installing valve guides question

Can the valve guides on a commando be extracted and installed correctly, without using the special Norton extractor tool? I have the drifts and a torch, is there a huge down side to heating and pounding out? I was going to freeze the new guides, and heat the head for installation. Can't wait to get new guides in, and cut 3 angle seats! cheers

Better to heat the head in an oven............remove old guides, then out back in oven for a while than install new ones. Personally I would say removing and installing the guides with head heated, is better method using force when cold.

Heat the head in oven as advised first. Be careful that your drift fits fairly close on the inner valve guide diameter as it's easy to gouge the valve guide bores if not (I learnt the hard way but dressed the burrs with a scraper) by getting the drift out of line. Make sure you support it so you don't break any fins. It's an easy job.

I agree with needing to heat the entire head if not using the tool. Spot heating may be enough to remove old guide but the critical issue is getting the new one in without damaging the guide or the head. I also found the i needed to validate the size of the bore to make sure I had the right size guides, requiring reheating of the head for reinsertion of the new guides.

After install of new guides, clearance of valve to guide must be re affirmed. When the head cools and tightens around the new guides the id of the guide can be reduced. I had a guide tighten and interfered with the piston bending it. Adjustable reamers are available that small and 2 sizes were required to span the delicate dimension

I think in this regard the tool would be nice to eliminate critical moments like this and to simplify an important installation. If the things cool too fast or surfaces gall a litte, your screwed.

Granted, some installation go without a hitch, others don't. Your call!

"get the tool, to make your life easier"
i think this is what i was waiting to hear, partially because i want a new tool. i am also curious if an old or new valve will ever have concentric contact to the old seat when new guides are installed? in other words do you always have to cut new seats when installing new guides? cheers

noco said:

"get the tool, to make your life easier"
i think this is what i was waiting to hear, partially because i want a new tool. i am also curious if an old or new valve will ever have concentric contact to the old seat when new guides are installed? in other words do you always have to cut new seats when installing new guides? cheers

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EDITED
Count on it. But no more than needed. And after a good lapping your compression will be like new or better. Don't go half assed here. Inspect your seat with good pressure and a bright backlight. Don't be fooled by thinking your can lap out a sliver of light. A fresh cut will leave an very slight angle for the valve to peen itself to a very fine seal after a couple of runs. This is the optimal procedure to creat a tight head.

I purchased a Neway Valve seat cutter on ebay and past it on to the next needy person for the same price. Honest comminication was the key to this transaction.

I have purchased a half a dozen tools that I may never use again. I am think of creating a post to lend out stuff for the shipping costs. Crank timing gear puller for example.

I recall the guide drift I got on ebay from someone in CA was toast before the first guide was out, so this would not be one of those tools.

As others have said, heat in an oven. Another thing to try & do before you try removing the old guides is to get as much carbon off the old guides, where they protrude into the ports, as you can. This makes them come out easier & there is less chance of damaging the bore of the hole they fit in. If you had the facilities, milling off the ends in the ports would be even better. I think knocking them out with a well fitting drift is better than using the tool, if you can even get the tool as I've never seen one for sale. I think the head would cool quite a bit while you fit the tool.
You probably will need to clean the seats after you fit new guides but shouldn't need much metal, if any, taking off.

Ian

I doubt very much whether any type of tool designed to install valve guides by force on a Norton head would still be available, as its something thats simply not needed.

However Tto avoid the need to change guides if you take the head to a good engine machine shop they should be able to sleeve the existing ones, which will if the job is done properly mean very much reduced wear in future, and should cost less than replacement and a 3 angle cutting job on the seats.

Carbonfibre said:

I doubt very much whether any type of tool designed to install valve guides by force on a Norton head would still be available, as its something thats simply not needed.

However Tto avoid the need to change guides if you take the head to a good engine machine shop they should be able to sleeve the existing ones, which will if the job is done properly mean very much reduced wear in future, and should cost less than replacement and a 3 angle cutting job on the seats.

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Not a bad idea. However, I think most of us Nortoneers would rather be the masters of our own fate. Short of grinding crank journals, I cannot think of anything i haven't done or would not do again if given the opportunity or need to do so.
The bottom end may be the heart of Norton but it's the top end that makes it happen. A job well done on a head rebuild is a great accomplishment and something to be proud of.

For the last forty years ,i drill the guide [port side ]off first ,untill the drill "just touch's the alloy"this removes the carbon built up guide, then drill the guide out about 2mm undersize, this allows a dead easy removal . with no guide bore damage.

Wow, now that's wierd...I've been putting together the thread I just posted over the last while (while doing other stuff too) and after posting here is this one. Must be one of those Jedi mind tricks!

I do have one thing to ask/add. I've always put the guides in some dry ice, heat the head to 500F deg. Then get the guide hole a little hotter with the torch. With a drift and minimum force the guide drops right in and no crooked problemos. I'll have to say, I have never heard of resleeving a valve guide. Beddy beddy in-ta-restin'!

Mike

I did mine a while ago... because I could I made a tool(s) to do it. For the removal I turned down one of the old valves so it was slightly smaller diameter than the OD of the guide and brazed the threaded section of an M6 bolt on the top. For the top part of the removal tool I used a piece of 25mm bar and drilled a hole most of the way through it that was big enough to fit over the guide, a smaller hole was drilled all the way through. This could also be done with a piece of tube and a washer....

For putting the new guides in I made two more parts, simply brazing an M6 thread onto an exhaust and inlet valve. On the top side I turned over the 25mm bar that I used to remove the guides, this was actually turned so it pushed the guides from the shoulder rather than the top although again this could be done with a suitable size pipe and washer.

No matter what method you use clean the carbon off the old guides and heat the head to remove and refit the guides... if you use the oven it will smoke out the house, to put them back in I sat the head in front of an industrial space heater and turned it to make sure it didnt get too hot in one place.

The idea of sleeving a guide seems a bit silly, the machining required is more than the effort to put in new guides in the first place, and secondly if we are talking about the cast iron guides they will not be strong enough to press a sleeve into.

Seems to be a awful lot of confusion related to valve guides, so maybe this might be of interest: http://www.enginebuildermag.com/Article ... tions.aspx

Another method to remove old valve guides is the following;
Tap a screw thread in the top of the old valve guide, and insert a suitable bolt.
Use a long drift to drive the valve guide out from the other side, by knocking on the underside of the bolt.
This method prevents the valve guide end from forming a "bellmouth " and makes it easier to remove,
since the valve guide is "stretched" rather than compressed during the removal operation.
Of course, removing carbon and heating the head may still be necessary too.

Peter.

Just FWIW...

I have read here that heating above 350 is not a good idea on alloy pieces. The person who posted it is knowledgable, but for the life of me I can't repeate from memory exactly why. But it is probably related to hardening of the alloy.


Russ

TOTALLY BS 350' F is any issue to Al to distort to matter - period end of story throw in the ole towel and wrap it up. WAY more risk not to heat the Al up to frying pan oil smoke-burn off temps to get it to release items or accept new ones. Normal head temp at hwy speed is over 325' F and racers can reach 425+F w/o issue, if their parts seated in tight enough with enough heat to begin with.

Vary interesting post! I haven't touched my head yet so I have to ask, does the removal and pressing take place from the combustion chamber side of the head?

hobot said:

TOTALLY BS 350' F is any issue to Al to distort to matter - period end of story throw in the ole towel and wrap it up. WAY more risk not to heat the Al up to frying pan oil smoke-burn off temps to get it to release items or accept new ones. Normal head temp at hwy speed is over 325' F and racers can reach 425+F w/o issue, if their parts seated in tight enough with enough heat to begin with.

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OK, you made me go find the post:

"Probably wouldn't need to go hotter if everything goes right. But the aluminum temper is not affected until the temp exceeds 375 degrees so heating to between 300 and 350 gives a little margin for error. You would want to be careful if your using a torch to heat it that hot because you could sure make hot spots that could cause damage. Jim"

The Jim, is Jim Comstock (aka comnoz). I trust him on this. Here is the thread.

gearbox-bearings-install-t8607.html?hilit=degrees

I am not an expert, but I stored away the warning for future use. I pass it on here in the event it helps. It was not in reference to vavle seats. But if you don't need that much heat, why test it?

T95 said:

Vary interesting post! I haven't touched my head yet so I have to ask, does the removal and pressing take place from the combustion chamber side of the head?

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The go from indside toward the outside for removal. A double diamter drift is the common tool you see in texts for this job. They would look something like this:

http://cgi.ebay.com/ebaymotors/ws/eBayI ... OTORS:1123

Russ

Thanks Russ.
Funny, the e-bay seller you chose is only about 50 miles away.