I dissolve the carbon with a spray product. The vast majority comes straight off, the remainder I find needs a bit more persuasion and I use a nylon scraper.
The stuff I currently use is a Penrite product and it’s very good (just can’t remember the name) but I used to just use oven cleaner for the same job years ago. I helped rebuild a few fancy racing engines and got a bit of stick for using oven cleaner earlier on so changed to something more automotive. It did the job without the “toxic” alkaline stink of oven cleaner so I’ve stuck with that range of things since.
Some people go to a lot of trouble polishing the piston and so forth but so long as it’s clean and free of defects it won’t make a scrap of difference.
If you’re using digital calipers check their accuracy and repeatability. I don’t own any because most of my gear was bought before they came in but I had a colleague measure a bolt using his and I made a replacement based on his measurements and it was oversized because his calipers weren’t accurate. To check them a relatively inexpensive set of gauge blocks will work fine.
Last edited by Ironbark; 21/09/22 12:05 AM.
