Chain Guard on F1000

[Richard Dziak]

There was allot of discussion in the ApexSpeed General Discussion area under:

FB vs FC.......about chains, replacing chains and chain guards.

I learned allot from all the input.

I have attached a photo of my chain guard, that is just above the rear sprocket.

Do you think that this is adequate protection?

Any suggestions for the ultimate protection of the engine?

I don't want to question the engineering of the car, but other opinions could be helpful. I would hate to lose an engine. Since the chain rotates/moves to the rear, is this guard enough?

Double click on photos to enlarge.....

[carnut169]

The guard would meet the rule, imho. I don't see anything near the front sprocket so your engine is not protected. I ran the stock cover which did protect it somewhat.

[Brands]

As Sean says the guard looks like it meets the regulation, but perhaps if you are worried it could be extended foward. Mine is a steel U shaped channel that covers most of the chain from the back of the sprocket to the motor.

[formulasuper]

The damage that is done to the engine case when a chain comes apart is caused by the chain getting jammed between the front sprocket & the shifter shaft housing & the rest of the engine case. The GCR requirement of a chain guard is for "protection of the driver" & I don't think there is any way to fully protect the engine with a chain guard. (IMO)

[S Lathrop]

It seems to me that the most important area for the chain guard is from the rear sprocket all the way to the front on the drive side. Ted James posted a picture of a broken chain that did the engine in.

Does anyone know what the most common type of chain brake is? Does it fail while it is on the front or rear sprocket or as it leaves the rear sprocket? Or does it fail on the bottom side and whip around the driven sprocket?

[formulasuper]

Steve, I've never had a chain break on my Busa powered RT5 which has nearly 150% the torque of the 1000 cc engines & I don't understand the problems others have had with sprockets wearing out & chains overheating. I did have the aluminum rear sprockets wearing badly until I finally triangulated my rear subframe correctly to stop the flexing under the load of the strong torque, but now they are showing little, if any, wear & my chain never shows any signs of getting hot. I spray them with chain wax a couple of times during a weekend, it does make a mess as it slings off, but it's less of a mess than busted engine cases. I'm guessing any chain problems are caused by incorrect alinement?

[Matt Conrad]

The chain guard on our cars 100% meets the SCCA rules and we have never had an inspector question it. From my persective, I believe the chain guard rule is there to protect from having a broken chain flying out the back of the car and into other racers and onto the racing surface. We did have a chain come off once and our chain guard evidently did its job as the chain merely laid on top of the rear diffuser.

The issue of protecting the engine is sort of a Catch 22. You can run a sprocket cover and that can offer some protection....but I've also seen the broken chain rip all of the bolts holding the cover in place out of the block...you still have a broken case.

This isn't as big of a problem as it is being made out to be...but it is something to be aware of when you make the decision on when to change the chain. It is better to be safe than sorry.

Richard...you've run your car quite a bit and the chain on the car is the original one. I would recommend you change it.

Matt Conrad
Phoenix Race Works, LLC

[formulasuper]

SCCA GCR 9.3.39 "Chain drive cars shall be fitted with a protective case/shield to retain the chain in case of failure." I take this to mean the chain must remain inside the engine bay, & can't come out & become debri on the track.

[rickb99]

Perhaps what's needed to keep the chain on the sprockets is better understood these days. Yet, while flagging this year, I'm aware of at least 3 cars of the various chain drive flavors that have lost their chains.

Prior to the newer designs and the desire to save 3/4 of a pound of weight, this is what chain guards used to look like. The theory may have been, better to have a mangled chain guard then a mangled set of suspension and chassis parts:

[Richard Dziak]

All of the above chain guards that Rick supplied in his photos above look to be very sound, and possibly much better than the new designs. They all had similar protective methods.

I agree many racers may be more interested in saving the 3/4 of a pound in over all weight, for the added .001 second in timing.

[lowside67]

Is that really what it is? My car weighs in at 785lbs dry with video system. Most new FBs (Stohr/Phoenix) claim to be around that weight, +/- a few pounds. I can appreciate that I am a smaller guy than most (150lbs) but is it hard for most people to get to minimum? (I am the guy trying to figure out where to hide 50lbs in dumbbells in my car!) I am actually going out of my way to add a few things to the car that would serve a purpose and a bit of weight. Are these chain guides removable easily to change sprockets or are they designed to be more permanent?

-Mark

[rickb99]

No, the ones illustrated above all come off with a couple of 3 or 4 bolts.

I was kidding about the weight thing

Obviously I have no idea what has happened. But being me, I'll guess. Looks like chain guards went from what stands a chance of doing the best job of saving car parts and keeping the chain inside the vehicle to; What meets the GCR requirements.

Look at that one D/SR with straw tires. Without that longer chain guard, can you visualize the chain whipping up there and slicing the fuel line in half? I can. Same is true on the OMS D/SR with the anodized parts. You just can't see the fuel line as well cause it's right at the top edge of the photo. But, the chain guard is protecting it and other vital stuff.

Looking at Richard D.'s car, I see a couple of already there places to use as pickup points for a longer chain guard of steel plate or 6061 aluminum type.

P.S.
Chain guards do not keep chains from breaking. Please replace per all the pros-at-this recommendations.

I just bring the fire bottle, pick up the links off the track and call the flat-tows.

MARK:
Are you coming down to either of the last 2 ICSCC races in Portland or Seattle in Septmber???

[Richard Dziak]

What brand of chain and size are you using on your F1000?

I have used the following in the past....

Tsubaki Sigma 530 High Performance O-Ring chain.....

Is any body using something different.

I want to secure/buy the best available.

[kmt63]

on the west dsr the chain guard is made from 1/4x1 1/2 wide aluminum flat bar.it is mounted to the side of the diff case at the rear.it has a bend in it and covers the rear sprocket to about 2 o clock.it extends to within 2 inches on the front sprocket.then it is mounted to the diff case in front.it will keep the chain in the car.in 3 1/2 years of running this car.i have never seen a chain break.we did have a rear drive hub come loose and the chain came off the sprockets.but nothing broke on the engine.this guard is not in the way to change sprockets.the only time you would take it off would be to change engines.

[glenn cooper]

of the chain guard rule is to retain the chain in the car, and NOT allow it to get onto the track surface.
Unless the chain is virtually encased in a structure, good luck with that!
Realizing that that puppy is churning along at quite a clip, it is storing tons of potential (destruction) energy...
In my case at VIR, the break occured at the master link. IT was completely missing.
The chain was laying in the engine bay/difuser area. The chain was assembled correctly with a professional quality press fit tool.
My initial visual inspection, pre loading up and heading home revealed no crankcase damage. Until I get it all apart tomorrow that may change.

Bottom line is I shoulda listened when Sean O pointed out many months ago that we should be tossing the chain in the bin after 4 races. I probably had 6 races on it.
It's an interesting thing lifing components. Just the day prior I inspected each roller after a WD40 cleaning, looking for pitting and any other tell-tale signs of wear. It all looked good, operative word being "looked".

I lubed it up, and noted that it was properly adjusted, which on my chassis is approx 1/2" of play, checked while rotating the wheels and checking in the same spot (top run, 1/2 between sprockets) at intervals all along the chain, inspecting for tight or loose spots. None were found.

I feel it all comes down to metal fatigue. We are asking these chains to cope with a great deal more stress than their original application, and eventually something is gonna give.

GC

[RussMcB]

I'm no expert, but I did read the RaceCar Engineering article about chain driven race cars yesterday. It had a few interesting tidbits. X-ring chains (like I think most of us use) do a better job of retaining grease, but the original grease can still escape if the chain gets hotter than 165 degrees F. Another downside is you can't relube them because of the oring. I think that means (as you say) that chains need to be changed periodically. Heat (caused mainly by internal friction) is the big enemy of chain life. Interestingly, it sounded like larger sprockets may actually cause more heat, if I understood correctly. Too tight chains can cause more friction, too. After reading the article, I thought it would be worthwhile to duct cooling air towards the chain and/or sprocket(s).

The only "test" I've ever heard to see if a chain is still good is to hold a chain on its side and see how much it droops. Doesn't help us much if we want to tell if an installed chain is about to give up ...

An interesting video from my front chain during a chassis dyno run last year:
http://vimeo.com/1131103

[Richard Dziak]

In regard to changing the chain. I myself had a very close call just one month ago at Phoenix International. While I had not replaced the chain after 1100 miles on the Phoenix F1000, the car was slated to go to Dustin Wright for a complete review and inspection of the car since delivery in Sept 2007 after the race. When Dustin inspected the chain, 2 links were cut in between the rivets just two links from each other. Only the other side of the chain links kept the chain from breaking totally. The chain held during the race, but one area of the spocket teeth was shaved down. I was very lucky not to destroy anything on the car as the chain held.

Dustin suggests changing the chain at 500 miles. My AIM Dash measures mileage on the car. The original chain was a Tsubaki Sigma 530 High Performance O-Ring Chain and has a tensile strength of 10,600 and is recommended for 1200 CC max.

In reviewing chains on several internet sites, there are weaker tensile chains. So perhaps buying the best available is the best way to go.

Sean O' also warned me months ago to change out my chain. While the car suffered no damage of any kind, I know I will change out the chain more often. The chain may be one part that we overlook, and I won't let that happen again. $200 for a chain can save thousands in potential repair costs.

A good lesson learned. On another thread started today I asked what brand of chain do you all use, or buy as a replacement?

[formulasuper]

I'm no expert, but I did read the RaceCar Engineering article about chain driven race cars yesterday. It had a few interesting tidbits. X-ring chains (like I think most of us use) do a better job of retaining grease, but the original grease can still escape if the chain gets hotter than 165 degrees F. Another downside is you can't relube them because of the oring. I think that means (as you say) that chains need to be changed periodically. Heat (caused mainly by internal friction) is the big enemy of chain life. Interestingly, it sounded like larger sprockets may actually cause more heat, if I understood correctly. Too tight chains can cause more friction, too. After reading the article, I thought it would be worthwhile to duct cooling air towards the chain and/or sprocket(s).

The only "test" I've ever heard to see if a chain is still good is to hold a chain on its side and see how much it droops. Doesn't help us much if we want to tell if an installed chain is about to give up ...

An interesting video from my front chain during a chassis dyno run last year:
http://vimeo.com/1131103

I was standing right beside Russ's car when this video was made & I have to say, seeing it made me step back away a few feet. As you can see we attached a metal ruler to see if the shaft was moving forward under stress, however it never moved. All the slack that was created in the lower section of the chain was caused by chain stretch, which brings up the question, why leave any slack in the chain when adjusting it. Since that time I have been preloading my chain on my Busa powered Ralt & have never hasd any kind of chain problem.

[carnut169]

. Just the day prior I inspected each roller after a WD40 cleaning, looking for pitting and any other tell-tale signs of wear. It all looked good, operative word being "looked".

I lubed it up, and noted that it was properly adjusted, which on my chassis is approx 1/2" of play, checked while rotating the wheels and checking in the same spot (top run, 1/2 between sprockets) at intervals all along the chain, inspecting for tight or loose spots. None were found.

GC

I've seen people hold a chain out flat and look at the curve to determine wear/ stretch, use tools for measuring chain stretch and utilize the rear sprocket pull method. I understand that it's the endplate holes that stretch, the rollers only wear if there is an alignment issue.

Point is, replacing after 4 events works for the dsr guys and should prevent using your chain guard, DNFs, destroying a motor or worse, injuring yourself or others.

I ran RK GB 530 GXW & it can be found for less than $200. Never broke a chain.

Here is is for $150... (just did a quick Google) http://www.indysuperbike.com/custome...&cat=0&page=11

[Richard Dziak]

CHANGING A CHAIN........


When changing or replacing a chain, are you actually taking the CV axle apart to access the sprocket or are you leaving the CV axles in place and just fastening the chain using the new rivets and a chain cutting tool/riveter tool and replacing the chain without removal of any parts. I have not actually replaced the chain myself, but had Dustin at Phoeinx Race Works replace it. He removes the CV axle and works from that point.

Please advise......

[Wright D]

The nice thing about the design of the Phoenix is that the chain is not threaded though chassis tubes or spar supports as it is on other F1000's. This means that you can build a spare chain on the bench and have it ready to install. Building a chain in the car at the track in between sessions can be frustrating. Many times the car is down low, not to mention that everything is hot and typically full of chain lube. In the Phoenix you simply remove the CV flange bolts, loosen the chain, and slip it off the sprockets. Slip the new chain on as easy as the old one came off, bolt up the half shaft, and re tension the chain. I have done this and a gear change in less than five minutes.

In the Phoenix cars that have a tripod style CV joint the process is even faster. We simply pull the upper A-arm bolt out of the camber block, and tilt the wheel out to remove the half shaft. One bolt to remove the half shaft and chain.

[carnut169]

That sounds nice Dustin!

I broke/ installed the new chain with everything in place. They make a chain holder/ puller that makes this task easier but with good chain tools it's not that bad. Just adjust your diff forward (or put slack into the system) first.

[glenn cooper]

Russ, just saw your chain/dyno pull vid, it had been awhile. How much play, measured half way between the sprockets would you say you had at the time?
Was it a high quality O ring chain (I have to ask)?

There is definitely a need for a certain amount of downward "on-power droop" on the lower chain run of a motorcycle, in order to cope with suspension movement. This is a good thing. As our front and rear sprockets never see any arcing movement in relation to the front sprocket as they do in a swingarm equiped m/c, we don't need nearly that much.

I allways cringe when I hear someone say "I've got to tighten the chain up".
Maybe I'm taking them too literally, as I often come back w/ a semi wise ass, all knowing "Yeah you should really adjust that thing to the correct tension"...

Scott - I have never heard of a drive chain needing or benefiting from being preloaded.

EVERYTHING I know and have read points to this being a very bad thing.
Guitar strings, yes. Damper springs, yes. But preloading a drivechain seems like a good way to get it to run hotter or ceratinly wear faster.

Yeah I know you mentioned you have never had a chain break, and here's a guy who just suffered a failure telling you what's what...

But seriously, you feel that preloading it is somehow going to help in chain life?
Have you spoken to any of the chain tech folks in regard to this?

GC

[RussMcB]

Russ, just saw your chain/dyno pull vid, it had been awhile. How much play, measured half way between the sprockets would you say you had at the time?
Was it a high quality O ring chain (I have to ask)?

IIRC, I could probably move the chain about a quarter inch without too much effort.

I've been using the RK GB 530 GXW chain. Back when I was shopping it seemed to be considered the best available.

The Racecar Engineering article was interesting, but seemed to lack something. I remember thinking at the end of the article, that's it? One thing I would have liked to have seen mentioned was an idler sprocket. If I keep my race car, I'm considering adding one, mainly to make tension adjustment easier. My set up uses shims of various thickness.

[glenn cooper]

to chime in here.
1/4" of play, measured half way between the sprockets on the upper chain run resulted in the amount of chain whip witnessed in your vid?????

Something is not adding up.

GC

[RussMcB]

I probably measured on the lower run, but not sure if it makes a difference. The chain was not loose at all. That's why we were all so surprised to see that much movement. As Scott said, we all guessed that the chain must have stretched during load for that to happen.

[glenn cooper]

Did you check the free play AFTER that run?
Bottom run, top run, prolly doan make no steenkeen dif-rinse...
GC

[kmt63]

when we would dyno new cars for customers.we would always bring the tools to adjust the chain after the first few pulls.it will stretch a bit after it is first driven.we would set the chain to 1/2 inch free play between sprockets at the top.i have seen the chain slanging that russ has the vid of.thats what they do.it was a bit freaky the fist time i saw it.

[glenn cooper]

Russ, have you checked the jackshaft sprockets for true? What manufacture are they?
All it would take is a little bit of being off to start some type harmonic or whatever to whip it like it shows...
GC

[RussMcB]

Did you check the free play AFTER that run?

I'm sure we did, but I suffer from CRS so can't remember exactly what transpired. Maybe if it was 10 minutes ago, not 10 months. :-).

Like we said, the chain did all those gyrations even though it felt like it was adjusted pretty well, and then we watched/measured/video recorded the next run to see if maybe chassis flex was allowing the sprockets to move. They weren't.

The magazine article mentioned that chains and sprockets aren't smooth like fan belts and pulleys. There is a lot more complex stuff going on. It's not even a constant pull like you would think.

On edit. My sprocket alignment is spot on, painstakingly measured and adjusted.

[formulasuper]

to chime in here.
1/4" of play, measured half way between the sprockets on the upper chain run resulted in the amount of chain whip witnessed in your vid?????

Something is not adding up.

GC

Coop, The chain checked just as tight after the video run as it did before. That's why it has to be stretch, like a rubber band it returns to it's original length after the tension is removed. That's why I preload mine, to prevent having so much slack under tension. It works for me, never gets hot, doesn't wear out the chain or sprockets. I've used the same 2 chains for 2 seasons & my Busa has 50% more torque than a 1000 cc engine.