New 300 head, new valves, lapping necessary?

[cjbchopper]

Got a new head for my px 300. New valves going in it. Do I need to lap them in? Or being that everything is new can I simply install them and go?

[Green Hulk]

When installing new valves take the head to an automotive machine shop and have them do a proper 3 angle valve job.

[cjbchopper]

The head is brand new from brp, not used. Just to clarify

[Green Hulk]

The head is brand new from brp, not used. Just to clarify

any time you install new valves into any head, new head or used head you must always have a valve job done on it. You can’t just “lap” the valves like you do on a lawn mower engine.

[cjbchopper]

Good to know. I thought the new head was fully machined and I could simply install the new valves. Thanks for the info Jerry.

[Green Hulk]

Good to know. I thought the new head was fully machined and I could simply install the new valves. Thanks for the info Jerry.

No, you always have to seat the valves properly with a 3 angle valve job.

[jetplane]

No, you always have to seat the valves properly with a 3 angle valve job.

How many times can we make the 3 angle valve job on the valve seats on the same head ?

[Green Hulk]

How many times can we make the 3 angle valve job on the valve seats on the same head ?

I have done valve jobs on the same head several times and the seats were still fine. Very little material is removed during a valve job.

[jetplane]

I have done valve jobs on the same head several times and the seats were still fine. Very little material is removed during a valve job.

Thank you so much Jerry . It should be 1/10 of mm after each job .