Verner Pulleys

Hello, thank you everyone for your comments about cams, cam belt tensioners… I've read quite about about cams and the K1.8 motor recently and learnt many things.

I'm always looking for ways to make the engine better = smoother, better fuel use and maybe a power gain, greater reliability and safer.

I've come to the conclusion that standard FL cams are the best option due to the toque curve approaching its peak at approx’ 2500rpm and remaining pretty flat after that to about 5500rpm it does rise a bit, but not much. A desirable trait in a vehicle when off road.

The cam pulleys on the FL are the standard MG Rover ones I'd guess. I noticed when I was reassembling the head off of my R25 [1.6] and fitting the new cam belt that the cam pulleys didn't line up perfectly. Yes everything was fitted correctly - trust me that was checked and rechecked very carefully! The car runs very well - good acceleration and power…

When Piper 270s are fitted it’s encouraged that Verner pulleys are used as well to optimise timing and thus engine power too.

My question is this: would the standard FL K1.8 benefit from Verner pulleys. My guess is that as st’d, these like my R25, won’t align perfectly either. Would Verner pulleys allow for optimal cam timing and thus a smoother power delivery and a positive effect on economy - be it very small?

It is theoretical at the moment so ignore the potential cost factor.

HTR

You might find a benefit from vernier pulleys but equally, you might not.
You will only find a benefit if the cam timing is out. This isn't the same as the timing mark slightly out. To check the cam timing, you need to measure the exact period of valve lift, correcting any errors by adjusting the vernier pulleys.
The standard K series 1.8 uses symmetrical cam timing for inlet and exhaust of 12 52 52 12. This means the in inlet valves should open at 12° BeforeTop Dead Centre (BTDC) and close at 52° After Bottom Dead Centre (ABDC).
The exhaust valves should open 52° Before Bottom Dead Centre (BBDC) and close at 12°After Top Dead Centre (ATDC).
This gives a total valve open period of 244° which is pretty mild, hence the flat torque curve.
A vernier pulley set will only help if your current fixed pulleys hold the cam or cams in the wrong place.
There are several other options to optimise cam timing too.
1st off the K Series uses 2 identical cam pulleys mounted to the cams in different slotted holes depending on them being fitted to the inlet or exhaust cams. No two pulleys will be identical so by swapping there location could improve the timing?
You can also pin the current pulleys to the cams in the correct place, this would then fix the timing permanently for each cam.
All this of only minor consequence as a cam timing error of a couple of degrees makes almost no difference on a cam set as mild as the 244° duration standard cams. Especially as a timing belt fluctuations can cause an error of 2 or 3 degrees any way.
You will get better results having some porting done on the head and improving the air flow into and out of the engine.
Oh Piper also do a set of 248° (BP255H) cams designed to increase torque.

Thank you for that. Not really worth doing. Those 255 cams have a higher lift on the valves than the 270. Would you need to replace the valve springs with that lift?

HTR

Piper 255 cams are 8.84 mm lift iirc. There's no need to change the springs.

Thank you for your advice. I'm trying to find out more info' about those 255 cams. Can anyone on this forum comment as to their benefits in a FL K1.8?

As I have a spare head for a K 1.8 could you advise on porting and polishing?

I've browsed the MG Rover forum and read the mentions on this forum as well. I'm especially interested in the inlet side and the valve area. I think I understand about port matching and polishing of the exhaust to reduce carbon build-up.

There are thought provoking comments on the MG Rover forum re' throttle bodies and polishing them and the different options re' air filtration / CAF... [st'd Vs K&N panel Vs induction kits Vs cone/pod filters].

I'm interested in trying to make the motor 'breath' easier for the following reasons: improved throttle response, power available lower in the rev range, economy.

HTR

With the porting the head. The standard K series head inlets flow something under 90 Cubic Feet Per Minute (CFPM). This can be improved on using the standard 27mm valves. The area under the valves has a marked ring in the casting, these should be blended into the rest of the ports throat. Also smooth the whole port from manifold flange to valve throat. Don't remove to much metal, just enough to remove casting marks. Don't bother polishing the ports, it's a worthless exercise.
There's loads on the Web about porting the standard K series head.
The whole inlet system is a problem power wise but difficult to remedy. Make sure the inlet manifold and head ports are aligned with a minimum of step been them.
The standard 48mm throttle body is good for 130 BHP. Getting lots of cold air into the throttle body is important and can definitely be improved on.

There is a huge amount of information on this site. http://www.s262612653.websitehome.co.uk/kengine/#modifyhead
My wife has a 165 BHP MG F, some of the information in the above site helped me in the quest for more power.