Joined: Sep 2018 Posts: 126 Threads: 37
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0
Location: cambridgeshire
Joined: Aug 2017 Posts: 1,257 Threads: 32
Reputation:
28
Location: Cheshire
Car type: Race Ulster, 1926 Special, 1927 Chummy, 1930 Box
If it ain’t broke don’t fix it.
Alan Fairless
Joined: Aug 2017 Posts: 2,748 Threads: 31
Reputation:
95
Location: Auckland, NZ
Looks like corrosion from long standing. Hopefully not rust coming through.
I have heard many stories of long stored engines with corroded bores running quite satisfactorily.
Although it may complicate oil consumption engines can run with surprising little power loss despite considerable wear.
Until recent times .007 taper was considered acceptable for large engines and many ran with .010 or so. Now books recommend rebore at a mere .003 taper!
Joined: Aug 2017 Posts: 405 Threads: 18
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2
As you are wishing to improve performance, if it was me I would get the engine out and make a general assessment including bottom end etc. This might be preferable to a piecemeal approach.
Nice looking head.
Charles
Joined: Aug 2017 Posts: 520 Threads: 82
Reputation:
7
Location: Deepest darkest Kent
+2
If it doesn't use much oil and you have good compressions then leave well alone.
Joined: Aug 2017 Posts: 3,215 Threads: 100
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26
Location: Darkest Bedfordshire
19-11-2019, 08:40 PM
(This post was last modified: 19-11-2019, 08:41 PM by Chris KC.)
One thing it does need is a quick decoke. As for the rest, it's more a matter of what you can feel (or measure) than what you can see.
Joined: Aug 2017 Posts: 772 Threads: 26
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Location: On a hill in Wiltshire
I am running an engine with bores a lot worse than that, quite deeply pitted in places.
It starts easily on the handle, runs ok. Probably uses oil, but I don't do enough miles in that car to notice.
Joined: Aug 2017 Posts: 3,247 Threads: 360
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Car type:
My '29 had a Ricardo on for a while and the engine was probably similar. i.e. long unused and no knowledge of other than things being "well checked over". It ran beautifully with it on but even with the lowest CR version possible, it is still going to increase pressures throughout the engine, so just monitor...
Are you using the Ricardo head gasket, or one of the standard?
Joined: Aug 2017 Posts: 176 Threads: 11
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Location: Upton upon Seven
Car type: 1931 RN, 1933 RP
One of my engines has marks and indentations in it’s bores like that.
It has had the bores honed and new rings fitted. The marks are just the same.
Compressions are good and no smoke or excessive use of oil.
Engine works well.
Roly
1931 RN, 1933 APD
