Vernier Pulley Setting Up
Discussion
Afternoon all, looking for some advise with regard Vernier Pulleys. I have just re-built my 205 1.9 XU9JA engine following a session round Rockingham earlier in the year. Any way, I changed the rings and bearings etc... and decided that whilst it was in bits i'd buy myself a new cam so I brought myself a CatCam with a 282 duration. Once installed and the engine running it was a dog to drive at low RPM so a mate suggested a vernier to try and nail the timing to make it as good as it could be. So, spent £100 on a vernier, whipped it on (looks lovely) but i'm stuffed if I can get my head around the setting up of the damn thing, i've left it a 0 degrees for the time being with the ignition advanced by 30 degree as per the Peugeot book, what the bloody hell should I be looking for/trying to achieve with this thing, next to looking nice it's poxy useless to me at the moment. I understand the principle behind the manufacture of these, adjustable timing at both ends of the cam but I can't find anything to suggest that I should have it 3 degrees advanced for better mid range power for instance...
HELP PLEASE!!!!!!!!!!
Thanks in advance to anyone with more useful brain cells than me!!!
SP
HELP PLEASE!!!!!!!!!!
Thanks in advance to anyone with more useful brain cells than me!!!
SP
Does the cam maker not suggest any particular setting or are they assuming you will just set it at zero?
Steve
ETA I have a timing disc if you need to borrow one. It may show that even as you have it set now it may not actually be zero. Even crank pulleys have a reputation for dubious accuracy of TDC markings.
Steve
ETA I have a timing disc if you need to borrow one. It may show that even as you have it set now it may not actually be zero. Even crank pulleys have a reputation for dubious accuracy of TDC markings.
Edited by Steve_D on Monday 21st September 17:08
The only way you are going to find the optimal cam timing is with a rolling road session.
However, the cam manufacturer will have a set of timing figures that you can use as a baseline. Unless you are very lucky, setting the vernier to zero will not give you these figures. There are two main methods for setting up cam timing and you will need at least one (preferably two) dial indicators set up to accurately find TDC and set cam lift.
However, the cam manufacturer will have a set of timing figures that you can use as a baseline. Unless you are very lucky, setting the vernier to zero will not give you these figures. There are two main methods for setting up cam timing and you will need at least one (preferably two) dial indicators set up to accurately find TDC and set cam lift.
Soton Pug said:
Afternoon all, looking for some advise with regard Vernier Pulleys. I have just re-built my 205 1.9 XU9JA engine following a session round Rockingham earlier in the year. Any way, I changed the rings and bearings etc... and decided that whilst it was in bits i'd buy myself a new cam so I brought myself a CatCam with a 282 duration. Once installed and the engine running it was a dog to drive at low RPM so a mate suggested a vernier to try and nail the timing to make it as good as it could be. So, spent £100 on a vernier, whipped it on (looks lovely) but i'm stuffed if I can get my head around the setting up of the damn thing, i've left it a 0 degrees for the time being with the ignition advanced by 30 degree as per the Peugeot book, what the bloody hell should I be looking for/trying to achieve with this thing, next to looking nice it's poxy useless to me at the moment. I understand the principle behind the manufacture of these, adjustable timing at both ends of the cam but I can't find anything to suggest that I should have it 3 degrees advanced for better mid range power for instance...
HELP PLEASE!!!!!!!!!!
Thanks in advance to anyone with more useful brain cells than me!!!
SP
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&HELP PLEASE!!!!!!!!!!
Thanks in advance to anyone with more useful brain cells than me!!!
SP
Hi there! my brain cells are worn out these days but here goes! (Sorry this reply is four years too late but it might help somebody else) Usually when camshafts have no timing marks there is a trick method for timing them up. This was the case with a Lancia Flavia that I owned in the 1970s. The engine was a flat 4 hemi head with one camshaft per bank and short alloy push-rods. A long duplex chain was used to drive the camshafts and as it wore the timing would go out. According to the owners handbook the camshafts ought to be re-timed every 6000 miles. Now I had to buy it a new chain as the old one had got so slack that it had jumped. The cam sprockets had vernier adjusters with dowels but how was one to time it? (Each tooth of the sprocket could be subdivided into twelfths or maybe sixteenths so it was possible to get the timing very accurate indeed)
The answer came from the store-man at Lancia's main agent in west London UK. (seldom will one find such a knowledgeable store-man) Here is what he said:-
"You've got two engines there working on the same crankshaft. The camshafts are symmetrical so by setting the tappets to 40 thou you can bisect the angle of overlap. You turn the cam until the push-rods are tight but not lifting (just check that they will still spin) That sets TDC on the cam. With the crank set to TDC you put the chain on with the dowel in the nearest hole and nip-up the cam wheel bolt. You now repeat the process on the other bank."
There was a bit more to it than that but that was the gist of how the job was done. Afterwards the car went like a bat out of hell and it was amazing that a mere 1500cc could produce so much power!
If the cams are not symmetrical other methods will need to be used. Degree wheels and dial gauges may be useful. The cams should at least be supplied with information as to what they do. At one stage most of the British motor industry used to use two generic cam timings. There was the Triumph cam timing which was ideal for everything and a slightly hotter "sports" cam timing which was used by Jaguar and Rover cars that had an "S" appended to the model. The "S" cams were a lot livelier and much better for high speed work but just where the book with the timing data is I don't know.
Good luck!
PS I recently timed-up a Land Rover Discovery 300TDi It was a horrible job as it is so easy to be one tooth out. It was actually miles out when I bought it and the pistons and valves had been striking one another. The consensus of opinion is that the paint mark method is no use as (1) How do you know the belt was timed correctly to begin with? (2) The stretchiness of old and new belts can vary a lot. Usually with these belt timed engines it is essential to buy timing pins (AKA locking pins). If the belt is replaced with the engine in the car a mirror will be needed so that the marks can be viewed square-on. Looking in from the top virtually guarantees that the belt will be one tooth out. Some engines such as the Perkins Prima have camshaft locking holes as well as a crankshaft locking hole. One locks the parts in the right place and swaps the belt. Peugeots are the same. Good luck!
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