Author Topic: Valve guides  (Read 546 times)

Offline Fergie

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Valve guides
« on: 08.03. 2020 12:07 »
In the process of Rebuilding an A7 SS Alloy head. One of the jobs is making new valve guides with oil seals on them. Has anyone details on a seal that might be suitable for a 5/16 stem vale?

Online Billybream

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Re: Valve guides
« Reply #1 on: 08.03. 2020 16:06 »
SRM have them, part no 60.7363, seal with spring, you have to modify valve guide to fit them, I think they are off a Truimph.
No doubt other shops sell them,  approx. £1.75 each.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Offline Fergie

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Re: Valve guides
« Reply #2 on: 08.03. 2020 18:17 »
Thank you  Billybream. Found them on SRM's site. Eventually.  *smile*
No problem modifying the guides as i am turning them up on the lathe.

Offline Fergie

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Re: Valve guide seals. Might be of interest.
« Reply #3 on: 16.03. 2020 14:12 »

I'm fitting valve guide seals to the valve guides I'm making for an A7 SS head.

SRM has them listed as 60.7363 and of today's date, they are in stock.
Norton also used seals on the Commando model which should fit a modified BSA A7/A10 guide.

Has anyone on the forum fitted and used valve guide seals on their BSA? 

   

Online Greybeard

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Re: Valve guides
« Reply #4 on: 16.03. 2020 15:25 »
Why?

Online JulianS

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Re: Valve guides
« Reply #5 on: 16.03. 2020 16:09 »
Fitted Norton seals years back but not sure of I noticed any difference.

Online berger

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Re: Valve guides
« Reply #6 on: 16.03. 2020 18:29 »
seals would be good if it was modified to overhead cam with buckets of oil sploshing about, just saying *fight*

Offline Fergie

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Re: Valve guides
« Reply #7 on: 18.03. 2020 14:24 »
Why?
Several advantages as follows.

Less oil consumption through the more precise flow of oil to the guides.
Tighter valve clearance. = More heat transfer through to the head.
Better control of the valve on the seat because of the tighter stem to guide clearance= less wear on valve seats and valve face.
Less carbon buildup= engine runs cleaner for longer.
Fewer emissions from the engine= less pollution   

That's the theory anyway.  *smile*

Offline Fergie

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Re: Valve guides
« Reply #8 on: 18.03. 2020 15:06 »
seals would be good if it was modified to overhead cam with buckets of oil sploshing about, just saying *fight*

Hi Berger,
There should be lots of oil sloshing about in the A7/A10 rocker box as its mostly a splash system. The rocker and valve tips need to have quite a lot of oil for lubrication as do the valve stems.
The rocker shafts are well lubricated via the rocker feed so they are OK. However, Air cooled engines because of the higher temperatures they run at, generally require larger running clearances including valve guides than water cooled engines.
If we are able to decrease valve guide clearances and still provide adequate lubrication we have the advantage of dissipating heat from the guides quicker and therefore more efficiently from the engine.     
There are also several more advantages in using valve guide seals as outlined in my previous post to Neil.   

As regards converting to OHC it's on my project list and i have some parts gathered already. Got a crank from Draganfly yesterday.  *yeah*

Offline Fergie

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Re: Valve guides
« Reply #9 on: 18.03. 2020 15:13 »
Fitted Norton seals years back but not sure of I noticed any difference.

Hi JulianS,

These look the same as SRM are selling.
Have you any dimensions for the guide where you fit the seal?

Regards, Fergus.

Online JulianS

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Re: Valve guides
« Reply #10 on: 18.03. 2020 17:37 »
Regret no dimensions.

Online berger

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Re: Valve guides
« Reply #11 on: 18.03. 2020 18:27 »
think i'll go down the pub and see if corona19 is about *beer* *help*, your saying the guides need oil but your putting seals on them that will stop oil...  and the seals will get hot and crispy, can't see how a seal is going to stop any movement / slop in a system going that fast *dunno*

Offline chaterlea25

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Re: Valve guides
« Reply #12 on: 18.03. 2020 22:34 »
Hi Fergus,
Here is a link to commercial tools that will cut the guides for seals
https://www.summitracing.com/search/part-type/valve-guide-cutting-tools
Sorry I do not have a dimension for modifying the guide, A commando or T140 guide would provide the dimensions  I think
Alternatively I would think any decent engine shop would posses either a tool or stock guides that accomodate seals
so provide a measurement
Basically the guide diameter is reduced so the seal will fit and there is a semicircular groove at the lower end of the reduced part for the seal to grip onto

As to the benefits of fitting seals, I have them on my SR since I built it so probably 30k miles,
oil consumption is negligible and carburaution improves as air is not drawn down the guides

John
(haven't forgotten the stand lug drawing)
1961 Super Rocket
1963 RGS (ongoing)

Offline Fergie

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Re: Valve guides
« Reply #13 on: 18.03. 2020 23:10 »
think i'll go down the pub and see if corona19 is about *beer* *help*, your saying the guides need oil but your putting seals on them that will stop oil...  and the seals will get hot and crispy, can't see how a seal is going to stop any movement / slop in a system going that fast *dunno*
I wish i could go down to the pub as well, but the government has advised them close. So there all closed where i am. *sad2* They were even closed for Paddys Day.  *angry*

A valve oil seal is the only seal in the engine designed to leak oil. Its a controlled leak allowing enough oil to keep the valve lubricated.
A valve seal will NOT STOP sideways movement or slop, that's the job of the valve guide.

Regards, Fergus.   

Online berger

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Re: Valve guides
« Reply #14 on: 18.03. 2020 23:24 »
I learn summat every day me *beer*  I might put some of these lubricating seals on the norbsa build ;)