It IS possible to remove (and refit) the head whilst the engine in in-situ, BUT if you have never taken one off, it can be difficult finding, and getting to, some of the bolts at the rear front of the engine. If one does decide to take the head off in-situ, one needs to take both the fan-shroud top cover off, and the thermostat housing. It is also easier to get to the bolts/screws at the front of the engine if a trolley-jack is put under the engine (to support it), the rear cross-member is removed and then the engine can be lowered, just enough to make getting at the front of the engine a lot easier.
If somebody has never worked on a 500/126 engine before, and with this sort of problem, I would recommend that the engine is pulled out for a complete inspection. If 'tmrsgv' is having problems finding a mechanic/engine-shop to work on the engine may I suggest, as I have done with our American colleagues, try a good motor-bike shop----the 500/126 engines are air-cooled twins, just like a classic (and a few modern) motor-bike.A classic VW engine-shop might be a good alternative.

I just went though my first engine rebuild under different circumstances. Aside from mine being a rare engine size and extremely hard to find parts. The rebuild was very straight forward. You can do it!!! I'd suggest going with a kit with barrels and pistons to make it easy, that was half my battle. And for the price, why wouldn't you?!


I'd agree with marking the distributor to make sure timing is set. That took me a bit to get dialed in because I didn't. Like others have said, we're here to help!

ChiapC said:

I'd agree with marking the distributor to make sure timing is set.

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Now that's two of you saying to mark the distributor position before removal; I don't know how you would do that.

The engine has two possible TDC positions and two corresponding rotor-shaft positions. The rotor shaft is free to move after the distributor is removed and if you leave it in position, (as you will if you attempt to repair the engine with minimal disturbance), why would you mark it anyway?

It's very easy to reset the distributor timing and there's every chance that if it's done from scratch it will be done better than how you find it.

We don't want tmrsgv running away from this fearing for complexities that don't exist.

Peter, you are a person skilled at stripping/re-building these little engines. All it takes is a touch of 'tip-ex' after you have set the engine to TDC (on the pulley/crankcase marks), a spot of tipex (or centre-punch mark) on both the distributor body and adjacent crankcase and the rotor-arm and distributor body might just help the inexperienced to reset the timing to a position where the engine will at least start. Obviously, the timing must be re-checked when the engine is back up and running, and adjusted as required.

the hobbler said:

Peter, you are a person skilled at stripping/re-building these little engines. All it takes is a touch of 'tip-ex' after you have set the engine to TDC (on the pulley/crankcase marks), a spot of tipex (or centre-punch mark) on both the distributor body and adjacent crankcase and the rotor-arm and distributor body might just help the inexperienced to reset the timing to a position where the engine will at least start. Obviously, the timing must be re-checked when the engine is back up and running, and adjusted as required.

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......to use one of your words Tom, I'll "concede" that that may help. Tippex rather than centre-punch on the rotor-arm though.

fiat500 said:

Now that's two of you saying to mark the distributor position before removal; I don't know how you would do that.

The engine has two possible TDC positions and two corresponding rotor-shaft positions. The rotor shaft is free to move after the distributor is removed and if you leave it in position, (as you will if you attempt to repair the engine with minimal disturbance), why would you mark it anyway?

It's very easy to reset the distributor timing and there's every chance that if it's done from scratch it will be done better than how you find it.

We don't want @tmrsgv running away from this fearing for complexities that don't exist.

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Being a complete amateur and minimally skilled in the engine department, it took me a substantial amount of time to get my distributor set. I read plenty of forums that said point the rotor towards the rear of the car cylinder #1 when it's at TDC. I did that and messed with it for a long time. Then, after being frustrated and using my resources (friends, smarter than me) they said what matters is where the #1 wire is on the cap, not where the #1 engine is in the car. I'm used to the VW world, where it is the cylinder. I think having a mark of sorts may have helped, or maybe I would've screwed it up either way. I'm learning though, (and having fun when things work) which after all isn't that the point!?!?

I do appreciate when differences of opinion can be mutually agreed upon to have a neutral resolution. Would you two mind talking to our government over here in the US please? Thanks! (Not to get political, just having some fun)

Chase

Refitting the distributor used to worry me a little but after doing it so many times I saw a pattern in that with the crank pulley 10 degree marks lined up looking down on the distributor like a clock face the low tension lead nut and bolt always seemed to be at the 6 O’clock position as well as the rotor arm. So I start there and the engine will generally start And be ready for fine tuning.

Back to the cause of this problem; having come across a couple of the thin copper washers that should be under the nuts which secure the carburettor, I wonder if copper was used partly so that it was less likely to cause damage if dropped inside the intake? I guess it was primarily there to prevent damage to the relatively fragile metal of the carb. itself. Since nyloc nuts are used for this fixing there is no practical need to use spring-washers and these would actually cause damage to the metal.