13 replies to this topic

[secondopsman]

Hi i have just stipped a 1275 metro engine ready for a rebuild and im after recomendations for a camshaft. I would like the car to still be a nice drivable around town car with a steady tick over, Also im sure i have read on here some were that the cam bearings should always be changed when the camshaft is and they have to be reamed out after is this correct as i cant seem to find it now
Thanks Pete

[Stevie W]

Hi i have just stipped a 1275 metro engine ready for a rebuild and im after recomendations for a camshaft. I would like the car to still be a nice drivable around town car with a steady tick over, Also im sure i have read on here some were that the cam bearings should always be changed when the camshaft is and they have to be reamed out after is this correct as i cant seem to find it now
Thanks Pete

Hi Pete,

Yes you are correct, you should change your cam bearings and have them reamed to the exact size.
Most machine shops can do this for you for around £30 I think.

As for cams, then Swiftune SW5 cam is meant to be a good all-round mild road cam which gives a smooth tick-over and a broad torque range for road use. Remember the cam you choose has to be timed in correctly for maximum benefit and just lining up the timing dots pn the gears will not give the maximium performance.

Hope this helps,

Cheers,

Steve.

[secondopsman]

Ah so do i need one of the vernier timing discs thingys and some knowledge on ho how to use it
Pete

[Rosslin Racing]

years ago when the question of cam came up you heard you have to fit this or that that today the SW5 is first on the list of quoted cams WHY?

[Stevie W]

Ah so do i need one of the vernier timing discs thingys and some knowledge on ho how to use it
Pete

Hi Pete,

David Vizards bible on tuning the A series engine goes over the technique for timing a cam in with some good detail.

Regards,

Steve.

[Stevie W]

years ago when the question of cam came up you heard you have to fit this or that that today the SW5 is first on the list of quoted cams WHY?

I suppose its a fairly new cam that most people have heard of and its supposed to give some torque increase whilst leaving the enigne more driveable with a smoother tickover than some other cams.
I'm not saying this is the only one to use for mild road work, its just that it was at the front of my mind having just installed and timed in one on my 1293 A+ engine!!!

Steve.

[secondopsman]

So the sw5 cam is a good alrounder then!

[liirge]

The SW5 is a lovely Road cam, preferable due to its ability to deliver torque under the right build combinations (Bill sollis, 1380), the Cam is also able to provide power accross the band, not affect the idle, and keep emmisions down lower than other cams. It's a nice cam, however IT IS VERY MILD, many people on here have commented on how they barely notice its actually there, especially applied to a Small Bore car.

[Cooperman]

Personally I like the Kent 266 or even the 276. A properly timed-in 276 with a decent head and about 10:1 comp ratio, or slightly more, will produce noticeable power improvement without too much loss of bottom-end torque.
With a Kent cam (or any decent cam really) it's important that the engine can breathe well, so the head needs to be nicely flowed and matched to the manifolds.
New cam bearings are recommended, but if the old ones are in good condition, it's not vital. However, with a full re-build, it's false economy not to change them, and change everything else like oil pump, water pump, cam followers, bearings, piston rings (or re-bore and have new pistons), etc.

[Nightrain]

276 is crap in a 1275, you lose all the bottom end and don't gain that much at the top. If you want a tame'ish cam go with the SW5/266 or even an MG Metro cam, for something with a bit more go, then the 286 rather than the 276.

[Cooperman]

Now I've had excellent results with the 276 in 1275 motors. It's a bit like the old 544 BMC rally cam in many ways.
I had a guy who drove my car with its 286, but decided that he didn't want something as lumpy for forest rallies, so I fitted a 276 with all the other bits you would expect and it gave 97 bhp at the flywheel. It pulled well from lower down than my car and is still a joy to drive. Comp ratio is 10.5:1, inlet valves are 35.5 mm with 30.5 exhausts. It has a lightened steel flywheel.
Another one I did recently gave 92 bhp, but the head was not so good.
The cam to avoid has always been the BMC 731 which gave no noticeable overall improvement in a 1275.

[Nightrain]

Now I've had excellent results with the 276 in 1275 motors. It's a bit like the old 544 BMC rally cam in many ways.
I had a guy who drove my car with its 286, but decided that he didn't want something as lumpy for forest rallies, so I fitted a 276 with all the other bits you would expect and it gave 97 bhp at the flywheel. It pulled well from lower down than my car and is still a joy to drive. Comp ratio is 10.5:1, inlet valves are 35.5 mm with 30.5 exhausts. It has a lightened steel flywheel.
Another one I did recently gave 92 bhp, but the head was not so good.
The cam to avoid has always been the BMC 731 which gave no noticeable overall improvement in a 1275.

LOL the 544 has a lot more in common with the 286 than the 276. A 1275 with a 276 would NOT make 97 at the crank, it may well with some dodgy calculations to work it back from the 70 it had at the wheels.

[nzmember]

LOL the 544 has a lot more in common with the 286 than the 276. A 1275 with a 276 would NOT make 97 at the crank, it may well with some dodgy calculations to work it back from the 70 it had at the wheels.
[/quote]
For a road engine I've had excellent results with a 276. Lumpy tick over but pulled strong and smooth from 1800 rpm to over 6000. I prefer it to the 286 I have that needs to be over 3000rpm to really pull - the 286 might give more power but not so useful for a ROAD engine.

[haz]

Re: reaming the cam bearings...

these are reamers... http://img.alibaba.c...0590/Reamer.jpg

It's not exactly what it says on the tin, no one uses a reamer on their cam bearings. Or if they did they have had some rather expensive bespoke tooling made, I priced it up in HSS to around £700 for all 3 reamers.

What people really mean by reaming is fettling... ie a bit of scotchbrite rubbed around with one of your digits. You could also use a bore honer but I wouldnt advise it and if you do, use the finest honing stones you can lay your mits on. The basic idea is, if your cam goes in but its tight, you keep turning it until it runs itself in (the bearing material is very soft). You'll need to continually take it out and clean the fine swarf away and any lapping paste you may be using.
If it doesnt go in at all (like mine) you need to give it a very light rubbing all around and as evenly as possible until it does begin to push fit.

To help you dial/turn your cam into your bearings you might want to put the cam sproket on to give you a bit of purchase.

hope this sheds some light on it, as i was a bit confused when I was told I had to ream my cam bearings to suit my cam... i measured the cam journals on a lazermic, made cutting tool drawings and everything!