All double rollers are not created equal
Got a source for those claims of mismachined blocks? That would be interesting to be sure, and I'm going to wager paper money the chain tensioner was more about controlling timing as the engine wore to maintain emissions.
Nothing wrong there. Once it wears down to the rollers, it's going to stop wearing and that wear won't amount to enough plastic at any one time to hurt anything. HD uses tensioners like this on their primary chains, and they last for decades. At best, I'd consider machining grooves into it so the wear wouldn't happen like that from the start.
1980s introduction, the LA 239 V6 (and later the 3.9-liter Magnum V6) engine experienced a rattling or lifter-type noise in the timing chain cover area. As a fix to this problem, Chrysler issued technical service bulletin (TSB) #9-07-97 for the 1990-1997 V6 engines. The TSB required the dealership technicians to verify if chain/lifter noise existed, and if present, they were instructed to install a timing chain tensioner.
Why a link chain? First, we felt a factory-type link chain would provide a greater surface area to ride against the guides of the tensioner. This increased surface area would reduce the wear on the Teflon® surfaces of the guides.
A roller-type chain would dig into the guide surface to the point of the increased surface area of the roller links. Second, a
link-type chain reduces chordal action. The term chordal action describes the rise and fall of each link of the chain at the time it makes contact with a sprocket tooth on a timing gear. The rise or fall results in linear variations of the speed of the chain, and if the rise and fall are significant, the camshaft operation may be jerky with excessive noise and rapid chain and sprocket wear. Our chain would have minimal chordal action resulting in smoother camshaft rotation, reduced noise, and increased timing chain longevity.
Lastly, the link chain design has a smooth tooth-to-link action, which reduces the link impact and, again, increases timing chain life. A disadvantage of the link chain design is its reduced ability to work well with increased camshaft loads. A second disadvantage, the link-style chain cannot operate effectively with complex chain layouts. In both cases, we believed our link chain would be acceptable because we were using a stock camshaft and valve train, and the timing chain layout was straightforward.
So if your going to be running a stock camshaft you will be able to run a tensioner safely with a factory type chain and gears. This type of chain is not strong enough for greater spring pressure and lobe lift when using a larger cam and springs as stated above.
You didn't have to ask me to prove anything this info it is available all over the web. I only copied it and pasted it. But guys like you just like calling people out because your probably one of the idiots that wasted your money on one. Before you ask for proof maybe you should fact check yourself.
I am only sharing this info to inform the many members who listen to salesmen like you and waste their money. You all can do what you want but don't say you have not been told.
If you are building a stock engine with a factory type chain and gears the tensioner can be used, If you are building a performance engine with a larger cam and a true roller chain and sprockets the tensioner should not be used . Remember use a "double tru-roller" not a junk "double roller" Double rollers are to look at and say you have a roller chain . Installing it is a waste of time.
As far as mis machined blocks. Why would you think some of the new engines had a chain slap? And why not just install another chain? We see mopar blocks like this getting done. Mopar blocks have a raised cam tunnel and have a problem being out of spec on late 80's and up engines . That is why you can get expensive different length chains for them. My R3 block has this issue as did one of my X blocks.