View single post by Esprit2
 Posted: 04-06-2015 04:02 am
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Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 337
Barthol wrote:
(Snip)... I got the below tolerances measured in 1/100 mm and they all looks to be more than double of the max allowed 4,5 1/100 mm

Will this be the reason of my engine burning oil and covering my surroundings in blue smoke during acceleration?

When I send it out for reconditioning should I then go for the smallest possible tolerance between the guide and stem ?

Sorry, but I didn't follow everything you wrote; however "more than double of the max allowed 4,5 1/100mm" is a pretty clear statement.

If your current valve stem to guide clearances are twice the max allowed, then yes that could explain why the engine is burning oil.

And yes, when you have the valve guides re-done, shoot for the minimum side of the tolearance range. The clearances will tend to open up with wear, so new guide clearances should be closer to the minimum in order to optimise the service life before the clearances exceed the maximum limit again.

Here are the valve stem clearance specs:

Valve Stem Outsid Diameter - Intake & Exhaust
7.125-7.137mm (0.2805-0.2810")

Valve Stem Clearance in Guide - Intake & Exhaust
0.008-0.046mm (0.0003-0.0018")

Valve Guide Inside Diameter - Intake & Exhaust
(ream to size 'after' fitting into the head)
7.145-7.170mm (0.2813-0.2823")

Valve Guide Length - Intake & Exhaust
53.34mm (2.100")

Tim Engel