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General Murphio's Meanderings

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General Murphio's Meanderings

I'm going with your theory that the seized rocker had caused excessive wear/pressure on the valve stem/guide. I doubt the intake was closing properly and that's why it's got hotter than it should.
 
Franko500 said:
I'm going with your theory that the seized rocker had caused excessive wear/pressure on the valve stem/guide. I doubt the intake was closing properly and that's why it's got hotter than it should.
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....and why it was a pig to start from cold for a longish time and had become a bit chug-chuggish after cold-start over the last few days.:bang:
To think, I suspected timing, the 123 distributor, dirty carb and latterly had decided that the float-level must be wrong....I see it all so clearly now.:D
 
There's a 500 head and crankcase on Ebay with new hardened valves for 50 quid and 10 quid postage.
 
Paolo66 said:
There's a 500 head and crankcase on Ebay with new hardened valves for 50 quid and 10 quid postage.
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Thanks Damian. I think that is someone who is a member of this Forum. The thing that slightly worries me is that it has been machined down to remove the gas-ring and the inlet valves are enlarged. But i have emailed him about it.
 
fiat500 said:
Thanks Damian. I think that is someone who is a member of this Forum. The thing that slightly worries me is that it has been machined down to remove the gas-ring and the inlet valves are enlarged. But i have emailed him about it.
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It's Nathan Robertson who I bought Paolo off
 
Paolo66 said:
There's a 500 head and crankcase on Ebay with new hardened valves for 50 quid and 10 quid postage.
Click to expand...

I went to visit Nathan yesterday and filled the back of my car lightening my wallet in the process. I did see the 500 head etc and had thought about buying it but having gone for 3 job lots of parts in as many weeks I thought I should show a little restraint. I think the head is a steal at that price. In the meantime if anyone is looking for any parts new or used let me know :)
 
Nathan says the head has been sold anyway..and I have a suspicion that I know whom to.:D
Still, I'm literally better off without it.:D
Engine and gearbox out in one lump this afternoon...a personal best under one and a half hours.... no rushing. I put a pallet under it, propped it an extra couple of centimetres, detached it and then pushed the car forward. With a bit of a wiggle but no strain to me or the mechanicals, everything came out in one piece.
MAL_2787 by Peter Thompson, on Flickr
 
What a pain! I had to start by stripping the alternator and cowling that I had only just fitted to the 500 engine soI could refit it to the 650:bang: But that done I was almost at the point where the head falls off. So obviously I helped it as I was curious to look before I go away with work for a few days.
MAL_2789 by Peter Thompson, on Flickr
The damage is as I expected and does look repairable. It has been running very hot on that side and no wonder, and the exhaust valve has burnt away a bit. There is a big build-up of hard ash near to both of the inlet valves. On an aside, the pistons and barrels are looking good and I can still make out he honing marks from the rebore.(y)
I suppose I will be needing new valves, guides and seats and i am tempted down that road. Another option is to just put a different head on. I sense a new thread being started.:D
 
fiat500 said:
Thanks Damian. I think that is someone who is a member of this Forum. The thing that slightly worries me is that it has been machined down to remove the gas-ring and the inlet valves are enlarged. But i have emailed him about it.
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It's so long since I did my 500 and I got so used to the 650 stripdown and rebuild, that I didn't remember that the 500 doesn't have a gas-ring in the head and it has non-identical sized valves in any case.:bang:
 
A lot of carbon build up there? I haven't seen that much before on a 500 head before? I wonder if it's down to modern fuel? I know that a lot of modern cars surfer quite badly from it but they tend to be fuel injected, but as I have said before on other threads unleaded fuel burns hotter, from what I have read, so that could explain it? Certainly explains the issues you have been experiencing. Lucky the valve seat decided to remain in one piece otherwise it could have been really ugly.

The problem is you are going to get many people in the UK clocking up the sort of miles you do, so it's going to be difficulty to have anything to gauge it against.
 
fiat500 said:
It's so long since I did my 500 and I got so used to the 650 stripdown and rebuild, that I didn't remember that the 500 doesn't have a gas-ring in the head and it has non-identical sized valves in any case.:bang:
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You were confusing me there for a minute until I looked back at my old pictures. I never really noticed that the 500 didn't have a gas ring on the head just the barrels and that the 650 has it on both.
 
I took Murf out for a spin with his new engine today; about 40 miles in total. It's quite hard to keep him under the speed limit, never mind the running-in speeds.:D
I'm sure that the gearbox has a higher ratio because chugging round town really is that if I stay in 4th gear...it strictly is 3rd gear any speed up to at least 35mph.
There's a bit of a clunk sometimes as I go over a rough bit of road. It may be that I need to create more clearance for the exhaust or possibly the gearbox mounting needs tightening or having the 126 stiffener fitted. The engine is much quieter with hardly any valve clatter but the gearbox has a more whiny sound.
The combined weight at the rear, with a heavier flywheel, alternator and a slightly beefier gearbox seems to give the car a lighter feel at the front end.....even more of the go-kart feel.
But he best thing about him is the easy starting hot and cold. The insulators for the carb and the fuel pump are thicker and are possibly made from a different material than the 500 so the petrol doesn't seem to boil away after a short stop.
When the engine was properly warmed up it started to randomly miss a little. This was very similar to the way the original engine had been behaving lately. The only common denominators that could have been causing this are the coil and the 123 distributor, and I have previously eliminated the coil. So I cleaned up the Magnetti Marelli distributor robbed from my spare 600 engine and will give that a try. .On a short trial run I had no problems but it needs to get really hot to be sure.
Overall, the novelty of Murf suddenly being able to keep up with the traffic and feeling so sporty is really good. But I am missing the distinctive sound he used to have and his pushy behaviour will take some getting used to.
 
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