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Old 12-27-2009, 07:44 PM
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Can I lap my valves in?

I brought some World 305 heads a while ago that came with all parts but were not assembled. The seats and valves look fine but I was told by someone (who I don't know) that they'd have to be reground since they haven't been kept in order.

Is this true or can I just lap the valves and check they seal properly with machining blue ink?

The heads have only had 2 years or less usage.

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Old 12-28-2009, 12:30 AM
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If they're the original valves, I don't know why you couldn't blue check them to find their home, then hand lap to fine tune the seal. A little time consuming, but there's only 8 of each.
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Old 12-28-2009, 01:35 AM
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I agree- the valves will seat as long as there's no real damage/wear.

Lapping using the fine grade compound should suffice- after a quick lapping on a blued seat/valve, you will see whether or not they're going to seal or not. As for locating the exact hole the valves came from, I never tried this- but might well be worth a try.

After lapping and meticulously cleaning things to rid the parts of the grit, put the heads together (springs and valves) and position them in such a way that you can fill them w/kerosene or some other non water solvent to see that the valves are sealed well. There shouldn't be leakage past the seats.

If as-new condition is important to you, and cost isn't a consideration, take the heads and valves in for a 3-angle valve job. You could consider a 30 degree back-cut on the valves, too. But overall, you could get by w/the lapping idea. Others are sure to disagree w/this- and that's fine. I only can say what has worked for me in the past.
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Old 12-28-2009, 07:55 AM
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I agree, use some machinist blue to confirm the width and position of the seat and if all looks good then hand lap with fine lapping compound.

Vince
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Old 12-28-2009, 05:24 PM
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Thanks for the help people
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