V6 Timing chain questions.

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V6 Timing chain questions.

Postby vlad01 » Sun Jun 25, 2023 8:28 pm

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.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.

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