[Healeys] Ring Choice - closing the loop

[m.g.sharp at sympatico.ca]

Thanks Charlie, I have a BT7, and already have bought a rear main oil seal conversion kit, but thanks for the offer.

 

Mirek

 

From: Charles Schott <schottc at knology.net> 
Sent: April 19, 2021 9:07 AM
To: m g sharp <m.g.sharp at sympatico.ca>
Cc: healeys at autox.team.net
Subject: Re: [Healeys] Ring Choice - closing the loop

 

Mirek,

 

You might be too far along for this, but if you're doing a 100-4 engine I have a new single lip seal conversion kit for the rear of the engine. It requires machining of the crankshaft and the engine block. Also, you can buy a timing chain cover that has been modified to take a single lip seal.

 

Regards,

 

Charlie 

 

  _____  

From: "m.g.sharp--- via Healeys" <healeys at autox.team.net <mailto:healeys at autox.team.net> >
To: healeys at autox.team.net <mailto:healeys at autox.team.net> 
Sent: Monday, April 19, 2021 7:14:19 AM
Subject: [Healeys] Ring Choice - closing the loop

 

Many thanks to everyone who responded to my question about the rings.  Seems that there are examples of people fitting that fifth ring and leaving it off, and no-one reported a problem or bad experience either way.  It also seems there is no hard knowledge on why that bottom ring was fitted, but several of us, me included, think it may have been aesthetic: simply to reduce the noise from piston slap.  I thought Earl’s response was most telling in that he had been through a complete engine cycle (i.e. he is on his second rebuild after 140,000 miles on the first) with a 5-ring piston and there were no issues noted on the strip-down and good performance.

 

While I have no doubt that extra ring may result in extra friction and rob the engine of a horsepower or two, no-one has measured it, so we do not know if that is significant in any way.  The only other potential down-side is that the bottom ring will scrape the oil from the cylinder wall on the down-stroke, reducing lubrication on any piston-cylinder wall contact between the two oil control rings.  However, the bottom ring may also prevent the piston from making contact with wall, or at least reduce the friction, so maybe that is not an issue.

 

My goal is a well-built, reliable, original car with factory-level performance.  Given that, and some concerns about the unknown consequences of an empty ring groove, I am electing to install the 5th ring.  Also, I think there is wisdom in Hank’s comment that as a general rule parts should be installed as the manufacturer intended – who are we to second guess the engineers who thought it necessary to add that ring?

 

Interesting discussion, and if anyone ever turns up hard engineering evidence as to why that extra ring was added, I would be very happy if they would share it.

 

As always, this list is amazing for providing a forum for providing a forum for discussion on the things we find interesting – as arcane they may be!

 

With thanks, Mirek


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