Maruha’s timing belt set

This time let us talk about the timing belt examining one of Maruha’s set parts – NA6/TB-1.
We will explain why the timing belt is an important part and why we recommend a simultaneous exchange of the water pump which is at the backside of the timing belt.

1. Cam cover gasket
2. Camshaft oil seal
3. Crank angle sensor O-ring
4. Timing belt
5. Timing belt ・tensioner & idler
6. Water pump
7. Thermostat housing O-ring
8. Our other recommendations

1. Cam cover gasket

There are many cases of smearing of the cam cover’s oil.
In most of the cases the cars that have been used for long years are leaking from this part.
In the beginning, the rubber gasket is soft, but in the end it becomes hard. A gap occurs and the oil starts leaking. There are cases, when the engine oil stays in the plug hole.
In some serious cases, just like on the picture, you cannot even lift it, it breaks.

2. Camshaft oil seal

The camshaft’s oil seal can be exchanged relatively easily.
We remove the cam cap and remove the used old seal that’s around.
We apply grease (Maruha uses molybden grease) to the inside to lower friction and resistance.
We lock it after applying sealing agent to the cam cap.

3. Crank angle sensor O-ring

There are a lot of cases of oil leaking from this part.
As we already opened the cam cover, we recommend simultaneous exchange.
Don’t forget to check the ignition timing after the exchange.

4. Timing belt

And now to the most important part – the timing belt!
It is the belt that connects the crankshaft and the camshaft.
If it breaks, the engine stops. It becomes the reason for big troubles.
It should be exchanged after 10 years or after 100.000km.
It is important to exchange it in time.

5. Timing belt ・tensioner & idler

The roller bearing that pulls the timing belt.
Even here we recommend simultaneous exchange.
One side is sliding type and has the function of a tensioner. The other side is the idler, that decides the position and has the function of a guide.

6. Water pump

The water pump often causes water leaking. On the inner side an emperor is being installed, which generates the water stream. If you see some signs of leaking around the crank pulley, than it’s for this reason.
It is set up in the backside of the timing belt and for this reason we recommend simultaneous exchange.

7. Thermo housing O-ring

The O-ring at the front housing

In the beginning it wasn’t part of the set, but we added it.
The efficiency of the work is better if we remove the thermo housing and it’s not a very expensive part, so we decided to add it into our kit.

8. Our other recommendations

These parts don’t belong to the construction, but we recommend their simultaneous exchange according to the circumstances.

For a better work efficiency we remove the radiator. If possible, we recommend the exchange of Maruha’s double layer aluminum radiator, hose, thermostat etc.
Except these parts we recommend the exchange of the fan belt and the bypass hose.
In some cases the crankshaft’s front oil seal too can be exchanged. If you have a special tool, this work is very convenient. Furthermore, we recommend the exchange of the alternator too.

All the above parts belong to the NA6/TB-1 set.

We prepared sets for NA8, NB6 and NB8 too. For the price check out this page.


Maruha Motors Co., Ltd.
Ushizuma 2095-6, Aoi-Ward
421- 2106 Shizuoka city, Shizuoka prefecture
TEL: 0081-54-294-0076
FAX: 0081-54-294-1312