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Sunbeam's Fiat 125


Sunbeam

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Re brakes, the rear most reservoir is for the front brake circuit as this gets used first, then with more brake pedal travel the rear circuit (front res)  starts coming online.

If onlr front was draining while doing the rear circuit too, wonder if the pushrod is set up too long or short or something and not quite pushing the bits in the cylinder to use the rear circuit chambers? Maybe the sliding bits in the cylinder have been put in backwards? I had this issue on the 1100t van.

Have had issues in the rear with the proportioning valve on the diff too, esp when it's lowered but usually it's just stuck off doing nothing.

But if they seem to work fine, maybe it's just Fiat things?

Driveline vibe - had exactly same issue, hard to assemble the driveshaft out of phase but try disconnecting the 4 bolts from the diff end, turn 180 then reattach. Could be the angle of the diff pinion too? Does it match the gearbox/front shaft angle?

It's looking good man!

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I got a good tip from one of the old blokes at club night. Since all the mounts and the centre bearing are new, it’s possible that the front section of the shaft is out of alignment. This is apparently made worse by the aftermarket centre bearings sitting at a slightly different height. He reckons alignment of the front half is crucial and explained a cunning way to check it. It involves removing the donut but makes it seem pretty straightforward, so I’ll check that for sure. 

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yeah, front shaft should be treated as effectively an extension of the crank/gearbox centreline and should be parallel. The guibo is only designed to deal with the engine/box moving slightly on its mounts, not suspension travel.

A couple of washers between the bearing and mount will raise it, or between the mount and chassis will lower it.

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  • 3 weeks later...

stink about the pulley - I remember having similar issues when i swapped out the old pump for the newer style one on my old 1608. Swapping in a 2 liter solved most of those issues :).

Also had the faff with swapping to electric fan from the 2300 water pump mounted one, had to source a 1500 pulley to sort it, whcih was much easier than trying to find the old style water pump

i think there are a couple of types of (non electro fan) twin cam water pump pulley, one deep one shallow (early/late or small cc/bigg cc? - i dunno ) , but if you have swapped from the big ol' factory electro magnetic one to a more modern style maybe you have the wrong pulley? Could be the cranks are slighlty different offset too?

I have a couple of both here to measure if you want? 

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Right, I just got back from town. I dropped in at a club member’s place where he has his 1608 on an engine stand. The pulley from his engine is identical to the 2 I now have. However the stickout of the water pump on his engine is about 7mm less than the ones I was supplied which makes everything line up perfectly! So, the water pumps made by GMB for the 124 aren’t quite right. We did find a strange looking pulley in a box of bits in his garage that has a better offset but the centre hole didn’t fit over the snout of his pump by 0.5mm but I brought it home to try anyway.

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Cool project. Many many many years ago as a lad one of my mates had a 125 and another had a 124 sport which were way ahead of the era of affordable  cars at the time. 

I think  Nominal's  suggestion is well worth a look. We have the same issue with water pumps for the Tiger, and that is what is required if you don't buy a pump for a Tiger. 

Momo steering wheel is cool. I have one on the Tiger with a wood rim.

I had issues with the boss kit with the mx5 boss kit for the Minx, though not a Momo wheel. The one i got for a mx5 i sent back and used the one i already had for the minx. Both had the same spline and taper. It's a real piss off when you think you have it all sorted and it's not.

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  • 2 months later...
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The 131 box is a good change with a slightly longer 5th, feels a bit more truck like compared to a 4 speed or 124 5 speed though. Like the axe work on the tunnel! I did it with a welder.  Had to use a fairly large hammer to make room for the filler plug, and the top of the bellhousing. Also needed to move the handbrake back a little to fit with the longer lever extension, but not too dificult.

Funny, Ive got a spare 1608 that had aluminium washers under the water pump pulley to space it out a bit- seems like fiat made pulley offsets different depending on the phase of the moon at the time..

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  • 3 months later...

They are a long way out from what you need. It is hard to tell from the pic which pipe is the worst pipe but you would hope that you would be able to make it work with minimal adjustment. What did they say they could do with accuracy when you contacted them ?. 

It would be reasonable to know why they are so wrong. Looking at all the bend angles, it looks as though they can bend them, but they are not in the correct place.

Give them a call and ask.

I built headers for the Tiger and they mandrel bent the tubes for me from 6mm mild steel rod I bent to the shape I wanted. They did tell me though that they can only bend to certain limitations so I had to do a bit of cutting and welding. It wasn't a concern as they had told me and it was a tight engine bay.   

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Yeah, thats not 3D scanned nor did they take more than cursory look at the pattern you gave them to "copy".

Id take it all back and ask them to not have the work experience kid play with the pipe bender this time.

Close isnt good enough with that kind of part (as well they know as exhaust people), and thats not even close. 

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3d scan and bend for that price is a steal, its not so easy nor quick, so often its seen as the perfect repro method, but it has its limits and needs full understanding of all the variables to execute right, rough workflow

Prepare part for scanning

Scan the part

Import file

Rebuild in CAD using start & finish as guide

Add bends to match available dies

Adjust for best fit

Export

Bend

Recheck

If ol mate murphy didn't visit (he always does)

Adjust file

Rebend

Job done, but at $100/hr for the skilled labour + scanner + software etc etc, you don't get much time to make a buck.

After all that, errors are often present, but after a few iterations you figure it out and then can go onto CNC bending hundreds of copies.

In saying that, if thats what they sold you on, you'd expect they had the workflow down to deliver, from the photos it looks like the forward pipe needed a lazy bend to sit inside but the machine could only do a tight bend putting the two into the same space, rather unfortunate.

 

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To show you what I did. You can see by the pattern I made that they could not match the bends perfectly. And you can see in one pic how much I had to cut them to get them to work. I would call that fettling. Not what you have to deal with. The pic of it welded is the other side but still relevant I think.

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I’m getting there. I’ll post an update in due course. The benders have given me a couple of off the shelf 90 degree bends which will get me over the line I hope. The outer pipe ended up being ok. I have to make the inner one fit it now. I didn’t want to get too upset with them as a club member works there and hooked me up with a solid deal $ wise. 

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