[Healeys] Four cylinder woes, part two!

Bob Spidell bspidell at comcast.net
Sun Mar 15 10:37:20 MDT 2020 

FWIW, I've used manganese-bronze guides--two sets--in my BJ8 for about 
120K miles with nary a problem with the valve train.  For my last 
overhaul, about 6K miles ago, my overhauler/machinist didn't bat an eye 
when I brought the guides to him, and they are a highly-respected 
performance shop.

TBH, I never gave my choice a lot of thought, it just seemed bronze was 
the way to go.  Extensive research--okay, 10 minutes of searching the 
interwebs--yielded a qualitative answer:

"Cast iron cannot be used with stainless steel [valves] because of its 
tendency to gall."  ([] mine)

- https://www.enginebuildermag.com/2013/04/valve-seats-guides/

Again, I never gave it a thought, but went with stainless exhaust valves 
since that seems to be the predominant option.


Bob


On 3/15/2020 8:15 AM, Steven Kingsbury via Healeys wrote:
> Bill,
>    From the research I have been doing, I am finding that what you are 
> saying here is correct. 0.003 seems to be the preferred clearance in 
> the bore for the valve stem. As such I am being torn in a number of 
> ways as to what I'm going to do. As I sit right now, I'm going to 
> order the steel guides as I have already ordered the manganese-bronze 
> ones, and take them to the shop where I'm going to have the work done.
>    My final decision might be a coin toss, but more than likely with 
> all the information, guidance and remarks I have heard here from 
> fellows on the list, the 0.003 bore hasn't caused problems with those 
> using them in cast iron heads. And who knows, maybe they will discover 
> some minor cracks in my head and then I will have no choice but to go 
> with the aluminum head and my worries will be over.
>    Bottom line, I can't thank you and others on this list enough for 
> the education and guidance I'm getting. Confusion or not, this is 
> still a fun experience made all the more so by folks in our community. 
> Thank you all!
> Cheers,
> Steven Kingsbury
>
> On March 14, 2020 at 7:28 PM, WILLIAM B LAWRENCE <ynotink at msn.com> wrote:
>
>> Since the thermal expansion rates of bronze and iron are so different 
>> the bronze guide can be crushed by the iron surrounding it thus 
>> causing the valve stem to stick. The solution is to provide extra 
>> clearance in the guide, which kind of negates the benefit of 
>> replacing the guides in the first place. They do work well in alloy 
>> heads though.
>>
>> Bill Lawrence
>> BN1 #554
>> ------------------------------------------------------------------------
>> *From:* Healeys <healeys-bounces at autox.team.net> on behalf of David P 
>> <frogeye at porterscustom.com>
>> *Sent:* Saturday, March 14, 2020 2:36:26 PM
>> *To:* healeys at autox.team.net <mailto:healeys at autox.team.net> 
>> <healeys at autox.team.net>
>> *Subject:* Re: [Healeys] Four cylinder woes, part two!
>>
>> Steven, this is starting to make us both crazy. You have proved, 
>> nearly conclusively that the rings and valves are sealing. To be sure 
>> of those findings do this. On the offending cylinder rotate the 
>> valves in the guides to ascertain one of the heads isn't bent and 
>> only seals in one particular position. Second bring the piston to 
>> near TDC and push on it to see if it moves laterally more than intact 
>> rings would permit. Compare with the other pistons. This might 
>> indicate a broken or weak ring that doesn't show up under cranking. 
>> Lastly, yes a well worn cam lobe would indicate insufficient time for 
>> cylinder filling. You might also look in the radiator for air bubbles 
>> when cranking---another issue for gasket failure. Healey 4cyl  heads 
>> are notorious for leaking around the cyl bores esp with a solid 
>> copper gasket. There is a gasket outfit in Lubbock TX that can make 
>> individual rings, say 0.002-0.0025" to place over the gasket to 
>> provide extra squish around the bores. PS always check compression 
>> with the throttle wide open. DP
>>
>> On 3/13/2020 5:42 PM, Michael Salter wrote:
>>> Bronze guides...
>>> https://www.netbug.net/blogmichael/2007/05/15/bronze-giudes-in-cast-iron-cylinder-heads/
>>>
>>> On Sat, Mar 14, 2020, 12:17 PM Steven Kingsbury via Healeys, 
>>> <healeys at autox.team.net <mailto:healeys at autox.team.net>> wrote:
>>>
>>>     This is the first I have ever heard about the bronze valve
>>>     guides being crushed. I had always heard they were the better
>>>     ones and they are by far the more expensive. Not that money
>>>     and/or expensive makes something better. I have heard though,
>>>     that they are better, so this is a surprise.
>>>        And yes, I will be checking everything over with a fine tooth
>>>     comb all this weekend. With the amount of carbon I found on the
>>>     valves I am for sure going to be checking the piston rings even
>>>     though the cylinder walls are quite pristine. The reason?
>>>     Finding less than stellar workmanship in the previous work done
>>>     of this engine, I just don't trust that the rings were done
>>>     correctly to begin with and since I'm here, I'm going to check. 
>>>     Peace of mind will be well worth it.
>>>     Steven
>>>
>>>     On March 13, 2020 at 11:47 AM, WILLIAM B LAWRENCE
>>>     <ynotink at msn.com <mailto:ynotink at msn.com>> wrote:
>>>
>>>>     Another consideration is whether you have bronze valve guides
>>>>     in an iron head. These can cause problems due to the different
>>>>     thermal expansion rates of the materials. The iron can crush
>>>>     the bronze and cause the valve to stick.
>>>>
>>>>     Bill Lawrence
>>>>     BN1 #554
>>>>     ------------------------------------------------------------------------
>>>>
>>>>>>
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>>>>>>
>>>>>>
>>>>>>     -- 
>>>>>>     Best wishes
>>>>>>
>>>>>>     John Harper
>>>>>>
>>>>>>     AHC UK 100 Register Secretary
>>>>>

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