Strange engine problems

[twincamman]

Moving the plug from wire to wire and sparking the plug will tell you what cylinder you are timed on

[billwill]

the finger will be blown off the plug hole when the correct stroke is found ?there will be no quuestion ?thenset the dist in the correct gear with the rotor at number one about 11 oclock just before number one on the dist spark the plug [ with the dist body serial number and flat spot facing the block ]?if your 180 degrees out just use number 4 as number one ?.I have done that before and the engine runs fine .ed

>if you're 180 degrees out just use number 4 as number one

That'll be a real fine way to confuse the next owner, Ed.

[twincamman]

I don't think we're concerned with the next owner at this time ...but you could mention it to him when he buys the car .....Ed

[Chancer]

I took to heart the comment about making too many changes to the car and have gone back to square one.
Something I did notice whilst setting the timing today. When I put my finger in #1 plug hole whilst rotating the crank to TDC I could not feel any pressure although I did hear some hissing. The n/s #4 cam lobe is pointing towards the centre so I moved on. Thinking about it in retrospect (and over a glass of wine) I am wondering if the hissing was from a valve rather than leaking past my finger. Maybe a burnt valve or the timing has slipped on the intake cam. I learnt the lesson that diagnosis is better than diving in and stripping bits off the car

Good to see that you are gaining valuable experience, pretty much everything I have learned has been from my mistakes and lets hope there are plenty more to come

Hard to tell from your description but perhaps you were at TDC on the firing stroke for number 4 and not number 1 cylinder, try again and turn the crank another 360? to be sure, then try all the other cylinders.

It is beginning to sound like you may have added more faults so going back to the beginning is a good idea, refit the distributor with the original cap and leads in the correct position and orientation and set the static timing, not sure if you have points or electronic ignition but the timing is set with the points just opening, I have seen many try with the points just closing from assuming the wrong distributor shaft rotation direction.

Remember that the rotor arm will move maybe 30? when you engage the distributor on its bevel drive so you have to initially put the rotor in the incorrect position, hard to describe but you will soon work it out.

Good luck.

[Heuer]

Did some more work trying to solve this problem today. Compression test shows 170psi on all cylinders. Timing has been re-checked and is good. I changed the c/b capacitor just in case.

I am still considering it to be a fuel supply problem so I hooked up my big Mity-vac to the boot end fuel hose and put some fuel under pressure into it. This filled up the pump glass bowl and the car started, albeit roughly.I made an extension fuel hose and ran it into a jar of petrol but despite cranking no fuel was being drawn. So I am back to the fuel pump but neither the original pump (tested by Brian Buckland) and the new glass bowl pump from Paul Matty do their job. Presumably it is all but impossible to install the pump with the lever under rather than over the jack shaft cam so my conclusion is the jack shaft is the common denominator?

Any thoughts?

[Chancer]

Presumably it is all but impossible to install the pump with the lever under rather than over the jack shaft cam so my conclusion is the jack shaft is the common denominator?

Any thoughts?

Something is churning away in the depths of my memory, some while back while pondering this thread I had a feeling of d?j? vu, I'm sure there is a pitfall along those lines that I have fallen into in the past but blowed if I can recall it.

Something about the lever, or a spacer???

Try slackening the retaining bolts so that it can rock a bit, you should see it rocking when the engine is cranked, otherwise take off the top of the pump and watch to see if the diaphragm goes up and down when cranking.

Maybe something to do with the diaphragm push rod has to be turned to engage properly in the lever?

I know I have had this same problem but it could be up to 40 years ago.

[twincamman]

ok ?you need 3 things for an engine to run lets start with fuel ??get some ?.then we will go on from there .

[oldchieft]

Presumably it is all but impossible to install the pump with the lever under rather than over the jack shaft cam so my conclusion is the jack shaft is the common denominator?

Any thoughts?

Something is churning away in the depths of my memory, some while back while pondering this thread I had a feeling of d?j? vu, I'm sure there is a pitfall along those lines that I have fallen into in the past but blowed if I can recall it.

Something about the lever, or a spacer???

Try slackening the retaining bolts so that it can rock a bit, you should see it rocking when the engine is cranked, otherwise take off the top of the pump and watch to see if the diaphragm goes up and down when cranking.

Maybe something to do with the diaphragm push rod has to be turned to engage properly in the lever?

I know I have had this same problem but it could be up to 40 years ago.

I think you could be thinking of page 88 of Miles Wilkinson's Lotus Twin-Cam Engine book.

Jon the Chief

[Chancer]

Only if I have psychic powers that I am unaware of.

What does it say?

[john.p.clegg]

" The fuel pump,placed incorrectly,gouged the jackshaft.Naturally,this seized the engine "

John

[Heuer]

The fuel pump requires a 1/4" thick insulation spacer together with two gaskets. All these are in place. Assuming the pump is correctly sitting on the cam (the previous one obviously was for 6,000 miles) but not drawing fuel my conclusion is the jack shaft is not doing its job i.e. activating the lever to its full extent. Having not had one of these engines apart before can anyone think of a situation where the jack shaft can turn, perhaps intermittently, without affecting the cam shaft timing?

[oldchieft]

A lot of fuel feed problems are air leakage on suction side.

I would get some clear tubing to bypass the suction line then you can see if the tank pick up is drawing air as well.

Jon the Chief

[Orsom Weels]

The fuel pump requires a 1/4" thick insulation spacer together with two gaskets. All these are in place. Assuming the pump is correctly sitting on the cam (the previous one obviously was for 6,000 miles) but not drawing fuel my conclusion is the jack shaft is not doing its job i.e. activating the lever to its full extent. Having not had one of these engines apart before can anyone think of a situation where the jack shaft can turn, perhaps intermittently, without affecting the cam shaft timing?

It's already been mentioned that the jack shafts can break for no apparent reason, there seems to be at least three of us on this forum that have witnessed this. It's not inconceivable that a diagonal or uneven fracture could result in intermittent drive. Failing that, as I mentioned in an earlier post, it could be possible that the dowel was not fitted in the drive sprocket & the retaining bolt has loosened sufficiently to allow it to slip. This would throw your distributor timing out, of course, whereas the former wouldn't if the break was behind the distributor/oil pump drive scroll. Is it possible you could rig up a gravity fuel supply direct to the carbs & see if it will run OK like that? If you can prove fuel supply is the issue with the bad running, you can then concentrate on finding why two fuel pumps are not being driven by the jack shaft.
Regards, Tim

[Apx]

I had a similar problem which turned out to be a fuel pump issue. To identify the issue i set a remote fuel tank from a 1/2 litre plastic bottle gravity fed straight to the carbs and checked fuel levels in the carbs, with that all ok the car ran and i worked backwards from there using a spare fuel pump which solved the issue. If already stated apologies but I'm in the jungle with poor WIFI.... cheers

[quaybook]

Just a thought, blocked breather hole in fuel tank filler cap?

Vernon