Sleeving valve guides

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Bobolink

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My local machine shop is sugesting boring my worn valve guides & inserting some sleeves. They appear to be about 25 thou thick & bronze in colour.

Has anyone found this to be satisfactory or should I just ged a new set of guides for them to install?

If I get new guides, what is to choose between cast iron or colisbro that RGM supply? Which would be most suitable for my stock '71 750?

Thankyou all, in anticipation of your usual swift responses.

Bob.
 
I cant remember the name but there is a process that sleeves valve guides, some big engine reconditioners use them and they are very successful and not costly, I've had them done in Brisbane. its quicker and cheaper and less damage than knocking your old guides in and out. I wouldnt bother with the idea of attempting to do one off sleeving , it just wouldnt be worth it and risky I'd say.
 
I can see the attraction with not removing valve guides. as every replacement makes the bore just that little bit bigger each time, plus if not done properly some carbon if not removed will score the hole, Having said all that, its not the norm to resleeve.
I start the replacement by drilling off the guide that sticks into the exhaust port, until the drill just "kiss's" the alloy, this ensures all the crud is removed, then i heat the head and a good fitting stepped mandril will tap out the old guide, I some times drill down the guide on the milling machine untill there only 1mm a side left in, then they require only a light tap, But its a bit extream as it takes some care and time and a angle plate..but a good job,
I guess every one will have a differant method...
 
No engine reconditioner with modern equipment is likely to want to replace guides nowadays, inserts or sleeves will work far better, and in most cases will mean little material needs to be removed from valve seat to make it concentric with guide bore.
 
The last time I saw a Norton motor with sleeved iron guides parts of the guide had broken away in the port and gone through the engine. I wouldn't do it on a cast iron guide in a Norton . Jim
 
comnoz said:
The last time I saw a Norton motor with sleeved iron guides parts of the guide had broken away in the port and gone through the engine. I wouldn't do it on a cast iron guide in a Norton . Jim
Click to expand...
Only for the thicker cast iron 850 guides it works just fine. Already sleeved dozens with K-lines, works a treat!
 
I might consider it on an 850 guide if Kibblewite guides were not available. Jim
 
I was NOT a fan of the K line system, IMHO if the material is soft enough to size it with a ball broach ( like the K line ) it is to soft to have much of a life expectancy.

nortonspeed said:
Only for the thicker cast iron 850 guides it works just fine. Already sleeved dozens with K-lines, works a treat!
Click to expand...
 
1/2'' guides do tend to split when using liners, the early K Line liners were quite soft, but the harder ones split more guides
 
Thankyou for the replies. My guides are quite thin in the ports so I think I shall be replacing rather than sleeving.

Should I go for the cast iron ones or the Colisbro type?

How hot does the head need to be to successfully drift them out & in?

Regards

Bob.
 
Gday Bob, this link could be of some help, it says 150 deg F (slightly warmer than a hot day in OZ)

http://www.ehow.com/list_6364320_tips-g ... -head.html

I have bought the Colisbro guides for my Commando head from Mick and Angela Hemmings, purchased the tool to remove and install guides aswell. Its all sitting in my bike shed waiting for a quiet moment on the farm!?
 
150F is way way too little! It is more like 150-200C (no more) according to the factory Norton manual.

Russ
 
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