Arco gas? (2025 Update)

er, because you care about factual accuracy?

eh? the point is that honda made some serious headway in cylinder head design that detroit has taken decades to emulate.

no. they weren't then. and even now, look at specific power outputs...

I agree completely. Honda engineers are still designing rubber-band timed valve smashers that aren't worthy of being melted into beer cans.

I think Steve is a throwback to GM fans who could only find one point of supposed GM superiority over Hondas so they got a hard-on for timing chains vs. belts. Saturn went so far as to tout the fact that they used chains instead of belts as a selling point. (I doubt that most of their customers knew a timing chain from a daisy chain, but that's another discussion.) Most of those Saturn buyers ended up paying big bucks to replace those chains when they wore out in spite of the fact that they were made out of metal. (Who would of thought that something with hundreds of rapidly moving metal parts could ever wear out?) Of course, replacing the belt didn't cure the voracious oil consumption, the cracked heads, the failed head gaskets, the flimsy motor mounts, warping brake rotors, the broken transmissions and the alternators that failed about as often as the batteries. Still, these were some of Detroit's most reliable cars.

in their euro stuff, gm were one of the earliest adopters of "rubber bands". what's that sporty little opel they tried selling out here in the 70's?

chill. rubber bands allow a motor to remain on the peak of operating efficiency throughout its life because they don't stretch. chains can't get close. as for valve smashing, high compression allows better power yield. high rpm allows better specific output. add the two together and you have a very spunky little motor. but there's no room for "slop" like a non-interference motor. i say the benefits outweigh the "disadvantage" many times. particularly when you look at the economics of belt change vs. efficiency.

You guessed wrong. I've never EVER been a GM fan.

And there's nothing wrong with timing belts at all. What's insane is using them on interference engines. Yes, lots of carmakers, including my own manufacturer of choice, are doing it these days. But common use still doesn't make it good engineering practice, it just means that everyone is compromising design in order to maximize profit. Cut some valve reliefs, for pete's sake! Or if that compromises combustion chamber design too much, then bite the bullet and use a tensioned chain drive. Heck, even GM got that right on the Northstar engines!

A) they DO stretch. B) they break.

Specific output, or "horsepower per liter," is a meaningless measurement. Who gives a rat's rump how much an engine displaces, so long as it doesn't result in a huge increase in packaging size or a drop in efficiency? Adding displacement is *just* as valid a way to increase performance as adding a turbo or variable valve timing. And, up to reasonable limits, it is just as efficient. For example, did you ever notice that the "archaic" Buick 3800 is one of the most efficient engines in its power class?

Everything I've read seems to indicate that belt stretch isn't that far different than chain stretch over time, given a slack-side tensioned chain system with a good roller chain and a good dynamic tensioning system. If slack chains were a real problem, you wouldn't find them on so many high-end engines worldwide. Belts are a far cheaper option with equal or SLIGHTLY better performance.... UNTIL the catastrophic failure.

Heh... That's one of the reasons that all my "old" cars are Studebakers. Timing failure is almost a "never" event. And the majority used phenolic camshaft gears...

JT

Except that it does. You will have to increase your Buick V6 to 4.7L to get the horsepower of a Honda 2.2L. How do you think that will work in an S2000?

I don't know what "valid" means in this context, but there are some real disadvantages to adding displacement such as size, weight and efficiency.

Buick Lucerne Acura RL Accord Accord

Just comparing the Buick to the RL tells the tale. The Acura weighs

The V6 Accord weighs a little less than the Buick (how much of that is due to the lighter engine?) has about 25% more horsepower and it gets

Of all these Hondas, the closest in horsepower to the Buick is the 4 cyl Accord. It has 16% less hp which is offset by the fact that the engine probably weighs 300 pounds less than the 3.8L in the Buick. It gets 5-6 mpg more than the Buick and will probably beat it in a drag race. Pick the available manual transmission and it will go even faster and burn less fuel.

If you want to compare with Toyota, check out the Avalon. 36% more horsepower and 3 more mpg.

So what is so great about that Buick engine?

indeed.

In my neck of the woods (Northern lower Michigan) gas is gas. It usually all comes from the same jobber or place.

So I love all the advertising Shell is doing telling you their gas is better than the other guy's, when the delivery truck finishes down loading at a non-brand station, then drives across the street to fill up a Shell station.

I am not suggesting this happens everywhere, but those in the know will tell is occurs all the time. :icon16:

Yes, I get it.

A) it only means its HARDER to avoid interference, and B) if you have to have interference, time it with a chain and do the engineering to manage the chain correctly.

They are great from the manufacturers point of view because it gets rid of some hard design problems. And you can usually make them last beyond the warranty period, so when the valves go through the piston tops the manufacturer can blame the owner for "poor maintenance."

Its no "secret" at all. Hell, my 1993 Chrysler 3.5L v6 has 10.1 compression, is NOT an interference engine (though it uses a belt) and runs on regular gas (though mid-grade is recommended.) The second generation of that engine did turn into a slight interference design (low probability of breaking a valve since the duration of the interference event is very short, though non-zero). All it takes is a more rigorous piston and chamber design process to minimize detonation trigger points AND keep the required clearances. Is it "without compromise?" No, of course not. But its perfectly rational for a street engine where you know a certain percentage are going to break their timing belts. At least if you want to have satisfied customers.

Dynamic tensioning makes sure that the timing error is only in one direction, and also stabilizes the timing. IOW, wear in the links of the chain causes the cam timing to retard and ONLY to retard if you have a tensioner on the slack-side of the chain. But without dynamic tensioning the interations between the masses and loads on the spinning cam/crank/chain combination can cause the cam timing to wander between an advance and a retard. Cam-in-block v8s use chains all the time without any tensioning, but the chains are so short that the total error (slop in each link times the number of links) is negligible no matter what. Racers go ahead and either use gears or tensioners even for cam-in-block engines, but its certainly shooting a squirrel with an elephant gun for a street engine. Overhead cam V-type engines have a lot more links so they can accumulate many times the cam timing error of a cam-in-block engine, but with a good dynamic tensioning system its STILL NEGLIGIBLE and stable enough for any street engine. Certainly negligible enough to prevent valve-bashing, even if there's some slight performance degradation near the end of life of the chain- but that's on the high side of 300k miles compared to 100k for a belt!

The overall statistics disagree with you.

Your Honda engine is FAR more more "de-tuned" from Honda's IRL engine than a Chevy LS-3 or an SRT-8 Chrysler Hemi is "de-tuned" from a NASCAR engine. You should write Honda and complain about your horribly de-tuned engine! You DESERVE better! Honda is screwing you!

"De-tuning" as you call it, is what we call "design margin" in engineering. Deal with it, its good for you even if you don't think so. Every automaker practices this method, otherwise there would be no such things as hot-rodders and rice-boys.

Apparently its you who don't understand the concepts.

Yeah, it would cause cam ADVANCE as the chain stretches. Guess which one reduces peak performance more? Advancing- because it reduces horsepower an return for a little more torque right off-idle.

In the first place, why the hell would the cost be ANY different?

In the second place, your second argument is simply not true at all. You cannot put the primary dynamic tensioner/damper on the tension side, because the normal operating load of the cams and any accessories driven off the cams would tend to gradually compress the tensioner during normal operation, allowing the slack side of the chain or belt to go VERY slack indeed. The only thing you could do is use a fixed tensioner on the taut side, which went out with the VW Rabbit engine in the 80s. But you can put a dynamic tensioner/damper on the slack side, because during normal operation it will take all induced tension OUT of the slack side and keep the belt or chain as snug as possible. On the brief transients of reversed belt tension when decelerating, the damper prevents the tensioner from slacking off significantly.

All you are doing is proving that you've never degreed a cam on a cam-in-block engine. True roller timing chain sets are easily that close.

Why address something that doesn't NEED addressing? Why tilt at windmills?

"Detroit" DOES use them.... when necessary (Cadillac Northstar, Ford Modular, Chrysler 2.7, 3.7, and 4.7). And it doesn't when they're unnecessary (GM LT and LS smallblocks, Chrysler 5.7 and 6.1 Hemis, all of which produce more power than 4 Hondas)

Unfortunately, I do own a belt-timed engine and have owned others without dynamic tensioning in the past.

That's fundamentally wrong. While its true that belt makers go to great lengths to reduce stretch, it is not zero.

No, "dude," I'm not misreading. You're right, I've certainly never seen valve bashing with mere drift, but that is EXACTLY what one of your non-engineering-based friends has been arguing is a reason for belts.

BMW doesn't think so. Mercedes doesn't think so. Cadillac doesn't think so. Chrysler doesn't think so. Ford doesn't think so. Toyota doesn't think so.

Steve wrote: u who don't understand the concepts.

Ouch, In my earlier haste I completely mis-stated this. A stretching chain or belt can never advance the *average* timing of the cam, only retard it. Without damping, there can be excursions of advance and retard, but since the cam on AVERAGE is being dragged along by the crank, it will lag behind the crank (retard) to whatever extent it is allowed to do so by the cam drive.

The drawback to putting a tensioner on the taut side is that as the cam drive (be it chain or belt) stretches, the added slack will be accumulated BETWEEN the crank and cam, maximizing the amount of retard by the total stretch of the belt or chain. OTOH, if you tension on the slack-side, the retard is minimized because all the extra length is carried harmlessly on the slack side, and the only retard experienced is the delta-length of JUST the length of belt or chain on the taut side at any instant, which is necessarily less than 1/2 the total amount of stretch.

you should have bothered to look that up earlier before shooting your mouth off.

rubbish - read the next chapter. the only stretch that matters is that between the crank and the cam, the tight side. the rest of it can take an excursion back up through the drivers side door column, around the trunk and back down the local high street for all it matters to cam timing.

1. see above for relevance of the slack side.

bottom line, don't blow smoke up my kilt steve - i hate seeing grown men grovel on their knees.

So he can continue to provide us with a cheaper alternative to lining the pockets of Bush & Cheney's friends?

"claymore" said in ca.driving:

Since when does Venezuela own Arco?