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Oil release valve plunger stuck

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Michael Oritt

Michael Oritt

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Further to my post of a few days ago about low oil pressure I pulled the bottom end apart and will be replacing rod and main bearings. I removed the oil release valve cap nut and spring but cannot get the valve itself--the plunger--out. I had a small magnet probe that seemed to go all the way into the plunger's recess but it would not extract the part.

Is there some trick here? I had it out a number of years ago and do not remember encountering any problem. I could probably pass a tap into it from the side and engage the inside of the plunger so I could extract it but there must be some better way. Suggestions/experience appreciated.
 
Dave Russell described using a dowel to fit the inside diameter of the plunger to properly seat it after lapping. Perhaps the dowel-technique could work to help extract the plunger. I like your alternate tapping method as well. Maybe a strategically placed blast 60 psi compressed air - with catcher's mitt? That'll get it. GONZO
 
Gonzo--

Thanks for the input. The top end of the engine is still together so I suppose if I put on an oil filter and blow air into the oil line running from the oil pump to the block that will exert pressure against the plunger.

I think Dave's suggestion of a wooden dowel is better than my idea of a tap--no metal shards! I often think of Dave--his knowledge was encyclopedic and his approach very no-nonsense.
 
On A-series engines it is not uncommon to use a tap to extract the plunger. Find a tap that will just barely catch the inside diameter of the plunger. Get the tap started then pull it out with the plunger attached.
 
A large fluted EZ Out would do the same. Since they are tapered it might not fit into the bore far enough before it it too fat.
 
The ID of an original plunger is .500". If you can't get it to budge with the dowel method, a 1/4" NPT tap will just start to engage and grip the end of the plunger.
 
roscoe said:
A large fluted EZ Out would do the same. Since they are tapered it might not fit into the bore far enough before it it too fat.
Click to expand...
The problem with EZ-outs__misnomer of a name if there ever was one__is that by driving them in, outward pressure one the piece to be removed (be it a bolt/stud fragment or valve plunger) is increased against the bore that it's stuck in. Just the opposite of what you need.

I like the dowel method, and would've mentioned it myself if Gonzo hadn't beaten me to it. The wood will compress into the plunger long before it can influence the outside diameter. The dowel is most useful when seating a new plunger with a spot of fine valve-grinding paste to the existing seat. Use up the better amount of a can of brake-parts or carb cleaner to flush it out afterwards.

So what did the shells look like, or did I miss that post?

PS: I miss Dave too; encyclopedic knowledge indeed!
 
I am going to try compressed air up through the hole where the oil pipe goes into the block and if no luck will proceed to the dowel. More news as it develops.

The shells look very good.
 
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Buy a can of freeze spray, freeze it and it should shrink slightly and come right out.
 
A 1/2"-13 bottom tap would not get started but I found a 1/2"-13 taper tap that sufficiently engaged the inside of the plunger and allowed me to pull it out. The plunger looks okay.

I was able to find online specifications for the release valve spring for six-cylinder cars at austin-healey.com (A=2.7 litre cars and B=3.0 cars):

Release valve spring length:
A 2.562 (65.09 mm)
B 2.687 (68.26 mm)
Number of coils:
A and B 13
Diameter:
A and B .484 +.000 -.015
(12.30 mm +.000 mm -.318 mm)

but nothing for 100's and since there is an oil return passageway on the 6's that is not on the 4's I don't consider those dimensions relevant. My spring measured 2-15/16" long with 18 coils so it is a different animal altogether. It will be interesting to see if there is a noticeable difference in spring pressure between this one and its replacement.

I'm still working on getting the bottom end apart--the front and rear main caps are not being cooperative but I am patient.
 
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