Oversized valve guides? - or help me repair my head

[grelland]

Hi there.

I had a breakdown on my way to the SCC (Scandinavian Cal-look classics) meet this year, and have not had the time to start fixing it until now.

But the issue was that the valve guide came loose in one of my heads, and I am wondering what options I have.

These are Scat wedgeport 44x37.5mm heads, and the engine is a 2110cc oxyboxer.

Here's a video:
https://youtu.be/Ua1x7L3PiQU

So what are my options?
-Oversized valve guides?
-weld and machine?
-paperweight?

I have a milling machine and TIG welder in my garage but have never attempted something this "complicated".

Advice highly appreciated

[grelland]

Hi there.

I had a breakdown on my way to the SCC (Scandinavian Cal-look classics) meet this year, and have not had the time to start fixing it until now.

The issue was that the valve guide came loose in one of my heads, and I am wondering what options I have now.

These are Scat wedgeport 44x37.5mm heads, and the engine is a 2110cc oxyboxer.

Here's a video:
https://youtu.be/Ua1x7L3PiQU

So what are my options?
-Oversized valve guides?
-weld and machine?
-paperweight?

I have a milling machine and TIG welder in my garage but have never attempted something this "complicated".

Advice highly appreciated

[Kafer_Mike]

Oversized valve guides are available in 4 sizes (.002", .005", .006" & .008"). If you simply 'dropped' a guide and there is no surrounding damage, it's an easy fix.

[grelland]

Oversized valve guides are available in 4 sizes (.002", .005", .006" & .008"). If you simply 'dropped' a guide and there is no surrounding damage, it's an easy fix.

Looking at the video; do you think that qualifies as "no surrounding damage"? I am not sure if the fact that the "knob" around the guide disintegrated...

[Clatter]

They make a thing called a ‘crutch’ also known as a valve guide shim,
That is a cylindrical aluminum spacer the same thickness as a guide boss.

You mill away the old guide boss to flush with the spring end (perch) surface, where the shim rides,
Then the crutch is used in it’s place, with an interference fit to the guide as the boss was.

Hard to describe in words..

It’s not the most elegant/reliable solution, especially in a performance environment, but was done thousands of times over the years.

Alternatively you could weld it all up and machine it all back to shape,
But due to the heat involved,
The seats would need removed first,
And that’s a lot of work.

Might be your only choice depending on how much needs cut to get the guide tight in place again.
If it doesn’t clean up by the biggest oversized guide you might be hosed.

Some make their own guides, though..

[grelland]

I have considered making my own guides, but first I need to get a lathe...

but you state that "They make a thing called a ‘crutch’ also known as a valve guide shim,"; who are "They"?

[farmer]

Send the head(s) to Getbackontrack Aarhus DK. He can fix it for you. No problem.

T