7 replies to this topic

[gazza82]

Going to be fitted with a 12G295 head and large bore exhaust, but what cam?

Suggestions we have had so far are:

Piper 255
Swiftune SW2
Minispares EVO002
Kent 256
MG Metro (so equiv of Kent 266)

Anyone using any of these and can provide feedback?

As it is a road car it doesn't need to be a high revving engine and not too lumpy at low revs. Torque more than HP!

[OzOAP]

Piper 255 get my vote.

[whistler]

I've built an over bored 1098 following Keith Calver's article on small bore engines. He recommended the Piper 255 as a good road cam for this type of engine. The 1098 is a long stroke engine which is good for torque but generally speaking not good for revving over about 6000rpm. Have a read about these on Keith's website. CalverST.

[ACDodd]

I recommend my own ACD - RT cam,

Below is a graph for an 1150cc engine running twin hs2 carbs 1.3:1 rockers and a ported 12G295 head.

Attached Files

•  1E588A4C-508C-46D5-A956-B14E919CF5EA.jpeg   34.47K   30 downloads

[panky]

Out of interest my 1098 Minor traveller is fitted with a 12G940 head modified for the valves to clear the block face comfortably. How much extra lift would the 255 cam give over the standard 1098 cam? assuming it's the same one as in a Mini.

[OzOAP]

Out of interest my 1098 Minor traveller is fitted with a 12G940 head modified for the valves to clear the block face comfortably. How much extra lift would the 255 cam give over the standard 1098 cam? assuming it's the same one as in a Mini.

Std cams normally have 0.320 lift, Piper 255 has 0.360

[panky]

Thank you. So another .040" to loose, hmmm

[unburntfuelinthemorning]

Anyone using any of these and can provide feedback?

 

After much consideration I chose the MG Metro cam for my 998 build. 

 

I wanted good power and economy with long term reliability. 

 

I'd used a Kent 256 previously (0.320"/0.320" lift on standard rockers and 254/254 duration) which was a nice cam with excellent fuel consumption and smooth idle.

 

The Kent 266 offered the same lift but with 260/268 duration. 

 

The MG Metro cam has lower lift at 0.250"/0.250" and a reduced inlet duration at 252 degrees (exhaust 268 degrees) 

 

I chose the MG cam as I felt the lower lift would decrease valve train wear and the short inlet duration would keep fuel consumption within sensible bounds while the earlier exhaust valve opening would help clear the cylinder better after the useful work of the power stroke was completed and slightly increased overlap would improve cylinder filling.

 

I'm pleased with the result.  On an engine with a Calver modified standard head and a single HIF 38 it's a very driveable road engine which is willing to rev over 6000 (although in practice no point in going past 5500), pulls cleanly from very low revs and has just a very slightly lumpy idle.  Fuel economy similar to standard.  

 

There probably is very little difference between the Kent 256 and MG Metro cam if you compared them back to back, they are both very good cams for up to 6000 rev/min and in a 1098 you should have a smooth idle too with the MG cam.  If fuel economy isn't an issue I'd probably go for the Kent 266 on a 1098.  As for the other cams you list I have no experience of them but I'd doubt you'd go wrong with any of them if you time them in carefully.  Camshaft selection is an easy subject to over think!

 

Here's my results, not huge numbers but not overstressed and with a 3.76 diff it's quite nippy.

 

Edited by unburntfuelinthemorning, 25 November 2022 - 08:24 PM.