Talk:Cam-in-block

Untitled

How about some pictures? —Preceding unsigned comment added by 70.185.250.195 (talk • contribs) 03:37, October 1, 2006

Removed

Remove the following (speculative and subjective without references):

• Simplicity
  • By their nature OHC engines tend to be more complex than pushrod engines, particularly considering that an OHC V6 or V8 can have four camshafts. This adds cost, mass and increases the number of moving parts.
• Slight power advantages
  • In any belt-driven OHC engine there is a residual loss of power through the belts that rotate the camshafts, a loss that would not happen in a pushrod engine.

Cam-in-block, or "Pushrod" engines as they are more commonly known, have become fairly obsolete, having been replaced by most mainstream automotive manufacturers.

Removed the following (speculative and subjective without references):

• Low-end torque
  • Generally speaking, OHV engines are tuned to begin making power much sooner than their higher-revving OHC counterparts, to maximize the shorter overall powerband (see limitations, below). In combination with the ability to increase displacement while keeping the overall packaging compact, this can be and often is exploited for fuel efficiency, when mated to a transmission with a tall cruising gear; the extra torque keeps the engine responsive at low RPMs.

The production of torque has nothing to do with the type of valve actuation system used. IJB TA 15:11, 25 July 2006 (UTC)

Modified. See http://www.thecarconnection.com/Auto_News/Techno_Beat/In_Defense_of_Pushrods.S198.A7178.html for reference.

Again, the production of torque has nothing to do with the type of valve actuation system used. OHC engines can just as easily be made to produce large amounts of torque at low rpm, so this is not really an advantage specific to OHV engines. IJB TA 20:13, 30 July 2006 (UTC)

OHC torque: Consider Ford truck engines. IJB TA 18:48, 31 July 2006 (UTC)

Removed:

• Hydraulic valve lifters are easilly acommodated, with presurised oil readilly available from the gallery used to lubricate the crankshaft.
• For solid valve lifters, manual adjustment is easilly provided at the rocker arms where the pushrods are seated.

HLA systems were problematic in early OHC engines but this is no longer true, many OHC engines currently use HLA systems without problems. For many mechanical OHC systems the adjustment is provided on the rocker and is easily accessed simply by removing the head / valve cover. IJB TA 21:20, 4 October 2006 (UTC)

Does Not Reflect Industry Vernacular

I was surprised to find Flathead engine redirecting to Cam-in-block. I've dealt with engines for many years, and the term "Cam-in-block" has never been used.

If there are no objections, I intend to incorporate any good points of this article into the Flathead and other articles, and nominate this page for deletion. In the meantime, I will fix the redirects. --Alex 06:56, 29 July 2006 (UTC)

What would be the reason for doing this? Searching for any of the "cam-in-block" configurations will bring up the correct article. Also breaking all of the configurations up into individual articles will likely result in stub articles. IJB TA 23:58, 29 July 2006 (UTC)

The flathead, pushrod and similar articles all had well developed content before they were turned into redirects. Those redirects have simply been reverted. --Alex 12:14, 30 July 2006 (UTC)

I see. No objections here. IJB TA 20:30, 30 July 2006 (UTC)

I was the user who merged the articles and made pushrod, flathead engine, OHV, etc. redirects to this page. I originally posed a question at Wikipedia:WikiProject_Automobiles as to whether it would be worthwhile merging these articles, as I for one found the information contained within often repeated across these articles, and many of them were grossly inaccurate. Pushrod engine for instance discusses OHV engines, to the expressed exclusions of, say, engines with flat heads. Both are pushrod engines. And all OHC engines are, by definition, OHV engines too.

The goal was to create one, comprehensive article that discussed all engines with camshafts located within the block, thus trimming the fat out of the smaller articles and making it easier for the reader to find the information they want without having to search through five smaller articles most of which say roughly the same thing anyway.

I chose "Cam-in-block" as the title because, contrary to your assertions, it is industry jargon used to describe all engines with camshafts in the block. A quick google search will reveal that soon enough: the first couple links are wikipedia and the mirror at answers.com, but the rest are for the most part industry sites (notably GM and Chrysler sites). --93JC 17:53, 11 August 2006 (UTC)

Flathead engines are definitely not pushrod engines. The lifter.adjuster bears on the bottom of the valve stem. A pushrod goes between lifter and rocker arm in an ohv engine. There is no rocker arm (tappet) or pushrod in a sidevalve.

Cam in block is not that common a term. Never heard of "I-head". Side valves and overhead valves are quite different, while F-heads, or Inlet over exhaust engines are a combination of the two. "Valve Configurations" is what I was searching for to get here. If someone wants to merge this with pushrods, they would have to remove side valves (L heads).Seasalt 13:06, 11 October 2006 (UTC)

Cam-in-block may be used rarely to describe these configurations but it is accurate. I-head is another rarely used term but it is also accurate. Really cam-in-block and I-head are just not the common household terms, but they are the accurate industry terms. My only concern with these articles on the cam-in-block configurations now that they have been separated is that they are titled by the common household names and not the accurate industry names, Flathead instead of L-head, Pushrod engine instead of I-head, though F-head is titled correctly. Also, I guess I do have an objection to merging cam-in-block with pushrod engine. To me it would seem best for this article to have simple descriptions of each of the cam-in-block configurations with links to the full article for each one, then to have those articles titled correctly and expanded. Then to simply have redirects on inquiries for pushrod engine to go to I-head, or flat head to go to L-head. Anyone else think this might work? IJB TA 04:07, 12 October 2006 (UTC)

Whether they are "accurate" or not, they are not exclusively "correct" either. I would leave it alone, and allow the Cam-in-Block to be merged with pushrod or Overhead Valve without flathead. Seasalt 08:06, 12 October 2006 (UTC)

The names could stay as they are if that's what everyone here prefers. I just think that Cam-in-block should remain a separate article, there's no reason it needs to be merged. It works just fine as a description of engines that have the cam in the block. Although if it does remain a separate article I still think it should have simplified descriptions for each configuration. IJB TA 21:12, 15 October 2006 (UTC)

Generalized joint article is OK, but I disagree that redirection should point from partial term to the general (sidevalve to Cam-in-block for instance). Redirection I understand as a synonymic link, so sidevalve should be redirected to flat head engine article, where link to generalized article Cam-in-block could be found (under See also section). As I understand, sidevalve and flat head engine are the same, where Cam-in-block is joint term, including additional terms of OHV and F-head, which are not sidevalve configuration. Mingis. —Preceding unsigned comment added by 193.219.59.93 (talk) 12:52, 10 December 2008 (UTC)

L-head, F-head, and I-head? No T-head?

This article uses the term "L-head" to mean "side valve (SV)", "F-head" to mean "inlet-over-exhaust (IOE)", and "I-head" to mean "overhead valve (OHV)". I have heard both terms used for each application, but I keep thinking that the "valve" designations are more descriptive than the "letter-head" designations.

This is especially so for side-valve engines, as not all of these were "L-head" engines. High-performance side-valve applications, before OHV and OHC took over, often used the crossflow "T-head" system with two camshafts, one on either side of the block, opening valves on either side of the head. Daimler AG used this system in the first Mercedes, the 1901 "Week of Nice" cars, other sports or racing cars of the era used this as well.

Cars are still being manufactured with "I-heads", most notably by General Motors using their development of the small-block Chevrolet engine. No-one calls them "I-heads", though; they are invariably referred to as OHV.

I must be old now, because I remember when OHV meant pushrod OHV because "cam-in-block" was the norm, with the term OHC meant that the engine had an overhead camshaft because that wasn't the norm. I guess "cam-in-block" came into use because there are no automotive, motorcycle, or heavy vehicle engines with side valves anymore so the old OHV/OHC/DOHC designations don't make sense any more.

Sincerely, SamBlob (talk) 16:41, 11 January 2011 (UTC)

Wot?

I realise that this article attempts to gather together the various types of non-OHC engines, but the opening sentence is at odds with the title, since the camshaft is very often not located in a traditional cylinder block. Very many of the examples given do not in fact demonstrate this idea of cam-in-block.

There is obviously a case for differentiating between a 'cylinder block' bolted to a separate crankcase, and a monobloc 'engine block'. See Talk:Monobloc engine, where I am in agreement with @Andy Dingley: (courtesy ping) whose original article made things clear. I tend to reject the notion that cylinders cast integrally with the top half of the crankcase (monobloc) constitute 'the cylinder block', especially where the camshaft is located below the cylinders in a non-OHC arrangement.

If the definition of a cam-in-block design is that the cam is in the cylinder block, and an L-head is given as an example, why does the picture of the Ricardo L-head engine show the camshaft... located in the crankcase, to which the cylinders are obviously bolted?

The term cam-in-block certainly applies to monobloc engines with the cylinders cast integrally with the top half of the crankcase, eg the ingenious Ford flathead V8 engine#Camshaft and timing where it "has a single camshaft located inside the engine block above the crankshaft." Similarly, the camshafts of the Zündapp 9-092 twin-cam OHV engine are technically within in the 'engine block' of similar monobloc design, such as the straight-8 Buick shown here.

The camshaft arrangements of F-head or IOE engines vary - the pic of the Yale engine very clearly shows the exhaust valve pushrod poking out of the crankcase: on the other hand, in the complex Rover P4 engine the camshaft is indeed integral with the cylinder block, as shown here. Other F-head arrangements are shown here, with the camshaft below with the cylinder block and not not integral with it.

However, I suggest that these are the only type of engines which meet the definition of cam-in-block, since most of the other examples refer to much older designs with separate cylinder blocks with the camshaft in the crankcase.

The picture showing the principle of a T-head engine also shows (in my opinion) the camshaft located beneath the cylinders, apparently in the crankcase (although the entire engine seems to be cast in one piece...) The File:Rose car engine.jpg also in the T-head article, shows very clearly the one-piece heads and cylinders firmly bolted to the crankcase, with the external pushrods sticking out, driven by the camshaft... in the crankcase.

As to the I-head or OHV engine: especially in countless older motorcycle engines, eg the BSA 650 OHV pictured here, the cylinders are bolted to the crankcase, with the camshaft located firmly... within the crankcase, geared directly to the crankshaft.

I would tend to suggest that these other non-relevant sections be returned to their individual article status. Furthermore, there is not a single reference in the whole article, and I have tagged it. MinorProphet (talk) 00:25, 13 June 2021 (UTC)