to knurle or not to knurl

[john schlemmer]

Hi. Just installed new valve guides and reamed them with 9mm reamer,in the 930 heads. and have new intake and exhaust valves. Read in some older blogs that the new guides might be allready to big around in side. The valves are intervalve i purchased form pelican. Also the heads are cut at 45 degree angle and look to be in good shape ,and i think the valves are cut to the same size, can these be lapped in with out cutting the seat? thanks in advance john

[cgarr]

No, you have to cut the seats.

[brighton911]

For sure John, second on what Craig said. A new guide will never be concentric with the valve seat. You could try lapping all day but you would never get a proper seal or margins. The only way to accomplish it is to installl the pilot tool in the guide and cut each seat using three different angles of cutters to achieve the proper margins.
Now your title says knurl so I'll take a chance and comment about that. Yes, knurlling will reduce the ID of the guide but also reduces the inner surface area of the guide a whole bunch. So if you have it done, expect to have them worn out in no time.
You will not be disappointed by having this job done the right way, there aren't any easier/cheaper solutions that last.

Dave

[john schlemmer]

thanks guys, will do john

[kclem19]

By the way, Craig (cgarr) does great work at a fair price and will answer your questions. My heads look like new!