Valve adjustment

[Guy W Johnson]

I have an  88 esprit, the engine was rebuilt 10,000 miles ago.

 

The car does sit 4 to 6 months of the year. Do I need to adjust my valves?

 

Guy

[Mr_John111]

You can certainly check the clearances quite easily using a set of feeler gauges.

However, having checked them, if they need adjusting its quite an involved operation involving removal of the cam belt and camshaft housings

Then there is an iterative process of measuring the existing shims and obtaining thicker/thinner ones depending on the gap

Unlikely to wear that much in 10000 miles

John

[Guy W Johnson]

The problem is that my car seems to make a ticking sound. At idle the tick seem's to be loud but if I am cruising  at 45 50mph the engine is totally quiet. Any Thoughts??

 

 

 

Guy  

[dodge1979]

There will be a slight tap tap but nothing loud...have you thought what oil your using may have an effect on it? And are you certain there isnt a crack or hole in the exhaust manifold...this can sound like a clicking...a tiny pin hole in mine when I first had the car did this..

[Guy W Johnson]

I will take a look.

[ragingfool35]

not to hijack your thread...

I too have a clinking sound from the cam area.  removing the cam covers and all accessory belts and rotating engine slowly, it seems to be in the exhaust valve system.  there is a loud clink that can be felt with hand on engine block as cam lobe just about leaves tappet on 3 of the cylinders.  it has been getting progressively louder at idle, but higher rpms seems to quiet it.  I don't see the cam lose contact with the tappet (my eyes aren't great anymore though)  but it seems like a valve hangs open then closes the gap between the tappet and cam suddenly, unlikely as that is.  I don't see any broken inner springs with the cam towers removed.  cams don't make noise spinning in the removed towers, but they are not under load

I was curious about my current shims.  seems they are on the thin side but still in the range of Lotus replacement thickness.

car has 68k.  is this close to what others have measured?

 

 

shim thickness

 

intake .092 .089 .091 .090 .088 .084 .084 .090

 

exhaust .092 .092 .095 .094 .093 .093 .092 .098

Edited June 12, 2013 by ragingfool35

[Mr_John111]

As you say, all of those shims are within the normal range.

However, it's the gap between the cam lobe and the top of the cam bucket that is the important measurement.

This needs to be measured cold with the cam towers torqued down. The gaps are 5-7 thou for one and 10-12 thou for the other. It's in the manual which I haven't got handy so I'll almost certainly say the wrong way round if I guess.

There are several threads on here covering shim checking, my tip would be to buy a digital vernier gauge or micrometer and a good set of feeler gauges. Then use a spreadsheet, again it's available on here, to help identify which shims you need to swap

John

[fjmuurling]

Inlet valves: 0.010" - 0.012"

Outlet valves: 0.005" - 0.007"

 

Just fill in the yellow fields after unzipping.

 

Valve Clearance.zip

Edited June 12, 2013 by fjmuurling

[Mr_John111]

^^^*

There you go!

[ragingfool35]

i think those values are reversed?  gaps were all at the low end.  I had made a spreadsheet with target value at the high end.  thanks though I have a lead on the source of the noise.  will report back shortly

[ragingfool35]

Guy

I found the problem.  my pulley has a loose fit on the intake cam.  the belt is rotating the cam compressing the valve springs until other side of lobe where springs close the valve.  here the springs try to rotate the cam in the opposite direction.  the small amount of play causes my loud clink, at high rpm, there isn't time for this to happen.

try tightening your cam pulley retaining bolts and see if it makes a difference.

[fjmuurling]

In my previous post the clearances for the inlet / exhaust valves were reversed. The attached calculation sheet is correct. So below are the correct numbers:

 

Inlet valves: 0.005" - 0.007"

Exhaust valves: 0.010" - 0.012"

 

 

Just fill in the yellow fields after unzipping.

Valve Clearance.zip

 

(maybe a moderator can remove the wrong post in order to avoid confusion)

[jonwat]

Inlet valves: 0.005" - 0.007"

Exhaust valves: 0.010" - 0.012"

 

This isn't difficult to remember, the larger gap is always for the exhaust valve as this gets much hotter than the inlet valve & so expands a lot more requiring far more clearance to stop it constantly being in contact with the cam lobe & so never fully closing. 

[Guy W Johnson]

I'm sorry I am in the middle of building a s*****d  gazebo. I have had no time to get my car.

 

To be honest I'm nervous about checking the "cam pulley retaining bolts".

 

If the pulley was loose, wouldn't you notice it by jiggling  it.  

 

 

Guy

Edited June 18, 2013 by Guy W Johnson

[teachauto1]

I am setting the valves on a 907 Lotus engine after I replaced the head gasket, ground the valves, and had the head repaired /surfaced. I need a parts source for valve shims.I am a instructor at Bellevue High school never worked on a Lotus before.

[andydclements]

Do you have a local Saab specialist (as Saab folded there will not be dealers)? If so, the valve shims from certain models fit (15.5mm diameter which I believe is the Saab 900 engine).