TRactor motor timing chain tensioner

[michalotti_tr]

Saw this on the mailing list and thought it might be a good subject for the Forum:

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On page 23 in the book "More BS about TR's", Bob Schaller talks about his version of a modified timing chain tensioner. He retrofitted a Toyota 20R oil pressure tensioner to his timing cover.

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Has anyone done this? Any advice, caveats, tricks to share?

 

[ALLAN]

what is a oil pressure tensioner?

 

[michalotti_tr]

Sorry, I quoted directly from the other inquiry: an oil pressure tensioner is a timing chain tensioner that uses the oil pressure to supply the tension on the timing chain.

 

[billspit]

I assume its about the same as on my Nissan truck. It has a small oil gallery to the oil system to provide pressure to keep a little tension on it.

 

[tr6lover]

heh timing chain tensioner?........i am putting a set of timing gears in my engine when i start assembling it. ill have to take some pics and post
randy

 

[AlanT]

At least one consideration is how much oil pressure the tensioner is designed for. For example if you use an MGB tensioner designed for 60lbs of pressure in an Aston-Martin DB4-6 engine which pushes 140lbs of pressure ,the tensioner will last about 3000 miles and you get to buy 12 valves and maybe pistons. Not really a problem on a stock TR engine.

 

[vettedog72]

Alan:
I all ways wondered about high oil pressure and the "wash out" effects on bearings. The idea was if the pressure were "too high" (don't have a clue waht too high is) there would be an erosion process that would basically wash out the bearing surface and prematurely wear the bearing beyond limits. How does the Aston avoid that?

 

[AlanT]

Aston-Martin engine tolerances were the tightest that I have ever seen. There are three sets of standard ,.010 and .020 bearings. (black red and green markings graduated in .0005) If I remember correctly the rod bearing to crank ran at .001.