47 replies to this topic

[silky]

Sorry, but my knowledge of engines is rather poor, so need some help.

On my way to having my car MOT'd yesterday, approx 5 miles from the garage, my 1275 '90 carb cooper decided to dump all of her oil on the motorway and blow the engine. The AA Man had to tow me the rest of the way to Bill Richards (who seems to be a very nice man).

Bill said that it will need new pistons and as he has to do something to the cylinders, it would cost the same to re-bore it to a larger size (say 1293, 1310, etc).

My questions are:

1. What's a sensile re-bore size and is the difference in performance really noticable?

2. He mentioned upgrading my camshaft while I have the engine out. I have looked at a few from the minispares/speeds, etc but what's the difference between 266, 276, etc and which one would be best for zipping about the town? Again, is the performance increase worth the cost?

3. Is there anything else I should consider upgrading which would make a big difference on performance?

I am on a seriously low budget (£500-600 max) so any advice is great!

Edited by silky, 26 October 2007 - 08:03 PM.

[mini_kel]

U can just go for the next bore size 1293!

I`d have 1330 as a personal choice

Upgrade the cam whilst engine is out! if it`s just for around town a 276 or sw5 will be fine

[Big_Adam]

1. What's a sensile re-bore size and is the difference in performance really noticable?

2. He mentioned upgrading my camshaft while I have the engine out. I have looked at a few from the minispares/speeds, etc but what's the difference between 266, 276, etc and which one would be best for zipping about the town? Again, is the performance increase worth the cost?

3. Is there anything else I should consider upgrading which would make a big difference on performance?

Yo, I'm going with you want power on a shoe string budget then. Okay, your budget is £600 max. Looking at mini spares 1275 and up pistons are around £50 a pop. Add £80 for the rebore, then time taken (engine out, stripped, bored, rebuilt) your lookin at a fair chunk of the money gone in a few simple steps.

I'd suggest getting a proper quote before you look at going faster. Or you won't be going anywhere.

[dklawson]

I agree with him that while the engine is out you should consider a new cam. I have the SW5 and like it for city driving. The engine still idles quite well and it has plenty of torque starting from just below 2000 RPM.

I doubt you'll notice a huge difference boring out to a particular size unless you also invest in a ported head. Yes, the compression will be a little higher but without some head and valve work the engine won't breath differently.

I don't know your labor rates but I wouldn't count on getting out for the 500-600 GBP you mentioned unless you're able to re-use a lot of the existing parts. Pistons will probably set you back at least 100 GBP, and you may need new timing gears. You should plan on a new timing chain, and of course... there's the gasket set. God only know what other "problems" will be found when you start tearing the engine down.

EDIT: Big_Adam was posting as I was typing. FWIW, I am running the P21253 pistons from Mini Spares. They are currently listed at 36 GBP each including VAT. I bought mine as a set and seem to remember they were less expensive that. Anyway, that's 144 GBP before you machine anything.

Edited by dklawson, 26 October 2007 - 08:54 PM.

[alexcrosse]

as long as you can afford insurance id go 1380, nice n powerful with no real crank work. Stick with bill richards, he is a brilliant bloke, enthusiatic and offers alot of help. if your going 1380, 276 will be a drivable city cam, but i have a friend with a 1380 and a 276 and he regrets it and wants a little more, so i would suggest a 286, i have one and it seems to go very well in the 1430. Or, if you have the money, as mini kel sayes the SW5 is a brilliant cam, also 286 degree duration but alot cleaner and easier to go for MOT.

My advise
1380
SW5 cam
Stick with bill richards.

[silky]

Bill seems like a top guy. He said he'll do the full costings on Monday for me, but to have a general budget in mind.

He said he'll do a basic quote to get it back on the road and a full quote to make it spanking.

I have been warned that if I go for the full bore, I'm buggered if it did ever go again. Making 1330 a safe bet. Been looking around t'internet and everyone says the SW5 is best - might suggest that to him.

A set of pistons from MiniSpares will cost me £230 - but only £150 from MiniSpeed. Is there any difference in the pistons?

[Sprocket]

U can just go for the next bore size 1293!

I`d have 1330 as a personal choice

Upgrade the cam whilst engine is out! if it`s just for around town a 276 or sw5 will be fine

LOL you cant compare the 276 to the SW5 cam the SW5 is more like the 246

[Sprocket]

SW5 is a brilliant cam, also 286 degree duration but alot cleaner and easier to go for MOT.

My advise
1380
SW5 cam
Stick with bill richards.

Really???


You wont get over 100bhp/ 100lbft with the SW5

[silky]

Not over-fussed with horsepower. Just want a half-decent amount of torque and half-decent fuel economy.

I've just got a playmini exhaust to go on too - someone mentioned it's gonna be loud. I hope not too loud!

[ginigwunkle]

ah stop messin with these tiny 73.5mm pistons and drop some 74mm ones in!

1400cc with std crank, drop a 286cam in, 296scatter even....

[alexcrosse]

100bhp 1380s rnt always that drivable, expecially budget ones! SW5 is 286 degrees

73.5mm pistons, and 74 if it buggers again (which a br engine wont). And even if it does, blocks aint expensive. Powermax pistons will be the ones thatll go in on a budget 1380, looking at £160-170. Good pistons, not as good as omega tho... worth the money! only £40-50 more too.

Edited by alexcrosse, 26 October 2007 - 09:26 PM.

[mk1leg]

Hi..!..Silky...Been reading prev posts, I sujest 1293,SW5,ajs duplex, lightened and bal fly and backplate, and stage 3 head, this will leave you with 3 more rebores............hope this helps you decide..........

[Sprocket]

100bhp 1380s rnt always that drivable, expecially budget ones! SW5 is 286 degrees

73.5mm pistons, and 74 if it buggers again (which a br engine wont). And even if it does, blocks aint expensive. Powermax pistons will be the ones thatll go in on a budget 1380, looking at £160-170. Good pistons, not as good as omega tho... worth the money! only £40-50 more too.

This one is a 1380 as built by Swiftune racing its one of there classics, big engine mild cam(SW5) nice head, 1.5 Roller tip rockers, Twin HS4 SU carbs, cone filters/stub stacks, Carbs was fitted with a Custom ACDodd needles and RED springs.

Produced figures of 90.5bhp@ flywheel, and 86.7lbft @ 3500rpm respectively.

Here are the exact figures if anybody want to plot them, runs taken in 3rd gear, power at wheels was 81bhp peak.


Rpm Bhp Lbft
1500 20.41 71.46
2000 27.89 73.24
2500 35.71 75.03
3000 49.32 86.34
3500 57.82 86.77
4000 65.31 85.75
4500 73.47 85.75
5000 81.29 85.39
5500 87.41 83.47
6000 90.48 79.20

This engine also had leak down figures of 15%, 23%, 25% and 14%.

This was also the most powerful SW5 equipped car I have tested to date, though it should be it has the spec!!

http://www.mlmotorsp...opic,124.0.html

irst off is the excellent Swiftune SW5 road cam, these figures are based on my observations based on 2 new examples I measured about 2 years ago. The figures are to be read as average of the 2,

Checking height: 0.016" @ lobe

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

Nominal lobe lift: (Intake): 0.281" (Exhaust): 0.281"

Duration (Intake): 244 (Exhaust): 244

Lobe centre angle (Intake): 106 (Exhaust): 110

Lobe separation angle: 108

Lift on overlap: 0.036"

Accuracy: Good

Next is the much under used Kent 246 a nice all round road cam that has a little more bite than the SW5, these figures are based on kents own specs, plus with my own additions looking at 1 cam.

Checking height: 0.016" @ lobe

Timing: (Intake): 18/54 (Exhaust): 54/18

Nominal lobe lift: (Intake): 0.285" (Exhaust): 0.285"

Duration (Intake): 252 (Exhaust): 252

Lobe centre angle (Intake): 108 (Exhaust): 108

Lobe separation angle: 108

Lift on overlap: 0.048"

Accuracy: Good

http://www.mlmotorsp...topic,11.0.html


Please stop giving bad advice. Be sure what you say is right or you will make yourself look like an arse.

I know what i am talking about. Most of the time

My 1400 is probibly more driveble that yours, its deffo a road car and that IS a fact

[alexcrosse]

Please stop giving bad advice. Be sure what you say is right or you will make yourself look like an arse.

I know what i am talking about. Most of the time

My 1400 is probibly more driveble that yours, its deffo a road car and that IS a fact

well, I was recommended a 286 or SW10, I made a mistake, sorry boss. However, I suggest you don't talk like that just because your happily tucked behind your computer desk mate. I never said yours wasn't drivable did I! Also, you have never driven my car, and I wouldn't even consider letting you. Mines perfectly drivable for me, clutch is perfect, low down torque is better with long stroke engines, and my 286 cam offers the perfect power curve. If you want to correct someone, be polite about it.

"100bhp 1380s aren't always that drivable, especially budget ones!"

right, lets analyse this quote of mine shall we, is yours 100bhp? no, not at the moment. Is it a 1380? No, it isn't. Is it a budget engine, no it defiantly isn't. Mine is neither of these either. Its over 100bhp, its not a 1380, it is drivable, and its not budget.

And by the way, your spelt probably wrong, your making yourself look like an arse.

[mini_kel]

I have a 1330 tom bell race engine producing 105bhp on a single 1 3/4 carb with a 286 cam,and i have the dyno sheet! I have been told with the sw5 i will easliy make more torque with the sw5,this was on peter baldwins rollers,I have a 45 to go on next also