tensioner replacement 6MBT5.9

[jeandebe]

I need to replace the tensioner on my ’86 6MBT5.9 210 on a 1987 Alura 30. The original has been discontinued. Picked up a new tensioner, Dayco #P5333477, from Seaboard Marine. Looks like it might work, but the notch on the new tensioner doesn’t fit in the current bracket/plate. Is it possible to get/order a bracket that would fit the new tensioner? Has anyone else had difficulty replacing a tensioner on a very old (but well running, thanks to Seaboard Marine) 6 MBT5.9 210 or similar?

Topic

[jeandebe]

got an answer

Jack and Brendan teamed up to help find an answer. They found a combination of a replacement tensioner, bracket and idler pulley that would work on my ’86 6MBT 210. Awesome! Can’t wait to install it.
So appreciate the advice from the forum, Tony and the staff at Seaboard Marine. Makes such a big difference. Thank you!!!!
Below is a picture of the tensioner, plate and idler pulley assembly.

[jeandebe]

tensioner pictures

Your pictures were really helpful. Thank you so much for sharing your time and expertise. Looking forward to your findings.

Also thank you for your helpful staff. Each of them have been so helpful with advice, finding parts and availability. They are awesome. All of you are so appreciated!

[Tony Athens]

I found a picture–Early Belt wrap with late flipped over idler. I am now 99% sure you just have to re-look at the mounting.. But also, because it is tensioning INSIDE the belt ( like a QSB does w/ a grooved pulley) it very well could, or is a different part…………..Need to do some research this week.. It’s been a long time.

[jeandebe]

“flipping it”

Thank you for your response, Tony. By ‘flipping it,’ do you mean flipping the bracket – unbolt it and turn it 180 degrees so the bottom is the top and the opposite side is facing you? If so, how would I know if the hole in the bracket for the node is in the correct position for the new tensioner. (the old tensioner didn’t use a node, it was held in place by tab of metal protruding from the back of the tensioner) Would flipping the bracket change how the belt was reapplied?

Would it be easier to know the new tensioner was in the correct position if I ordered a bracket to match the new tensioner?

[Tony Athens]

Old vs New style tensioners

Study these two pictures for awhile. You have the earliest design of the “belt wrap system”, and when you want to use a new style tensioner with the old bracket/belt wrap, you need to “flip it over”.. Then, all lines up properly.

It’s been a few years, but “I believe” it applies even when using the old style belt wrap bracket like you have..

Identifying Early & Late Style B-Series Belt Wraps

[jeandebe]

opps – one more pic

sorry this pic didn’t appear in the last reply

[jeandebe]

here are pics….

Pics of new & old tensioner- both sides, front engine belt assembly with old tensioner.
Also pic of how old tensioner attached to bracket (it just rested on the bracket with a tab of metal as the notch. Then pic of new tensioner on the bracket. (doesn’t fit well because it has a round notch) And, pic of bracket without any tensioner.

[Tony Athens]

Put both tensioners side by side– take pictures of both sides..

Can I “see” a front view of your engine with the old tensioner in place ?

Something sounds odd……………………………………Tony

[Author]

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