tappet clearance

Talk about the E-Type Series 3
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baganz.sven@web.de
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#1 tappet clearance

Post by baganz.sven@web.de » Sun Nov 11, 2018 10:53 am

Dear colleagues,

just a short sunday morning workshop question to those with more experience than I have.

Checking the tappet clearance of my E I found that I have between 0.007 and 0.012 in clearance.
On the A bank 5 valves have 0.012in which is minimum as I read.
Because so many are out of tolerance I have to adjust anyway.

So no which clearance would you set?
Can I leave 0.012 an the set all other valves also to 0.012 or should I adjust all to 0.013 (or 0.014)??

I have no experience which clearance is the most appropriate?

Very funny that the pre owner has told me that he has checked the clearance and everything is OK. :cussing:
Thank you for advice

Sven
Sven
'71 S3 coupe LHD manual

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jagwit
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#2 Re: tappet clearance

Post by jagwit » Sun Nov 11, 2018 11:16 am

Hi Sven

To leave 5 out of 24 valves, will save some labour, but not much really. Ideally, you should have a large selection of shims to choose from.

I would therefore encourage you to set them all to .013/0.14 as recommended.

Also note the thickness of the shims that you remove from each tappet. None should be thicker than ABOUT 2.8mm (0.110") - this is not a hard and fast rule, just Philip's (moi) guideline. If they are, someone may have shortened the valve stem (probably because of valve seat recession) and you should check for interference between shim and valve spring seat. Ask me how I know this.... Also check for valve guide wear and valve seat recession.

Its a very time consuming job, so be patient. Its also a good time to replace the valve stem seals.

Most importantly though, DO NOT accept that the cam timing is correct. Please get the cam timing tool and check with your own eyes that the cam timing is correct.
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

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Ole-xke1974
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#3 Re: tappet clearance

Post by Ole-xke1974 » Sun Nov 18, 2018 11:00 am

A bit of additional information on the topic from my side.
I followed some recommendation to set the valve clearances 0.002" bigger than spec, which should increase low end torque.
Whether I have more low end torque or not, is a butt dyno assessment. Maybe.
What I do know is that the tappet noise is more than I want in my otherwise quite refined "sports" car and will set aside a weekend sometime in the future to return to standard gaps.
Important tools to have on hand apart from your standard shop tools are the cam setting tool also mentioned but you will also need the timing chain tensioner release tool.
Good luck and take your time ..... Ole
1974 SIII E-Type w. XJ S2 4sp w. O/D

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baganz.sven@web.de
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#4 Re: tappet clearance

Post by baganz.sven@web.de » Sun Nov 18, 2018 11:57 am

Thank you for the comments.
Is the timing chain tensioner retracting tool necessary?
It is not mentioned in the manual.
The cam tool and the JD40 I have.

By the way, there is no temperature mentioned for measuring (e.g. 20°C)
Normally the manufacturer mentiones a temperature.
At the moment there are -2°C in my garage do I won't work on it anyway.

Best regards
Sven
Sven
'71 S3 coupe LHD manual

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jagwit
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#5 Re: tappet clearance

Post by jagwit » Sun Nov 18, 2018 3:26 pm

baganz.sven@web.de wrote:
Sun Nov 18, 2018 11:57 am
Is the timing chain tensioner retracting tool necessary?
You don't need it to get the cam sprockets off, I suppose, but you surely will need it , or something like it to release the tension on the chain to be able to get the sprockets back on.

Be sure to release the locking catch on the tensioner BEFORE you start to de-tension the tensioner, and KEEP IT released while de-tensioning the tensioner.

I try to de-tension the tensioner as little as what I can get away with in an attempt to try avoid it breaking.
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

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#6 Re: tappet clearance

Post by baganz.sven@web.de » Sun Nov 18, 2018 3:39 pm

Hello Philip,

:thankyouyellow:

greetings from Braunschweig/Germany

Sven
Sven
'71 S3 coupe LHD manual

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#7 Re: tappet clearance

Post by baganz.sven@web.de » Mon Nov 26, 2018 7:57 am

By the way, does anyone have experience with the ambient temperature the Jaguar workshop manual refers to for tappet clearance adjustment??
Sven
baganz.sven@web.de wrote:
Sun Nov 18, 2018 11:57 am


By the way, there is no temperature mentioned for measuring (e.g. 20°C)
Normally the manufacturer mentiones a temperature.
At the moment there are -2°C in my garage do I won't work on it anyway.

Best regards
Sven
Sven
'71 S3 coupe LHD manual

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jagwit
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#8 Re: tappet clearance

Post by jagwit » Mon Nov 26, 2018 12:30 pm

baganz.sven@web.de wrote:
Mon Nov 26, 2018 7:57 am
By the way, does anyone have experience with the ambient temperature the Jaguar workshop manual refers to for tappet clearance adjustment??
Sven
Sven, I recon you can ignore temperature.

According to https://www.engineeringtoolbox.com/line ... _1379.html, steel's linear expansion is about 0.00011mm per meter per 10ºC. A valve stem of about 150mm will thus expand 0.0000017mm (0.000042") per 10ºC. If my sums are correct?

No feeler gauge can measure that....
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

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#9 Re: tappet clearance

Post by baganz.sven@web.de » Mon Nov 26, 2018 1:37 pm

Hello Philip,

for Aluminium cylinder heads this is different.
I just ask because for my actual VW van from 1989 the workshop manual show 2 different values for valve clearance. One is for a "warm" engine, one for cold.

Fortunately it's too cold in my garage at the moment so I will not proceed at the moment.
I will adjust when we have reached 20°C again. :santa:

Best regards

Sven
Sven
'71 S3 coupe LHD manual

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jagwit
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#10 Re: tappet clearance

Post by jagwit » Mon Nov 26, 2018 1:48 pm

baganz.sven@web.de wrote:
Mon Nov 26, 2018 1:37 pm
my actual VW van from 1989 the workshop manual show 2 different values for valve clearance. One is for a "warm" engine, one for cold.

Fortunately it's too cold in my garage at the moment so I will not proceed at the moment.
I will adjust when we have reached 20°C again. :santa:
There is NO WAY you will be able to measure / adjust the Jag V12 tappet clearance while the engine is still warm :bigrin:
Best Regards
Philip
71 E-type V12 Coupe,
80 XJS (EFI by Megasquirt & EDIS-6 + 5sp manual overdrive)
73 Jensen Interceptor
74 Interceptor (EFI by Megasquirt + overdrive 4sp auto)

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