ilko

Since the 1986 MY 951's don't come with it I was wondering if it's worth spending the extra $$ on an auto tensioner. What are the pros and cons of doing this?

Oddjob

Dont think you can add one to a pre 87 block - Im about positive that the mounting points for the auto tensioner are not cast into the blocks prior to MY87.

jacklet

no they are not, do a search i don't even know if you could drill an 86 block for them

ilko

Oh ok, I didn't realize that. I saw an auto tensioner for sale on Ebay and wanted to get a feel of how that would work on an '86.

Thank you fo answering my n00b question

sharky47

You'll find mixed opinions on this. I personally do not believe the auto tensioner is worth it. It does not tension during operation, only when you loosen the nuts and release it. It doesn't always tension accuratly and is a headache to work with - I would just as soon change out my late cars the the eccentric roller type tensioner - but to each his own......

Ski

The bosses are there so yes you can drill them, tap them and have one, as jwl did for his 86 2.8L conversion. As Daniel said, feelings are mixed. If you get one that binds up, they can be a PITA but if you have a good one that springs back right, it can almost be on the mark for perfect tension.

Perry 951

I also put the tensioner on my '86 block. Drill and tap the holes on center, toss in the studs, and bolt it in.

ELLSSUU

Yes the bosses are there.

Brett and Perry, Terry and I have kicked around the idea about drilling my block to accept the auto tensioner. If you had to do it again.................is it worth it?

Ski

I have a nice free tensioner, jwl bought one from 944 ecology - both of them, you can push it down almost as far as it goes, let it pop, and belt tension has almost been spot on where you would want it. I like the idea of adding one personally.

951collector

I would definitely advise doing it!

I had the stud from the eccentric bolt shear and wreck a $3k head. I have also heard of others having the same thing happen.

The bosses have been on all of the blocks I have seen.

If you buy a new tensioner make sure it is assembled properly. I have had them sent to me wrong...So has 951Perry......he had a few belts snap because of it.....People here were telling him his block was warped!

Go to clarks-garage.com and look under "timing belt tensioner failure to see the ugliness that can happen!

ELLSSUU

Do you know the depth etc. that was drilled? Did you take it to a machine shop or what?

951collector

I know that you were not asking ME....but, I drilled them just long enough for the studs/bolts...you don't want to go too deep(ouch). I actually did one with the engine in the car, which is a bit tricky but possible. Drill it, tap it and go.

I know I appear to be a noob but I was on the rennlist before it was the rennlist...I just forgot my password.

ELLSSUU

Not a doubt about you in my mind as if you were able to add the tensioner then you're def. got a notch or two on me. I think I'll try it.

Terry, you still have a tensioner laying around?

951and944S

I probably have a good tensioner laying around somewhere.

The key to make them operate as new is to disassemble it completely, clean all parts thoroughly and reassemble with lithium or high temp moly grease.

The springs are said to weaken over time but in fact it's pretty well isolated from heat and it's not as if the spring is active.

I attached a few pics that I've transferred from hard disc to hard disc as the years went by. They're from a block that I sent to Perry, 86, without tensioner, showing the bosses where the threaded holes should be on later blocks.

Also a picture of a later block and a tensioner....

Brian - I have a few old archived pics if you're interested for posterity's sake...

TS

951collector

You will need a right angle drill if you are going to attempt it while the motor is in the car