Valve Shims
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From: sweller on 3 Apr 2010 11:11 I need various valve shims to fit a 1965 Jaguar 3.8 XK type engine. However, they need to be a lot thinner than those normally available. The required dimension is a diameter of 17.5mm in a range of thicknesses from 1.92mm to 2.30mm (0.076"-0.090") Is it possible to buy shims "off the peg" or does anyone know of a car that uses the same size in that range of thicknesses. I'm led to believe the SAAB 900 (old shape 8v) uses the same diameter shims - does anyone know if this is the case? Thanks. -- Simon
From: Rob on 3 Apr 2010 21:33 On 4/04/2010 2:11 AM, sweller wrote: > > I need various valve shims to fit a 1965 Jaguar 3.8 XK type engine. > However, they need to be a lot thinner than those normally available. > > The required dimension is a diameter of 17.5mm in a range of thicknesses > from 1.92mm to 2.30mm (0.076"-0.090") > > Is it possible to buy shims "off the peg" or does anyone know of a car > that uses the same size in that range of thicknesses. > > I'm led to believe the SAAB 900 (old shape 8v) uses the same diameter > shims - does anyone know if this is the case? > > Thanks. > Its cheaper to have the valves ends done. You can have the shims ground - they hold them on a magnetic chuck and surface grind. Whats caused the need for thinner shims? have the valves sunk into the seats? Unleaded petrol, in a leaded engine? If its the SAAB also Triumph and think Marina for shims. There is still a limited size range. r
From: sweller on 4 Apr 2010 01:15 Rob wrote: > > I need various valve shims to fit a 1965 Jaguar 3.8 XK type engine. > > However, they need to be a lot thinner than those normally available. > Its cheaper to have the valves ends done. ....but this would require the head to be removed? > Whats caused the need for thinner shims? have the valves sunk into the > seats? Unleaded petrol, in a leaded engine? It actually needs thicker shims than it's got but still slimmer than the available range. I suspect the valve seats have been over cut at some point in its 45 year life and 'homemade' undersize shims have been fitted as a result. I believe XK heads are ok on unleaded and the valves don't seem to have receded as the tappet gaps haven't closed up - quite the opposite, hence the need for new shims. It's a healthy engine, good compression and it returns 24mpg (good for an S type!). > If its the SAAB also Triumph and think Marina for shims. There is still > a limited size range. From my research the SAAB shims are available in the sizes I require but I need to confirm the diameter - does anyone know the diameter of the Triumph (which model?) or Marina ones? -- Simon
From: Dave Baker on 4 Apr 2010 06:46 "sweller" <sweller(a)mztech.fsnet.co.uk> wrote in message news:xn0gsgcxhq6ds000(a)news.individual.net... > > I need various valve shims to fit a 1965 Jaguar 3.8 XK type engine. > However, they need to be a lot thinner than those normally available. > > The required dimension is a diameter of 17.5mm in a range of thicknesses > from 1.92mm to 2.30mm (0.076"-0.090") > > Is it possible to buy shims "off the peg" or does anyone know of a car > that uses the same size in that range of thicknesses. > > I'm led to believe the SAAB 900 (old shape 8v) uses the same diameter > shims - does anyone know if this is the case? You need to check that diameter which I don't recognise. As far as I'm aware most of the old Imperial engines like the Jag, Lotus, Imp etc used 5/8" (15.875mm, 0.625") diameter shims. Aftermarket suppliers then made these as 15.55mm diameter shims to allow them to also fit other engines including the Saab 99 and 900, Maestro and Montego 1.7 and 2.0, and Rover 2.3, 2.6 engines. The Saab ones are available down to 1.77mm. However if yours really are 17.5mm diameter these would very loose in the valve cap, not that this would actually stop them functioning. Shims can be ground thinner within certain limits. They are generally case hardened with a case thickness of about 10 to 15 thou which you don't want to grind right through. That means you can take about 5 thou a side off. 0.25mm total. Your other two options are shortening the valve tip which is fine as all OE valves are through hardened right down to below the collet grooves and using lash cap shims which fit over the top of the valve stem and don't use the valve cap for location purposes. -- Dave Baker Puma Race Engines --- news://freenews.netfront.net/ - complaints: news(a)netfront.net ---
From: Mrcheerful on 4 Apr 2010 06:58
Dave Baker wrote: > "sweller" <sweller(a)mztech.fsnet.co.uk> wrote in message > news:xn0gsgcxhq6ds000(a)news.individual.net... >> >> I need various valve shims to fit a 1965 Jaguar 3.8 XK type engine. >> However, they need to be a lot thinner than those normally available. >> >> The required dimension is a diameter of 17.5mm in a range of >> thicknesses from 1.92mm to 2.30mm (0.076"-0.090") >> >> Is it possible to buy shims "off the peg" or does anyone know of a >> car that uses the same size in that range of thicknesses. >> >> I'm led to believe the SAAB 900 (old shape 8v) uses the same diameter >> shims - does anyone know if this is the case? > > You need to check that diameter which I don't recognise. As far as > I'm aware most of the old Imperial engines like the Jag, Lotus, Imp > etc used 5/8" (15.875mm, 0.625") diameter shims. Aftermarket > suppliers then made these as 15.55mm diameter shims to allow them to also > fit other engines > including the Saab 99 and 900, Maestro and Montego 1.7 and 2.0, and > Rover 2.3, 2.6 engines. > > The Saab ones are available down to 1.77mm. However if yours really > are 17.5mm diameter these would very loose in the valve cap, not that > this would actually stop them functioning. > > Shims can be ground thinner within certain limits. They are generally > case hardened with a case thickness of about 10 to 15 thou which you > don't want to grind right through. That means you can take about 5 > thou a side off. 0.25mm total. > > Your other two options are shortening the valve tip which is fine as > all OE valves are through hardened right down to below the collet > grooves and using lash cap shims which fit over the top of the valve > stem and don't use the valve cap for location purposes. or if you are a real animal you can take a little grinder and grind the end of the valve in situ. I saw this several times in the early days of the Suzuki GS engine which had shims. Even worse is that the owners claimed it had been done by a motorcycle shop. |