Talk:IOE engine

Capital letters for the acronym in the title, please. 21:17, April 18, 2007 —Preceding unsigned comment added by 87.254.64.18 (talk • contribs)

Should IOE and F-head articles be merged?
I agree that the IOE engine and F-Head Engine articles overlap. There are two types of F-head valve layout, IOE and EOI. EOI (exhaust over inlet) was less common, but it was used by Indian and Martinsyde in the 1920's and Motosacoche in the 1930's. At present Wikipedia seems to have no article explaining the EOI engine.

I suggest two options:

1. Merge the IOE engine and F-Head Engine articles as F-Head Engine and add a section describing the EOI layout.

2. Merge the articles under IOE engine and create a new and separate EOI engine article.

One deciding factor may be how widely understood each term is in different countries. "IOE" and "EOI" are used and understood in Great Britain, and the substantial IOE Wikipedia articles in german and italian suggest that this term is used in Germany and Italy too. F-head is used in the United States. The Wikipedia stub-article in swedish shows that the equivalent term F-topp is one of the terms used in Sweden, but I do not know whether this is understood widely in the Swedish historic vehicle movement or confined to people involved with engines from the USA.

My preference would be for option 2.: create separate IOE engine and EOI engine articles. This would allow each article to trace a timeline of the development and use of its respective subject, and include adequate detail, without either article becoming too long. The EOI engine article could probably list all manufacturers that used the layout and still remain compact.

Have you a preference? If so, please say which and why!

Motacilla (talk) 21:42, 5 October 2008 (UTC)


 * I'd support a merge, under your suggested option #1 Andy Dingley (talk) 18:32, 14 October 2008 (UTC)
 * I'd support a merge, under option #1. TomRawlinson (talk) 20:31, 24 October 2008 (UTC)


 * I'm looking at the use of "pocket" valve and wondering whether this should be "poppet" valve. The image appears to show a spring-loaded poppet intake valve (no obvious link to the cam), as was used on the Glenn Curtiss V-8 used to set his famous speed record.  The IOE with a poppet intake is really a distinct type of engine, I think, so I'd rather not see it merged.Kbk (talk) 05:41, 6 December 2010 (UTC)


 * Which use of "pocket valve"?, because it's a genuine term (albeit archaic and obscure) and I'm tired of fixing "spelling corrections" on WP that are nothing of the sort.
 * IOE engine is a poor article, because it omits most of the variants of it, all of the early variants, and nearly all of the technical aspects of this arrangement. To be any use at all it needs to recognise this broader and uncovered scope and stop describing it as if it was a motorcycle engine alone. Andy Dingley (talk) 11:17, 6 December 2010 (UTC)
 * No, as I understood it from the article this is a separate term and should be spelled as is -- it's because it's located in a "pocket" off to the side of the cylinder. (Or part of the cylinder off to the side of the piston.)
 * Could of course be because the article has been improved since this dozen-year-old comment I'm replying to ;-) -- haven't checked the history. CRConrad (talk) 10:57, 24 May 2022 (UTC)

Maintenance tags
I notice that the "unreferenced section" tags were removed under the claim that they were "repetitive" and "not doing anything to make a better article". I disagree. They indicate which sections have no references at all, such that they should be referenced if references are found, and may be deleted if they are not. Sincerely, SamBlob (talk) 20:10, 4 August 2011 (UTC)
 * See WP:OVERTAGGING: "It is very rare that more than two or three tags are needed, even on the worst articles. Adding more tags usually results in all of them being ignored."A single tag at the top tells you the article contains unreferenced sections and/or facts. Individual Citation needed tags point to specific areas where more refs are called for. Adding section tags on top of that? Redundant. It isn't as if the more you tag it the more likely somebody is going to come along and fix it.The alternative is to say that for every cn, you need a Refimprove at the top of the section, and then another Refimprove at the top of the article. Three maintenance tags for one missing fact. Absurd.All you really need are Citation needed tags; anything beyond that is histrionics, and as the essay says, they're likely to have the opposite effect and be ignored. --Dennis Bratland (talk) 21:43, 4 August 2011 (UTC)

Citation task list
Lead: The term "pocket valve" is cited... and also mentioned nowhere in the main body. It would probably be best to mention the alternate names somewhere in the body of the article, this may be done before or at the same time as the writing of a proper lead that summarizes the article.
 * Done. No citation is given for the term "F-head" at present, but the citation for "pocket valve" includes it and can be copied to suit, and other sources for the term can be used as well. Sincerely, SamBlob (talk) 13:35, 10 January 2013 (UTC)
 * The cited source uses both F-head and IOE terminology and can be used to source both terms. Sincerely, SamBlob (talk) 13:40, 10 January 2013 (UTC)

Description section: Uncited, although sources stated in the citations in the lead and the "Origins" section might be used to verify this section.
 * Only one uncited sentence left. The term "pocket valve" is mentioned and cited in this section. Sincerely, SamBlob (talk) 13:35, 10 January 2013 (UTC)

Origin section: Apparently fully cited.

Advantages section: Uncited.
 * Partially cited; can anyone verify the advantages still uncited? Should they be removed? Sincerely, SamBlob (talk) 13:35, 10 January 2013 (UTC)

Rover IOE engines: First two paragraphs, which contain all the technical details about the combustion chamber, are uncited. Paragraph about similar combustion chamber being used by sidevalve Packard V12 cited. Last paragraph, about the applications of the Rover IOE engine, seems to be partially cited.
 * More citations for first paragraph found (in addition to the citation that was overlooked in this assessment), but the parts about the squish and the thin gas layer are still uncited. Apart from the last sentence, the second paragraph is still uncited. The paragraph about the Packard V-12 has been moved to a subsection at the end of the section. No new citations have been found for the paragraph about the applications of the Rover IOE engine. Sincerely, SamBlob (talk) 13:35, 10 January 2013 (UTC)

Other users section: "Motorcycles" part almost fully cited, with the exception of the last sentence, which shouldn't be too difficult to source. The first paragraph in the "Automobiles" part is fully cited. The first part of the second paragraph, about the Rolls-Royce Wraith and Silver Wraith engines, is also cited, but the part about the Vanden Plas Princess 4-Litre R engine is uncited.
 * Mention of the Rolls-Royce Wraith has been removed based on sources indicating that the Wraith had an overhead valve engine; one of these sources is cited as it has information on the IOE Silver Wraith. Apart from the initial source (which claimed that the Wraith engine was IOE), no source has been found claiming that the Silver Wraith engine was a B60. Sources have been found claiming that the B60 and B40 engines were used in military vehicles, and that the Princess 4-Litre R's FB60 engine was the only passenger car development of these engines. I will therefore not cite the passage as it is, preferring to rewrite the passage according to whatever sources I might find. Sincerely, SamBlob (talk) 13:35, 10 January 2013 (UTC)

Exhaust over intake (EOI) section: Fully cited.

Sincerely, SamBlob (talk) 00:05, 3 January 2013 (UTC)


 * One major ref is missing, which would be Ricardo. He goes into quite some detail on the virtues of IOE, particularly in reference to the Rover. It's significant because it's in 1954 (considered "late" for a comment on such a "primitive" design) and he also describes it as "a form of combustion chamber as near to the ideal as any yet developed", quite the contrary to the crude and obsolete view usually held of it. Ricardo also makes similar comments about sidevalves in general, at least after his turbulent head, and being Ricardo he's right about it – at least for the pre-1960s fuel chemistry of the day. Andy Dingley (talk) 01:34, 3 January 2013 (UTC)


 * Yes, I did overlook that one. Sorry about that. It is still there. Sincerely, SamBlob (talk) 13:35, 10 January 2013 (UTC)

Insistence on dead ends
Pool petrol redirects to Rationing in the United Kingdom; pool petrol is not mentioned anywhere in that article, let alone the section of the article to which the link redirects. The article Squish (piston engine) does not exist. I had removed these dead-end links, but they have returned. What purpose do these links have, other than to frustrate readers trying to find out more about the concepts only to find dead ends? Sincerely, SamBlob (talk) 03:19, 3 January 2013 (UTC)


 * Please read WP:REDLINK
 * If you have a problem with either the target of the redirect from pool petrol, or the content of the article in that link target, then the place to fix it is at that article, not by removing the link from here. Andy Dingley (talk) 03:35, 3 January 2013 (UTC)

Hemi-head and title of the page.
I don't understand how the Rover IOE engine can in any way, shape or form be called a "hemi-head" engine. The name "hemi" comes from being hemispherical, and the combustion chamber in the photograph does not look like a hemisphere, no matter how you "tip and invert" it. A hemi-head is so shaped to place the valves on opposite sides of the cylinder, and at a wider angle of valve separation than a typical OHV head. An IOE engine should have almost 180deg of valve separation inherently, as one valve opens up, and the other opens down. Perhaps this cylinder head is well shaped, but it's more like a poly-head or wedge head than a hemi-head.

Also, shouldn't "Intake-over-exhaust engine" be written out in the title, instead of "IOE engine"? That seems too informal and relaxed somehow. That's why we have an article on "Overhead valve engine" and only redirects from OHV engine..45Colt 15:42, 11 July 2015 (UTC)


 * A hemi head, if it has any meaning for combustion chamber design (and flamefront propagation rather than gasflow through the ports) is about an approximately isotropic path length from a central ignition source. For OHV engines this needs a central plug and valves on opposite sides (the "hemi head" you describe). With the Rover IOE layout, including the slanted cylinder head plane and the angled piston tops, it's another way to arrange a central plug and good flame propagation. In that sense it's a hemi head.
 * As the shape goes, it's not even that far from hemispherical. Placed asymmetrically and at an angle, but the shape is still approximately such. Andy Dingley (talk) 20:38, 11 July 2015 (UTC)