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Valve Guides

cobbadog

Registered
Looking at the head today and I have a pair of valves that re usable but I can buy a new pair of steel valves at a reasonable price but the valve guides in the head are worn, well worn. They are not just a parallel tube like in shape rather they are stepped in shape and because of this they are a bit tricky to get a hold of. What is there is definitely steel and possibly cast steel not the bronze as you would find in later engines. The best pair of valves I have show some slop when they are in position and the head of the valve is in the seat. Top of stem can be wiggled slightly.
My choices as I see it now is to have some over sized valves made and ream out the existing guides to suit. Standard size was 7/8" diameter stem.
Buy some standard 7/8" valves or use the ones here and try to make replacement guides. To do this I would need to get the originals pressed out which I guess is not a drama and only a slight cost.
You can see on the top there is the hole for the stem to fit into then it steps down to a wider flange then it goes inside the head. Both guides are similar except one is longer than the other. I know this is not going back to work again and only be a rally engine but this could be the cause of a lot of smoke (yippee) or a bad starter. What advise is out there on this issue please?20200610_112353.jpg20200610_112425.jpg
 

Scotty 2

Registered
Hello Cobba
A job for the lathe. Make a drift to whack the guides out (punch from the inside, they're not that tight) then find an old sash window cast iron weight and start turning. You'll probably find the guides are cast iron. The easiest way to find out is to get your angle grinder out and touch it on a guide and get Dee to see what colour spark comes off the guide.
Cheers
 

Glenn Ayers

Subscriber
Last Subscription Date
04/17/2020
I know this is not going back to work again and only be a rally engine but this could be the cause of a lot of smoke (yippee) or a bad starter. What advise is out there on this issue please?
There would only be a "Lot of Smoke" .... IF there were oil constantly splashing around the top of the valve stems.

( I would "Run It" )

It's unlikely they are Steel.

.
 
most likely a cast head, but still if your asking take it to a engine reconditioner do do his thing.

Take the old valves and retainers / springs.

H and J machining make valves they are a sponsor on smokestack, if your engine man cannot find a valve that will work or a repair with your own parts.
It may take a while to get the valves as flights are shut down. only sea freight out of usa

get a quote first then its up to you.
 
Last edited:

Darryl

Registered
I’d just use the guides the way they are but the simplest fix is to use K- Line bronze valve guide inserts. There’s a piloted reamer you drill through, then drift in the insert, then push a broach through to size it to original . Then re cut the seats. All without removing the guides from the head. But like I said, I wouldn’t touch them.
 

Scotty 2

Registered
another option, knurl them. if they are not terrible sloppy run it.
Can you expand on this a bit please? What do you knurl? They fit well into the head.

Oi Cobba. Did you find they were different diameters as well as different lengths?
 
Knurling guides is a temporary fix, its done with a tiny stepped roller set at an angle in the pilot. The tiny roller looks like a can opener roller just absolutely small with tiny shafts each side.
You put a special tool on the guide to drill the relief which goes down about 2 mm this is the start point, because of the little angle it is set at when you turn it, it feeds down the guide.
It upsets the metal and makes the hole smaller, you then ream it to size.
you can tell it has been knurled by looking in the guide and also the relief is quite visible on top of the guide.
Not a long term fix, only a temporary one.

Its best to do a good job once, so if guides needs work , valves are no good do what's needed to bring it back to being really good.
Seats if done properly should blue up without too much effort, be of the right width / correct angles.
But since your asking basic questions about type of material the head is, its best to leave the work to a skilled person who has the right tools handy.
Most likely being so old everything will be custom. custom reamer , custom valves etc. not a common head in everyday use.
 

cobbadog

Registered
Thank you to all the replies and helpful tips.
Dobbo, I have been in tough with Bill and he has 2 new steel valves that are a 7/16" stemm and then the can be made to length to suit. But then the guides still have some play in them. One set of valves are real bad and you can see the wear on the stems. The best pair of valves feel ok and measure fairly well for diameter and just need the faces reground along with the seats in the head. Bill had no guides to suit the 7/16" that he could put his hands on when I spoke to him last.
Scotty, both guides are the same except one side protrudes further down into the port than the other, why, I don't know.
Our one and only engine shop tends to get you to chase the parts and when I came to the guides to buy some I initially thought they would be a straight length of tubing that is cut to size, pressed into place then reamed to suit the stems. Then when I looked at these ones they are stepped to suit the head and hold the valve springs etc. Yes I could have a go at making some new guides providing I can get the cast steel. When I Googled valve guides as to what they are made from they said a type/s of bronze and cast steel but did not say cast iron and I thought they were 2 different steels the iron and the steel.
I have to juggle this project and keep sorting out the next thing to do in between a flood of work. So I will keep thinking about this possible all night during the restless sleep hours and keep the mongrel work crap going so we can and will escape next month with the van with phones turned off.
 

Scotty 2

Registered
When I Googled valve guides as to what they are made from they said a type/s of bronze and cast steel but did not say cast iron and I thought they were 2 different steels the iron and the steel.
They are two different materials. That's why I said to touch the grinder on the guide to see what colour spark comes off. Orange/yellow or white.
Length of spark gives away what the material is as well. Try it out with a bit of old caste iron and a bit of angle iron (mild steel).
 

Ray Freeman

Registered
I think they could be made out of ordinary cast iron. Get some 3D if you want good material,same as what you make rings out of. I made guides for my Lister L out of windows sash weights.
 

isandian

Registered
I have made new guides from cast iron, and yes, the old window sash weight is a good source of material. On the other hand, I have had several guides in old stationary engines fitted with guide inserts by an engine reconditioner (KC's at Castle Hill).
 

cobbadog

Registered
We have only one steel recycler in Taree who is always happy to receive metal but will not part with any as it is a One Steel yard now run by that Company and if it gets weighed into the yard it must go out to One Steel only so finding sash weights will be tricky.
I like the idea of those guide inserts so will have a look at them. How are they held in place?
 

J.B. Castagnos

Registered
Last Subscription Date
01/01/2006
Window weights can be a gamble, I tried to them before, some are OK some have hard spots, one must have chilled when cast and wasn't machineable. For the cost I'd rather by a piece of known good material. If you need valves you could by oversize rod, ream the guides and make the valves, most of the early engines were two piece, steel stem and cast iron head.
 

muzzery

Registered
Regarding cast iron lumps, I don’t know much about the quality of the iron, but I pulled a few front loader washing machines apart with my kid years ago. The balance weights were usually either cast iron or concrete. Good sized iron lumps, six inches long and a couple thick. I used one to have cast iron bucket washers turned for my ibc piston pump
 

isandian

Registered
We have only one steel recycler in Taree who is always happy to receive metal but will not part with any as it is a One Steel yard now run by that Company and if it gets weighed into the yard it must go out to One Steel only so finding sash weights will be tricky.
I like the idea of those guide inserts so will have a look at them. How are they held in place?
Contact Jack at KC's 9894 6644.
 

isandian

Registered
Regarding cast iron lumps, I don’t know much about the quality of the iron, but I pulled a few front loader washing machines apart with my kid years ago. The balance weights were usually either cast iron or concrete. Good sized iron lumps, six inches long and a couple thick. I used one to have cast iron bucket washers turned for my ibc piston pump
I inherited a couple of blank power press tool bolsters that were massive. I cut one up into manageable pieces and even turned up a set of 6 7/8" piston rings out of it. It proved to be very good quality cast iron. Bit rough on the old lathe knocking off all the corners!
 

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