I built this Engine like eight years ago! Bought it back 3 owners later Street/strip car. Im going to use it again

I have had two mopar chain tensioners break on me, both times they broke at where the spring is attached to the tensioner. Second one broke off and started to wear a hole in the side of my billet aluminum timing chain cover. I will NEVER! use one again on a performance engine.

Article was in Circle Track, yes it was probably a 355 chevy and the chain and gear were about the same while the belt drive made more than 10 more hp.

R.

I put one on my 360 truck engine that had a double roller timing chain, but I don't have very many miles on it, so I'll just see what everyone else thinks. Maybe if I get to a point where I need to remove the cover, I'll check it for wear.

IIRC that was a 4 gear drive, not a 3 gear.

I'd love to see the article if it was a 3 gear. Can you post the link?

I just use a good double roller chain, less friction.

Less friction than what?

Motor oil on nylon.. cant get much slipperier than that, I would say the friction would be minimal at best, also mine has been on my 408 for 7 years now with no wear issues or breakage.

I have torn apart 100s of magnum motors and only see them on 5 speed equiped trucks from the factory, supposed to keep it from jumping if you park pointing up a hill with the trans in reverse or vise versa. If you acidentally let it pop backwards it can make it jump when the chain gets sloppy. The 318 in my dakota with 5 speed came with one so they are not V6 only. Also they never used them with a double roller chain only the one with all the links sandwitched together so lots of surface area to absorb the load.

Based on all the guys with problems VS no problems I would say don't use it but I have never used on on anything but the factory style chain in a rig that came with one from the factory.

As to the "wears out the tensioner pads" issue - timing chains are built from a lot of stamped steel pieces that nothing has been done to dress the rough stamped edges. I wrap the chain around the timing gear and dress the edges of the outside of the chain with the wire wheel on the bench grinder, followed by a very thorough cleaning. This knocks loose and removes all the little burrs that chews up the pads, and leaves a noticeably smoother, almost polished surface.

Pretty simple fix, HUH?

with this, rough edges from the stamped links can act as saw teeth and cut the nylon pad.

I find it kinda funny to see how many guys think the need justifies the risks. I can't tell you how many 9-10 second passes I put on a "high quality" low cost timing chain and never had an issue with jumping timing. Heck I don't even have my MSD distributor locked out and only use a thrust collar. And my junk is raced weekly from April 1st into November. Maybe for those running a cheap timing chain its worth the risks.

Here is what the tensioner pad looks like after a few dyno pulls when using a high perf double roller chain.

Small block mopar didn't come with them for decades with no problem now people insist you need one.

Use a good double roller and call it a day.

Thought I'd add my experience to this.

Chain tensioner spring broken after less than 40 hours. Pieces of spring in the oil pan. Cloyes chain, Cloyes tensioner.
The broken spring end also wore a hole in the timing housing.

If there are problems/failure with the chain tensioner there are assembly issues that were not resolved...
No ifs ands or buts. I'm sure the choice of chain has a lot to do with "problems".

I ran small blocks on the road course for years [decades] with a tensioner. 4 engines built with tensioners. One engine had to come apart due to valve springs fracturing [chinese mopar performance springs] . No issues found with the chain and tensioner - tensioner was reused....thousands of miles road course pounding...then thousands more. Extended periods of operation between 2500 - 6500 rpm - like 45 minutes of non stop pounding beside thousands of miles of spirited driving. [go get your hellcat] The engine that had to come apart had over 12,000 miles of pounding... If there was going to be a chain tensioner problem i would have found it. Must be lucky... The tensioner provides rock solid timing and keeps the cam from running "late".

I would certainly not rule out any assembly or parts selection issues.



If anyone is able to suggest any particular issues I should consider, and also how and why I could choose a more suitable chain, it would be much appreciated ?





Thanks

Matt

I won’t use one again. It was a roller master iswis chain. Not many miles/runs on it. It broke the guide and the flat spring started to chew through the side of the cover. I will just buy the best chain I can find and know it is a maintenance item. Wasn’t a ton of spring pressure either. 130ish on the seat solid flat tappet.

I used them on several motors through the years. Always with a good double roller timing chain. There is NOTHING wrong with trying to better control the timing, so it makes sense why you'd want it.

That being said, on my last build, when I took it apart to freshen it, mine looked EXACTLY like AndyF's picture above. I can't tell you why I had some success before, and later not. My guess is it has to do with how tight the chain is to start with. When the chain is really tight, you really have to preload the spring on the tensioner. I'm guessing that side load really digs in sometimes, and not others for whatever reason.

For the record, I won't use them anymore. Not worth the risk in my opinion for minor gains.

My daily driver 69, 340 4spd dart, occasional strip car has 12,500 miles on my tensioner. I put one on it to help fix my slopped double roller chain. Even has the chain that's not smooth and supposedly wrong for a tensioner. Have had it apart 3x changing my solid cam to hydro street cam every time I go race it. Looks like the motor has never rotated it looks so mint. Don't ask me??? But that's my experience