HELP!! Just Discovered A Factory Update On 308 QV Alt/WP Belts

It looks like that on the early 308-4V with the single belt they went to a slightly smaller alt. pulley (no doubt to help keep the voltage output up at idle), the alt. supporting bracketry got "flabbier" (cantilevered off of the front of the engine rather than being directly between the alt and the side of the engine) and longer, and the alternator itself is a little further away from the crankshaft axis (increasing the length of the belt spans). Haven't ever heard of this being a reported problem on the 308-2V single belt set-up. I don't know what the "stock" belt length is for your early 308-4V, but if you stay with the single belt system you might see if you can get a slightly shorter belt length to fit (to try to reduce the belt spans). I know that on the 308-2V that that single belt is available in 975mm or 1000mm lengths.
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At the mention of service bulletins I'm wondering if there's a list of them someplace for the rest of us.

I don't mean to hyjack the thread. Sorry if that happens.

Bob Wassam

 

I'd guess that the updated 308 QV late pulley and tensioner would now be available as used parts (completely acceptable for the pulley) and that the tensioner should also be a simple SKF part available new at sub-OEM pricing...so by putting the kit together on the internet you should be able to save some money.

 

I would really look at all of your accessories. I have both setups on different 308s that I have or had. I have never had a problem with the single belt driving the waterpump and alt. Check and make sure that an item isn't touching the belt from time to time when running. Check that the waterpump and alt. spin freely. Another thing which I have seen on mnay cars is when most likely the waterpump went bad the belt melt and sections were stuck to pullies etc. If you don't get all of the burnt rubber out of the pullies this can cause your belt to break prematurely.
I wouldn't go through the trouble of a new crankshaft pulley and a new waterpump belt tensioner etc. for this.

 

The early 4v is a poly belt and a horible design....I have it and break an alternator belt about once a year, they need to be tigher than h*ll and if it slips at all, the belt litterally melts and the only thing left is a bit of cord wrapped around the pulley. The later design is much much better.

 

Tommy -- Please look at the figures again. The 2V and early 4V both have two v-belts -- one for the AC and one that is shared by the wp and alt. The late 4V has three v-belts with the AC, wp, and alt each having their own separate v-belt (and I actually got that figure out of the '84 MondialQV OM because the '84-'85 308QV OM has it wrong -- imagine that ).

No, that's probably the correct "stock" 308-4V (single) belt length (1000mm), but if you have enough adjustment range in the alt position available you might try the Gates 7m975 belt instead (if you can live with the alternator body getting closer to the AC compessor). It's not a huge change (and since F didn't do this as the "fix" for the problem it's a sign IMO that the design is more fundamentally flawed). You still might have some underlying fundamental problem that this won't make any difference (e.g., the pulleys not being nominally in-plane, or the alternator mounting flexing under load such that the alt. pulley's position/alignment just gets so wacky that it spits the belt off) -- but, if you've had problems with a couple or more of the 7m1000 belts, just putting another one on doesn't seem very useful to me.

No argument from me that the late 308-4V is a much, much better design for the alternator belt system (although the number of belts is starting to get unreasonable IMO). That kit is going to have some significant hard parts (e.g., for adding the v-belt drive pulley to the crankshaft and for hanging that idler pulley off of the cam belt cover) so the $ might get crazy if it can only be acquired via the usual inefficient path with a couple of extra 2X price increases -- let us know how it works out.

 

Just a thought Tommy, but do you think one of the pulleys may be just out of align enough that it needs to be shimmed (washer) to make the belt pull in a "straight" path. May be worth a look before you pursue a more exotic remedy.

Again, just a thought.

Drew

 

I had the same problem of losing belts on my 83 QV Mondial.
As my a/c was not working, my mechanic "reconfigured" the belt run. We also used bigger (thicker) belts.

 

My car is the same setup as Tommy's. I've never had a belt break, and I've been on the current set for 10 years and 30,000 miles (yeah, I know, time for a change).

 

Just replacing the w/pump on my 83 MonQV. Looking at the history it has been refurbished a few times... one wonders...

 

Nothing to wonder about. With the single belt design, one must run the belt tension high enough that it doesn't slip and instantly turn to dust as mentioned above. This very same belt tension puts excessive load on the water pump bearings, thus tearing up water pumps at an alarming rate compared to most manufacturers. It's definitely a problem and the three belt design will fix it, especially if you go the extra mile and make custom pulleys so that you don't have to use that rediculous plastic belt.

Someone, build it and they will come...

John
P.S. At least three broken belts in 8 years, although one was due to coolant leaking on the belt causing it to slip. I never leave home without a spare.

 

I spent a couple hours one dayto get it perfect...but it didn't seem to help. The key seems to be to let it still a low rpm after start-up for a minute or 2 until the belt warms up. If I hear any squeal, I shut of the engine and re-start, tapping the throttle or driving with a squeak will pretty much ensure a blown belt within 5-10 seconds.

 

Has anyone ever heard of someone adding a tensioner to the H2O/Alt belt set-up?

 

A few months ago, I decided to change the belts on my 84 QV Mon, only 'cos I had that part of the car in bits (another embarassing issue, called Hunt the Oil Cap). Three belts required, got in touch with QV London who had never heard of a QV with 3 belts but galvanised into action the find out. Anyway to cut a long story short, got the belts and put them on, the AC being a particular sod to get on.
Reading this thread started me thinking, I have had the car 5 years or so now, still on the same Water pump and never had a drive belt give trouble. makes me think, maybe its a worthwhile conversion.

 

While tearing into my car's cooling system to fix an overheating problem, I had my WP removed and restored. Upon re-installation, I had belt squeak even though I didn't move the alternator. My first drive out melted the belt around the WP pully. A second effort with a new belt had the belt last roughly two hours before that one, too, melted around the WP pully.

Something was, apparently, causing the belt to slip around the WP pully, and the resulting friction was melting the belt to failure. A telltale puff of brown/black smoke followed by the alternator light coming on meant the worst had happened again. My mechanic (Karl Troy) did everything he could think of to figure out why this was happening. He even removed my water pump and connected it to a power drill on his bench to spin the pump to check for alignment/bearing problems, and couldn't find any issues. He DID find that the inner bearings inside the water pump had their grease fitting seals compromised during installation - they were slightly dented, and if the bearing grease had interacted with very hot coolant this might have led somewhere. However, the WP spin tests were done with these bearings and the WP span fine for very long periods. We decided to replace these bearings, put on a new belt, and I've been on the road ever since with no issues.

The tension on this belt is VERY tight - if someone had a 'upgrade kit' for the dual-belt design that allowed for less belt tension and more belt reliability, I would be very interested in purchasing it.

 

Old thread - but same issue. I put on a brand new WP and rebuilt my Alt and started the car and after a few minutes at idle - a really loud noise from the pulley/belt drive system -- pulled the alt and went back to the rebuilder -- he bench tested it under all types of speed and load and for a while -- whisper quiet -- ordered a new belt from the dealer to e certain I had the right length 7M1000 came -- I will try this again - but will be pretty po'd if I have to pull a brand new and expensive WP -- I am thinking a solution might be to delete the a/c and run a single belt to the alt and a single belt to the WP using the a/c tensioner to tension it -- Problem: getting all this in the proper plane -- maybe I can shim the alternator to move it's plane of belt travel -- then again -- not sure I should monkey around -- and just use it stock and somehow get it to work ... the OEM pulleys are ridiculously narrow for the load and span --- the next solution maybe more robust pulleys, never had a problem before - so maybe I just got burned on a new " high performance" WP. should have left well enough alone.