Jump to content
Click here to contact our helpful office staff ×

Verniers


ben7

Recommended Posts

Just received a pair from Dave Andrews at dvapower, cost was £147 +£8P&P. Cheapest place I found, and Dave has always been very helpful with queries - eg he provided the correct cam timing for the supersport cams. I strongly believe that his providing such invaluable information is a very good reason for ordering the bits from him.

 

All I've got to do is fit mine now, but I've been in bed with flu all week ☹️

 

Dave

 

 

Edited by - Dave McCulloch on 20 Nov 2003 14:35:02

 

Edited by - Dave McCulloch on 20 Nov 2003 14:35:33

 

Edited by - Dave McCulloch on 20 Nov 2003 14:35:57

Link to comment
Share on other sites

Pierre,

 

That's exactly the reason for them, but rather than tune them, time them.

 

there is no need to do it on a rolling road if you know what cams you are running and the design settings for them.

 

Setting up on a rolling road would enable you to test various setting and time the cams for most power (or some other setting).

 

Andy

Link to comment
Share on other sites

Pierre

 

I just had verniers fitted to my car. Unfortunately from your point of view (but very fortunately from mine 😬) I also fitted a competition exhaust at the same time, and had the engine management system set up on a rolling road. Total result was an increase from 143 to 159bhp, although those figures are probably not precisely comparable (different rolling roads). However, the difference in the way the car drives is enormous - much better all the way from 3k rpm up *thumbup*

Link to comment
Share on other sites

Correcting the cam timing can have a small affect on peak power, but it can have have a massive affect on torque especially in the low and mid range RPM. Half a tooth is seven degrees which is very significant and can represent between 20thou and 60 thou of lift at TDC depeding on cam profile. In my experience a misalignment of 7 degrees can make a difference of between 5 - 10 % in mid range torque. The most I have seen gained by correcting cam timing alone on one engine is 42 lb/ft at one point in the curve.

 

The drivability is also much improved when the cams are timed as the Gods intended.

 

Oily

Link to comment
Share on other sites

Thanks for the help guys re inital post. I panicked a bit when the site went down yesterday morning, so ended up buying direct from Piper - would have gone through Oilyhands otherwise *wink*.

 

I was intending to print out the vernier section of Oily's excellent paper on the K series to help out the garage. I note though that this was last updated Feb 02, any body know if it's still up to date?

 

Ben

Link to comment
Share on other sites

You really need to look at Oily's website http://members.aol.com/DVAndrews/kengine.htm but it's actually quite a straight forward process. It helps if you can see someone do it before you do it yourself. After watching Oily time a set of cams, the instructions on the site made perfect sense and I managed to time my own cams in about 2.5 hours - which included making my a set of brackes for the dial gauges (my verniers were already in place on the cams).

 

You only really need two dial gauges (one for the piston and one for the followers) with some extensions, a set of brackets and the settings for your cams (supplied in the spec sheet - but also on oily's pages).

 

Putting the verniers on is fairly simple too, set the engine to 90°BTDC. Mark one vernier as inlet and one as exhaust (a little scratch with a file over the relevant letter in the PIPER stamp does the trick). Lock the cams (cam locking tool) and take off the cam belt. Unbolt the pulleys and take them off. Then line up the notch for the roll-pin on the vernier and the standard pulley by placing them on top of each other. Then mark the timing position off the original pulley on to the new one. Put the pulleys back on the cams (I think one should advance/retard them slightly before installation - someone else can confirm this) and time them up.

 

It really is quite straight forward if you follow Oilys pages through, not something that you should be put off by if you're reasonably competent at home mechanics.

 

Hope that helps

 

Andy

Link to comment
Share on other sites

I'm just in the process of replacing my standard pulleys with the verniers Dave supplied, following Dave's website instructions. Mine's a 1998 engine, and no problems so far. Took about 2 hours to get the old pulleys off (though I'm not sure I needed to remove the crank pulley, which also necessitated removing the alternator belt - wasn't sure if the timing belt would come off cam pulleys otherwise). Expect it to be about the same time again to refit, plus a bit extra to time in the cams. I haven't done much "engine" work before, so tend to work at a steady and methodical pace!

 

Dave

 

ps see my other thread re how long do hydraulic lifters remain "primed"

Link to comment
Share on other sites

Interesting stuff. I have looked into this myself recently and the general opinion was that verniers are only of any noticeable benefit on higher output engines, not necessarily the 1.8 kSeries 140 bhp that I have. Is that the case?

 

Best Regards, Felix.

 

 

Link to comment
Share on other sites

The SS variants are generally in dire need of verniers, the correct timings are around 65-70 lift at TDC on the inlet and 45-50 on the exhaust. Actual timings are a country mile away from these figures , the last one I did was 2 thou lift at TDC on the inlet (thats 20 thou *less* than the stock K16 cam for goodness sake) and 95 thou on the exhaust. Retiming gave a far better torque curve below 4000 and a small gain above, with much less of the all or nothing feeling.

 

Oily

Link to comment
Share on other sites

Probably crap. My 1.4k was way out & I think Oily said to me of the hundreds of Ks he has seen, very few are even approximately at the optimum. Manufacturing tolerances etc.

 

Its probably likely you'd benefit - the difference in my peaky 1.4 is very noticebale. Power delivery is much more linear, with no step & there is more low down torque. The car actually accelerates in 5th gear now. With my cheap verniers + Dave fitting them for about £100, I was very happy with the tuning & the cost!!

Link to comment
Share on other sites

tom, don't you have a supersport ?

 

The 115bhp 1600 will run standard cams. I doubt that there is much to gain from fitting verniers on this engine without a cam swap to something more agressive.

 

Oily would be able to confirm for sure. Might be worth Ian hanging on and buying some cams and verniers together to see a huge improvement.

 

Andy

Link to comment
Share on other sites

Agreed, mav (my brother) had his verniers fitted to his SS by DVA. The timing on the standard pulleys was way off.

 

He'll be along in a bit to confirm the difference in drivability but he was well impressed.

 

I fitted a set to my 270 cams and timed them up and the difference was amazing.

 

It's well worth the visit to Oily to see how its properly done, take a camera along too and watch the process carefully. If you help with the work, there are two advantages - 10% off the fitting charge and you learn how to do it - he will also do it at your pace and explain everything in as much detail as you want.

 

Andy

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...