Diagnose Engine Rattle

[SimonBrown]

Yes, I did turn the tool in the correct direction to tighten the chain. I have not made a video of the engine running hot as I have noticed a fuel leak from the feed pipe which will need fixing first. I think really I am going to have to wait and see if this noise worsens, as I can’t see it being an easy diagnosis and a major engine strip seems a bit extreme, even if I find anything.
As said earlier the noise is only at 1300 rpm, which is easy to drive around, and only lasts for about a minute and a half.
Thank you

[SimonBrown]

Further help needed!
Still trying to rectify this rattle, which I have narrowed down to being noise from under the cam covers.
Looking at oil feed:
On starting from cold with a cam cover removed, and with oil drained from the wells beneath the cam. Oil sprays immediately from the chain, but little appears to lubricate the cam.
How long after starting should I expect to see oil from the cam bearings?
With regard to the banjo and bolt to the back of the head, is it critical the hole through the bolt lines up with the hole up through the braided pipe?
If so, how is it torqued correctly?
Thank you
Simon

[mgcjag]

Hi Simon...great to meet up at Jagfest.....cant answer your question re oil through the cam bearings but assume after our chat youve looked at the mis alignment of the hole in the banjo bolt with the oil feed through the flexi cam feed pipe fittings....its been discussed before on the forum re a reduced oil supply through the smaller reduced opening.....does it actually make a difference?.....but personslly i would want full flow.....dont think the torque figure is an issue...just tighten with new crush washers....if your stripping it down then check with an airline that there is nothing stuck in the camshafts old siliconn etc.....Steve

[SimonBrown]

Hi Steve,
Good to see you too, thought it was a great event!
After our chat I have checked the hole coming up from the pipe lines up with the hole in the bolt and all looks fine.
I am concerned that after approx 20 secs running there still appears no oil in the wells beneath the camshaft.
Thank you
Simon

[mgcjag]

Hi Simon...20 sec is far too long...i thought previously you said you had good lubrication....as soon as you see oil pressure on the guage it should squirting out of the camshafts.....not untypical on a new build you can pressurise the oil befor startup....plug a garden spray type pump into the oil gallery and pump....it will soon be up to the cams and you can hear it running back down to the sump.......maybee worth you trying.......Steve

[SimonBrown]

Lubrication looked good, when cam covers were removed, the wells beneath the cams were full of oil.
Oil pressure is good.
At 7-800 rpm oil sprays from the chain, but not noticeably from the cam area.

[SimonBrown]

Finally diagnosed?
I have just removed the cylinder head and valves, and think I may have finally found the cause of the intermittent cold engine rattle, video at the start of this thread.
No1(rear of engine) inlet valve is quite tight in operation. Not sticky tight, but oily tight, smooth but heavy in movement.
This could explain why below 1300rpm it is quiet, but as revs increase it rattles as the springs can’t keep pace of the necessary speed of return.
As the engine warms the noise disappears.
Anyone else experienced this?
Simon

[christopher storey]

Simon : it is either a defect in the valve stem e.g. the slightest of bends, or in the guide. I should check the valve for straightness, and if in doubt replace with a new one. An easy check is to try another valve in the No1 inlet guide - if the stickiness is still there it is likely to be a guide problem ( which might be curable with a reamer ) , but if absent when 2 or 3 different valves have been tried, then it is almost certainly a valve fault

[PierreW]

Any news?

[SimonBrown]

All valves removed.
All inlet stems are covered in a gold coloured goo, along with the inlet ports. This goo progressively builds until it slows the valves down.
I have cleaned all valve stems and all now move with ease.
Since the engine rebuild 7 years/ 3500 miles ago I have only ever used Esso Super Unleaded with a Millers additive. I am particularly conscious of not too many cold starts/short journeys.
Any ideas how this can be avoided again?
Thanks
Simon

[abowie]

Any ideas how this can be avoided again?

What's in Miller's engine additive?

[chrisfell]

"What's in Miller's engine additive?"

Snake oil.

[paydase]

Maybe some ZDDP

[mgcjag]

"Esso Super Unleaded with a Millers additive"
The Millars additive is for the fuel.....Steve

[SimonBrown]

Just to confirm it is Millers fuel additive I have been using in Esso Super Unleaded.
As this is the second time the head has been off in 3500 miles since the engine rebuild I can’t afford for this to happen again!

[abowie]

a gold coloured goo

Going out on a limb, this may be from the brass valve guides.

As to why though.....

[mgcjag]

Hi Andrew..i was just thinking that. ...would have been good to collect some goo and bave it analysed....Steve

[nichmoss]

In the first post, Simon, you said that you've had this since the engine was rebuilt so it seems unlikely that the build up of brass, if it is that, would be causing the problem. It must have taken time to build up so you'd imagine it would have been a progressive problem. You need to address that obviously but it sounds like a secondary issue.

I'd be inclined to get another opinion from someone who can look at this on the bench so a trip to a machine shop would not be a bad idea. I was surprised to find someone close by in Somerset who knew these engines well so you might find someone local to you. I forget where you are, though. If you say, someone may be able to advise.

I've never heard of a brass build up like this but I suppose the clearance between stem and guide might be too little and so it's picking up. How it tracks across to the ports is not obvious and I'd be more concerned about this coming from the additive you're using.

I use Esso Supreme (was E0 until this month) and have never used any additives at all but I've always just used the best fuel I could get over the last 25 years and only started regularly using Esso six years ago.

Good luck, Chris

[flatfloor 3.8]

A gold coloured goo
[/quote]
I have seen this before, (not so much a goo rather a brassy coloured film) and is usually the result of using far too much fuel additive.

[SimonBrown]

I started using the additive following the engine builders advise after the first head off incident
Will stop using it now though
I am also inclined to get the head checked over by a specialist before reassembly
Thank you