Strobe timing

on2wheels · Post by **on2wheels** » Tue Sep 21, 2010 8:45 am

Hi,
I am thinking of investing ?20-?30 in a strobe timing light.
Have any of you guys used one on an e-type?
I understand you aim the gun at the timing marker on the fly-wheel and
adjust the dizzy (undo the pinch bolt) at the same time. I still have the old mechanical type.
Is this possible (one man working) on an e-type?
Any advice on make of instrument? Draper or Gunson?
Any advice on setting the timing in general gratefully received.

Nick.

christopher storey · Post by **christopher storey** » Tue Sep 21, 2010 10:36 am

Nick : I use one regularly. Get one with a white light , powered from the battery, which is much brighter and of shorter duration than those which use the HT to light them up. There are many varieties available, some being quite sophisticated with speed checking devices etc, but I use a fairly basic one. How easy they are to use depends on whether you have the earlier timing marker which is underneath the car, or the later type on the left side of the timing cover, which is much easier, although you need to be careful to keep the leads clear of the exhaust manifolds! The lights' most useful function is to check both mechanical advance ( with vac disconnected ) and total advance incorporating vac advance . Be warned that it is best first of all to check the accuracy of your pointer using a dial gauge to determine TDC - sometimes the pointers can be as much as 5 - 10 degrees awry

on2wheels · Post by **on2wheels** » Tue Sep 21, 2010 7:28 pm

Chris: Thanks for the info.
A little more explanation regarding setting the pointer please?
I know I must set the points gap before I start. Are you referring to this operation?
Thanks,
Nick.

christopher storey · Post by **christopher storey** » Wed Sep 22, 2010 8:18 am

Nick : no, nothing to do with the points. The problem with the side pointers at any rate - I have no experience of the bottom mounted ones - is that the slots through which the fastening bolts go can be bigger than the bolts, and thus the pointer can slide around a little when being assembled, and thus may not point to 0 degrees when the engine is at TDC . Hence it is best to check by getting the engine to TDC , for real accuracy checked with a dial gauge down the plug hole so that you are in the middle of the "null point" of movement of the piston at TDC , or marginally less accurately by sticking a rod down and seeing when it reaches its highest point

on2wheels · Post by **on2wheels** » Wed Sep 22, 2010 10:29 am

Chris: My car is 1965 4.2L.
I can see two white, looks like paint blobs, at the front on the lower pulley.
I assume one is TDC and the other 10 degrees BTDC.
Doesn't look anything like the picture in the Service Manual page Fig 32. page B.45.
Below the pulley is a pointer.
The procedure must be........
1. Check accuracy of pointer by rod down plug hole to get TDC as you describe.
2. Loosen dizzy pinch bolt.
3. Aim strobe gun at the second white paint blob and the pointer? 10 BTDC
4. Move dizzy until strobe appears stationary.
Does that appear right?
Thanks.
Nick.

christopher storey · Post by **christopher storey** » Thu Sep 23, 2010 10:14 am

Nick : if you clean your pulley with a wire brush or similar you should find that it is comprehensively marked with Before and after TDC at 2 degree intervals from about 24 degs BTDC to 10 degs ATDC. I usually re - mark these with Tippex , wiping the surplus away with a thinners rag until the etched marks are clearly visible. It is then easier initially to set the timing statically , by turning the engine in the correct direction until it is at the 10 degs BTDC mark . The timing is then set by loosening the distributor clamp and turning the distributor , holding the rotor so that it is "trailing" the direction of rotation, until the points just crack open. If you do this with the ignition on ( best to disconnect the HT lead from the coil) you can usually hear/see the crackle of the spark at the points as this happens. Then check it all out dynamically with your light . It's easier to do than to describe!

on2wheels · Post by **on2wheels** » Thu Sep 23, 2010 11:25 am

Thanks Chris,
I appreciate your perserverance with me!

Nick.

christopher storey · Post by **christopher storey** » Thu Sep 23, 2010 2:02 pm

Nick : I should perhaps have said that the marks are on the periphery of the crankshaft damper and not on its front face . They are often covered either in paint or in rusty debris which is why people often do not notice them!

Echezeaux · Post by **Echezeaux** » Fri Sep 24, 2010 7:22 am

Hi Nick,
Following what Christopher said, here are some pictures of what I have done on my car.
I was chasing some pre ignition problem, and found the timing mark on the recond crankshaft damper out of place.

The tool I used to check piston at TDC

In cyl 6, piston down

Piston at Top Dead Center

With a dial gauge to be sure to be sure

You can now check your mark on the damper in relation with the pointer.
Mine ,the blue-ish one was quite out,so now you can correct it if needed.

Timing 10 degrees

Thierry

chuffer · Post by **chuffer** » Fri Sep 24, 2010 8:25 am

Echezeaux wrote:I was chasing some pre ignition problem, and found the timing mark on the recond crankshaft damper out of place.

Hi Thierry,

Nice tool!

Re the error, aren't the two holes in the pointer slotted which would enable you to take up the apparent 3 degrees of error and still have the blue mark as TDC?

Ray

Echezeaux · Post by **Echezeaux** » Sat Sep 25, 2010 8:42 am

Thanks, but in my case I found that you cannot move the pointer much.
2mm each side maybe ?

Thierry

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