Cam Belt Change Virgin - Few Questions

[ReganAndCarter]

Fiat Scudo 2004 2.0JTD (PSA HDI engine)

A cam belt change on my van is quite a way off, but I was wondering about the feasibility of changing it myself next time. I've done many different jobs on cars and motorcycles over the years, but never changed a belt. Googling and looking on Youtube, it doesn't seem too difficult, as long as you take your time and are very methodical. I would get a Gates kit and do idler, tensioner and pump all together. The only area that I'm not too clear on is the best tool and method for setting the right tension. My questions;

Is the Sealey belt tensioning gauge in the link the best tool for my situation (DIYer) and vehicle?

Will the gauge even fit where it needs to go between camshaft and fuel pump?

Will I be a able to operate and see the numbers on the gauge when it's in position?

Are there other tools/methods I should consider?

Where would I get the force and deflection specs to use the Sealey tool from?

Belt Tensioning Gauge | VSE110 | 1 year Warranty | Sealey

Ensures accurate measurement of belt tension. Clear increment and dual scale for ease of use. Tension chart guide is included. Suitable for belts of varying thickness.

www.sealey.co.uk

I've read some people who did this job and relied on measuring the deflection of the old belt before removal with finger pressure and a rule then using the same measurement on the new belt - or twisting the belt 45 or 90 degrees. I'm guessing that such rule-of-thumb methods aren't recommended?

 

[Mottie]

Isn’t there a tensioner gauge built into the tensioner?

Where would I get the force and deflection specs to use the Sealey tool from?

If you do get this tool (and I’ve never used one in 50 years of carrying out repairs) it says that a tension chart is included.

 

[Burnerman]

I guess this is the RHZ or RHX engine?
I don't think you'll have any particular issues with this one, but the camshaft locking pin is actually through an elongated slot on the pulley so plenty of dabs of white paint recommended, both here and at the crankshaft end.
I like to clip the belt on as I go with spring loaded clothes pegs.
It's important to either lock the flywheel or to ascertain that it really doesn't move - not very likely anyway.
The high pressure injection pump isn't timed so you can ignore that.
The big problem with these PSA lumps is loosening the crankshaft bolt....it's always bloody tight and it's best to heat the thing up first to release the locking compound. You may shift the bolt by having the van in a high gear, getting someone to stamp on the brake whilst you heave on the crankshaft nut.
As for the tensioning tool, I've never used one and twisting the belt between the camshaft and fuel pump with your fingers is fine - you'll get to 90 deg but no more.
John

 

[ReganAndCarter]

Isn’t there a tensioner gauge built into the tensioner?


If you do get this tool (and I’ve never used one in 50 years of carrying out repairs) it says that a tension chart is included.

Thanks for your reply, Mottie. No, looks like the later HDi engines on the MK2 Scudo/Expert/Dispatch has a system where you turn tensioner until a pointer lines up with a slot - setting the tension for you. Shame the earlier vehicles don't have this as it looks fool/diyer proof. The earlier tensioners like mine just have a square hole next to the hole for the central mounting bolt. A lever tool with squre end goes into hole and you just turn tensioner to add tension then tighten bolt. Trial and error doing this until you get the right tension.

The chart has the settings you set the tensioning tool at - basically a conversion chart, nothing specific to individual vehicles. However, you need the vehicle manufacturer's specified force to be applied to the belt in Newtons or decaNewtons as well as the amount of deflection of belt you should get when that force is applied. Cross reference these two figures on the chart and input the resulting figure onto the tool's dial. Unfortunately the newton and deflection specs are said to be in manuals, but as Haynes unbelievably never did one for these vehicles, I'm snookered.

The action starts at 7 mins on here if you have time to waste -

Can I ask how you would tension a belt that doesn't have a tensioner that self-tensions?

Gates.jpg

• ReganAndCarter
• 19 Dec 2022

 

[ReganAndCarter]

I guess this is the RHZ or RHX engine?
I don't think you'll have any particular issues with this one, but the camshaft locking pin is actually through an elongated slot on the pulley so plenty of dabs of white paint recommended, both here and at the crankshaft end.
I like to clip the belt on as I go with spring loaded clothes pegs.
It's important to either lock the flywheel or to ascertain that it really doesn't move - not very likely anyway.
The high pressure injection pump isn't timed so you can ignore that.
The big problem with these PSA lumps is loosening the crankshaft bolt....it's always bloody tight and it's best to heat the thing up first to release the locking compound. You may shift the bolt by having the van in a high gear, getting someone to stamp on the brake whilst you heave on the crankshaft nut.
As for the tensioning tool, I've never used one and twisting the belt between the camshaft and fuel pump with your fingers is fine - you'll get to 90 deg but no more.
John

Thanks, John - think it's the RHZ. Yes, I've seen people putting plenty of marks on cam/crankshaft. Some even mark 2 or 3 old belt teeth and the slots they sit in on the camshaft pulley with old belt in situ and the same on the belt at the crankshaft. Then they remove old belt and transfer the marks to the new belt on the teeth in the same positions. When the new belt goes on and is tensioned/turned the marks on belt should line up with the marks at cam and crankshaft. Think this is belt and braces to make sure belt is sitting right.

Clothes pegs are a good one, or cable ties. You mention the camshaft locking pin with elongated slot. I saw a video where the marks on the cam and/or crankshaft didn't quite line up and I think the cam lock pin was slightly tight in the holes when it all went back together and was spun a few times. He got a slight adjustment on the crank pulley woodruff key - only millimetres - but enough to get everything to line up perfectly. So there's also poss room to be slightly out as the woodruff key is slightly narrower then the slot in pulley.

 

[cdbe]

Did my one and only belt change to date on my Berlingo 2.0Hdi, it was quite straightforward - I locked it up with some drill bits. I loosened the crank pulley by wedging a socket wrench on the bolt and turning the engine over in gear - plenty of "how to's" online. I used the 90 degree method to tension the belt.

Take plenty of picks of the belt route (and the aux belt) to aid reassembly. It might be worth checking the crankshaft pulley as it's a potential failure point. I didn't bother on mine as it looked ok and mine was an age, rather than mileage, belt change.

 

[Mottie]

Can I ask how you would tension a belt that doesn't have a tensioner that self-tensions?

Just experience and feel really but what you could do, before removing the old belt is take note of how much deflection you have on the longest section of the old belt and give it slightly less on the new one! Personally, I don’t think I’d go to 90° on a thick diesel engine belt going round numerous pulleys, maybe on a skinney petrol engine belt with a long section that just goes round crank, cam and tensioner pulley but everyone has their own method.