1998 C70 Coupe, Timing belt tension specification

Post by **RickHaleParker** » 25 Jun 2015, 07:11

1998 C70 Coupe, Engine B5234T3 with mechanical tensioner and 142 tooth timing belt.

I'll be replacing the timing belt with IPD kit 120612. I do not have the Volvo tension gauge. I do have a Universal Cam Belt Tension Gauge. Does anybody know the recommended deflection and force for the timing belt? Where should I place the Tension Gauge?

Post by **Ozark Lee** » 25 Jun 2015, 08:41

The tension gauge is built into the tensioner. The tensioner is adjusted to a point where the indicator is inside of the "window" between the two forks at the top of the tensioner. There are some slight offsets for temperature but just getting the indicator in the window is close enough.

...Lee

Post by **RickHaleParker** » 25 Jun 2015, 11:29

I have read the procedures in VADIS. The procedures are not what my inquire is. The targeted results are.

I am the son of an automotive design engineer. Father always told me, follow the procedures, some engineer wrote then that way for a reason. Whenever possible verify the results. Because it is human to error and sometimes defects do make it through the manufacturing process. I am asking for the belt tension specs so that I can verify the results. Considering that the '98 B5234T3 is a interference engine this would be due diligence.

The previous owner have taken this engine almost half way to the conveted half a million miles. I have no intent of it blowing on my watch.

Post by **Ozark Lee** » 25 Jun 2015, 13:03

While I am certain that there is indeed a design specification I have never seen one published.

As a practical matter the chances of a failure due to inaccurate tension are infinitesimally low when compared to a complete failure of the mechanical tensioner itself or a water pump failure.

If you find such a number please post it back, I think I still have a gauge left over from an old Porsche 4 cylinder. Even with the Porsche many people set the tension with a grossly inaccurate Cricket click gauge.

...Lee

Post by **jimmy57** » 25 Jun 2015, 13:24

Vovo does not publish belt tension specs for "white" engines. The hydraulic tensioner took care of it and then the eccentric tensioners have the goalposts as marker for the correct tension range with engine cold.

The cast iron block 16 valve 4 cylinder had a spec of 4 but no unit was listed since the tool was provided by Volvo and it had no units on its face, just the numbers.

I worked for the manufacturer when that car was new and there was no information in any of the published info for technical personnel.

Post by **RickHaleParker** » 25 Jun 2015, 13:34

The closes thing I have found so far is:

Check measure the belt tension
Wait 5 minutes after aligning the timing belt.

Position measuring instrument 998 8500 (Volvo Belt Tension Gauge ) between the exhaust camshaft pulley and the coolant pump.

Read the value using a mirror. The measuring instrument must not be removed before the reading is made.

For the 21 mm belt, the tension must be within the range of 3.5 - 4.6 units.

For the 23 mm Belt the following applies:
B 5204/5254/5234 2.5-4.0 units
B5252 2.7-4.2 units