How tight can you tighten a belt?

Engines, Transmissions & Final Drive questions and answers

Moderators: timk, Stu, zombie, Andrew, The American, Lokiel, -alex, miata, StanTheMan, greenMachine, ManiacLachy, Daffy

User avatar
jerrah
Racing Driver
Posts: 724
Joined: Mon Mar 10, 2008 2:54 am
Vehicle: NA6
Location: Brisbane

How tight can you tighten a belt?

Postby jerrah » Mon May 30, 2011 11:27 am

I have a 4pk belt driving a high drag accessory. On the weekend I replaced the pulley on the accessory with a smaller item and now I'm getting belt squeal above 4000rpm (10psi and then drops to 8psi when slipping) I have a new belt (cut down 5pk1345 to 4pk width) which I've tightened up like a bow string - just how tight can I make this belt before I start risking damaging bearings and belt snapping?

Otherwise I guess I can go for a toothed belt or convert to 6rib but I'm not sure where I'd find a 6 rib crank pulley to suit a B6 engine.
1991 MX5

User avatar
NitroDann
Forum sponsor
Posts: 10280
Joined: Thu Nov 05, 2009 12:10 pm
Vehicle: NA6
Location: Newcastle NSW
Contact:

Re: How tight can you tighten a belt?

Postby NitroDann » Mon May 30, 2011 12:06 pm

You can get a product that stops belts slipping from any auto shop. Or you can tighten it to all get out.
First make sure everything is very clean.

Dann
http://www.NitroDann.com

speed wrote:If I was to do it again, I wouldn't even consider the supercharger.

User avatar
jerrah
Racing Driver
Posts: 724
Joined: Mon Mar 10, 2008 2:54 am
Vehicle: NA6
Location: Brisbane

Re: How tight can you tighten a belt?

Postby jerrah » Mon May 30, 2011 12:26 pm

Pulleys are clean. I was pretty sure that product just stopped you hearing the slipping? I think I'll have to tighten it up more in the short term and think about upgrading my pulleys to 6 rib. Belts will be easier to acquire too.
1991 MX5

User avatar
jerrah
Racing Driver
Posts: 724
Joined: Mon Mar 10, 2008 2:54 am
Vehicle: NA6
Location: Brisbane

Re: How tight can you tighten a belt?

Postby jerrah » Mon May 30, 2011 12:36 pm

Actually, I might look into throwing in another idler pulley to get better wrap on the pulley, might reduce slippage.
1991 MX5

User avatar
NitroDann
Forum sponsor
Posts: 10280
Joined: Thu Nov 05, 2009 12:10 pm
Vehicle: NA6
Location: Newcastle NSW
Contact:

Re: How tight can you tighten a belt?

Postby NitroDann » Mon May 30, 2011 12:53 pm

Though there are anti squeel products that only make them quiet (wd40 works just as good and is cheaper) there are also antislip products that leave a permanantly half dried super tacky glue on the surface.

Like half dried puncture repair kit glue for a pushbike.

Dann
http://www.NitroDann.com

speed wrote:If I was to do it again, I wouldn't even consider the supercharger.

project.r.racing
Speed Racer
Posts: 3722
Joined: Sun Jan 18, 2009 10:16 pm
Vehicle: Non MX-5
Location: Glasshouse Mountains, QLD

Re: How tight can you tighten a belt?

Postby project.r.racing » Mon May 30, 2011 5:13 pm

you'll snap belts before you even come close to damaging bearings.

project.r.racing
Speed Racer
Posts: 3722
Joined: Sun Jan 18, 2009 10:16 pm
Vehicle: Non MX-5
Location: Glasshouse Mountains, QLD

Re: How tight can you tighten a belt?

Postby project.r.racing » Mon May 30, 2011 7:53 pm

Though of buying a 4PK1325 and not cutting into it? Helping the strength of the belt?

User avatar
jerrah
Racing Driver
Posts: 724
Joined: Mon Mar 10, 2008 2:54 am
Vehicle: NA6
Location: Brisbane

Re: How tight can you tighten a belt?

Postby jerrah » Mon May 30, 2011 8:27 pm

Tried a 1325 and it'd be a stretch to get it over the tensioner. 1345 is perfect and a brand new 1360 works but I don't have much adjustment.

4pk1345's exist but nobody I called on the weekend had one and Repco never got back to me today about ordering one in. 5pk was just to get me by and seems to be ok. I really tightened up the tensioner tonight and it seems to have solved the belt slip problems, now I just have to solve the problem of sounding like an air raid siren. :P

5pk1345 is the standard belt on a Pajero so they're common and readily available.
1991 MX5

wun911
Speed Racer
Posts: 2114
Joined: Tue Sep 11, 2007 12:13 pm
Vehicle: ND - 2 GT
Location: Melbourne

Re: How tight can you tighten a belt?

Postby wun911 » Tue May 31, 2011 8:12 pm

yeah I have used the anti squal it spray on nice and slick but turns into a black sticky mess after only a couple of weeks realy hard to clean off.

Better just buying a smaller sized belt and making it tighter...
every ounce counts

deviant
Racing Driver
Posts: 1717
Joined: Thu Apr 15, 2010 7:23 pm
Vehicle: NB8B
Location: Rockingham - Western Australia

Re: How tight can you tighten a belt?

Postby deviant » Tue May 31, 2011 9:13 pm

The anti-squeal stuff is okay if you are stuck...Like if your belt is so worn it is not gripping any more. It's not really meant for long term use as you end up with crud stuck to it which will accelerate belt wear.

User avatar
jerrah
Racing Driver
Posts: 724
Joined: Mon Mar 10, 2008 2:54 am
Vehicle: NA6
Location: Brisbane

Re: How tight can you tighten a belt?

Postby jerrah » Wed Jun 01, 2011 9:06 am

5pk1345 cut down to 4pk and done up tight is working fine. No slippage yet and I've done 200km or so on it.
1991 MX5


Return to “MX5 Engines, Transmission & Final Drive”

Who is online

Users browsing this forum: No registered users and 167 guests