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Valves


Guest greavesy7

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I had to replace an inlet valve a few years ago simply because I lost one during an engine rebuild....(and found it behind the bench about 2 months later)...

 

I didnt have the seat recut but I did lap the valve in with paste and had no issues with compression etc...when the engine was back up and running.

 

I don't know if this is the correct method but it worked for me!

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The only reason to recut a valve seat is if the seat is pitted or you fit larger valves

As said above you should be able to simply lap the new valves in

Take your time and take some time then test with fluid in the port and see if it leaks out

 

Now just waiting for Alan builder to tell me I'm wrong

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Guest robinj66

Wot he said

 

 

Have alook on You tube - do a search for "lapping valves" and there are plenty of demonstrations for the lapping-in process and also testing for leaks.

 

In my (distinctly amateur) experience you can tell when a valve seat needs replacing or reecutting as there is obvious damage or pitting in the contact surface.

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Guest Ian & Carole

ive lapped a few heads in ive just never tested them with a fluid i normally just do it untill bothe the sufraces have a smooth light grey colour : )

 

Back in the dark ages as a lad I was taught to use "engineers blue" just a pin head amount on the valve and one smooth spin of the valve and check both faces for a continual line of "blue" on both the valve and seat faces.

But a good continual grey colour gives the same guide, "blue" was just easier to see.

Paraffin was the fluid of choice, away from naked flames, obiously.

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