[Healeys] valve guides

Michael Salter michaelsalter at gmail.com
Sat Mar 28 20:09:12 MDT 2015


So Gergo,
if I understand you correctly in a situation where the guide was not
installed in a head and it was then heated the outside diameter and for
that matter the inside diameter of the guide would increase due to thermal
expansion....correct?
However, the difference, when the guide is installed in the head is that
the head material, i.e. the hole that the guide is installed in, would
prevent the guide from expanding or, expressed another way, because the
hole in the head would not increase in diameter as much as the guide would
increase in diameter the head material would effectively compress the guide
and prevent it from expanding..... correct?

Michael S

On Sat, Mar 28, 2015 at 4:38 PM, Austin Healey <pajtamuvek at gmail.com> wrote:

> Yes it does. The material has to expand somewhere. It cant go in the
> oposite direction.
>
> g
>
> 2015-03-28 20:12 GMT+01:00 Michael Salter <michaelsalter at gmail.com>:
>
>> Hi Gergo,
>> just so I'm clear...you are suggesting that the internal diameter of the
>> guide will get smaller as it heats up therefore that extra clearance is
>> required?
>> Michael S
>>
>> On Sat, Mar 28, 2015 at 3:08 AM, Austin Healey <pajtamuvek at gmail.com>
>> wrote:
>>
>>> Bronze guides expand more when they heat up. Thats why You have to use
>>> greater clearance. But when they work, the clearance will be the same. Worn
>>> out guides have two negative side effects: oil consumption, and premature
>>> wear on the valves as they dissipate heat slower due to rocking on the
>>> valve seat. The exhaust guides are more prone to oil consumption, exhaust
>>> guides are more prone to overheating.
>>>
>>> Gergo
>>>
>>> 2015-03-27 20:01 GMT+01:00 Michael Salter <michaelsalter at gmail.com>:
>>>
>>>> Hi Raymond,
>>>> The factory specification calls for 0.0025 to 0.0015 clearance for the
>>>> inlets and 0.002 to 0.001 clearance for the exhausts if you are using cast
>>>> iron guides however if you are using bronze THAT WILL NOT WORK!!!
>>>> To be safe with bronze guides you will have to hog them out to about
>>>> 0.006" clearance..which means there is really no point in replacing them.
>>>> I would point you to this article
>>>> <http://www.netbug.net/blogmichael/?p=384> on my blog...been there
>>>> done that...
>>>>
>>>> Michael S
>>>> BN1 #174
>>>>
>>>> On Fri, Mar 27, 2015 at 2:17 PM, RAYMOND SMITHSON <rjsmithson at shaw.ca>
>>>> wrote:
>>>>
>>>>> I am rebuilding my 3000 cylinder head and have found the inlet valve
>>>>> stems have .008" clearance but the exhaust stems have only .002" clearance.
>>>>> Does anyone know if this is common?
>>>>>
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>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> *If you can't fix it with a hammer, you've got an electrical problem.*
>>>>
>>>>
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>>>>
>>>>
>>>
>>
>>
>> --
>> *If you can't fix it with a hammer, you've got an electrical problem.*
>>
>>
>


-- 
*If you can't fix it with a hammer, you've got an electrical problem.*
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