camshaft sprockets

[CBUEB1771]

@ Russ Newton,
Some do and some don't. From Miles Wilkins, page 68, "and then mark it if it has not been marked already". Don't ask how I know. But I can tell you the engine will run much better once the correct sprocket is on the cam-shaft.

I have assumed too much! It has been a long time since I opened Miles Wilkins' TC book. The PO of my +2 had it serviced by a well-known race car builder and it is entirely likely that he would have marked the exhaust cam sprocket if is was not already. I've owned my +2 for about 35 years so I sometimes make assumptions that features which existed when I bought it were done at Norwich.

[Uboat]

Thanks for your help folks,
The sprockets came off like a charm once I dropped the idea that the chain should be loosened from one sprocket first. Next session, I will lift the head using a crane,
/Ulf

[andyhodg]

Hi Ulf

Be careful lifting the head using a crane. The head is likely to be stuck to the block slightly and if you attempt to lift of with crane it could easily come unstuck all of a sudden and come free in an uncontolled manner. The head isn't very heavy and once you have broken any seal between the head and the block it will lift off by hand easily.

Take care

Andy

[garyeanderson]

Hi Ulf

Be careful lifting the head using a crane. The head is likely to be stuck to the block slightly and if you attempt to lift of with crane it could easily come unstuck all of a sudden and come free in an uncontolled manner. The head isn't very heavy and once you have broken any seal between the head and the block it will lift off by hand easily.

Take care

Andy

elan-f15/weight-twin-cam-head-t22855.html

A die cast head is 15 kg with guides, valve seats, studs, caps and core plugs, no valves.

Gary

download/file.php?id=13221

[billwill]

When you come to refit, ideally you will need two guide rods often made from old head bolts by sawing off the head and then sawing a screwdriver slot in the end. these will be used to keep the head gasket in place while lowering the head.

YOU CAN BEST ACQUIRE OR MAKE THEM NOW.

After removing the head bolts you can then fit the two guide bolts before trying to lift the head, They will then prevent the head from swinging about wildly on the hoist or jumping around when the head gasket joint 'lets go'.

See my topic on doing a Clay Test, for pictures of lifting the head with a hoist.

post175169.html

[nomad]

Just did this and a couple of taps with a wood block released the gasket bond. Engraved the sprockets with an "I" and an "E" because they are definitely different. Somewhat amazed there is no locating dowels.

Kurt

26/3754

[rgh0]

Just did this and a couple of taps with a wood block released the gasket bond. Engraved the sprockets with an "I" and an "E" because they are definitely different. Somewhat amazed there is no locating dowels.

Kurt

26/3754

There should be dowels that locate the sprockets on the hubs!!!!!!

cheers
Rohan

[nomad]

I meant to locate the head! Definitely dowels on the cam shafts. Don't remember ever pulling a head that didn't have locating dowel's of some sort. Did a little reading [if all else fails, read instruction's!] Using temporary locating stud's should work fine. I did not as I removed it and fortunately didn't damage anything. My timing chain chest has been stippled with a center punch sometime in the past to help hold the gasket. It worked.

Kurt

26/3754

[nomad]

I meant to locate the head! Definitely dowels on the cam shafts. Don't remember ever pulling a head that didn't have locating dowel's of some sort. Did a little reading [if all else fails, read instruction's!] Using temporary locating stud's should work fine. I did not as I removed it and fortunately didn't damage anything. My timing chain chest has been stippled with a center punch sometime in the past to help hold the gasket. It worked.

Kurt

26/3754

[john.p.clegg]

[quote="nomad"] Engraved the sprockets with an "I" and an "E" because they are definitely different. .

Kurt

26/3754[/quote]

Excuse my ignorance but how do they differ?

John

[garyeanderson]

Engraved the sprockets with an "I" and an "E" because they are definitely different. .

Kurt

26/3754

Excuse my ignorance but how do they differ?

John

Hi John

Russ has explained the difference pretty well to you the last time. I am not sure what the "wink" is for. Why is it that this re-run comes from you?

Gary

elan-f15/camshaft-gear-markings-t17852.html

What is the difference between the exhaust ,inlet and idler shaft sprockets....or is all snake-oil?

John,
The two sprockets are subtly different. I just placed an exhaust sprocket on top of an inlet (both with alignment marks up) and rotated them until the bolt and dowel holes lined up. The teeth also ended being exactly in phase. The difference is that the alignment mark on the exhaust sprocket is rotated exactly one tooth clockwise with respect to the timing mark on the inlet sprocket. Both timing marks are right in the middle of the "valley" between two teeth. In other words the sprockets are identical except for the placement of the alignment marks. As Alan points out the exhaust sprocket is marked with a hand engraving. Lotus would not incur that expense if the sprockets were the same. The jackshaft sprocket has no timing mark at all, not needed in the Twin Cam application.

[john.p.clegg]

Thanks for the reply,maybe when you get to my age you might understand a little more of the problems of senile dementia...

John

[nomad]

I never noticed the E mark by lotus on the exhaust gear. I'll look for it.

Kurt

26/3754

[nomad]

No special mark on my exhaust gear. Intake is marked with a "7" and exhaust with "8" and that is the only difference other than the dowel holes being in a different spot.

Kurt

26/3754

[garyeanderson]

Top photo shows an Exhaust sprocket (stand alone, different from the one below)

Middle picture is an Exhaust sprocket stacked and aligned with the dowel holes lined up

Bottom is the exhaust sprocket slid down far enough to show the intake and exhaust aligning marks.

Gary