Classic cars forum & vehicle restoration.

[Martin A]

I suspect that my Mk1 Zephyr has an air leak into the inlet manifold. I want to take the inlet manifold off and check/replace the gaskets.

The Ford repair manual mentions steel as the gasket material:

"Locate the inlet manifold on the side of the cylinder head, slipping a steel gasket between the manifold and each inlet port."

What should I make the three gaskets from? I'd have thought ordinary gasket paper, say 0.5mm would do fine. It's not high temperature/pressure. But if Ford saw fit to make gaskets of "steel" maybe I should use something other than gasket paper. Coke can aluminium? Soup can tinplate? I'll be very grateful for advice/opinions on what material to use.

Martin

[47Jag]

Martin,

Are you sure it's the inlet manifold that is leaking. Have you eliminated the vacuum to the wiper system. There's the hose itself plus a check valve and a reservoir tank. If you have a propane torch try turning on the gas with the engine running at idle and waft the propane gas along the manifold joints. If there is a leak the engine revs will go up indicating the this is where the leak is. But eliminate the external stuff first.

Art

[Martin A]

Art,
Thanks for the suggestions. It should be quick and easy to eliminate the wiper system as a leak. I don't know for sure that there is a manifold leak. Nor can I (yet) rule out a carb problem.

However, this engine has clearly been in the hands of somebody who was not a wizz on gaskets (wrong gasket fitted at petrol pump, causing oil loss; rocker cover gasket incorrectly fitted, causing oil loss when topping up). So the inlet gaskets are at least under suspicion - if they are there at all.

Any opinion on whether ordinary gasket paper would do? So far as I can see, the pressures and temperatures will be in the range suitable for paper gaskets.

Martin

[Rene]

why not use an original gasket?
http://www.carpartfinder.info/for-sale/Ford/Zodiac/Intake-Manifold.php

[Martin A]

Rene, Obviously if I knew of a source of original gaskets, I'd happily make use of a set. (There are three of them - one for each inlet port.) But, so far, I have not managed to find a source of inlet manifold gaskets for a Mk1 Zephyr. Cutting gaskets from gasket paper is quick and easy.

[JohnDale]

[Rene]

You could try here http://sucarb.co.uk/conversion-replacement-sets/ford/zephyr.html
They have conversion sets for su carburettors but also gaskets.

[Martin A]

Rene - thanks for that. However, the SU setup is a Raymond Mays conversion for the Zephyr. My car has the original single Zenith VIG-6 carb on the original Ford manifold.

JohnDale - thank you. John Blythe has also been recommended to me for a different part I am trying to track down.

Art/47Jag - I think you may have hit the nail on the head. I disconnected the wiper pipe from the inlet manifold and closed off the opening. With the car sitting in the drive, the engine then ran with no trace of backfiring through the carb. I'll take it for a drive tomorrow and see if the problem really has disappeared.

I wonder if the suction pump (incorporated with the petrol pump in the Zephyr) gives enough suck to work the wipers without its outlet being connected to the inlet manifold? I'll see tomorrow when I take the car for a drive. If the suction pump alone is not up to the job, then maybe it will be time to start thinking about converting to electric wipers, if the fault in the suction system cannot easily be sorted out.

[My very first car was a 1957 100E Anglia. Fed up with the wipers stopping whenever I tried to overtake something in the rain, I fitted it with electric wipers, using the wheel boxes from a Mini and the wiper motor from (I think) an A60.]

[Rene]

Martin i think the su conversion is not important,the head will be the same so the gaskets will also be the same...........or not?

[Martin A]

Rene - I'm not sure. I remember they were called "Raymond Mays Cylinder Head Conversion" raising the output of the engine from 68bhp to around 100bhp, so I had assumed it was not just the manifold that was changed. I know that the mod used a couple of cast exhaust manifolds in place of the sheet steel pipe of the original exhaust manifolds.

However, my assumption that the problem had been solved by disconnecting the wiper pipe was premature. On the positive side, the suction pump incorporated into the petrol pump does give enough suck to work the wipers (not fast but probably usable in light or moderate rain) even without the help of the inlet manifold.

My car still backfires through the carb now and then. I tried replacing the distributor cap but with no effect on the problem. Then I noticed that it sometimes also backfires though the carb when my foot is hard down on the accelerator, so it seems unlikely to be due to a small air leak.

A distributor cap problem seems to have been ruled out. That leaves (so far as I can see) the carb as the remaining suspect. I have a spare carb that I have overhauled and, as soon as a missing part arrives, I'll try a carburrettor swap and see if that solves the problem

[Peter_L]

I remember my father being so fed up of the vacuum wipers on his Mk II Consul that he changed the whole wiper mechanism plus the car it was attached to.

[Dipster]

[47Jag]

Martin,

If it's spitting back through the carb then I would suspect a valve problem, assuming your confident that the ignition is OK. You could have a sticky inlet valve or a broken valve spring. If the engine idles OK you could rule out a vacuum leak I would think. Is the spitting back random or is there a sort of pattern to it?

Art

[Martin A]

Art,

Thanks for that suggestion. Yes, the fact that it idles ok and the spitting back also occurs at full throttle does seem to make an air leak seem unlikely.

I'm reasonably sure the ignition is ok. Ignition timing seems right according to strobe. A few days ago, the car became very reluctant to start. (Started fine before then). I changed the condenser. Still reluctant to start. I changed the ignition coil and it then started instantly. Yesterday, I also changed the distributor cap and the HT wiring.

Took the car for a drive this morning. Current symptoms:
- Hesitates on and off when being driven at constant speed on flat road.
- Occasionally spits back noisily through carb, when being driven at constant speed on flat road. Randomly and only now and then.

Both symptoms disappear if the choke is pulled out slightly.

My current plan:
- Drain the petrol tank and refill with fresh 98 octane (clutching straws but easy enough to try).
- When replacement bits for the spare carb arrive, replace the carb.

I imagine it will be easy enough to check there are no broken valve springs with the rocker cover removed. How would I check for a sticky valve?

What symptoms would a faulty petrol pump produce? [I know that fuel arriving in the sump is one possible result of a faulty fuel pump.]

Somebody suggested that a leak between the exhaust manifold and the inlet manifold might exist (they had seen that in Vauxhalls).

Many thanks for your help.
Martin

[Peter_L]

If it were me and having worked on these engines, if pulling the choke out a bit cures the problem points to a too lean a mixture and likely between carb and the cylinder head. Remove and fit new gaskets. I had one engine that developed a crowd frightening "Bang" when the engine was switched off, on removal of the inlet manifold the leak past the gasket was obvious.

You did say that gaskets on yours were suspect so maybe start with the suspect.

Have you run a compression test to check if the valves are 100% closed ?