Verniers?

[SPW]

Is there much benefit in fitting verniers to a standard K series engine (135bhp, 1.6 Supersport spec) or is it a waste of time?

[Dave Hardcastle]

The main reason for fitting them is when the cams are changed, to allow different cam timing.

[Wrightpayne]

As the supersport cams are upgrades, I'd say yes worth fitting - factory tolerances when machining mean every engine built is slightly different. Having the cams timed to suit your engine just optimises everything. 
 

I had mine done by Oily (of this parish) and while I dont think it makes more power it definitely picks up a lot better.

One thing I'd recommend investigating is shimming the cambelt sprocket  on the crank. There is a few degrees movement once the bolt is undone meaning cams need retiming when the belt is changed next. The shim to eliminate the slack means its just like a normal belt swap.

 

[SLR No.77]

#1, Maybe, maybe not, it depends where your cam timing is now. Ideally measure the timing before making a decision.

Stu.

[simon_h]

As you are going to measure them when fitting verynears I would measure beforehand and see if one or two offset dowels will cover the task for a few pounds rather than a couple of hundred 

[oilyhands]

Supersport cams (hydraulic profile), should be 50 / 44 thou lift at TDC, in my experience they are always a country mile out because they are designed to run on a different lobe centre than the stock cams and the stock pulleys are for the stock 110 lobe centre, the slack in the system also retards the cams by 4-6 degrees compounding the error. On average SS cams as installed have around 10 thou lift at TDC on the inlet and 65 on the exhaust which is around 8 degrees retarded on both cams. I keep 15 degree(1 tooth) offset dowels in stock, these can be rotated to give any offset between + and - 15 degrees, they are a pain to setup, but have the benefit of being relatively inexpensive. The tip to shim the bottom sprocket is a good one..

 

Oily

[SPW]

Thanks for the information. I have a new pair of Piper verniers, just have to decide whether it's worth fitting them so will check the current timing to see how far out it is.

#6 Oily, just to clarify, are the figures you quoted for Supersport (1.6, year 2000, 135bhp) cams of 50/44 thou the ideal values for inlet/exhaust valves respectively at TDC?
 

Thanks

[oilyhands]

If you have hydraulic followers then those figures are as quoted, if you have solid followers (check if there is a clearance between base of the lobe and follower) then the values are 59 thou and 47 thou lift at TDC for inlet/exhaust respectively. I will be gobsmacked if the existing timing is anywhere near, please publish what you find for general information.

Oily

[SPW]

Thanks Oily, will do. I'm assuming hydraulic followers as the engine has never been modified since built by Caterham, is that a reasonable assumption?

I'll drop you a PM about parts.

[oilyhands]

Some factory built cars have solid followers, just check to see if the cam lobes have a clearance to the followers, take off the cam cover, find a lobe that is pointing up and away from the follower and see of you can get a 4 thou feeler gauge between cam lobe and follower, if you can they are solid, another good indicator is that solid followers usually have a dull grey ring around the peripheral of the top like a polo mint, this is the original patina left over when the follower was hardened.  The cams do not wipe the whole surface but leave a tell tale ring.

Oily