V6 Timing chain questions.

[vlad01]

I've got some questions about V6 timing chains and people's experience with them when modifying engines.

I am wondering if the Rollmaster double row sets are reliable long term, say on a mild to moderate daily driver?

Will or can they last say 2-300K ? I expect them to stretch like any chain but is this a problem long term that results in a failure?

Related to the above question, since it's hearsay that a Rollmaster shouldn't run a damper. Is this really true? I have heard conflicting recommendations and some evidence either way.

I've seen one old video on youtube showing new and old Rollmaster on an ecotec and the stretch was quite a bit, but on the new chain it was IWIS and on the used chain it was Rollon which are know to be shit and stretch. So all in all a pretty useless comparison.


If they do stretch, does the chain whip cause issue such as further stretch and failures?

I imagine cam size has some influence on these issues.

I found some old posts on a Buick forum talking about damper failures and fast wear from mere spring upgrades. A fair bit was mentioned by OZ38 who's a member here.
I speculate this is due to whipping that a combo of inertia from the factory balance shaft and the higher spring pressures.

For double row, there is no balance shaft so the valve train has no effective inertia, so only load in theory, so I would imagine there wouldn't be this whipping.

A recent factory chain replacement on my shitbox resulted in a very noisy balance shaft bearing and gear chatter due to a tighter coupling. So proving these things are not intuitive or straight forward.


My rough plan is to freshen up the engine in the white car after change of plan (acquired a T5 box and bits for a conversion, getting rid of the built auto) and I am thinking of, Mahle forged slugs mainly for the higher comp, crow stage 3 cam (mild 207/210 and 470 lift) and just good quality valve train and some mild head work, stock everything else. I have 100% confidence in everything except for the chain long term.

My red car has similar specs but a bit more wild, not by much and I can beat on it and no issues what so ever, but I don't drive it daily and have not done anywhere as many Ks to know if there will be any issues. I think I have only done maybe 4k so far.


One consideration I am thinking about is having the Rollmaster driven sprocket's teeth hardened since they aren't. There is a mob in Melbourne that do all kinds of hardening and have a fantastic rep for these things. This should reduce the perceived stretch since most factory chain I found most of the slack comes from wear on the teeth of the sprockets and chain teeth than the stretch itself. I have new chains and 400K stretched to buggery chains side by side and there was not much in it regarding stretch but tooth engagement you could clearly see and feel how far down and loose the old chain sat inside the valley of the sprocket. That's my idea anyway and will reduce wear regardless.

Rollmaster make a all nitrided set but they are vernier type only which I would not trust long term due to the pissy 6x M6 cap heads that hold it.

[vxcalais]

Hi vlad01, did you ever find out any answers to your questions ? I am eying off between single (strengthened) crow chain or double row chain. Everyone here in Australia use the double without a tensioner but seems the likes of Intense Racing and ZZP in the states all used tensioners with both performance single and double row as they all eventually stretch. Then there are those saying there is a double for tensioner and one without. Don't know what to believe any more.

[vlad01]

The consensus was any aftermarket roller chain, don't run a damper even if they stretch a little. Silent chain (OEM) run the damper, they are way more loose than the roller chain sets, new and old.

I think I even asked Dandy engines when I was bored one day at work as was near the area and picked their brains a for a bit, I recall they said never run them with the Roll master stuff, or at least they don't.

I have the Roll master single on my VR with a damper, I haven't seen any ill effect yet and it's been bit over 10K and hard abuse and over 10 years years now. But the chain was tight as upon installation and I have no balance shaft so it was probably completely unnecessary. Worth mentioning that roller chains have much smaller contact surface compared to OEM on the back side, so a damper will wear worse on them.

Also, the Formula Holden guys have been running the same Rollmaster double row sets for decades with 0 issues and they def do not run a damper and they are the best test for this as they run very high rpm and have the biggest valve train strains out of any V6 out there other than Indy 500 Buicks of the 80s.

They also have stuff all suspension and weight in the cars, so they jut across the road making the rpm flutter very often (broke cranks partly because of this in the 90s) and they do not run a harmonic damper or have any weight on the crank pulley and have super light flywheels, so the crank and valve train harmonics are off their face on this historial series, yet they reported no issues with the chains or valve train surprisingly, but they have had rod bolt failures here any there but they put it down to ARPs hit and miss with QC and bad batches of bolts getting out in the market (has happened at least 3 times in the last 15 years from anecdotal clusters of people reporting failure), rather than a problem with the engine combo as all of them who have switched to Carr bolts have had exceptional reliability from the engines.

Anyway, I take that sort of good endurance as being a non issue to have no chain damper.

[immortality]

How many miles do they put on a timing chain though before it's replaced?

[vlad01]

Here is a good video about chain wear and the stretch that comes with it.

https://www.youtube.com/watch?v=d7cWv_ccJtA

[vlad01]

How many miles do they put on a timing chain though before it's replaced?

Not sure, they do hours of use instead. I vaguely recall something like 50 hours? I assume an average speed of 160kh/h which I recall reading somewhere once, I think how they were our fastest race cars for a long time, averaging faster than V8 supercars at the time of the article. So maybe 8,000km of race conditions?

I suppose I can ask one of the guys in the know of the group.

[vlad01]

Also, going by that video and that I know roller chains need good lubrication. I thought, what if an oil squirter is added to help lubricate the chain directly and not rely on oil mist and splash.

Turns out some engines have them as standard, apparently Holden V8s had them in some models? I only found one forum post somewhere that mentioned and showed a pic of it.

There are aftermarket SR20 chain squirters that are just a M7x1 thread and can be plumbed into the oil galley or supply and positioned within the chain loop.

[Gareth]

The double row ever so slightly rubbed on my oil pump cover, more like polished. Check out the corrosion from the E85!!

[immortality]

How many miles do they put on a timing chain though before it's replaced?

Not sure, they do hours of use instead. I vaguely recall something like 50 hours? I assume an average speed of 160kh/h which I recall reading somewhere once, I think how they were our fastest race cars for a long time, averaging faster than V8 supercars at the time of the article. So maybe 8,000km of race conditions?

I suppose I can ask one of the guys in the know of the group.

It's a good test of strength but not a for longevity. I'm also fairly sure in those 50 hours or what ever it ran it always had premium/clean oil.

It's kinda like an add on TV where some car company takes a random engine off the production line, puts it on a dyno and sits it at max revs for many many hours. A great test of assembly but nothing resembling what a real engine experiences during it's life in a car.

Also, going by that video and that I know roller chains need good lubrication. I thought, what if an oil squirter is added to help lubricate the chain directly and not rely on oil mist and splash.

Turns out some engines have them as standard, apparently Holden V8s had them in some models? I only found one forum post somewhere that mentioned and showed a pic of it.

There are aftermarket SR20 chain squirters that are just a M7x1 thread and can be plumbed into the oil galley or supply and positioned within the chain loop.

Yes the Holden V8 comes standard with an oil squirter for the timing chain but normally it's deleted in performance builds. There are 2 oil bleeds in the timing cover on the Holden V8, one at the end of the oil gallery which as I understand it is just to assist with getting air out of the oil system on start up and the oil squirter for the timing chain. Typical practice is to block one and re-direct the other at the oil pump drive. Either way there is plenty of oil in the timing cover, roller chains shouldn't need a huge amount of oil.

Some engine builders also drill a hole from the engine valley into the timing cover to aid oil drain back as that is a major issue for the 304.

[vlad01]

The double row ever so slightly rubbed on my oil pump cover, more like polished. Check out the corrosion from the E85!!

IMG_2707.jpeg

That was a standard oil pump cover from memory wasn't it?

What was the chain like? looks a little stretched going by the marks.