Welcome to the North American Subaru Impreza Owners Club Friday March 29, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Normally Aspirated Powertrain

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 10-16-2000, 08:18 PM   #1
1.8L
Scooby Specialist
 
Member#: 32
Join Date: Jun 1999
Arrow H6 uses timing chain instead of belt.

Hello,

I think I'm happy about that. I think chains are more durable and have the advantage of not having to be sealed by a silly over $200 set of plastic covers that get in the way of any real engine work. Also, chains stretch less so that when you first romp on the throttle, especially with modded cars that have lots of power, the elastic belt stretches for an instant and timing gets stretched out and is wrong for an instant. The timing is probably less than a degree off with sane powerlevels (like our sub-350 hp levels). With a chain, it takes probably 3 or 4 times that power to get any kind of elastic response from the metal or the tensioning system, be it hydraulic or otherwise.

Downside is what? Why not use chains instead of belts?

Just curious and wanted to stir up some opinions. I know on the ultra high hp american cars, almost everyone gets rid of the chains because of the aforementioned stretching and replaces the chain with mechanical gears (noisy, so never included in OEM setups)...

Joel

[This message has been edited by Joel Gat, 1.8L (edited October 16, 2000).]
1.8L is offline   Reply With Quote
Old 10-16-2000, 08:25 PM   #2
RidinLow
Scooby Guru
 
Member#: 329
Join Date: Sep 1999
Chapter/Region: Tri-State
Location: NJ
Vehicle:
1995 325i
Arctic Gray

Post

Chains are noisier & more costly... those're the only things I can think of.
RidinLow is offline   Reply With Quote
Old 10-16-2000, 08:29 PM   #3
ColinL
Scooby Guru
 
Member#: 114
Join Date: Jul 1999
Chapter/Region: MWSOC
Location: Wichita, KS and Whoring, OT
Vehicle:
'03 Evo, Rice White
'01 Erion CBR 929

Post

Weight, for one. Think about the rotating mass of a long chain versus the belt. The belt is about 2 pounds versus what... maybe 12-15 for the chain?

A chain is absolutely more durable and less likely (nearly impossible) to loose timing though.

The timing cover for a SOHC EJ25 has exactly 13 10mm bolts. Besides, why would you think the H6 won't have a plastic timing cover? It has that lovely plastic lid on the block, so why not.
ColinL is offline   Reply With Quote
Old 10-16-2000, 08:35 PM   #4
1.8L
Scooby Specialist
 
Member#: 32
Join Date: Jun 1999
Post

Hello,

Colin, the H6 might very well have plastic everywhere. Plastic is like the OEM version of stickers for rice/wheat/whatever-boys. The more they put on the cars, the happier they seem to be. However, the biggest function of that plastic cover on our cars is to keep anything from getting on the belt since anything, especially oil, but including coolant, can degrade the rubber or induce slipping and cause a fatal engine death

With a chain, you don't have to worry about that kind of crap. There's still a cover, but you don't have to have something like 20 gaskets included with the cover (which I had the pleasure of figuring out recently when I rebuilt an engine and needed to replace that cover).

Weight is a good point, though. I guess that's another reason to avoid chains on low torque cars like 4-bangers and why it's okay to use them on the H6.

Anyone else read the article in automotive engineering? They seem to love new engines and always yap on forever about every new feature

Joel
1.8L is offline   Reply With Quote
Old 10-16-2000, 08:40 PM   #5
ColinL
Scooby Guru
 
Member#: 114
Join Date: Jul 1999
Chapter/Region: MWSOC
Location: Wichita, KS and Whoring, OT
Vehicle:
'03 Evo, Rice White
'01 Erion CBR 929

Post

Joel, no I haven't. Got a scanner?
ColinL is offline   Reply With Quote
Old 10-16-2000, 09:43 PM   #6
mikesoob7
Scooby Newbie
 
Member#: 2500
Join Date: Sep 2000
Location: Boulder, CO
Vehicle:
2002 WRX
Silver

Cool

My girlfriend has a Saturn SC2 which has a chain. It's significantly faster than my OBS and the engine seems to be more flexible overall even though it doesn't have as much torque, although a lot of it may be because it's a lighter car.

I think it was rated at 8.5 seconds to 60 which is pretty good for a 4 cylinder with a chain. I've always wondered if Subie engines would do well without belts since they're such a pain in the butt to change.

mikesoob7 is offline   Reply With Quote
Old 10-16-2000, 09:45 PM   #7
markus
Scooby Specialist
 
Member#: 438
Join Date: Oct 1999
Chapter/Region: W. Canada
Location: St. Albert, AB, Canada
Vehicle:
2004 STi
White on Gold

Post

Are chains not also skinnier?

Anyone? Anyone? (Bueller? Bueller?)

Assuming this is correct, a thinner/skinnier belt means the total overall length of the block may be shorter. Maybe this is part of the reason why Subaru was able to make the EJ30 (?) block only 25mm longer than the EJ25. Who knows? *shrug*
markus is offline   Reply With Quote
Old 10-16-2000, 10:01 PM   #8
Penphoe
Friendly Neighbourhood
Moderator
 
Member#: 269
Join Date: Sep 1999
Chapter/Region: VIC
Location: Burnaby, B.C., Canada
Vehicle:
2005 ABP LGT LTD BP6
00 Impreza RS GM6 RIP

Lightbulb

That's interesting that Subaru decided to use a timing chain on the new H6. Joel, you mentioned the problem of belt/chain slack on the timing. It's interesting to note that the H6 for the SVX does not use belts OR chains to control the timing of the cams! Yup, you guessed it -- it uses gears, but not just any gears -- Subaru used scissor gears to minimize the "slack/space" between the gears so that timing would be nearly perfect!

How do I know this? Well, my cousin owns an SVX - a '92 I believe, and he also has the coin to dish out for a set of Subaru maintenance manuals. He's big into the tech side of anything (cars, computers, AV equipment, etc.) and he mentioned to me about the engineering that Subaru put into the timing mechanism!

I guess the scissor gear mechanism was just a little too expensive for the latest incarnation of the H6. It'll be interesting to see what people do to the new one though!

LaterZ!
Darren!!

[edit] cauz I hit "Submit Now" before I put my signature on! DOH!

[This message has been edited by Penphoe (edited October 16, 2000).]
Penphoe is offline   Reply With Quote
Old 10-16-2000, 10:03 PM   #9
XT6Wagon
Scooby Specialist
 
Member#: 524
Join Date: Nov 1999
Location: WA
Vehicle:
04 STi
White

Post

Timing chains are narrower. They do strech less, but there are problems with tensioning them and chain slap that offset this. The extra mass is of minimal effect, since you can reduce rotating mass on the flywheel or crank pulley to compensate.

Subaru really need to do ALL timing off a direct crank trigger(s) this will lead to perfect timing and minor cam timing differences will not have that large of a effect compared to missed ignition of fuel injector timing.

The timing belt covers are really there only to keep large objects (bigger than dust) out of the timing belt. Atleast on the old SOHC 2 valve motors both the WP, and oilpump can leak right on to them as the WP is above a low spot in the cover, and the oilpump is behind the cover. I ran my old turbo for a long time w/o the covers with no problem. The 6cyl will have them only becasue the dipstick bolts to the center cover, and the passenger side one is needed to keep wires out of the pulley.
XT6Wagon is offline   Reply With Quote
Old 10-16-2000, 10:42 PM   #10
1.8L
Scooby Specialist
 
Member#: 32
Join Date: Jun 1999
Post

Hello,

Uhh, timing as in valve timing, not ignition timing The chain/belt directly turns the cams in an overhead cam setup. The ignition timing is done by various methods like crank trigger, cam trigger, etc.



Joel
1.8L is offline   Reply With Quote
Old 10-17-2000, 12:28 AM   #11
XT6Wagon
Scooby Specialist
 
Member#: 524
Join Date: Nov 1999
Location: WA
Vehicle:
04 STi
White

Post

Right, and I was told that the DIS ignition system triggered off the cam sensor leaving it at the whims of the belt or chain. No idea which triggers the injectors.

My point is that valve timing is not THAT critical. A .5 a degree error is not that big of a deal. Even one degree is relatively minor. I'd rather see that the EFI system is exact than the cams.
XT6Wagon is offline   Reply With Quote
Old 10-17-2000, 02:12 AM   #12
redwagon
Scooby Specialist
 
Member#: 2181
Join Date: Aug 2000
Chapter/Region: SCIC
Location: So Cal
Vehicle:
2003 Forester XS

Post

Hate to disagree, but valve timing IS critical. Think about how much variation in terms of time even .5 degrees early or late is. It's thousands of a second, in the scale of an event of hundredths of a second...it is significant. I had built drag motors (Kawasaki, motorcycle stuff) and setting the cam timing between races was a real difference in performance.

Belts stretch very little at these power levels as Joel suggests. The tiny little bit of 'give' in the belts helps to absorb the very slight uneveness in crank rotation caused by the crank throws not being at a perfect 180 degrees, the slight wobble from torsional vibration, the cylinder bores not being perfectly parallel and other effects. With gear and (to a lesser extent) chain drives, these irregularities are transmitted to, and affect the valve motion.

I prefer belts.
redwagon is offline   Reply With Quote
Old 10-17-2000, 06:11 AM   #13
Nat
Scooby Specialist
 
Member#: 759
Join Date: Jan 2000
Chapter/Region: NESIC
Location: Warwick, RI
Vehicle:
2012 Regal GS
2000 SV650

Post

Boy, working 14 months on co-op with timing chains I would have thought I could think of more advantages, but I can't. A timing chain system is more complex than belt from the examples I have seen. You will need an arm, guide and tensioning device on each bank to help control chain movement. About 95% of the time the tensioner is hydraulic, which will mean less oil to engine, and to variable cam timing devices as well. The front cover will have to have be able to seal the oil against the block since there is a lot of oil flying around in there. Chains can be pretty thin, but compared to a belt I don't think you are saving that much room. They are strong though, and I wouldn't mind having that peice of mind in an engine. I got a lot of parts back at work that I inspected with 100,000+ miles that were in great shape. Chains are also going to wear over time putting metal into the oiling system. I know that it isn't that much and will be filtered out, but there is that disadvantage. Designed properly, a timing chain won't have that much noise, but this also takes into consideration the front cover which usually acts like a speaker to amplify any noise made by the system. Despite what sounds like a discouraging post here, I think I would rather have a timing chain than belt. Longer life, better strength and a little more piece of mind for a stressed engine such as a Turbo RS.
Nat is offline   Reply With Quote
Old 10-18-2000, 12:40 AM   #14
yebokmj
Scooby Specialist
 
Member#: 2213
Join Date: Aug 2000
Chapter/Region: NESIC
Location: Salem, NH USA
Vehicle:
1995 Impreza w/EJ257
Brilliant Red

Post

I just thought I would metion that I went to a meeting about the H6 today and go to see it out of the car and all sliced up. The chaince is enclosed in a metal housing in the front of the engine and looks like it is pretty well sealed about a scew holding the cover on every 1/2 inch I don't think they exspect anyone going in there. Also they had the Porche boxter engine there they use belts on that one just thought I would mention it. It was very intresting comparing the two engines especailly where the subaru was only 8hp less.
Joshua
MY98 RS
Subaru Salesman
yebokmj is offline   Reply With Quote
Old 10-18-2000, 12:53 AM   #15
Jaxx
Scooby Guru
 
Member#: 177
Join Date: Aug 1999
Chapter/Region: NWIC
Location: Austin, Texas, USA
Vehicle:
The 93 W/EJ20K-sold
Subaru-less :(

Post

hmm.. i am wonering if the change to chains was influnced by the new varible v-tec type thingy.. to make it more accurite


at a loss for the correct word
-jared
Jaxx is offline   Reply With Quote
Old 10-18-2000, 09:58 PM   #16
Thug
Precious ❄
 
Member#: 603
Join Date: Dec 1999
Chapter/Region: NESIC
Location: Norfeast
Post

The Nissan Sentra SE-R used a chain. That's a 2 litre 16 valve that makes 140 hp. That's pretty good, especially for a car that came out in like 89. The chain setup obviously cant be too bad.
Thug is offline   Reply With Quote
Old 10-18-2000, 10:27 PM   #17
WRXwannbe
Scooby Specialist
 
Member#: 1954
Join Date: Jul 2000
Location: Long Beach, CA, USA
Vehicle:
1997 Impreza L/WRS
WRB

Post

nissan has crazy skillz with engines, thier present day V-6 was rated number one (don't know where I heard this exactly). anyway...........
WRXwannbe is offline   Reply With Quote
Old 10-19-2000, 09:31 PM   #18
Red-Imp
Scooby Specialist
 
Member#: 1742
Join Date: Jun 2000
Chapter/Region: SWIC
Location: Gilbert, AZ, USA
Vehicle:
2000 Imp 2.5 RS, SRP
& a fast red car ;)

Post

Here's a thought RE the durability of a chain vs. the durability of a belt.

On a high-milage engine, the belt will have been replaced, probably several times. Thus, the timing will be as precise as it was when it was new (minus valve/cam wear). In a high-milage engine with a chain, the chain wear will have accumulated, throwing off the timing more and more.

My thought is that it kind of offsets the durability advantage, since the belts are cheap and easy(ier) to replace. Of course, I've never heard of anybody breaking a chain and smacking a valve. I've heard of quite a bit of that with belts.

My $0.02,

-Red
Red-Imp is offline   Reply With Quote
Old 10-20-2000, 05:29 AM   #19
Nat
Scooby Specialist
 
Member#: 759
Join Date: Jan 2000
Chapter/Region: NESIC
Location: Warwick, RI
Vehicle:
2012 Regal GS
2000 SV650

Post

Chains don't really continue to wear. Most of the elongation that happens is when the engine is new. After that the wear tapers off and is only slight for the rest of the engine's life. When designing the system, the chain is initially just a tad short to take into consideration the initial break-in. This isn't saying that when someone doens't change the oil for 20K miles that chain elongation won't occur.....you gotta take care of things. I have seen plenty of chains that were high mileage that were in almost new shape
Nat is offline   Reply With Quote
Old 10-21-2000, 09:05 PM   #20
SubeTek
Scooby Specialist
 
Member#: 1714
Join Date: Jun 2000
Chapter/Region: RMIC
Location: Arvada,Co
Vehicle:
1999 RS-T COUPE
Black

Post

Hey All! I will be going to new model update training for the H-6 on 10-31,and 11-1. I will try to get as much info. as possible and post answers to any of your questions.

Bret
Subaru Senior Master Tech
SubeTek is offline   Reply With Quote
Old 10-22-2000, 02:16 PM   #21
Waltsacura
Scooby Newbie
 
Member#: 813
Join Date: Jan 2000
Chapter/Region: Tri-State
Location: Philadelphia, PA 19440
Vehicle:
07 Outback
Silver

Post

Joel,

I recently talked to a sube tech that went to school to see the H6 engine...one thing he noticed was the timing covers. He said there were like 40 bolt holding on the single cover (not like the three piece cover used on ours) and that the bolts were all different sizes and some were hex heads. Behind this cover was another cover allowing you to get at the oil pump and the water pump... but this cover had another 30 some bolts. His overall impression of the H6 wasn;t great. He said it reminded him a bit of BMW design= pain in the ass to werk on. He also said that Subaru seems to have changed everything that werked well seeminly just so they could do something new. He isn;t excited about werking on them... He said the pick up was great powerwise,.. a little more torquey off the line. I didn;t really press him for more info since I'm not really excited about getting a Legacy wagon... but if you have anymore questions that you would like me to ask him then let me know... [email protected]
Waltsacura is offline   Reply With Quote
Old 10-22-2000, 05:41 PM   #22
Andy_T
Scooby Newbie
 
Member#: 502
Join Date: Nov 1999
Location: Sydney, New South Wales, Australia
Post

Chains - less compromised. Noisier, but largely maintenance-free (unless you own an M car, in which case, a new chain every 100k miles is a good insurance policy). Chains are also thinner, unless you have an enormous duplex chain a la BMW 1.8/1.9 16v four, which is very wide (and noisy, too).

Belts? Quieter, simpler, cheaper, but need replacing. So the servicing costs are higher (you pay through servicing rather than through list price - nothing comes for free!).

Andy T
Andy_T is offline   Reply With Quote
Old 09-30-2011, 09:29 PM   #23
phxmotorelectri
Scooby Newbie
 
Member#: 288175
Join Date: Jul 2011
Default timing chain vs t-belt

Isn't the whole point for Subaru going w/ a timing-chain is to make life more simple for its customers? But isn't there a huge pitfall that Subaru is facing with the decision to start using a chain?
1) A chain on high production low cost cars is great for the average driver. IF the head gaskets never "pop".
But isn't the problem that all and I do mean all, 2.5 Subaru engines will pop a head gasket by 175k mi tops. I've owned 25 or 30 Subaru's from 1.8's to 3.3's and I swear it's a fact with every 2.5 no matter what "upgraded" head gaskets are used. Every engine they make except the 1.8 and maybe the 2.0 will eventually need a headgasket job. Heaven knows, that for any semi-knowlegable shade tree type person, doing a head gasket job on a Subaru is just no big deal. In fact it's kind of fun (except for the DOHC's anyway).
But I believe Subaru is going to start to see a real resale problem 6-8 years.
Because: no matter what Subaru says, their 2.5 engines will continue to pop head gaskets. No matter what they say or what changes are made, by about 175k mi pretty much every one will need a head gasket job.
Given that as a fact (and I'm sure this will generate many people on this forum who think Subaru has solved their H-G problem, but I'm equally sure that I'm going to be proven correct. And when the inevitable happens, and the bubbles start to come up through the radiator...then the new timing-chain engines will be a real bear to fix.
What was once an enjoyable afternoon repair (and a low cost fix) that assures our trusted "subi's" will hit 300k w/o anything else major happening, it will now become a real b--tch. A pain to work on, and much more costly.
Subaru's argument will be "We've fixed the head gasket trouble". Their argument will continue with "and now your Subaru will last 300k with no timing belt worries... heck Subaru has done you a favor!"... If it were really true I'd buy one right now, but I seriously doubt it.
Reality will dictate that this is just not true. H-G's will continue to blow, and what was once a fun quick nd simple job will become a nightmare.
What was once a fun engine to work on will become just another over engineered, needlessly complicated piece of machinery that just isn't fun to work on anymore.
But we should try to look on the bright side. Older Subrus with belts will be worth more in the used-car market. And for the next 15 years there will still be plenty of them available.
And then the inevitable will happen: either Subaru will go back to belts as Coke went back to the original flavor... or people will abandone their favorite snow car and start buying the brand that gives us an honest product at an honest price.
If any Subaru engines really do prove themselves as "head gasket proof"... as being able to hit 325-350k mi (right where even well designed t-chains usually wear out) then I will keep buying Subarus and applaud Subaru for taking the "bold"step into chains. But my money is on the fact that their head gaskets will continue to keep popping at 150-175 no matter what they do. My money is on the fact that this will prove to be a very bad decision in the long run.
Hope I'm wrong! I sure like Subaru's, both for their "snowworthyness", and for their ease of repair and reliability. I'm just afraid this move will pull the rug out from under half the reason we buy them.
phxmotorelectri is offline   Reply With Quote
Old 02-18-2012, 07:21 PM   #24
ManualOverAuto
Scooby Specialist
 
Member#: 304662
Join Date: Dec 2011
Chapter/Region: MAIC
Vehicle:
2001 Impreza L coupe
Sedona red Pearl

Default

I messed up lol, look at the next reply.......

Last edited by ManualOverAuto; 02-18-2012 at 07:26 PM.
ManualOverAuto is offline   Reply With Quote
Old 02-18-2012, 07:24 PM   #25
ManualOverAuto
Scooby Specialist
 
Member#: 304662
Join Date: Dec 2011
Chapter/Region: MAIC
Vehicle:
2001 Impreza L coupe
Sedona red Pearl

Default

Quote:
Originally Posted by phxmotorelectri
Isn't the whole point for Subaru going w/ a timing-chain is to make life more simple for its customers? But isn't there a huge pitfall that Subaru is facing with the decision to start using a chain?
1) A chain on high production low cost cars is great for the average driver. IF the head gaskets never "pop".
But isn't the problem that all and I do mean all, 2.5 Subaru engines will pop a head gasket by 175k mi tops. I've owned 25 or 30 Subaru's from 1.8's to 3.3's and I swear it's a fact with every 2.5 no matter what "upgraded" head gaskets are used. Every engine they make except the 1.8 and maybe the 2.0 will eventually need a headgasket job
Forgetting the 2.2? The phase 2 one was one of (if not the most) reliable subi engine made. Hoping not to jinx my own (currently at 108,xxx).

The 2.5s are getting phased out now anyway right? The new impreza/wrx/sti's are all using the new 2.0. I think that's a good move on subarus part. Can only squeeze so many liters into a four cylinder and expect good reliability. The smaller (1.8, 2.0, 2.2) engines always lasted longer, so hopefully they start going back to those.
ManualOverAuto is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Opinions on using the ipod instead of the integrated Alpine 9856/57 controls? jon6682 Car Audio, Video & Security 7 03-06-2007 10:35 AM
Wife used PS fluid instead of ATF - how bad is this? Siper2 Normally Aspirated Powertrain 19 04-30-2005 06:13 PM
anyone use a harness instead of seatbelt? JOSHMAN Interior & Exterior Modification 32 10-29-2002 12:51 PM
Using Cooking Oil Instead of Gas in a Subaru Jon [in CT] General Community 5 10-10-2002 01:17 AM
Help- used GL-4 instead of GL-5 Ryan24 Transmission (AT/MT) & Driveline 5 08-07-2002 09:50 PM

All times are GMT -4. The time now is 07:53 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.