Talk:V18 engine

Clarifications needed

Thanks BMRR for your efforts in finding these two examples of "big iron". I don't think we're quite done yet, not at least to Featured Article status. Some thoughts:

• Comparison to the W18 engines. For that matter that other classic 18 cylinder engine too, the Deltic.

• Explanation that a "classic" V18 would be two banks of inline 9 cylinder engines. Is this what we're looking at here?

• The V18 engine considered as three V6 modules coupled end-to-end. Is this what the Cummins engine represents?

• The Cummins engine? What's the bank angle, the crank angles and the firing order? Are these V6 based, or a true V18 designed from scratch? I'm assuming that both engines are two-stroke diesels, as most big diesels like this are.

• The Alco engine? What's this doing in a family that seems based more around inline 6s and thus V12s. How did they make a V16 from that? How did they get a V18? Again, what were the angles.

Thanks again for turning up these leads. Andy Dingley (talk) 17:34, 26 June 2011 (UTC)

Hi Andy, I'm working on finding answers to your other questions, but in the meantime, here's what I've been able to find thus far about the QSK78: according to the PDF brochure, it's a 60-degree vee. Strangely the brochure doesn't say whether it's a two-stroke or a four-stroke; however, this site says that it's based on the V16 QSK60, which is a four-stroke engine according to the QSK60 brochure. (The ALCO 251 series is four-stroke as well.)

In the case of both the QSK60 and the 16-251, is it possible that they took those existing V16 designs and simply added two cylinders to create the QSK78 and 18-251? (I know very little about engine design/development, so forgive me if that's a stupid question!) Thanks, BMRR (talk) 18:20, 26 June 2011 (UTC)

Thanks for removing the AfD template. I was halfway through closing it when my router died on me. Took me a few hours to get the spare one up and on-line again.

I've read the Cummins PDFs. 60 degrees is no surprise, but it raises the interesting question of how the crankshaft is laid out. I'm guessing the engine is basically balanced as if it was thre V6s in series. More interesting is the Alco engine - I just can't think how you take a V16 (a famously well-behaved layout) and then graft another pair of cylinders onto it, without it all going pear-shaped. Andy Dingley (talk) 23:08, 26 June 2011 (UTC)

I've been trying to find out what the V angle for the 18-251 is, but am not having any luck. The manufacturer won't say, citing confidentiality and legal issues. (Weird, since other manufacturers such as Cummins don't seem to mind having V angles published on their web sites...) In the process, I've discovered that FM makes several other big (and I do mean big!) V18s:

• Colt-Pielstick PA6B STC
• Colt-Pielstick PC2 DF
• Colt-Pielstick PC2.5 STC
• Colt-Pielstick PC2.6B
• Colt-Pielstick PC4.2B
• FM-MAN 32/40 DF
• FM-MAN 48/60B

–BMRR (talk) 19:39, 2 September 2011 (UTC)

Andy, sorry for the long delay in responding to your comments. I've had a death in the family. First, in response to comments above. The Cummins V-18 is a 4 stroke. I've worked around Cummins diesels all my life, and have an extensive historical library. To my knowledge, no Cummins ever made is or was a 2 stroke. As to the ALCO, I don't have the V-angle at the moment, but am waiting on some responses from railroad buffs. However, I did run across some Fairbanks-Morse info for MAN and other engine series. These are available in V-10,12,14,16,18 and 20 and seem to share a common V-angle within families. The MAN advertises a 52° degree angle. The others I'm not sure, but I obtained some cross section drawings which I can load up in Autocad to measure the V angles once my life gets back on track. I'm not sure how these engines deal with balance issues, but they are massively constructed and low speed, so maybe the balance thing isn't that much of a problem? I'll provide more comprehensive edits later. — Preceding unsigned comment added by 74.34.114.78 (talk) 04:17, 6 September 2011 (UTC)

If the 18-251 shares the same V angle as the other 251-series V engines — and my suspicion is that it does — then it would be a 45 degree V. –BMRR (talk) 16:03, 6 September 2011 (UTC) P.S. Very sorry to hear about the death in your family.