racer7088

Quite a few circle track builders now use the Rollmaster exclusively since they seem so strong. RDI will not even use some of the Cloyes right now on the Ford stuff. They go strictly off of feedback and real racing experience with these parts. They have had the best overall experiences with the Rollmasters and this is real racing use at high rpm and spring loads for long periods at a time and not occasional street racing and normal street driving 90 percent at very low rpm. Therefore again what we are doing in the LS1 world is a total CAKEWALK for a big double roller like that.

Could it break? Sure as ANYTHING can break but again it is just extremely unlikely since the LS1 is so easy on timing chains in the first place. People like the Double rollers for strength and longevity as they do typically last a lot longer under bad conditions. Breaking the chains with the kind of stuff that was being mentioned is just a huge rarity and that should throw a red flag up to any normal engine builder.

I HAVE seen many broken LS1 chains but they were all on cars where the owners did the installs themselves and none were Rollmasters and only one was a double roller. I have ALSO seen where people put timing chains on with hammers and screwdrivers and have bent links and chewed up gears and loose bolts ALL the time and the things still didn't let go yet but they were on the way so that is why I am saying this.

The important thing is that you find out what really caused your problem even if it was the extremely unlikely "spontaneous and unexpected chain breakage" problem we are going over here. Just don't fool yourself.

racer7088

MIke I have seen people run engine with no oil in then and not tell anyone untill they got busted. We have another car running right at coil bind here from a local shop that took out some springs and so on and so on. I could write a ten page book. Only you know what your situation is so you have to go from there. I regularly talk with techs from many shops that have no idea even of the installed height or lifter preload they are running and in fact I have never had one yet that knew EITHER if I asked them or the P to V for that matter. I TEACH this stuff and know exactly how bad people are about it as I have a large number of certified and experienced mechanics even at the school.

Also the chain could have been damaged but you usually see that when initially cleaning the chain before installation. A little inspection goes a long way as I've found some crazy things in my time. I've been racing cars since 1983 pretty regualrly. For 17 years I raced every other weekend and won quite a few different championships in the SCCA and we are quite a bit harder on stuff than the 1/4 mile people are besides the NOS effect!

Boostaholic

iTrader: (4)

Don't be, there are plenty of people including myself running these chains. I bet this one was just defective.

777

iTrader: (21)

cleaning the chain? what do you need to clean the chain for...i didn't clean mine..it was in a plastic bag..but it was like pre-greased..

Midnight F-117A

I had a timing chain break in a '74 Nova with only 60k on it.
Was going down hill, just let off the throttle, halfway downhill the engine stopped like someone turned it off. I put it in netural and attempted to restart it, no go.

So that left me with muscling the steering to a right corner at the bottom of the hill.
Tried to crank the engine and thought it was firing but not turning over; that was the sound of a piston smashing a valve inside!

Had the car towed to a shop, they took it apart and found out the timing chain broke.
It needed 2 new complete heads since the valves beat up the heads good, the pistons were fine.

2 years later, I took it to a shop finally that knew what they were doing (they're no longer in business, went bankrupt)
They took the valve covers off and noticed only 2 rockers moved very little, not the full range the other rockers were doing.

The old engine was taken out and I tore it down, found out the camshaft had cyl #7 intake lobe worn out to a circle and same thing for cyl #8 but it was the exhaust lobe. I still have the camshaft in my garage attic to show that indeed a cam can wear good and round off to a circle.

A new 377 stroker engine was put in with a 700R4 transmission.
It didn't run powerful as I excepted it to. About a 1/2 yr later, I had another shop look at it, they did a compression test and found 2 dead cylinders, WTF! i was running a V8 in a 6 cyl mode the whole time while it was installed.

The shop took the engine out and had it sent out for overhaul, the damn overhaul shop took over 6 months to finish it (really don't think they started working on it when it came in) and the mechanic was suspicious of the engine when it came back to the shop, he took it apart and found the camshaft bent, 2 pistons were cracked. He had to do the work at the shop in replacing all the pistons and the camshaft and disputed the charges with the engine overhaul shop.

Now it's in my driveway waiting for the spring to finally come. So much work and time wasted in this...

IconAutoSports

iTrader: (1)

Caribe, any updates on what happened? Any further damage?

Caribe

iTrader: (1)

They're pulling the heads in the next couple off days. I'll post up here when we see exactly what happened.

Tony99SS

iTrader: (5)

I may be able to shed some light on the so-called "unexplained" timing chain breakages referenced above.


My 99 SS with cnc ported heads, 918s, Ti retainers, TR 7.400 pushrods, TR224 on 114, and Cloyes Hex-a-just timing set w/ GM OE chain had about 5000 hard miles when the chain broke. Teardown revealed that there was apparantly enough slack in the chain that a lazy 5700rpm shift to fifth on the freeway induced a resonance or something of the sort in the chain. This resonance carried all the slack in the chain around to about ten o'clock on the upper sprocket - the point of least clearance between the chain and the block. When the cover was removed the chain was still jammed between the block and cam sprocket. Five bent valves later... I find myself no fan of Cloyes timing sets and a new disciple of chain dampeners.

Let me stress that this engine had 46,000 miles on the bottom end, but only 5000 on the heads and valvetrain, including both the sprockets and chain of the timing set. Any assembly errors would have materialized long ago, as I don't baby my car one bit. Three dyno pulls, four open track days (MSR and TWS) and lots of max effort street runs both around town and on the open road surely would have shed light on a problem (except perhaps chain stretch) long ago.

My conclusion: anything can break, give the right circumstances and stresses. Take all precautions possible: in this case I would say run a dampener in all manual trans applications.

Tony
(I need to update the colection of broken parts in my sig some day)

Lvmyz28

iTrader: (1)

I am also running a rollmaster double chain. I've had it on for a good 10k miles with a pretty big cam and no problems. Sometimes you just get a bad one. Maby the cam gear had an imperfection in it, maby one of the links in the chain. It happens!

StevieZ

iTrader: (3)

I've changed my cam and heads 2x and I found that the double rollmaster had loosened quite a bit. It was rock tight when I installed it and had about a 1/4" play last time I checked.

IconAutoSports

iTrader: (1)

Some updates... When we pulled the pan, we were only looking for one half moon shaped link. Well we found 2.

In the first picture, it looks like only one half link is missing...


We closely inspected the chain and found another link broken about halfway around from the first one...

TheMNkid

Great, I also have one but have not installed yet! It came highly reccomended but now I am second guessing it! We need more info! Sorry for my ignorance, but what is a dampner?

racer7088

If it makes you feel any better. All the ones I have seen broken were NOT Rollmaster. But most were the results of less than competent people and shops.

Mike's above is not what I am talking about but his could have been damaged before delivery etc. Who knows? It is also "possible" that it was defective as was said before but you can probably ask him yourself how many of these Rollmasters he's seen broken vs. the other brands.

ss rally red

iTrader: (8)

I am on my third cam with the stock chain(stock,hotcam,F11) everyone has and is welcolm to their opinion but even on spray I sleep well at night NOT worring about my timing chain breaking,flame away.

racer7088

Yes up until the last few years we used several stock chains even in solid rollers too. They are pretty loose usually since they are put on at the factory by machines but other than that they are decent. Nowadays with the bigger cams and especially solid rollers we always use the bigger chains.

black_z

iTrader: (4)

Shitty luck. That sucks man

Z06kern

iTrader: (18)

My double roller broke a few weeks ago, just now got a chance to tear the motor down. All the valves are bent and need to be replaced, no piston damage just a few scuffs that can be cleaned up.

The motor is a C5R blocked 427 in a 02 Z06 making 530RWHP. The car is street driven and the chain broke when I was going through the gears on a highway run approx 4200RPM.

I guess these double roller chains break more often than everybody thinks. The motor had several 1/4 mile passes and about 8 dyno pulls on it before it broke without warning.

I installed the double roller for cheap insurance that something like this would not happen. I just hope the motor stays together after I repair everything, who knows what this does to the bottom end even if there was no piston damage.

Z06kern

iTrader: (18)

My car fits this profile exactly this seems very strange!

ROCNDAV

iTrader: (100)

That does suck! People pay more money for these double rollers for added insurance against breakage. I just looked at my double roller and the links do read ROLON which I guess is the Indian brand. I heard that cars where these had broken were mostly T56 and the drivers downshifted/engine braked a lot. I do this so now I am scared. I don't want to get this thing together and have it break a few miles down the road.

Does anyone know if just the double roller chain can br purchased with out the gears (especially since mine hasnt been ran yet)? Are the JWIS much better or does it even matter?

Were the cam sprocket and crank gear within .010" of each other as installation instructions dictate?

ROCNDAV

Z06kern

iTrader: (18)

I still don't know if I'm going to put a double or single roller on it now. It seems it makes no difference, one thing for sure is I will be using the timing chain dampener. For as mush money as I spent on this motor making it "bulletproof" one of the cheapest componets break and take the whole motor with it.

Hell, now I'm afraid to run the motor hard the whole reason I built it up in the first place.