Has there ever been a production OHC sub-four cylinder engine with a timing chain?
I don't have an answer. I'm fishing for examples.
On-road mental wandering had me thinking that maybe the reason Ford went to a timing belt for the 1-liter is because the coarse camshaft pulses and crankshaft harmonics made using a chain difficult.
Counter example is V6 have even firing banks so the cam pulley loadings would be just as coarse, but they at least have a much smoother crankshaft rotation.
The odd-fire PRV V-6 used chains, so I don't think crank pulse regularity is an issue.
Usually belts are used to keep things quiet. Beyond that, you're either replacing a cheap component frequently, or an expensive component infrequently. Relatively speaking.
The BMW K75 motorcycles had DOHC triples with chain driven cams. IIRC they also had a crank driven balancer shaft.
For that matter, I'm fairly certain that all the Yamaha and Triumph triples are also DOHC with chain driven cams.
In reply to 11110000:
Timing belt replacements now are upward of 120-130k miles, so not that often! Much new development involves belt design that can be enclosed in the engine and survive the oil bath. OHC/DOHC timing chains often last the life of the engine, and are often not designed for easy renewal as a result. Nissan KA24E and 1st gen KA24DE had a timing-cover mounted oil pump, with a strainer support bracket bolted to the crank girdle, that required removal of the oil pan to change the pump or timing chain. 2nd Gen KA24DE deleted the bracket to make the change easier, but I also think they went to a lighter chain that may not be as durable.
Pretty sure the rotax 3cyl engines in seadoos and ski-doos use chains. (600-1500cc) n/a and supercharged.
HappyAndy wrote: The BMW K75 motorcycles had DOHC triples with chain driven cams. IIRC they also had a crank driven balancer shaft. For that matter, I'm fairly certain that all the Yamaha and Triumph triples are also DOHC with chain driven cams.
Huh. All righty then.
I could further postulate that the shorter deck heights of motorcycle engines might make using them to be more acceptable... but your post got me to thinking some more. BMW uses chains in pretty much everything designed after the 70s, and they have a new 3-cylinder engine...
Nope, looks like there's a timing belt sitting there on the crank end of the engine..
11110000 wrote: The odd-fire PRV V-6 used chains, so I don't think crank pulse regularity is an issue.
Pointless trivia- The reason the PRV was an odd fire 90*V6 is because it was designed as a V8, then shortened during developement because of the energy crisis in the 70's.
I hope this worthless fact doesn't kick an important date out of your memory.
Knurled wrote: Nope, looks like there's a timing belt sitting there on the crank end of the engine..
You sure? I feel like I'm looking at chain and guide...
Not cars, bur most Honda 4-stroke motorcycles used chains.
I've has singles, twins, and 4 cylinders with chains.
Not less than 4 cylinders, but using chains or over 100K on timing belt:
The 1.8L in my Elantra also has a chain.
The 2.5 in the 2003 Forester I used to own had the change interval at 105k miles.
ransom wrote:Knurled wrote: Nope, looks like there's a timing belt sitting there on the crank end of the engine..You sure? I feel like I'm looking at chain and guide...
Yup. I see a chain too - and that's the flywheel side of the engine... I sure hope those puppies don't have tensioner or guide issues... (on a BMW? Ha!!!) ...as those will be hell to R&R...
Berk timing chains. I'll take a belt every berking time... at least belts are designed to be service items. Chains rarely are.
Ian F wrote:ransom wrote:Yup. I see a chain too - and that's the flywheel side of the engine... I sure hope those puppies don't have tensioner or guide issues... (on a BMW? Ha!!!) ...as those will be hell to R&R... Berk timing chains. I'll take a belt every berking time... at least belts are designed to be service items. Chains rarely are.Knurled wrote: Nope, looks like there's a timing belt sitting there on the crank end of the engine..You sure? I feel like I'm looking at chain and guide...
Well, here's the link where I found that: http://www.bimmertoday.de/2012/09/18/bmw-dreizylinder-motoren-2013-technik-details-benziner-diesel-lopez-interview/ (Haben Sie Deutsch?)
And the direct image link to the (HUGE) fullsize copy is here: Big picture!
And... yeah, on closer inspection and playing with contrast, it might be a wide, flat chain, but it's damned hard to tell. And if those a guides, why are they not curved to prevent chain whip?
Chain vs. belt is an old discussion and people rarely change sides. I'm merely curious on the feasability of a "coarse" engine like a three (or a two or a one!) with a looooong OHC timing chain. If that's a chain, I wonder if being that close to the big ol' damper mass known as a flywheel (no doubt a dual-mass unit as well) would help things.
wbjones wrote: the Integra has a belt, but the RSX comes with a chain as does the CRV
sigh And those are all four cylinders. I'm only curious about engines with less than four.
My Saturn LS200 with the Gm 4 cylinder has a timing chain to run the hardware up top. I was going to have the chain replaced at 160,000 kms. I got a recall notice at 158,000 kms where they replaced the timing chain for free. TRUE STORY.
Knurled wrote: And the direct image link to the (HUGE) fullsize copy is here: Big picture! And... yeah, on closer inspection and playing with contrast, it might be a wide, flat chain, but it's damned hard to tell. And if those a guides, why are they not curved to prevent chain whip?
I'm still not sure we're looking at the same picture. That is in no uncertain terms a chain and the guides are definitely curved...
Agree about the belt-chain argument...
Yah, on much further inspection, those are guides.
Weird. I'm not used to seeing guides that don't have a massively pronounced curve.
This should be an interesting engine. BMW is claiming upwards of 225hp from 1.5 liters. It looks like they are going to a modular 500cc-per-cylinder design for threes, fours, and sixes.
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