Noisy Cam

[Scuddy]

Not sure if I should worry about this one but,,,..

Just had a new head installed on the proverbial 2.4. Immediately noticed increase in compression, pick-up, no bubbles in coolant, water levels behaving properly, less black smoke, etc . but also noticed increase 'tappet' noise from top running gear that wasn't that evident on the old head.

Head I bought was new but it had used running gear (perhaps not the best decision). Excuse my ignorance on the surf head but I didn't actually get to see the new one so I'm unsure if its valves driven direct from cam or via rockers??? The one that came off appears to be direct driven (no rockers)

Is it possible the infuriating ticking noise could be associated with the valves bedding in or sticking, a bad set up with incorrect clearances or some other mechanical problem. There's a 12 month warranty on the head but don't want to go down that route if its something I needn't worry about

Any checks that can be done without the head coming off??

Cheers in advance
Scuddy

[Guest]

Not sure if I should worry about this one but,,,..

Just had a new head installed on the proverbial 2.4. Immediately noticed increase in compression, pick-up, no bubbles in coolant, water levels behaving properly, less black smoke, etc . but also noticed increase 'tappet' noise from top running gear that wasn't that evident on the old head.

Head I bought was new but it had used running gear (perhaps not the best decision). Excuse my ignorance on the surf head but I didn't actually get to see the new one so I'm unsure if its valves driven direct from cam or via rockers??? The one that came off appears to be direct driven (no rockers)

Is it possible the infuriating ticking noise could be associated with the valves bedding in or sticking, a bad set up with incorrect clearances or some other mechanical problem. There's a 12 month warranty on the head but don't want to go down that route if its something I needn't worry about

Any checks that can be done without the head coming off??

Cheers in advance
Scuddy

Either check the tappets or get someone to do it. you don't really want to run these with clearances to big as the shims can pop out if too big a gap - the added vibration could then bend or break a valve. I know this is possible as it happened on mine and damaged a piston as well as trashing my 1 year old cyl head.

The valves run direct off the cam via tappet buckets and shims.

Cheers

[NiftyNev]

I agree with Andy.They may have just assembled with the old parts and not checked valve clearance etc.Get it checked ASAP.

Neville

[Guest]

There is a remote possibility that it is the valves bedding in - however if this is the case then the valves or buckets or shims were toast in the first place. I think that it is most likely either some dirt under a shim which caused any checking that took place to be wrong or as Nev said, they probably didn't check the clearances in the first place.

Get it sorted now or you will really regret it. If you drop a valve you are talking serious money to get it fixed including a new head, the piston that was under the valve, the affected big end and small end bearings, and possibly the turbo as it will suck in any swarf from the valve disintegrating. It is very easy for the shims to pop out or disintegrate if the clearances are too big which is pretty much the same on any OHC engine that uses shims.

My engine with a new top end has absolutely no tappet noise at all and that to be honest is as it should be. Set up correctly there is no valve train noise on the Surf engine.

Cheers

[Scuddy]

Thanks guys. Its right back to the garage to get this checked out and onto the head supplier tomorrow to register my disatisfaction and look for compensation if any remedial work is required.

I still have the old head which ran with no train noise, hence my surprise when I heard the constant ticking from the newly fitted one. My only concern will be the mechanic that fitted the new head, whilst his ability with diesel enginesis noy in doubt, has very limited knowledge of Surf engines and setting the cam train and tappets (such is the case in the north of Scotland where your average Surf aint common AT ALL)

Drawing on my very limited knowledge of cams/tappets/valves, I assume the ticking noise is caused by the temporary seperation of the cam and tappet surfaces and then the 2 coming together again as the cam continues to rotate? So in an ideal set up, when the valve is seated, the tappet and cam are still just in contact??

Is checking the valve clearances a case of rotating the cam thru 360 and checking to see if any gaps exist between cam and tappet when each valve is seated. Or is there an acceptable gap that can be measured.

Assuming the cam, tappets and shims on my old cracked head are OK, will it be possible to exchange part or all of the above to rectify faults found?

Sorry to bang on about this, but as you both clearly point out its not worth taking a risk and dropping a valve(s) and having the engine wrecked.

Andy,if you have any practical advice on checking valve clearances and setting up the train or know any threads on the forum that details with dimensions, etc. I'd be very very appreciative in hearing them.

Thanks again for the advice and patience

Scuddy

(----------------------------------------------)
(not out of the woods just yet

[Guest]

OK to check the tappets, you need to rotate the engine until each valve is off the cam completely (you need to do this 4 times as 2 valves will be released at the same time). Check with a feeler guage - not sure of the settings but it is something like 14 mil for the inlet and 20 mil for the exhaust I think.

The tapping is because there is too large a gap. There should always be a gap which in normal cases has a thin coating of oil on it which removes any noise from the small gap there.

Once you have checked the gap and found out what it is, you need to look at what it should be and ring up ukcylinderheads or whoever you got the head form and ask them to send some shims which will adjust the gap.

The shims will have a number on them which indicates the thickness - if this has worn off you need a u clamp shaped vernier gauge to check the thickness at the centre - they are dished in quite a bit.

If you have a 30 mil thick shim and the gap is 35 mil and should be 20 mil then you actually need a 45 mil shim (i.e. 15 mil thicker to take up the gap).

Hope that this makes semse.

You need a special tool really to remove the shims however they can be got out with careful use of a thin but strong screwdriver. The shims are held in the top of the tappet baucket which has a lip around the edge that you need to get the shim over the top of.

The process for checking the valve clearances and adjusting them is the same as virtually every Overhead Cam engine that has no rockers so I think your mechanic will have no problems doing the job. The head supplier you used will know the exact clearances if someone else on here hasn't go them to hand.

Cheers

[Scuddy]

Many thanks Andy for taking the time out to explain the process, really appreciated.

Since posting the original mail I've sourced a Haynes Hilux/4-Runner manual and found the info just as you described. For anyone venturing on this process I've attached a photo (don't have a scanner) which is legible of the relevant section.

It doesn't look that complicated but I've assumed you'll have to:
- get access to the crank pulley to locate TDC marker and turn over the engine.
- Have a new gasket for the cam cover (unless the old one is re-useable?) as its less than 2 weeks old.

I stll have the old head which has a selection of shims in place, getting these out won't be a problem.

I'll get in touch with the head supplier and see if they can advise on inlet/exhaust clerances, unless anyone else on the forum can confirm? After having seen the procedure I may tackle myself, if not the mechanic is sure to be competent to do it

I'll keep you posted

Thanks Again
Scuddy

Cheer

[Guest]

You don't really need to access the TDC marker, just take off the rocker cover (you need to anyway) and check the valve where the cam is completely off the bucket - i.e 180 degrees away. With any valve set like this then you should be able to do 2 valves at a time.

Don't bother about the old head, the shims are unlikely to be of any use whatsoever, you will need to measure the new head and remove the shims from that one to find what was originally installed and go from there. There is no base standard size of shim, they are installed as required on each head individually.

Cheers

[Scuddy]

Thanks Andy

Think I've figured out the clearances from the formula given in the Haynes Manual

Intake side : N=T+(A-0.25mm)
Outlet side: N= T+(A-0.45mm)
T=Thickness of existing shim (which would have to be taken out to be confirmed)
A=valve clearance measured with feeler gauge
N=New thickness of shim required

Hence if the gap is correct (0.25mm for inlet and 0.45 for outlet) the difference between measured (A) and required will be 0 and the correct thickness (T) is in there - no new shims required.

So I'm concluding clearance gap required for correct set-up is
Inlet : 0.25mm
Outlet 0.45mm

Can you re-use the rocker cover gasket that comes out?? Or is it a matter of reviewing and deciding ion the condition. Whats the best way to turn the engine to get the cams up? Can it be done off the Cam pulley or trial and error off the starter motor?

I'll have a play with the old head and take a few clearance measurements off that knowing that at least was a fairly smooth noise free operator

Thanks again
Scuddy

[Guest]

That sounds about right although the gaps sound big but I could be wrong.

Yes you can reuse the rocker cover gasket unless it is obviously dry and has no more give in it. Should be a rubber gasket and they eventually dry out and have no spring left in them.

Cheers

[Scuddy]

I've done the gap checks on the old head and they come out as below

Working from the pulley, no. 1 to no. 4 cylinders

Cylinder 1
Outlet 0.45mm
Inlet 0.20mm
Cylinder 2
Outlet 0.45mm
Inlet 0.25mm
Cylinder 3
Outlet 0.45mm
Inlet 0.25mm
Cylinder 4
Outlet 0.50mm
Inlet 0.30mm
I guess this concurs with the clearance figures in the Haynes manual?

The above represents the largest combination of feeler gauge that can be inserted between the cam lobe and tappet shim. I knew cylinder 4 was troublesome as this is where most of the water ingess happened. Having cleaned up and rotated the shims in position, they don't look in too bad condition and I can't see any evidence of dishing although I haven't been able to get them out to measure.

I'll try and check the new head tomorrow (wish I'd done it before being on the engine - but always wise after....), but will have to leave any changeouts to the mechanic as I have neither the valve lifting tool nor a micrometer...stuffed without either.

Scuddy

[Scuddy]

Well that explains the tappet noise.

Just checked the clearances on the new head, compared to the old head figures in the above thread they're frightening:

Cylinder 1
Inlet 1.10mm
exhaust 0.60mm
Cylinder 2
Inlet 0.80mm
Exhaust 0.55mm
Cylinder 3
Inlet 0.85mm
Exhaust 0.50mm
Cylinder 4
Inlet 0.60mm
Outlet 0.35mm

I'll be onto the head supplier then to see what can be done. Don't know if I should be driving her over long runs with these sort of clearance figures?

[Smurf]

I wouldnt drive it too much with those kind of clearances, the cam will be hitting the shim quite hard so may cause damage to the cam or shims.
It seems that many mechanics excuses for poor jobs on surf heads is that they are not familiar with them, this amazes me as the principles of all engines are basically the same and it really isnt hard to look up some tolerances and measure gaps, new shims are readily available and can also be ground down to suit. The machine shop where i had my head re-shimmed only really deals with race engines and have no interest in diesels but he knew off the top of his head what to set the shims at just through general knowledge of engines and when i checked the figures he was pretty much right.
10 thou inlet and 18 thou exhaust works well, no noise and good performance.

[Scuddy]

Cheers Smurf
My thoughts exactly. Why bother advertising selling shiny new heads with re-con'd running gear when you can't even be bothered to do some basic set-ups. Looking at the clearances from my new head I'd say he's even managed to get inlet and outlet shims the wrong way round on one of the cylinders. If I can source a valve lifter tool I should be able to take the duff shims out and measure up...question is where to get one??
Scuddy

[Smurf]

Why do you need a valve lifter??? you dont need to remove valves,just the shims and buckets. Have a practise on the old head, unbolt the cam and lift out, lift out shims/buckets, pry shim off of top of bucket, insert new correct size shim and put back.
Obviously to do this on the car you will need to access the timing belt and de-tension it having set at TDC, remove belt from cam pulley then unbolt cam.
As you have alredy measured you know how much extra you need, note down all clearances and sizes in order then note what size is fitted, work out the size needed to give correct clearance and get re-building, you can use shims off the old head if they will give correct size clearances so may be an idea to strip that down first to get the shims out.
Hope that helps