1.8T oil pump chain tensioner: Yes or No

[rongeur]

I am looking for some discussion regarding the 1.8t oil pump and it's components. I am in the middle of building a spare engine that had a balance shaft oil pump failure and instead of repeating the same risk of failure, I opted to try the 1.8T oil pump conversion for cost and simplicity sake. I went with the USP kit instead of building my own and had it delivered to the machine shop to install along side the rest of the internal machining. I finally received my engine back from the machine shop and the machinist felt that the oil pump would better be served shimmed using the intermediate plate from the original pump to take out the slack in the 1.8T oil pump chain and thus eliminate the need for the chain tensioner. I had him drill and tap the hole for the tensioner should I decide to not use the shim and stay OEM design (to the 1.8t pump that is). Pictures of the eliminated tensioner and machined intermediate plate are below.




The machinist I worked with was previously not available to the public and was contracted with high end engines for rebuilds (Ferrari, race engines, formula one etc etc). His take on the OEM tensioner is that is it a piece of s*** and just one more thing to fail as it is a bad design. I admit, I agree with his reasoning. There are many people who had complained about failing tensioners and exploding into plastic bits in the sump.

I am looking for some other educated opinons regarding race engines and chain tensioners and what the risks I am running not using one. I am cautious because I can't find much information in regards to other examples of eliminated chain tensioners. As it is now, the play in the chain is 1-2mm max and I cant imagine it skipping, especially once everything gets to running temps. When I removed the intermediate plate, the tensioner sits as most pictures online show, but the chain is pretty loose to the point if the tensioner fails, that chain would start smacking front seal and imminently fail if the plastic chunks don't starve the oil feeder first.

[aluthman]

Did he mill the intermediate plate down where the pump sits on it? Based on pictures I have seen of the 1.8T tensioner, I can't really argue with his logic.

[vce1232000]

I with the machinists expertise in using a shim instead of the tensioner. Also like too

[rongeur]

Yes, he milled the plate down to a determined spec which I assume was intentional for the application.

[aluthman]

The only thing I would be concerned with is longevity. The chain will stretch some as it ages, so will it still be good or will you need regular chain replacements?

[rongeur]

Time will have to tell, hopefully not at the expense of low oil pressure issues.... May consider dropping oil pan after some time to check for early wear.

[aluthman]

Ask the machinist if it is an issue on anything else he has built.

[yeoj112689]

The only thing I would be concerned with is longevity. The chain will stretch some as it ages, so will it still be good or will you need regular chain replacements?

This would be my thought as well because if there wasn't stretch tensioners wouldn't be needed. I would be to nervous to wonder if its going to jump off due to stretch.