Engine vibration

[morrislady]

Hello everyone. Hubby has just finished installing recon. gearbox and new clutch. Everything ok except for a vibration. This happens even when stationary and revs are increased. To give an idea of revs it starts at 35mph in top and gets worse as speed increases. New engine and gearbox mount rubbers have been fitted. Any help would be appreciated.


1967 2door saloon.

[bmcecosse]

Was the engine ok before? Does the engine seem to be firing on all 4 cylinders ok ? Maybe something wrong with clutch fitment to the flywheel.......... You could try looking into the bellhousing - take out the rubber bungs and shine a bright light in - NOT while the engine is running......

[morrislady]

Thanks for the quick response. Engine was fine previous. Will have a look into bell housing as you suggest, but I was pretty careful when installing on the bench. I notice the new rubber engine mounts were pretty hard. All parts from ESM.

Many thanks

[bmcecosse]

Yes - there have been comments in the past about 'solid' new engine mounts. May be worth swapping back to the old ones to see if the problem disappears.

[morrislady]

Just been a decent run and it seems to be a little better. Maybe the rubbers need bedding in? Had a thought last night about the fan blade. It got a little bent when fitting the engine and although I straightened it, perhaps it's a bit out of shape. Could this be the problem?

Thanks for the help

[mogbob]

" a little bent ".... as in a minor ( sorry about the pun ) bend of one of the fan blades.... or a major " a little bent " as in a swinging engine hitting a solid brick wall, full on, bending more than one fan blade.

The latter might ( ? ) contribute to vibration.Did the fan still rotate ( without the fan belt in place ) quite freely or was their some resistance at a particular point in the revolution ? Does the pully wheel look "in line" with the crankshaft and dyno/ alternator pullies when holding a straight piece of wood/ metre rule against them ?

Perhaps you could advise us on what you know/ find out.

Bob

[morrislady]

Thanks mogbob. One blade got trapped against the top of the radiator grill. I have removed the fan blade and straightened it. When on the car it rotates freely with no rough spots. When running it seems to be running pretty true but I don't know how much it has to be out of true to cause vibration. I'm thinking of taking the blade off and doing a short run to see if the vibration disappears.

[PSL184]

It wont hurt to take the fan off completely to try but I doubt it would give any noticeable vibration anyway....

[mogbob]

From your description it sounds as though damage is minimal and confined to " cosmetic " but it's worth go , taking it around the block that is, but...
no more than a mile or so starting with a cold engine, otherwise you might cook it.Remove the fan belt completely and write a note to remind you to replace it after the test run !!
This at least would eliminate a possible cause for you.

Just a thought ....the dynamo or alternator bolts/fixings are done up tightly, no slack ?

Ideally the pulley should run true when viewed from the side of the engine bay.A piece of white card/paper held against the inner wing, level with the pulley, held by a willing assistant would help you sight any movement.A millimetre or two would be clearly visible but the fact that you have no tight spots on the shaft rotation leads me to believe that it should be OK.

Bob

[PSL184]

You will not cook a minor without a fan fitted - I ran mine all year without one, no problems (as long as the rad is clear of course)

[bmcecosse]

It will be fine without a fan - but that's NOT going to be the problem!

[morrislady]

Tried it with fan blade removed - still have vibration, but suspecting these new hard rubber engine mounts. Will give them time to settle.

Thanks everyone for the help.

[newagetraveller]

If the nuts on the engine steady bar are too tight it can cause vibration.

[bmcecosse]

The solid mounts will 'never' soften - refit the old ones! But 'newage's comment about the steady bar is very true - may be worth taking it off to see if that helps - then refit with no 'tension'.

[morrislady]

Just read the article in the latest minor matters in 'technical matters' re. hard engine mounts. My vibration is still there so I'll be interested to see if Rob comes up with the answer.

[bmcecosse]

The 'answer' is to fit softer 'non solid' engine mounts......