Cam Shaft Timing.

Obtaining the correct cam timing of the twin cam lotus can be a fiddly, and sometimes exasperating process.

But it’s a big help if you have the correct tools plus a bit of knowledge to make the job easier, and almost guarantee that the cam timing will be dead accurate.

We have put together a short video to help explain what tools we have used, and why we use them. What we attempt to explain here may differ to what you might read elsewhere, but that’s OK, take what you read in total and sort out what will work for you, because that’s what we have done.

We wont be giving you any fool proof way of how to time the cam that you have, because they will all differ, and there are plenty of cam timing experts out there to show you the finer points of cam timing.

Some cam timing articles are easy to follow and understand, while others choose the path of confusion, and you’ll be left scratching your head afterwards.

The further your chosen cams are from the standard timing, the more need there is to degree and correctly time the opening and closing of the valves, especially with an overlap period that differs wildly from standard, just be very careful.

What we outline here are the tools you will require, the most important being a good degree wheel and a DTI or Dial Test Indicator, the rest of the bits can be made in your own workshop.

A quick word about the degree wheel, a very effective degree wheel can be made from a 360Deg plastic or sheet metal protractor, stay away from those huge degree wheels that you often see in the youtube videos, you don’t need them, and its been said that the bigger the degree wheel, the harder it will be to time your twin cam engine. The disc in the video on this page is about 8′ or 10″ Dia, and about the right size .

The most important item you will need is the cam shaft data sheet that your cam grinder should supply you – Yes, they all supply cam cards, but that is not enough, ask for a cam shaft data sheet, which will expand on the numbers they give you on the cam card or ticket.

The data sheet will provide all of the valve opening and closing points, and crank shaft degree checks that can be made with various amounts of valve lift.

The standard valve timing point these days seems to be at a valve lift of 050″, which is what we adopted for our project, and it turns out to be correct.

I can remember many decades ago when my first associations with the Twin cam engine began, a very prominent Melbourne engine builder of that time, explained to me the process of placing a .001″ feeler gauge between the cam shaft and the follower, he explained that the timing point or valve opening point was when the cam lobe just nipped the feeler gauge, so that was the opening or timing point that we chose, it must have been fairly accurate, because the engine performed really well for about 80,000 miles before a rebuild was required, which is where we are right now.

Back in the early days, I did not understand or know about a cam timing degree wheel or disc, and the only means of adjusting the cam timing was with those fiddly, and often frustrating offset dowel pins.

These days, we have adjustable cam sprockets, and boy, do they make the job of cam shaft timing easier, they provide everything from a micro adjustment, to several degrees of change without much hassle.

The adjustable cam sprockets you will see in the video have been re-manufactured from the original Twin Cam Lotus sprockets, so take a look at those also, that’s another project we completed a long time ago.

We may even do another article on those items in the near future.