Head removal to clean carbon

darylrobert · Post by **darylrobert** » 03 Jun 2021, 02:07

After trying a number of products ie Subaru upper engine conditioner, Liqui Moly de carb, Seafoam piston soak , each with some noticeable performance improvements to clean my 2001 XC70 carbon problem that only throws Knock codes and retards timing under heavy load after 3K RPM, no other codes.

Ive decided on removing the head and cleaning it myself, ive practiced on my junk XC70 motor and the pistons were easy to clean with seafoam or WD-40 and a rag but the exhaust valves had a thick white crust that was really hard, i used a screw driver and metal brush, should i just spend the money and trust a shop to clean it properly?

I cannot hear any valve noise, no tapping tappets no smoke and the car drives really well if not pushed, can i clean and install the head without touching the valves?

If there is no leakage or sign of a warped head do i need to get it re-surfaced?

I want to look after this car but not go overboard.

Post by **abscate** » 03 Jun 2021, 04:04

I’m a fan of having the shop do the head cleaning since I have them do the valve work anyway, they charge about $25 for the cleaning here.

Fiverivers set the Gold standard for owner head cleaning, though.

Post by **SuperHerman** » 03 Jun 2021, 09:06

It depends on whether you are going to farm out any of your head work or just clean it up, check it for flat, and reinstall. In other words, your budget and your solutions.

If your head is flat you can clean it up your self, lap the valves/seats and put it back on. Of course after cleaning up the crust on the valves.

On my old 2001 XC70 I sent the head to the shop for decking and cleaning only b/c the engine overheated. I cleaned all the valves, lapped the valves/seats, and cam. I then reassembled.

For cleaning the crust you mention, I placed the valve in a drill and used a softer metal blade (with a handle). Process is similar to turning wood. I finished with a Scotch Brite pad. Just be smart and you should have no issues. If the valves/seats are too far pitted you may need to have a shop attack the problem, including replacing some parts.

If you do some digging there is a post by a member where their head was rebuilt and this discussion was had in depth.

darylrobert · Post by **darylrobert** » 04 Jun 2021, 01:47

Is this the post SuperHerman viewtopic.php?t=26864 some good pics, i wouldnt be happy with the dents and scoring finish?..looks abit rough to me??

Post by **abscate** » 04 Jun 2021, 04:47

darylrobert wrote: ↑04 Jun 2021, 01:47 Is this the post SuperHerman viewtopic.php?t=26864 some good pics, i wouldnt be happy with the dents and scoring finish?..looks abit rough to me??

Just do better than this guy...you can’t make this stuff up...

Post by **SuperHerman** » 05 Jun 2021, 23:32

viewtopic.php?p=482818#p482818

Starting on page 7 is discussion on valve cleaning. Overall the entire post will be helpful.