Talk:Oldsmobile V8 engine

The bore of the Olds and Caddy were the same, 3.81. The Olds had a stroke of 3.31. This was verified in the owners manual of my fathers 1953 Olds. Your error is a mistake on page 593 of MoToR’s AUTO REPAIR MANUAL, copyright 1950.(13th edition, first printing) — Preceding unsigned comment added by Terry Furman (talk • contribs) 03:49, 7 April 2023 (UTC)

Last Carbureted Engine
I think the claim of the 307 last carburated engine is incorrect. The 1990 Jeep Wrangler with the 258 L-6, and the 1990-1992 Jeep Grand Wagoneers were all carburated.
 * I did some checking around, and can't find any reference to the 1990-1992 Grand Wagoneers even using the 258. I've only checked carpoint.com and alldata's recalls/TSBs list though, so I don't know how comprehensive they are.  Also, this page indicates that the 258 was last used in 1990.  You do seem to be right about the 90 Wrangler, however.  Also, I've come across reference to some Subaru or other using a carburetor in 1990.  Finally, would the Jeeps really be considered "passenger cars"? --King V 17:38, 6 April 2006 (UTC)
 * The SJ Grand Wagoneers didn't use the 258, they used the AMC 360, which I don't think got fuel injection since Mopar intended to dump it once the SJ was gone.--Sable232 03:01, 7 April 2006 (UTC)
 * That sounds about right. Still, I think the paragraph in question should remain unchanged, since it explicitly says "passenger cars", noting the exception of the 1994 Mazda truck, and even separately listing the Ford 351 Police Interceptor (which is closer to being a passenger car, except that the engine was a police-only option). --King V 15:41, 7 April 2006 (UTC)
 * The Isuzu pickup, in 1995, was absolutely the last carbureted vehicle of any kind on the US market. I distinctly remember Motor Trend's "New Truck Issue" in late 1994 stating that fact, but I'll have to dig it out. Also, the Grand Wagoneer only lasted through 1991 - the Grand Cherokee that replaced it was an early '93. Not entirely relevant, but I felt that needed pointing out. Duncan1800 (talk) 07:51, 21 January 2008 (UTC)
 * Well, while, as you say, it's not entirely relevant, it would still be helpful if you can dig it up and then have a note so that this would be a cited reference. Then it would be a good idea to at least change the bit in the article that refers to the Mazda.--King V (talk) 06:23, 28 January 2008 (UTC)

303
The 303 Rocket was also used in the "98" Olds series, 1949 - 1953

307 HO in Cadillacs
The 1990 Cadillac Brougham (maybe other years too), when Armor equipped, came with the high-output (VIN 9) 307. --Sable232 20:21, 15 July 2006 (UTC)
 * I've also heard that bit that says some Caddys came with the 307HO, but never have come across one. By Armor, do you mean armor-plated or otherwise bulletproofed?  If so, that's probably why I've never seen 'em!--King V 00:41, 18 July 2006 (UTC)
 * I'm not quite sure, I found it in some VIN documentation I came across. --Sable232 01:14, 17 September 2006 (UTC)

403 over 425 for arguable the best motor.
I dont think the 425 was arguably the best olds motor ever. actually for horsepower to square inch the 403 oldsmobile if spiced up a little bit will outperform any 425 oldsmobile. http://www.mondellotwister.com/ArtUnsungH.htm read some of this and I think it will change your mind about the 425.
 * This article covers factory production, not modified engines using aftermarket parts. Plus, one can argue one motor being "better" than the other for any number of reasons (hp/ci being but one aspect).  It's irrelevant to this article.--King V 01:54, 6 June 2007 (UTC)

On the face of it, the 403 was an undesirable stopgap engine for production years 1977-1979. GM liked it because the Olds combustion chamber design was efficient and produced acceptably low emissions without the added expense of an air pump. Performance enthusiasts were grieved to see this engine used in late 70's Pontiac Trans Ams and most of them still regard this engine as a downgrade. Most engines have some design or quality flaws and the 403 was no exception. To GM, this was a cheap-to-install high torque engine, but as usual, the quest for low cost came at a long range price: no special effort was made to control core shift in the casting of these blocks and some of them ended up with very thin walls on one side. Because the 4.351 in. bores were siamesed to permit their use in the dimensions of the Olds small block, excessive bore distortion could then occur which adversely affected oil consumption. If such an engine ever ran without sufficient coolant, it was also more than usually prone to blow a head gasket and (because of block distortion)suffer from the classic Olds 403 weakness in the steel shim intake gasket.

Another weakness is the way that this engine was installed by GM. Typically the 403 was equipped qith a/c but only had a three row radiator because it only had to dump heat that corresponded to 185 bhp. This engine was intended for high torque low horsepower applications. To this day, Europeans marvel at a factory horsepwer rating of only 185 from a gigantic (to them) 6.6 liters. Because of its low specific output it is a simple matter to increase the output of the 403, but it will then need at the very least a four row aftermarket radiator to get rid of the extra heat which will then be produced. The next step (for a performance enthusiast)is to remove and carefully store the outdated a/c system, because running the air conditioner will of course increase the load on the cooling system. Part of the reason for the low emissions of the 403 came from its restricive exhaust system and hopping up the engine without correcting this will only worsen the heat problem. The iron exhaust manifolds used on the various versions of the Olds small block made after 1974 were all externally similar and of good capacity. They used a cross-over pipe however which led into the passenger side manifold. This maniflod then had a second pipe which led into a single catalytic converter. These were small diameter pipes (the 403 cross-over was only 2 in. diameter)and the catalyst was an inefficient pellet type. The flow through the exhaust system can be improved significantly by enlarging the pipe junctions, using larger diameter pipes and a three inch matrix type catalytic converter. Fuel economy will be improved due to reduced pumping losses and emissions will be maintained at the designed level if the carburetion and timing remain correct.

As soon as these improvements are made, the limitations of the restrictive 1.5 in. diameter exhaust valves and asthmatic exhaust ports become obvious. The exhaust valves can with advantage be changed to 1.6 in. and the exhaust ports can be enlarged to suit. The massive valve guides that intrude into the exhaust ports can be cleaned up with a hobby grinder as well. To have these changes result in extra power and economy, it is important to maintain mixture at the lean level specified by the factory. Surprisingly little extra power can be got out of a 403 by reshaping the intake ports, but a further small improvement in this engine can be made by using an aluminum intake manifold (this will certainly have the important advantage of reducing the weight) and using a camshaft that has a little extra lift and exhaust duration. —Preceding unsigned comment added by 98.200.10.59 (talk) 18:01, 27 June 2008 (UTC)

Article Clean-up
In a number of sections of this article there is Bold Red Text stating expression error. It makes this article next to impossible to read. I would fix it if I knew how, but I don't. Is there someone out there that knows how to fix this issue so that the article would be easier to comprehend. Thanks Hypernick1980 (talk) 05:45, 18 February 2009 (UTC)

Proposed addition of early Oldsmobile V8 engines
Oldsmobile produced a V8 from 1916 to 1921 but it was a flat head engine, not OHV. Oldsmobile also built the Viking V-8 in 1929 and 1930 - it was a 90 degree, 81 bhp 260 CID V-8. It used a horizontal valve design with triangular type combustion chambers.Toneron2 (talk) 21:30, 28 January 2010 (UTC)

Crossplane crankshaft
I worked in the Lansing Oldsmobile factory in the shop next to the engine plant. I remember these V8s as using a crossplane crankshaft. I have not found a definitive explicit statement that this is correct. My memory could be faulty. The best I can find is "The cross-plane or two-plane crankshaft is the configuration used in most V8 road cars." Can someone point to the definitive answer? Nick Beeson (talk) 21:09, 26 February 2012 (UTC)

Chevy Corvair first or second production car to be turbocharged
Hello! So I noticed that this article says that the Chevy Corvair is the first production car to be turbocharged, however the actual article on the Chevy Corvair says the it's the second with the Oldsmobile Turbofire being the first. So which is it? The first or second? ― Blaze WolfTalkBlaze Wolf#6545 02:51, 18 March 2022 (UTC)