Engine Tappety Noise

ALAN COCHRANE · Post by **ALAN COCHRANE** » Sun Jul 20, 2014 9:01 pm

Hi Everyone

I've noticed on my last two outings that the engine has developed a tappety noise on load. If you dip the clutch the noise disappears.
If you rev the engine the noise is again quite noticeable. The oil feed to the cams appears to be good, evidenced by the amount of oil lying in the heads.
I've recently tightened the timing chains and cured the rattle that used to be heard while driving. The cams were checked for TDC after I'd finished and found not to have moved. Any advice gratefully received.

Cheers

Alan

Tony · Post by **Tony** » Mon Jul 21, 2014 8:34 am

Mine is the same, I do not know if it is pinking or the tappets. I am told this is normal, so i ignore it?

Let me know if you find an answer.

ALAN COCHRANE · Post by **ALAN COCHRANE** » Mon Jul 21, 2014 8:48 am

Tony

I've had pinking problems before and they sound like nuts and bolts rattling behind the dash. Pinking is usually at it's worst when accelerating in top from about 30mph. It can be cured by advancing the ignition to a point where it disappears.
The tappety noise is engine speed related and constant. Hope this helps you figure out what you're experiencing. It may well be something you have to live with-hopefully not though.

Alan

Durango2k · Post by **Durango2k** » Mon Jul 21, 2014 10:20 am

I think it's retarding, not advancing ?

Carsten

ALAN COCHRANE · Post by **ALAN COCHRANE** » Mon Jul 21, 2014 1:00 pm

Carsten

Well done you've spotted my deliberate mistake. It is indeed retarding to cure pinking.

Alan

Durango2k · Post by **Durango2k** » Mon Jul 21, 2014 4:00 pm

It would also work advancing the dissi - say 355 degrees :-)

Carsten

ALAN COCHRANE · Post by **ALAN COCHRANE** » Wed Jul 23, 2014 8:35 pm

I've been doing a search of the Forum and come to the conclusion that the tappety noise is due to incorrect valve clearances.
So I took the plunge and removed the cam covers yet again.
The inlet clearances varied from 4 to 8thou(should be 4 thou) and the exhaust clearances varied from 6-9thou(should be 6thou).
The worst offenders were inlet valve no6 and exhaust valves 1,4,5&6 which ties in with the tappety noise mainly coming from the front of the cam covers.
I'll check the valve cups for any wear at the same time and replace as required. Although none of them seem to rock when the corresponding cam lobe is facing away, so I might be lucky in that respect.
I'll report back when I've removed the cams etc.

Alan

abowie · Post by **abowie** » Wed Jul 23, 2014 9:23 pm

ALAN COCHRANE wrote:.
I'll check the valve cups for any wear at the same time and replace as required.
Alan

I would be very cautious about this. The tolerances between the cup and guide are very fine. I usually get each individual cup/guide pair machined to fit when rebuilding a head. I'm not sure that you can just drop in a new cup and in any event the wear is likely to be in the guide anyway.

If you do have a cup that is rocking the best solution is to install oversized cups. This requires the head to be removed and stripped and for the guides to be machined.

Oversized cups are available from all the usuals. If you have to go down this path I would recommend installing the "long skirt" ones available from SNGB or XK's.

In your situation the likelihood will be that once you have the clearances back at spec the noise will go away.

ALAN COCHRANE · Post by **ALAN COCHRANE** » Wed Jul 23, 2014 10:45 pm

Andrew

I take your point about machined pairs. My engine was completely rebuilt in 2006 by the PO and has done little mileage since. So I think it's safe to assume that there's been little wear since then. The cam lobes look like new and the oil feed is plentiful to say the least. The valve clearances were taken when the engine wasn't completely cold, so I'll check them again tomorrow- but I hardly think they'll be any better! I'm surprised how far out some of them are. One inlet valve had an 8thou clearance.

Alan

JEP41 · Post by **JEP41** » Thu Jul 24, 2014 5:34 am

Hi,

I am not sure the valve clearances you have are the cause of the noise. I have three engines I have built to +300bhp spec, using Neuman Cams and the recommended valve clearances were 0.008" inlet and 0.010" exhaust. With these clearance I have no audible tappet noise on any of these engines. One can be heard on Youtube under C-Type engine 1st run.

abowie · Post by **abowie** » Thu Jul 24, 2014 9:42 am

JEP41 wrote:, using Neuman Cams

The clearances depend on the cams and is specified by the manufacturer.

8/1000 clearance on an inlet valve with a standard Jag cam will be noisy.

ALAN COCHRANE · Post by **ALAN COCHRANE** » Sun Jul 27, 2014 5:18 pm

Andrew

I'm now at the stage of needing to replace the valve shims. I was expecting the existing ones to be stamped A-Z depending on their thickness. None have any markings and my Ebay cheapo special digital micromenter only has an accuracy of +/-4thou-fat lot of use that is!
Did you have to measure your existing shims with a super accurate micrometer before ordering new ones?

Alan

abowie · Post by **abowie** » Sun Jul 27, 2014 10:10 pm

The slightly less cheapo ones will go to 0.5 thou.

http://www.ebay.com.au/itm/400701148151 ... 1497.l2649

I have access to a collection of 100's of shims. What I have done in the past is use the mic on every shim I use. I reckon this is the only way to do it as I takes me a minimum of 3 runs through each valve to get them right.

PeterCrespin · Post by **PeterCrespin** » Mon Jul 28, 2014 12:31 am

ALAN COCHRANE wrote:Andrew

I'm now at the stage of needing to replace the valve shims. I was expecting the existing ones to be stamped A-Z depending on their thickness. None have any markings and my Ebay cheapo special digital micromenter only has an accuracy of +/-4thou-fat lot of use that is!

You sure you haven't got it set on metric?

abowie · Post by **abowie** » Mon Jul 28, 2014 7:51 am

There's 2 types coming out of China atm. One is "carbon fiber" (read plastic) and reads to 0.1mm.

The better ones are Stainless and read to 0.01mm.

It's astonishing that you can buy such a precision device for $11.95.

I bought my first vernier caliper in the mid 1980's. It was a used quality Japanese mechanical one with proper verniers and the little dial housing. From memory I paid $100 then for it. As an 18 year old Uni student, that was a fortune.

ALAN COCHRANE · Post by **ALAN COCHRANE** » Mon Jul 28, 2014 8:37 am

Andrew

Unfortunately mine is the former. It's been adequate for most things but not this.
On the upside my local friendly Triumph & MG Garage has said I can use their digital calipers.
I'm hoping that some of the shims can be swapped around cutting down on the number of new ones I need to order. I was planning to order shims on either side of the correct ones as well. Do you think this is a wise move? Hopefully SNG will take back any unused.

Cheers

Alan

abowie · Post by **abowie** » Mon Jul 28, 2014 9:50 am

There are people on this forum far more experienced than me in this but as I said it always takes me a couple of goes to get the clearances right.

Often your local Jag garage will have a collection of shims and with suitable inducement may let you use them...

Alternatively there's this:

http://xks.com/i-7150246-01-1272-valve- ... t-box.html

christopher storey · Post by **christopher storey** » Mon Jul 28, 2014 9:59 am

As a matter of interest , I have just done the same exercise on my Rover 2000TC . The shims on that are much thicker - 380 thou , yes .380 inches being typical , and many are not available so I made my own as others with Rovers have done, and it has been a success so far - about 1500 miles . A half inch bar of silver steel is necessary and either your own or a friend's lathe . I cut off chunks of about 450 thou and then machined them down to the exact dimension I wanted . It did require some to be redone at the first service because I had not got them to within 1 thou or so of the correct clearance . I don't know whether anyone has tried this on Jaguars ?

Post by **mgcjag** » Mon Jul 28, 2014 5:12 pm

Hi Alan......hade a very similsr noise on my S2 have u looked at cam followers for signs of wear......mine did so replaced with the long sleeve version did mot have the follower guides re machined........a friend had his 4.2 rebuilt recently but on stsrt up there was a tapping..pulled out the followers and they were worne....the rebuilder had used the existing ones......im sure u know but make sure the shims sit on top of the valve stem and not on the retainer.....good luck Steve

rfs1957 · Post by **rfs1957** » Tue Jul 29, 2014 7:28 am

Is there a clue to this in the very first post ?

"under load"

Piston slap ? Valve clearances of the orders quoted unlikely to make that much noise and are indifferent to load.

PS Are we spoiled ?! We're indignant about the price of precision tools yet appear not to grasp the consequences of the manufacturing imbalance that paying as much for three shims as for a tool to measure them implies.

PPS Maybe if you spent more on a mike you wouldn't need to buy so many shims !

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