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914World.com _ 914World Garage _ Very odd 914 sighting yesterday....
Posted by: horizontally-opposed Mar 10 2005, 10:57 AM
I was having lunch with an old 914 buddy in Novato -- the guy who built the silver 914-6 3.8 that keeps popping up for sale -- when a gray/silver (looked like that old-school silver that isn't so bright) 914 went by. Too quickly to collect all the details.
Fairly stock looking (I think it was still on four-lug wheels), but it sounded like it might have had an inline four, like a Honda S2000 or Toyota motor, but I am sure that's not it. Could it be?
If that was a Type IV, I want to know what was done to it!
This was on Wednesday March 9 on Bel Marin Keys Blvd @ 1:00 pm or so....
Anyone here know this car?
pete
Posted by: Martin Baker Mar 10 2005, 11:29 AM
I am sure I know the car, it has a Mazda rotary engine. Roger Hamlin just worked on it at his Sears Point shop. It is a silver 71, but it has the 5 lug conversion done to it, so it has 5 lug Fuchs on it. I saw it when my car was there getting the cage put in. He said it was a local car, and Novato is close to Sears. Maybe this was it. I know the paint on the car was very dull.
Posted by: horizontally-opposed Mar 10 2005, 05:53 PM
Yep, that's probably the one. Again, didn't get long enough to get a gander -- and it was doing 20-40 mph as it accelerated down the street.
I didn't want to bag on anyone's car (and still don't -- except for SLITS 
), but I'd say it was either really bad silver -- like Hammerite -- or faded. Coulda been on five luggers...I suppose. 
The thing that distracted me was that the engine sounded wierd -- for how smooth it was. And not very air-cooled. 
Pro'ly was a rotary. Damn, it sounded good...has it ever been done WELL?
pete
Posted by: jd74914 Mar 10 2005, 05:57 PM
| QUOTE (horizontally-opposed @ Mar 10 2005, 03:53 PM) |
| The thing that distracted me was that the engine sounded wierd -- for how smooth it was. And not very air-cooled. Pro'ly was a rotary. Damn, it sounded good...has it ever been done WELL? pete |
Rotaries still don't seem to have been perfected. Wankle (sp?) had a great idea, just seems to need some more work (I don't know anything about the rx8s, I've only heard that they get bad gas mileage.
) If anyone has pics of a clean install please post them. Its such a cool idea.
Posted by: lapuwali Mar 10 2005, 06:26 PM
| QUOTE (jd74914 @ Mar 10 2005, 03:57 PM) | ||
Rotaries still don't seem to have been perfected. Wankle (sp?) had a great idea, just seems to need some more work (I don't know anything about the rx8s, I've only heard that they get bad gas mileage. ) If anyone has pics of a clean install please post them. Its such a cool idea. |
I'm sure you'll get a lot of hot replies to this, esp. from a certain Canadian...
Rotaries had all kinds of problems early on (pre about 1977), but since then, they've been pretty reliable. They don't need rebuilding any more often than a typical piston engine, and they can be tuned to make remarkable amounts of power. Their chief downfalls are that they get crappy mileage (18mpg is common), they require excellent emissions controls as they're quite dirty without them, they generate a LOT of heat (requiring about as much cooling as an SBC), and they require good mufflling. An open piped rotary sounds TERRIBLE. However, a turbo is ideal, since it muffles well, and rotaries like turbos.
I've had two RX-7s, one a turbo, and never had the slightest engine-related problem with either of them.
Posted by: bd1308 Mar 10 2005, 06:31 PM
just take care of dem dar yonder apex seals
Posted by: jd74914 Mar 10 2005, 06:37 PM
| QUOTE (lapuwali @ Mar 10 2005, 04:26 PM) |
| I'm sure you'll get a lot of hot replies to this, esp. from a certain Canadian... Rotaries had all kinds of problems early on (pre about 1977), but since then, they've been pretty reliable. They don't need rebuilding any more often than a typical piston engine, and they can be tuned to make remarkable amounts of power. Their chief downfalls are that they get crappy mileage (18mpg is common), they require excellent emissions controls as they're quite dirty without them, they generate a LOT of heat (requiring about as much cooling as an SBC), and they require good mufflling. An open piped rotary sounds TERRIBLE. However, a turbo is ideal, since it muffles well, and rotaries like turbos. I've had two RX-7s, one a turbo, and never had the slightest engine-related problem with either of them. |
Those are the problems I was referring to.
I didn't mean to infere that they are bad engines.
I know people with rx7s who love them.
Posted by: Rand Mar 10 2005, 06:46 PM
A buddy of mine had an RX7 with a 13B. Minimal mods included a tear-port (a bit of grinding and polishing on the ports), a different intake manifold with a Holley 4-barrel, and a custom exhaust. It put out 200HP and was running stronger than ever at 100k miles (right before it finally scattered). The motors are tiny. There's nothin' like 2-stroke power... Not very torquey, but tons of power when you wind 'em out.
OT, but here's a http://www.bryanf.com/510/engine.htm that's cranking out 350HP with a turbo.
Posted by: lapuwali Mar 10 2005, 06:49 PM
| QUOTE (jd74914 @ Mar 10 2005, 04:37 PM) | ||
Those are the problems I was referring to. I didn't mean to infere that they are bad engines. I know people with rx7s who love them. |
Those problems are largely not a cause of "perfecting", but inherent problems in the design. The bad mileage is a function of poor thermal efficiency, caused by the fact that the "combustion chamber" is very long and thin, and too much of the heat energy ends up getting transferred to the coolant or out the exhaust pipe, which is what causes the other two problems. Interestingly, this "failing" is actually a huge plus when it comes to using fuels that are low in octane. Rotaries are quite resistant to knock, so much so that pure hydrogen works very well in them.
Nonetheless, their power to weight and size are pretty much unmatchable in the piston engine. They rev to the moon, and even the non-turbo versions are pushing out 250hp these days.
Posted by: bd1308 Mar 10 2005, 06:51 PM
now wait....the only reason for thier knock-resistance is because mazda or wankel crammed that thing with anti-knock sensors (AKA Microphones).....
Posted by: bd1308 Mar 10 2005, 06:53 PM
adding a quart of oil in the engine every 500 miles seems a bit absuird too
Posted by: jwalters Mar 10 2005, 06:59 PM
It is a two stroke--kinda--really a one stroke when u really look at it. It has to have oil to lube the apex seals--although allot of people do away with the oil injection pump and just premix the gas like a dirt biker--
I agree--revs to the moon and what other engine can reliably make 400+ hp on just 1.3 liters????
Posted by: lapuwali Mar 10 2005, 07:03 PM
| QUOTE (RandyLok @ Mar 10 2005, 04:46 PM) |
| A buddy of mine had an RX7 with a 13B. Minimal mods included a tear-port (a bit of grinding and polishing on the ports), a different intake manifold with a Holley 4-barrel, and a custom exhaust. It put out 200HP and was running stronger than ever at 100k miles (right before it finally scattered). The motors are tiny. There's nothin' like 2-stroke power... Not very torquey, but tons of power when you wind 'em out. OT, but here's a http://www.bryanf.com/510/engine.htm. |
Two strokes are very nice, but a Wankel isn't a two-stroke. One can argue that it's a no-stroke, or perhaps a three stroke (all three cavities around the rotor are "operating" at once). One could even say it's one continuous "stroke", since it never reverses direction.
Actual piston two-strokes do indeed hit the same (or better) power to weight of a rotary, but have pretty much the same problems with emissions, noise, and mileage. The most fully developed two-strokes were bike engines, which are themselves disappearing. The last of the 500cc four-cylinders made something north of 200hp, or 400hp/liter, which is substantially better than even 19,000rpm F1 engines are reaching these days (something near 900hp from 3000cc), and the engine only weighed something like 100lbs including the gearbox. The emissions problems had been largely solved by a group of Australians with some innovative fuel injection technology, but they failed to get enough interest from the major manufacturers to take up the technology seriously.
Posted by: lapuwali Mar 10 2005, 07:09 PM
| QUOTE (bd1308 @ Mar 10 2005, 04:51 PM) |
| now wait....the only reason for thier knock-resistance is because mazda or wankel crammed that thing with anti-knock sensors (AKA Microphones)..... |
No, the knock resistance is an inherent property of the design. The combustion chamber doesn't get nearly as hot (well doesn't retain its heat) as much as a piston engine, so volatile fuels like pure hydrogen are less likely to be lit off early. Technically, this is "pre-ignition", not "detonation" (which always happens after the plug fires). Getting the mixture lit in the long, thin chamber is hard enough that all rotaries have to have two plugs per chamber, timed to light off in succession rather than simultaneously.
They may well be putting knock sensors into recent engines, as they've pushed the limit pretty far (140hp in 1985, 250hp in 1991 with a turbo, 250hp now w/o a turbo), so perhaps detonation is now happening. Given the shape of the chamber, this actually isn't all that likely to be a problem, but I'm not as familiar with the recent (post about 1990) engines.
Posted by: Rand Mar 10 2005, 07:22 PM
| QUOTE |
| a Wankel isn't a two-stroke...One could even say it's one continuous "stroke", since it never reverses direction. |
Agreed. I was a bit loose with the term, but the point is they put out more constant power than a four stroke engine. There's no motion that goes through a cycle just to pull fuel/air in and then fire next time around.
They are so short that you would have a lot of room in front of the engine in a 914. Maybe even enough room to fit a radiator in the engine bay? Hmmm. (Although they need a beefy radiator, and would require some good duct work to get enough air flow).
Posted by: North Bay 914 Mar 10 2005, 09:41 PM
| QUOTE (horizontally-opposed @ Mar 10 2005, 03:53 PM) |
| And not very air-cooled. |
Roger plumbed the car with aluminum tubing for the radiator, which is in the front trunk. Bunch of other stuff as well. Got all the guages working right, for the conversion etc. To all those who don't know Roger Hamlin, he was a member (Fabricator/Chassis Setup) of the 1981 Sports Car World Championship Rahal, Redman. Garettson 935 Team. He is a super guy.
Posted by: bd1308 Mar 10 2005, 10:33 PM
they are real cool engines though....wish I had a RX-7
Posted by: boxstr Mar 11 2005, 12:52 AM
Here is a unique way to house a rotary motor, actually two unique ways. One is blown the other has a four barrel on top of the mainfold.
CCLINWANKELVILLE
Attached image(s)
Posted by: boxstr Mar 11 2005, 12:53 AM
32 coupe look...
Attached image(s)
Posted by: riverman Mar 11 2005, 08:33 AM
http://web2.airmail.net/atl/Rotary.html is a link to a guy who did one. Seems like it turned out alright.
Posted by: sean_v8_914 Mar 11 2005, 09:33 AM
in teh works...87 RX7 Intercooled Turbo II, 247 Hp, 2500 lbs, 8500rpm red line, I cant wait to drive it. teh turbo comes on like a light switch at 3600rpm, 16mpg on a good day
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