Technical Cambelt how many teeth

[paulbaxter]

Hi Everyone I have a 2001 2.8jtd motorhome.
I changed the cambelt everything lined up, but after starting there was a loud knocking.
I checked everything again & decided to change the rollers as well so a new belt came with the kit which I put on.
Again everything was all lined up, started again loud knocking.
On checking I noted the Injector pump was misaligned.
Now here is the question. I have done a bit of checking & there are possibly 2 belts 153 & 154 toothed belt. But on initially changing the belt I dumped the original.
So I am now wondering is the wrong belt fitted.
My motor factors supplied the belt that was listed.
How would I find out what is the correct belt????:bang::bang::bang::bang:

 

[Communicator]

The 2.8JTD engine, 8140.43s, is a common rail engine with electronic control of the injection timing. In this engine, the angular position of the high pressure fuel pump, relative to the crankshaft and camshaft is not important. It is the position of the camshaft relative to the crankshaft that is important.

If however you have a mechanical injection pump, the engine is not a 2.8 JTD, and pump timing would be critical for optimum performance. As has been mentioned in another thread, the pump timing of earlier engines is advanced to aid starting when the engine is cold.

To confound the issue as regards the number of teeth on the belt, I count 152 on an old belt, which was probably SKF. To even out wear, the ideal number of teeth would be a prime number.

The SKF box that my replacement belt for a 2.8JTD came in has P/N VKMA02383 clearly displayed.

 

[paulbaxter]

The badge on the side says it is a JTD, this is a Motorhome. I checked all my marks nothing moved except when I started it there is a loud knocking, surely if the valve timing was out it would put holes in the pistons.
After turning the engine over by hand there was no problem.
However my timing marks in relation to the cam & crank line up but the pump mark will not.
Is it easy to tell the difference between the two engines.
Thank You so much for your help.
When looking up a belt on Euro car parts it shows 153 teeth & when checking for kits it shows one with154 teeth.

 

[s130]

What is your full VIN number? That should be the definitive statement of the exact engine that is fitted to your motorhome.

If you don't want to put your VIN in public view then PM me.

 

[Communicator]

s130's offer is a good one, go with it.

I am not familiar with the 2.8 TD, but looking under the bonnet of my 2.8 JTD, I am confronted with the large black plastic sound reducing hood over the camshaft cover proper. Centre of this cover white label, with bar codes, middle line of label begins 8140.43s.


If no label, look at front of cover on your right, behind engine lifting lug are 4 x injector cables in a substantial rubber lined metal clamp. When I had the cover off to access the camshaft timing wheel, I found these cables to be one of the more difficult bits. However mine is a late 2.8JTD, and yours is early, so could be different.

When counting the teeth on my old belt, I marked every tenth tooth with tipex. Next used a pair of dividers to confirm that my counting was OK, by checking each ten in turn, (about 95mm so 9.5mm pitch). Was left with 1 tooth between two marks, so fairly confident at 152 total count.

 

[s130]

Received PM from paulbaxter and have replied. His VIN is for a DUCATO'94 DIESEL (1994-2002) 232.936.1.0 - CABINA MOTRICE 2800 JTD 18Q 2001

Fiat list the belt as P/N: 99456476 and when you web search this part number you get to sites like https://www.buycarparts.co.uk/oen/99456476 which list various makes of belt all quoting 152 teeth.

So we now have two counts for 152 teeth.

 

[paulbaxter]

Thank You to everyone. One major query has been cleared up. The belt should have 152 teeth.
It also shows that pump timing is not necessary.
I am left with double checking the valve & piston timing which I am now heading out to do.
Wish me luck.

 

[Anthony489]

Hi

I think your engine has a single cam and 8 vertical valves which lie slightly recessed in a flat cylinder head. On the intake stroke the inlet valve head will "follow" the piston as it goes down the bore from TDC. On the exhaust stroke, the exhaust valve closes just in time to get out of the way of the rising piston.

If there is a cam timing error, there's the chance that inlet or exhaust valves will clash with pistons. The error needed to cause this will depend on the exact design. I calculate it as about plus or minus 20 crank degrees but it could possibly be less. Let's assume the crank timing pulley has 23 teeth, that's 15.7 crank degrees per tooth. So if you are one tooth either way in error, you may or may not get light contact. If you are two teeth out you probably will.


If say your belt has 154 teeth instead of 152 or vice versa, that would also be enough to put you the equivalent of 1 tooth out on the straight (non tensioner) side of the belt

I can only suggest that you double check the timing. I'm not sure that you would be able to feel the extra resistance from light valve to piston contact when turning the engine by hand, but any metal to metal contact would certainly be audible when running. The rate would be two knocks per crank revolution.

 

[s130]

A thought just came to mind and I'm probably off target but I'll mention anyway..

I know you have a 2.8L diesel engine but I wonder if this is a derivative of the 2L petrol engine block.

On the 2L engine there is an auxiliary shaft which was used to drive the fuel pump and the distributor. As such there were no timing marks for this other than a 34 degree (can't recall the exact figure) of vertical position. This shaft if incorrectly timed could interfere with the crank shaft piston journals.

On a petrol engine with a distributor drive taken from this shaft on the block then any timing error would be obvious.

On later petrol engine with electric fuel pump and distributor driven from the end of the cam shaft this aux shaft became redundant. However it still has to be timed correctly to avoid the said interference.

 

[jontee61]

hi. the 8140--43s is a JTD/HDI engine which is a IVECO common rail direct injection used 2000 to 2006 on the Ducato but also on the fiatdaly https://www.fiatdalys.lt/en/catalog...M8,M9/0/GD/various-controls-belts-and-pulleys if you contact them with your vin number or direct im sure they will be able to advise you. they stock and supply all parts for fiat etc or just use the breakdown guide for the correct parts it should state number of teeth for your vin. hope this helps/