Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Plus8 fanbelt

Gates 7PK1025 is what I run but some folk who complained of squealing have fitted the weaker 6PK1025 for the quiet life although I have never experienced this running at the right tension.

There is a fair bit of leeway adjustment on the alternator so other length belts could do the job.

So 7 grooves and 1025 long or 40 1/2" in old money.

My 2002 car had the squeal. It was sorted by the dealer when I bought the car but came back after a couple of years. They had fitted a new belt. I took it off, cleaned all the pulleys, wiped the belt clean and it was in good condition. Replaced it, tensioned to just a small deflection and no further noise over 40k miles. Regular tension checks but no adjustments needed. I used brake cleaner on a rag to wipe the pulley "v" and grooved surfaces.
I had looked at gomog and considered changing to a different one but not needed in the end.

I’ve got a 6PK1025 on at the moment and carry a 7PK1025 as a spare…

Only ever had one fan belt issue on my 1985/6 +8 and that was while attending LM circa 2002, when in the company of Porsches and in hot weather I was pushing on for quite a bit of the day, and on my usual morning checks found the fan belt to be in a somewhat threadbare state.... Fortunately I ever carry a spare, and the tools to replace it having taken the time to ensure I have just the right spanners to complete the task by performing a dummy run.... Which really was a dummy run, as it was pointed out to me having completed the task and sharing how I went about it, someone in the forum ( eMog or MSCCDG )politely pointed out that there was an access slot cut out of the inner wing to ease the access to the alternator adjustment bolt....Whereas, I had gone about it from under the bonnet... Duh...!

Fan belt for my mid 80`s 3.5 +8 with standard Lucas alternator GATES 6225 MC AVX10 x 1125 La

Back in time the guys in the MT dept reckoned Gates were good quality belts, though that was a long time ago, and applying old thinking after years of downsizing, delayering, and off shoring, who knows who owns any company these days and the way standards might have altered...?

I use a 6PK1025 and it is very good

I have had the squealing fan belt on my +8 and I am always mindful of damaging the alternator bearings by overtightening the belt. I have used belt dressing via an aerosol can successfully to stop squealing on the +8 as well as on other belt driven machinery.

Red ... belt dressing is one of those nearly forgotten 'olde worlde' things that really works ... great stuff (but can be a bit messy if you overdo it 🙂)

K

A bit of spit sorts it till you get underway then you don't hear it above the V8 Sports exhaust. - what problem..

Better for the environment and readily available.

Or put a knurled pulley on ,stops all noise.

I have found that all vehicles talk to us, trying to tell what they need. What they say should not be ignored. For example, if your trad boils over, it is telling you it is overheating and that shouldn't be silenced by using (shiver) a waterless coolant like Evans. The cause should be investigated and cured like any symptom. If you have a squeak somewhere..why not track it down? I could go on

If your fan belt shrieks and squeals at you, it is trying hard to help you help it. It should be investigated rather telling it to hush by using belt dressing or "spit". Conservative doctrine says these belts should be changed in a set amount of mileage or age. But I am like Luddite. I carry an extra under my seat and swap it in when the one on the engine pleads for help or fails. Fan belts, like tyres, age used or not. The resin in them dries out and super tiny little cracks occur, allowing them to stretch in usage or blow and leak in the case of tyres.

The reasons for noisy fan belt are too important to ignore and ending the noise with a spray is akin to using scotch tape on a cracked sump. Aside from the shrieking, squealing and chirping, the belts slip on the alternator, prejudicing the car's electrical power. Or it slips on the coolant pump pulley, allowing the car to overheat..or both simultaneously. In my experience, shrieking is the result of a too loose belt. I want to know about that. The only exception to looseness is a wonky pulley or something turned by the belt as gone awry.

I still use a bar to pry my alternator until the belt is tight enough, as properly described above. However, there are aftermarket add-ons one can use to make the job elegant and easy! I keep meaning to buy one. https://shorturl.at/gIB7N They do away for the need of a pry bar.

Lorne