head has 33mm inlets and 29mm exhausts. I presume 36mm inlets could be fitted by re cutting the seats, but would this be to any great advantage if the head was not ported, and please excuse my ignorance but what advantage is there to bronze valve guides over steel?  
7. The flywheel is totally knackered (cracked) so I will also be looking for a new one at a reasonable cost.
8. There seems to be a fair amount of ware in both the rocker shaft and rockers so total replacement would seem a sensible option, so what would the best option be here bearing in mind the SW05-7 camshaft. Only a small point but I wish to keep the standard rocker cover if possible so Presume this rules out hi-lift rockers?   

 

  Many Thanks for any help and advice given

Stu

[jaydee]

While you wont get a 1275 to 90 bhp and still have low down pull, you can get closer with a 1293, but the problem will be having such high top end power figure with a wide power band. 75-80 bhp is a more realistic figure.

I all honesty wouldnt even think about the SW05, you need something more, like a 266 or similar, with roller rockers and the correct rocker geometry, and above all a good cylinder head (this means you really need to have it ported and gas flowed) then it will be a nice reliable engine with plenty of torque.

Have a chat with AC Dodd hes got huge experience with this kind of builds.

[ACDodd]

Ok realistically you need a full ported head with 35.7 and 29.4mm valves. Using stock rockers with the sw5 cam will see you into the 78 to 80bhp area with a fresh 1293 bottom end. If you want more you need to fit he 1.5 rockers that should get you closer to 90hp. However you did say that reliability is paramount. So if you do fit a ported head you will need to remove the head annually to re-sea the valves to maintain seat reliability and power. If you go for a stock head the need for regular valve jobs diminishes as there is much less of a heat problem which is what causes the wear in the first place. So if it is reliability you want over all else fit you sw5 cam with a rebuilt 35.7 x 29.4mm valves standard MG Metro head converted for unleaded fuel of course, use rebuilt stock rockers your fresh bottom end a rebuilt HIF44 SU and fit a 3.1 fd to make the most of the low reving torque. Also fit a lightened an balanced flywheel to make the most of the acceleration available. Ensure you set the compression to 9.5:1 maximum and this will punch out 70bhp & 80lbft all day long.

Ac

[KernowCooper]

1. Rebore to + 0.020” (1293) If this is whats required to rebore to, dont just bore to 1380 for the sake of it the power difference will be very little and you will still have some rebores left at 1293
2. Swiftune SW05-7 camshaft in new bearings with Vernier duplex timing gear. Cam is Still quite Mild consider a 276 good idle more top end
3. Pistons? Looking for help here. Not prolonged High Revs so standard pistons suitable
4. LCB manifold with RC40 exhaust 1 3/4 Size excellent
5. HIF44 with K&N cone type air filter on a separate inlet manifold. Yes will give good power watch some though as clearance on bulkhead tight, MG Metro inlet is good and a shade shorter
6. Head has 33mm inlets and 29mm exhausts. I presume 36mm inlets could be fitted by re cutting the seats, but would this be to any great advantage  if the head was not ported, and please excuse my ignorance but what advantage is there to bronze valve guides over steel?   Head is where the power lies, so ported and bigger valves recommended, Iron Guides are hard wearing so not a issue over bronze for your application IMO
7. The flywheel is totally knackered (cracked) so I will also be looking for a new one at a reasonable cost. Consider balancing Flywheel and Clutch
8. There seems to be a fair amount of ware in both the rocker shaft and rockers so total replacement would seem a sensible option, so what would the best option be here bearing in mind the SW05-7 camshaft. Only a small point but I wish to keep the standard rocker cover if possible so Presume this rules out hi-lift rockers?    High lift rockers waste of money as they will only give a couple of BHP at the top end, consider 1.3 ratio roller rockers instead

If you have the engine apart then consider getting the crank heat treated after machining and having it balanced with the flywheel and clutch on,  a centre main bearing strap fitted, and a High Capacity Oil Pump like the Turbo oil pump which can deliver 9 gallons a minute against 6 gallons a minute for the std oil pump.

 

And Remember the A Series engines power is mostly in the cylinder head so a good head is paramount to power

Edited by KernowCooper, 21 July 2013 - 02:10 PM.

[Stu1961]

Thanks for the input gents very much appreciated and lots of food for thought.

 

   From what I can glean I really need to start with the head so porting will be a priority along with bigger inlets and a new set of valve guides. One of the big attractions of this project for me is actually getting to build the engine myself and learning how they go together in the first place. AC you say that removing the head every 12 months and re seating the valves will be a necessity. For me I don’t see this as a problem as mileage covered will probably be minimal I think the term used on this forum is weekend warrior or in my case weekend but without the warrior, so bearing this in mind how often should I be removing the head in mileage terms? I see removing the head to carry out this operation as more like preventative maintenance.

 

    Totally agree with you  Kernow with the point regarding the Rebore above 1293 I think preservation is all important one day we will run out of usable blocks and that is inevitably what will happen in the future, besides the preservation issue going bigger means the engine will be prone to being more fragile defiantly not what I want. The bores themselves seem visually very good with the factories cross hatching marks still visible and only a barely noticeable lip at the top of each bore. The crank is in excellent condition having miced each journal in four different places there is no more than 3/10 of a thou difference anywhere which I think is well within the factory limits, will still go for a regrind though just to be on the safe side.

 

   Still leaning towards the SW05 Camshaft, looked on various sites and forums and as yet haven’t heard a bad word said, most seem to rate it very highly even  when  compared with  the 276.

 

   I get the impression Hi lift rockers certainly 1.5s only make a worthwhile difference on a very highly modified engine, would I be right in saying they also create a lot of stress on the valves.  1.3s Seem to be very close to standard rockers so are there any benefits from fitting even these.

 

   I will go for getting the crank hardened and balanced. What are your opinions on electric fuel pumps, I’m currently re building the SU mechanical pump along with the carb I will change the diaphragm as a matter of course though I have read that if the diaphragm fails it can cause major problems as any leaking fuel will dilute the engine oil. Are the diaphragms prone to failing?

 

Once again thank you one and all

Stu

 

 

 

 

 

 

 

 

 

[Captain Mainwaring]

Not prone to failing - but they can.

I personally prefer an electric pump.

 

I think I like the spec that give 70 BHP and 80 ftlbs.

 

As an aside, Interesting how you can get 10 BHP more from 18cc,

[jaydee]

Standard sintered rockers are an optimistic 1.21 while 1.3 rollers are 1.27, most cams are developed for a 1.3 ratio.

By having these rollers the cam will work at its best, and you have less wear at valve guides, cam followers and camshaft lobes

[KernowCooper]

Some have been disappointed by the SW05 Camshaft and were expecting more, I actually run the 276 in my 1330 and setup correctly its a nice cam, it has a slightly rough idle but nothing really serious more of a burble at 1000rpm, it pulls smoothly between 1000rpm and 2250rpm if the carburation is set correctly and comes in strong from 2750rpm to 6500+rpm (Power band 1500-7000rpm).

 

SW05 Timing Timing: (Intake): 16/48 (Exhaust): 52/12

276 Timing  ...............(Intake) : 29/61 (Exhaust): 66/34

 

Here is the MG Metro Cam to compare

 

Timing: (Intake): 16/56 (Exhaust): 59/29

 

There is also a bit of information I saw somewhere that the SW05 is a bit easier on emissions but my 276 has no problems come MOT Time.

 

While the SW05 may be a good cam it in my opinion wont have a power band like the 276 and really take off, looking at the specs its more like a 266, depends what your looking for in your application. The 276 is nothing like a 286 and can do the town bit without masses of revs and be tractable.

Edited by KernowCooper, 22 July 2013 - 10:20 AM.

[Fast Ivan]

Mini spares P21253 pistons would be ideal for this.

And for the spec your thinking of a centre main strap won't be needed and neither will the crank balancing as well as the turbo oil pump not needed IMO.

[KernowCooper]

Balancing though makes a much nicer 3 main bearing engine and you cant beat good flow in a oil pump, if the OP has the funds then I'd do the mods

[Stu1961]

Thanks again for the input everyone really appreciated. Taking all the bits that need machining to 'Bromsgrove Engine Services' tomorrow anyone on here have any knowledge of them, also looking at someone by the name of Don Loughlin just outside Kidderminster he is supposed to have a good reputation as well so not decided yet who will be doing the work, decisions, decisions. Think I will go for the 1.3 rockers.

Cheers
Stu