The Guv'nor, a Magnum opus

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The Guv'nor, a Magnum opus

Postby lord13 » Mon Jul 30, 2018 8:27 am

So, after an abortive attempt to sell I have reluctantly decided to keep the old girl . . . for now.

Why reluctantly? Well, I had an injury a few years back blah blah blah witter witter etc etc etc , you all know the story, sort of, basically it boils down to this, too much hard use of my left arm muscles causes all sorts of aches and pains that build up over time and it feels like a stabbing pain through my chest with a continuous dull ache in my bicep. Ouch.

Anyway too much changing of gears and now also the heavy steering of the Magnum causes that exact sort of thing to happen and it is very uncomfortable and jut not fun to drive. Part of me wishes I'd kept the HB as that was fun to drive, even with the gear changes. And especially as now the guy who has got it has immediately started pulling her apart and has rubbed down my nice white stripe and flogged the GT bonnet :( grrrr , I liked the rough look of my HB, the Magnum is a bit 'antiseptic' now...and I cant 'personalise' her because she is a Magnum and needs to be kept pretty much stock.

So I did decide to sell... and buy something else. . . something automatic. So Ebay shenanigans ensued , emails from obvious dealers, odd requests for private evaluations ( one guy wanted someone to value it with the intent that I would honour the valuation and sell it to him for that price, whatever that was ), RAC inspections ( that I assume would be by some guy without a clue regarding older vehicles), Low low offers...all that sort of rubbish, and a very nice chap that offered to build up an auto magnum estate for me so we could swap ( i'm still thinking about that one).... Also there were a few vivas on there of various degrees of build and model, that were getting astronomical prices and bids immediately, whereas mine stagnated at the start price ( yes I was getting a little bit jealous of the attention they were getting ), couple that with the fact that I was starting to get a little bit worried over what price it did finish at as If i'd've made a massive profit I would have been ashamed and would have given the previous owner a share to clear my conscience :(
Add to that the fact that when I popped over to see fellow member Carl in the old girl, it became apparent that she is STILL stripping fan belts and would not keep one on for long I couldn't possibly let someone attempt to drive home in the old girl after they had bought it. So I pulled her from ebay.

Yes, I am, to all intents and purposes, my own worse enemy. I don't know why I bother...I can't sell for *Bleep* :(

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So, for now, she stays … This thread can be a testament to the thing, and an ongoing advert, all I want is a fun to drive classic of the GM variety …. I am such a whinging mind changer at times :D

Anyway . . .

Fan belt …. what the hell?

She stripped one on the way the MH, I fitted one there to get home, she stripped it again a day later. I fitted another one, took my time had it all adjusted up properly, I took off all the pulleys and cleaned them up, and refitted it and got the correct tension etc. She held fine for a while, no issue, maybe if i'm absolutely honest it did look a little slacker after a bit of driving but nothing too bad, Then I took her for a run up to Grantham, 12 miles on country lanes with a great spot you can really let go on, took the old girl up to 70, she drove great, not an issue :D I get to where I was going and popped the bonnet and the belt looked like it was 10 years old, saggy and frayed, and low down in the pulleys. The underside of the belt had lost all the teeth of the vee, and there was rubber residue over the alternator pully.

The belt looks in line, maybe a slight deflection, the alternator looks slightly far forward, but there is no 'rearwards' adjustment left on it, it is right up against the bracket. But it looks like it is deflecting, the belt is saggy and bowed and in pretty bad shape. The alternator has a little bit of play in it, could it be that as the alternator spins up, the shaft wobbles all over the place and wears the belt to destruction? Or could the alternator bearing be on its way out and as it heats up it gains resistance and the resulting friction wears the belt sides, which cooks the belt and causes it to disintegrate? The edges of the belt do look to be 'sanded off' a touch. I'm all for replacing the alternator. What do you guys think?

Also, with replacing the alternator, I'm thinking of going for a 'ribbed' belt, just for ease of replacement and for removing the viscous fan and fitting and electric one, as it is so close to the rad there is barely any room for movement ( you cant get a fan belt between the fan and rad without forcing it, last time I changed the belt I took the rad out! ), I know I've seen this sort of mod done before, what pulleys are you guys using for the crank and water pump?

Well there we go, a lot of writing I know . . .. but I tend to waffle :)
Last edited by lord13 on Tue Aug 14, 2018 8:05 am, edited 1 time in total.
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Re: GVO 147N a Magnum opus

Postby droopsnoot » Mon Jul 30, 2018 10:41 am

lord13 wrote:you cant get a fan belt between the fan and rad without forcing it, last time I changed the belt I took the rad out!


Just picking up on this bit, this doesn't sound right to me. This is a photo of the engine bay on my hatch, it's not a great view but you can clearly see there's at least enough space for a fan belt without having to remove the radiator.



When I first rebuilt the hatch engine, I fitted a viscous fan that was quite a bit smaller than the proper OHC viscous fan. I sourced another one (because I thought that might be making it run hot), and that turned out to be incorrect. One of the main things that was incorrect was that the viscous centre forced it quite a bit forward on my pump. I can't remember how close it was to the radiator, or if it even fit in there. We all know that the Victor pump has a shaft that is too long to fit in a HC engine bay, perhaps the fan also sits further forward. In any case, I sourced a proper HC OHC fan and that did the trick. That sits much further back around the pump and pulleys, and has a shape on the back of the blades to let it clear the crank pulley nut:



Can you show some photos of that end of your car, perhaps one looking from each side, in case anything looks off?
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Re: GVO 147N a Magnum opus

Postby 1972nail » Mon Jul 30, 2018 1:49 pm

I had a friend's car recently that shredded the belt too. It was diagnosed by a good mechanic friend as an alternator bearing at fault that provided enough resistance to cause the belt to slip and wear excessively. However after looking at the car my self a week or two after the fix I noticed wear on the new belt, not excessive but more than expected for a 2 week old belt.

My diagnosis was that there was a weak battery connection and a bad earth to the block causing the alternator to be driven hard to try to charge the battery over a longer period than normal.

Anyway, the cause was probably a combination of both the tight bearing and bad connections causing excessive strain on the drive belt.

As Snoopdroop says, there should be a reasonable space to fit the belt past the viscous drive fan. I personally have fitted a 11" electric fan but had to move it well up into the top OS corner of the rad to get enough space to get the belt past the end of the bare viscous drive pump.

Back to your physical problem, a Corsa electric power steering column has been successfully fitted to a Firenza by a friend of mine. The only permanent mod to the shell was to drill one extra bolt hole behind the heater shroud to provide extra support. However, the mod did remove the shock absorbing function of the steering column. I can PM you details if required.
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Re: GVO 147N a Magnum opus

Postby lord13 » Mon Jul 30, 2018 11:52 pm

Ok thanks for the input... here are a few pics of the offending items...none from the side though, i took these today before i read the replys but i'll get some side shots up tomorrow.

Alternator to water pump pulley, not to much difference here ...

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Water pump to crank pulley, again not too much difference

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Alternator to crank...a fair bit of difference

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and in close up . . .

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So it does look like either the alternator is too far forward (cant move it back though as it is right up against the bracket), or the crank is too far back (the pulley bolt looks to have deformed the washer slightly, the washer is concave when it should be flat, which begs the question how bloody tight has it been done up?) so what to do? do I move the crank pulley forward by fitting a washer behind it? seems like a bt of a gash job to me....

Well that's what i first thought, until i had a closer look at the alternator pulley, it is of a different type with a thicker edge, which would put my straight edge further out than expected, so it would look like a big gap, I really need to take my measurements from the center of the vee somehow. I do have a different alternator pulley with the correct type of vee, i could fit that. Also I have been informed by the previous owner that the pump on it is off a Bedford CF (he got it like that he didn't fit it) and is slightly longer possibly, I do have a few water pump pulleys of various depth so i could play around with those i guess.

Now back to the alternator. . . it does have some very slight play in it, not much, but it's there, maybe at high revs it rattles around? I also thought that if the bearing was on its way out then it could possibly heat up and add more resistance to the pulley, thus making the belt slip and wear away?

Then I read 1972 nails comment on the poor connections... which reminded me of a little quirk the car has.
When you turn on ignition, the oil light comes up but not the charging light, but when you turn it off the charge light flickers. And if it stals or the belt goes, the light comes on as it would. But turn it off with the key and turn back to ignition, no charge light. It starts as normal obviously, and charges as normal when running, so I'm guessing that there is a wiring fault, a loose connection maybe? As you know, when you turn to ignition, the alternator draws a small current through the dash warning lamp to energise the circuits, and once started it feeds back through that circuit and puts out the lamp. If there is a bad connection it wouldn't draw this small current as the resistance would be too high, but once it is charging it would send a full charge to put out the lamp and when it stalls or gets turned off the residual current is enough to still defeat the resistance for a short whie........maybe ? I'm half guessing here...but anyway, if there is a high resistance in the feeds then the alternator would have a higher resistance as it tries to generate the necessary voltage/current to run the systems and charge the battery...possibly.... electrics are a bit annoying aren't they :(

I will investigate more tomorrow :)
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Re: GVO 147N a Magnum opus

Postby 1972nail » Tue Jul 31, 2018 8:58 am

I would suggest that you swap around the pulleys to get the best alignment possible, if for nothing other than peace of mind.

I had a problem with my charging circuit at the first, the big connector on back of the alternator had fractured and the two broken bits were still touching each other. This provided a charge big enough to put the light out but not enough to keep the battery charged. Alternator would heat up and belt slip and squeak.

A friend recently had some weird wiring faults, particularly in the side light circuits. I traced it to slight corrosion in the fuse box. In the past I had used a bath of citric acid to clean the fuse box and plugs up but the wiring was still on the car and not very accessible to drop into a bucket of acid!

Another friend had used a product called Viakal bathroom cleaner on his electrical connections. It comes in a handy pump action spray and can be delivered in small aimed doses. A bottle was purchased from Tesco and duly sprayed on the fuse box with immediate and very good results, The battery was disconnected by the way.... A further spray or two were applied to the wiring plugs with equally impressive results. A blast with the air line to dry it all of, it all was assembled and problems fixed.
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Re: GVO 147N a Magnum opus

Postby droopsnoot » Tue Jul 31, 2018 10:34 am

lord13 wrote:Also I have been informed by the previous owner that the pump on it is off a Bedford CF (he got it like that he didn't fit it) and is slightly longer possibly,


That might explain the outward screw-thread in your first photo, perhaps. A Magnum / Firenza viscous fan has a different fitting, if I recall the discussion on here a year or two ago correctly. Magnum has a flange on the water pump with a left-hand thread tapped hole in it. As I type this, I think it was a previous owner of this car who sourced the special spanner needed to remove the fan - which would make some sense.

If the crank washer has gone concave, one way around it would be to undo the bolt and reassemble it with the crank washer the other way around, so it's effectively convex. That wouldn't alter the position of the pulley as that fits flat against the step on the front of the crank.

One interesting thing in the Haynes Firenza manual: "On some later engines, specifically the 1759cc and 2279cc, a pressed steel crankshaft pulley is fitted, with a timing pointer on its rear face. This pulley is fitted in conjunction with a dished flange washer which is assembled with its convex side towards the camshaft pulley. With this type of assembly, a longer securing bolt is necessary; this bolt has a nylon-insert type of thread and is used without a lock washer." So your dished washer might not be incorrect, and a Magnum would certainly count as "later" from that manuals point of view. I don't have the Magnum version to hand to check.
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Re: GVO 147N a Magnum opus

Postby 1972nail » Tue Jul 31, 2018 1:44 pm

That is definitely a Magnum pressed steel pulley with the correct concave washer. The cast machined pulley was fitted to early engines, 2.0L and 1.6L I think, but changed for the pressed steel one on 1.8 and 2.3 engines. Although there may have been some cross over on early larger capacity engines. The early bolt and washer will not fit a later pulley.

The later pulley is favoured by tuners of this engine as it is stronger and won't bend if hit by anything big. I have fitted a later pulley to my engine for that reason....a bent pressed pulley. It is also easier to fit a crank timing wheel for electronic engine management as well as running truer.

Here's a photo of a cast pulley from another thread for comparison.



As far as checking the alignment of the pulleys in the centre of the 'vee' is concerned you could try to set up pen type a laser pointer and wedge or tape it into the water pump pulley. On rotation it will then sweep along the centre line of the pulley and then onto the other pulleys.

Or use one pulley as the reference, place your straight edge on it and measure from the straight edge to the centre of each pulley without moving the straight edge from the reference pulley.
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Re: GVO 147N a Magnum opus

Postby droopsnoot » Tue Jul 31, 2018 6:23 pm

I measured the gap today, on the hatch there is just about exactly 1" between the front edge of the fan, and the matrix of the radiator.
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Re: GVO 147N a Magnum opus

Postby lord13 » Tue Jul 31, 2018 9:27 pm

Good advice there guys :) I have been tinkering around today and may have come up with a solution.
I removed the crank pulley and inspected the washer, it is a massive thick washer and it didn't look like it could be deformed by mere tightening, also the bolt was fairly long and has groove machined into it with the residue of some plastic material in the groove...I guess some form of 'nyloc', there was also no way to fit a spacing washer so i left well enough alone, i just cleaned it all up and put back as it was. Now i've read the replys it looks like i did the right thing :)
I also left the water pump pulley alone as the other ones I have would put the belt way out, so i concentrated on the alternator. I cleaned up the contacts and made good all connections as a 'first port of call', then i removed the large pulley and fitted the thinner one off a scrap alternator i had in the shed, I also fitted a washer between the slotted lower bracket and the alternator casing ( when bolted up on the upper mounts there was a gap between the adjuster mounting and the body of the unit, which looked to be pulling the alternator to one side, the washer has eliminated that ) all this seems to have pulled everything back into line, looking at it from the top and sides it all looks straight on the belt runs...although i couldn't test it as the smaller pulley on the alternator means the belt is too long. I wasn't sure it was the right belt anyway, so i'll have to get a new shorter belt tomorrow and take her out for a quick blast to check all is good :)
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Re: GVO 147N a Magnum opus

Postby craig12 » Sun Aug 12, 2018 7:13 pm

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Last edited by craig12 on Mon Aug 13, 2018 8:19 am, edited 1 time in total.
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