R80 mono valve guides

davnjud

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Epic fail to get my exhaust guides out today. Heated cylinder head in oven at 220 degrees for 30 min - couldn’t drift them out with heavy blows. Eventually my drift burrowed down the valve hole and got stuck. dremel cutting, drilling and grinding protruding drift end to finally be able to knock it back out. Such fun. Oh and broke a fin. Very bad mood.

So any tips on getting the guide out. Have heard drilling them to make the wall thinner helps. Is 30 min at 220 degrees not hot enough.? I have ground down a nut to fit under my drift so it’s a perfect fit in the valve guide recess for tomorrow’s efforts.( I’m pushing it out from the inside so have not removed the clip )
 
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davnjud said:
Epic fail to get my exhaust guides out today. Heated cylinder head in oven at 220 degrees for 30 min - couldn’t drift them out with heavy blows. Eventually my drift burrowed down the valve hole and got stuck. dremel cutting, drilling and grinding protruding drift end to finally be able to knock it back out. Such fun. Oh and broke a fin. Very bad mood.

So any tips on getting the guide out. Have heard drilling them to make the wall thinner helps. Is 30 min at 220 degrees not hot enough.? I have ground down a nut to fit under my drift so it’s a perfect fit in the valve guide recess for tomorrow’s efforts.( I’m pushing it out from the inside so have not removed the clip )
Click to expand...
You’ve probably fucked the job anyway as you’ve effectively riveted the thing in.
 
I dont have a hydraulic press and used heat and a valve guide drift.

Snuck the head in the oven when my wife wasn’t looking.

It only took one hefty whack with a 2lb lump hammer and the exhaust valve guide fairly flew out.

The new one had been in the freezer a couple of days and was inserted immediately after

IMG_1697.jpeg
 
Stirlingmoz said:
I dont have a hydraulic press and used heat and a valve guide drift.

Snuck the head in the oven when my wife wasn’t looking.

It only took one hefty whack with a 2lb lump hammer and the exhaust valve guide fairly flew out.

The new one had been in the freezer a couple of days and was inserted immediately after

View attachment 418186
Click to expand...
In my previous life, we tapped the guide and drew the guide up through a gudgeon pin as a spacer, meaning the force went to the head, and no chance of spreading the guide
 
davnjud said:
Thanks for the advice - where did you get your valve guide drift from ?
Click to expand...
Sounds like you have a seriously tight guide.
It may have had an oversize one fitted in the past.?
And may have been hammered in.
Before continuing down the route of trying to drive it out with a drift,and potentially scrapping a head that will cost more than a few squids to replace.
ESP given that a drift has been forced down it,compounding the issue.
See if there’s a local engineer to you to drill/ mill it out.👍
 
Heads are.now at Lancaster engines for guide removal / replacement, reaming seat cutting and repair of some damage to head face caused when trying to hammer out guide. My conclusion do what other very experienced and capable home mechanics like jnicholson and brook reams do and take your heads to a pro like Mikey to get this tricky job done. If you are going to DIY it ensure you have the exactly correct size valve guide drift and a good set up to hold the head when you hammer after getting out of the oven. That’s where I went wrong. I hope I haven’t damaged my head beyond repair but it has been a close thing. Will update when I get the heads back.
 
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Not near you, these guys overhauled my Ariel Red Hunter head - Guides, seats, skim gasket face, vapour blast, nothing broken. Top job.

www.seager-engineering.com

Seager Engineering

www.seager-engineering.com

ps. They will also weld the broken fin !

Use somebody secure like DPD for couriering the head there.

Beaten to the suggestion.
 
davnjud said:
Heads are.now at Lancaster engines for guide removal / replacement, reaming seat cutting and repair of some damage to head face caused when trying to hammer out guide. My conclusion do what other very experienced and capable home mechanics like jnicholson and brook reams do and take your heads to a pro like Mikey to get this tricky job done. If you are going to DIY it ensure you have the exactly correct size valve guide drift and a good set up to hold the head when you hammer after getting out of the oven. That’s where I went wrong. I hope I haven’t damaged my head beyond repair but it has been a close thing. Will update when I get the heads back.
Click to expand...
Best result,
I apologise if my comments came across as arsey,but sometimes if things don’t go to plan,it really is best to stop and hand it over to experienced engineers.
It happens in our shop as well,our experience tells us to stop.
Take it to folk with the kit to sort it and our efforts haven’t made their job any harder.👍
 
Just to round off this thread Lancaster engines swapped out the exhaust valve guides and checked the seat alignment. Also repaired my broken fin and fill welded and skimmed one of the heads that I had damaged in my hamfisted attempts to hammer out the guides. £12 per valve for the guides swap/ valve check so I know where I’m going next time.

Back home new exhaust valves and lapped in with no leakage at all when petrol pooled above the valve seat. Negligible movement of the valve in the guide so happy days. Hope my experience informs others with cost and difficulty - best left to the pros and not at all costly.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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