While walnut shell blasting is likely to produce a more thorough clean than DIY manual frisking followed by Seafoam flush, it is likely to cost significantly more.
Assessing whether the extra cost versus valve finish is worthwhile is very much a conundrum for the owner.
Would love to see hard evidence on the influence of how a GDI engine is used has on the rate at which the inlet valves gum up.
One thing is a racing certainty. Once the engine breather has been diverted from the inlet, the valves should no longer require occasional cleaning.
