First Belt Tension - Is Two Out of Three OK?

[OK-944]

I know...there are a gazillion posts on this topic - but this is the first time I've set the belt tension on my 85.5, and I'd like to share a couple of observations.

I'm using a Krikit tool, and a few other criteria.

With the belt in place and everything timed - I set the belt with the forefinger and thumb "twist" method to get things in the ballpark...then gave the crank a couple of clockwise turns by hand to assure that the belt was more or less settled, and that timing remained accurate and consistent - which it did.

I then took a Krikit reading and came up with a little over 40 lbs. I then backed up the crank about a tooth's worth (as per Peter Arnn's suggestion) and read again with the Krikit - and got a little less than 40 lbs. This seems about right. The belt had been used, but only until retensioning by the P.O. Arnn suggests 38 lbs for a "used" belt - and he does specify backing off on the crank prior to taking the reading...which I did to arrive at this figure. I took multiple tests with the Krikit to make sure of consistency. My "thumb twist" test seems ok also...and I've gone ahead and torqued down the tensioner bolt.

But what has my scratching my head still is that I cannot for the life of me get the waterpump pully to move by hand pressure (one or two hands) as has been noted by other DIY belt tensioners as yet another criteria to test cam belt tension. What should I make of this? The waterpump itself has a few miles on it...but its bearing in nice and tight.

My inclination at this point is to move forward...get everything back together but leave the front engine cover off so I can see the belts as the engine runs, look for either belt flapping or whining...and do a little more checking with the Krikit.

Sorry if I sound obsessed...but I definitely want to get this right!

[HondaDustR]

Just make sure you do the water pump test at TDC, not with the crank reversed at all. You need to keep all the tension on the long side of the belt by slowly appoaching TDC from the normal forward rotating direction and stop without the crank reversing at all, say from compression, but that shouldn't happen at TDC if you approach it slowly. The WP pulley should turn but only with some effort. Slipping it with one hand no problem is too loose, and impossible to move is too tight. If you reverse the crank rotation at all, it transfers some or all of the "slack" to the long side of the belt, increasing the tension on the WP side, and giving a false high tension. This method is best used along with gut feeling and other methods, such as the twist method.

[Slam]

Appears to me you've got it right. Do the WP check as HondaDustR says, then go ahead and torque everything up and start the engine while having a look. When I use the krikit I do best of 7 readings and shoot for 38lbs, as you've got. There are as many schools of thought on this as there are 944 owners, but what it really boils down to is that as long as you are in there often enough and change your belts every second year or so you'll be fine.

[John_AZ]

I had the same Krikut and used the 90 degree the first time. I spent 3 hours one evening and then took it apart and re tensioned the cam belt the next day.

If the belt is too tight on the WP you will burn out the WP seal or the bearing. I am certain your waterpump pully can move easy without belt tension!

If CCW 1 tooth is not enough-----------turn the crank CCW until the cam gear moves 2 teeth to loosen the pressure on the WP pully. Use the Krikut to tension-tighten tension nut--turn the crank 4 times clockwise, and check the WP pully again. Now it should be too loose. Repeat again normally without the CCW rotation on the crank and check again. Repeat until the Krilut and WP pully test both seem right.

GL
John

[HondaDustR]

Originally Posted by John_AZ

I had the same Krikut and used the 90 degree the first time. I spent 3 hours one evening and then took it apart and re tensioned the cam belt the next day.

If the belt is too tight on the WP you will burn out the WP seal or the bearing. I am certain your waterpump pully can move easy without belt tension!

If CCW 1 tooth is not enough-----------turn the crank CCW until the cam gear moves 2 teeth to loosen the pressure on the WP pully. Use the Krikut to tension-tighten tension nut--turn the crank 4 times clockwise, and check the WP pully again. Now it should be too loose. Repeat again normally without the CCW rotation on the crank and check again. Repeat until the Krilut and WP pully test both seem right.

GL
John

Wait, doesn't turning the crank CCW, as in backwards, actually increase the tension on the tensioner/water pump?

[John_AZ]

Originally Posted by HondaDustR

Wait, doesn't turning the crank CCW, as in backwards, actually increase the tension on the tensioner/water pump?

HondaDustR,

You are right. I should have found out what year 944 OK-944 had. He has a '85.5 944.

OK-944, get the belt loose and retension.

I gave the method I use for the spring tensioner if the WP pully is too tight on my car with the mechanical spring tensioner.

John

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[OK-944]

On my 85.5, with manual tensioner, turning the crank ccw will create less tension on the right (long) side of the belt, where I do my Krickit readings/twist tests. I also remove the idler pully for these tests.

I'm assuming that testing (twisting/Krickiting) the belt on the long-run side is correct?

[John_AZ]

Yes, it is tensioned on the long side. You might want to remove the idler pully for more room.

The "official" method to tension an engine with the tensioning roller ---is to rotate the crank CW 4 complete rotations------stop when the cam gear mark and the bell housing TDC hole shows the flywheel TDC mark.

Then----turn the crank CCW 10 degrees (1 1/2 teeth on the cam gear).

Check and set tension.

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If your belt is too tight on the WP for your car with the "tensioning roller"-----do not rotate the crank CCW. Stop when you have rotated the crank 4 turns CW.

Set the tension with the Krikut or 90 degree twist. Rotate the crank 4 turns CW and test the tension with the Krikut, 90 degree method and the WP pully test.
The belt should now be loose.

Now do it all over again and this time rotate the crank 4 turns CW and try CCW only 5 degrees or about 1/2 cam gear tooth. Set the tension... Rotate the crank 4 complete turns and check the tension.

Repeat ----experiment ----until you get the tension "feel" you have confidence in.

When you use the Krikut, you have to check the exact same spot on the belt each time. My arm usually was getting numb after 30 minutes. Good luck.

John

[HondaDustR]

Taking the sparkplugs out makes a world of difference, unless of course you are a tensioning master and can get it on the first try.