Cleaning inlet valves on car with inlet manifold off.

I am considering mechanically cleaning my inlet valves in the head with the intake manifold off - any thoughts? guidance?

Story, my car had PCV issues (as in some other threads) which have now been solved with a proper filtered catch can in the PCV line. Unfortunately the inlet valves got quite gunked before I understood the problem but decided to leave as it was still running OK. Now I have an intake gasket failure so have the manifold off and can access the back of the valves. I was thinking of using a brass scraper to remove the worst of the gunk, with the valve closed!! and vacuum out, then finish with a spray valve cleaner once the engine is running again.

Comments?

I would say no. Too much chance of missing a chunk.
There are products to do this (SeaFoam comes to mind). My Dad and other older mechanics would dribble ATF or water through the carb after raising the idle speed considerably.


Tim

Thanks Tim, I had thought along those lines but then I got to thinking, isn't there more chance of putting a chunk through the cylinder with the water/ATF/Seafoam method? my understanding was these methods don't dissolve the gunk they separate it from the valve? or am I missing something?

Ray

hi

scrap and vav with valves closed you will get anything big enough to cause any problems.

tape a smaller hose to vac nozzle if needed to get in there !

Thanks, I think I will be giving it a go.

https://board.moparts.org/ubbthreads/ubbt...tml#Post1779934

Seafoam sprayed on the valves is probably good, it seems like several years ago, I read an article that said Chevron Techron was good at removing buildup. You can buy the Techron additive at the parts house and give it a try. If it works good mixed in the fuel, it might work well sprayed directly on.

The true Techron concentrate is the stuff. I say scrape it and run it through the engine. it's not like we're forming diamonds on the backsides of the intake valves!
When BMW was having problems with coking on the backs of the intake valves they blasted with crushed walnut shells. The idea being that walnut shells do no damage and will burn. Some years ago I bought a pair of heads for a TBI chevy 350 and took them apart. There was nearly 1/4" of spongy carbon cake on the back of each intake valve. I seem to remember it coming off easily.

Of course if you want to scrape with one hand and run the vacuum cleaner with the other hand that will work too.

R.