Save up to 15% with Adrian Flux insurance!

Technical Piston removal

Currently reading:
Technical Piston removal

Y

Yellblob

Member
Joined
May 13, 2013
Messages
52
Points
68
Hi all,

I hope you don't mind these fairly basic engine questions.

My engine is still in the car although I've gone as far as taking out the cylinder barrels (I've bought new nanni 540cc pistons and barrels)

q1. Is it possible to take the pistons out like this, or really should the engine come out?? Circlips and retaining rods look like they will be very awkward.

q2. Regarding reinserting the collets and spring caps using a valve compressor , what is the best order to do this in i.e compress springs including cap then drop in collets?

I've not done any engine rebuilds before!

Many thanks,

David
 
I would not want to try and fit that piston kit with the con rods in situ. Apart from the fragility of the piston rings if you have never fitted them before with the Nanni 540 kit the skirt at the bottom of the barrels tapers down to about 0.5mm in thickness. If you have not already done so drain the oil, remove the sump then you can undo the big end caps and remove them. You can then lift the original Pistons and con rods clear. If you are not replacing the big end shells make sure they stay in position.
Are you working with a workshop manual? As the Pistons and rods have to be correctly orientated.
New Pistons can be fitted to the conrods then installed into the barrels ready to be dropped down into the crankcase.
Loads more I could say on this but run out of time at the moment.
 
Completely agree with 'Toshi'--do NOT try and fit the pistons onto the con-rods with the con-rods still on the engine. I have done a number of engines, and I wouldn't even think about doing it that way. if you are going to fit the '540' kit, I would suggest that you fit a 3-1/2 litre aluminium sump--simple swap job, use the RUBBEROID gasket and NOT the cork variant. If I remember correctly, the 'Nardi' pistons that we fitted at Radbourne Racing (652cc) had to be heated to enable fitment of the gudgeon-pin (wrist-pin if you're a Yank). We did it by the simple (but in hind-sight, potentially dangerous) system of putting a small amount of petrol in the new piston, lighting it and when the fuel was used up, quickly and carefully, slip the gudgeon-pin into the piston (and through the Con-rod small-end of course)--prior to doing this we would put one of the piston/gudgeon-pin circlips in place to act as an 'end-stop' Good old days before health and safety!!
thumb.gif
smile.gif
 
Sorry, in all that excitement, I forgot about your 2nd question--yes, one end of the valve-spring compressor goes against the head of the valve, the 'forked' end goes over the spring-washer, which sits on top of the valve spring (be careful, there is also a washer at the bottom of the spring to stop it cutting into the cylinder head). When you have compressed the spring and washer, pop in the collets. When you have released the spring compressor and removed it, give the valve (at the collet end) a couple of good taps with a hammer to ensure that the spring, washer and collets are sitting correctly.
thumb.gif
smile.gif
 
Agree with the gentleman above, best case remove the sump and then remove the con-rods with the pistons. On the other hand in the end of the day i feel that it will better and easier for you if you remove the engine from the car. This will make your life easier, cleaner and eliminate any mistakes. Believe me it will be fan also. Regarding the 3.5 litter sump mentioned above, go for it, it is very effective.
Can't wait to hear about your results because i am also interested in the 540cc conversion.
Are you going to put any other things in the engine like a curb or something?
Thomas
 
Hi David,

I echo the comments of the learned gentlemen above. Take the engine out. For the hour it will take you to get it out, it will save twice that putting it together. Also it means that you can clean everything much better as you go.

Use an engine assembly paste when you put it all together, and use it liberally... on everything. Turning an engine over on dry bearings is a sure fire way of getting much more practice rebuilding engines.

I have rebuilt many engines in my time as a diesel mechanic and for myself. In fact I am waiting for some parts right now so I can rebuild the 'rebuilt' engine in the 500F I have just bought.

If you have never rebuilt an engine before then well done for giving it a go. As well as the helpful advice and vast experience offered here on this site the University of Youtube is your friend.

Chris
 
Hi all,

Ah thank you all for the helpful advice and taking the time. The cylinders and pistons were damaged so knowing that its been the right thing to take them out. I'll take the engine out when I have a few hours to spare and disassemble further as you have suggested. Should one heat up the pistons somehow to get the retaining rods out (the one with circlclips holding it)?
Thomas, what did you mean by curb, I'm intrigued?

Many thanks,

David
 
Yellblob said:
Should one heat up the pistons somehow to get the retaining rods out (the one with circlclips holding it)?
Thomas, what did you mean by curb, I'm intrigued?
Click to expand...

I think Thomas' gordinir8 first language may be Greek, so he has an amazing command of written English (as does Adriano Adry500); but I think that's just a typo for "carb".

I'm pretty certain that on my standard pistons I was able to remove the "rod", ie. gudgeon-pin/wrist-pin/piston-pin without any special technique other than a well fitting tool with which to drive it. But basically it's simple physics... really cool down the pin in the freezer and Haynes suggests heating the pistons in boiling water. Obviously you need to be fairly organised to use these techniques and quickly fit them together.

If the pin is already fitted in the new pistons and can be moved without straining or damaging the piston, you can drive it out just sufficiently to leave the gap for fitting the con-rod, without removing it completely, which will help when driving it back in.

As others have said, get your head around the correct orientation of the pistons to conrods; it will "kill" you if you do all this and then realise that they are the wrong way round.:bang:
 
Last edited:
David you did not answer my question about a workshop manual because if you do not have access to one then I would down tools until you do. You will also need a decent socket set, 3/8" drive is a good choice, a torque wrench and a piston ring clamp. I tend to keep ice cream and oven chips in the freezer and have never felt the urge to offer Pistons up to the fire gods by setting them on fire :)
I just checked the Nanni kit I have here and the gudgeon pins are a nice press/slide fit with a hint of oil. A spare gearbox input shaft makes a great drift for tapping them into position.
 
Yellblob said:
Thomas, what did you mean by curb, I'm intrigued?
Click to expand...
As fiat 500 correct mentioned its s typo of carburetor, unfortunately edit option is active for a limited time only in this forum, i really don't understand the reason and i have discuss it with the moderator that he believes it is better that way, i don't.
Anyway i am curious what will happen to this engine if you put a 28 ''carb'' a sport camshaft and maybe do some head porting. It is my cheap alternative option to a 650 engine that i am also thinking for my car.
Also here is a special gudgeon pin removal/installation tool that you can buy or fabricate your own that might help you.
http://www.triumphrat.net/classic-vintage-and-veteran/232350-gudgeon-wrist-pin-tool.html

Thomas
 
fiat500 said:
:D:D:D
I bet you don't even stick your engine blocks in the dishwasher....flavours next day's dinner-plates a treat. ;)
Click to expand...

Not so long ago the War Office went to see her mother for a week or so.

She came home a day early and found my spanners just finishing the cycle in the dishwasher with the rest of my weeks dishes, a gearbox spread all over the kitchen table and an engine block in the oven baking some paint. I kid you not.

Oh how we laughed.....
 
Hi,
Yes, I have two manuals, but perhaps because I have deviated from what they advise I found info. sparse on this particular situation. It was too tempting to remove the cylinders!
Sorry, I should have thought carb. too. I think I'll try and keep it simple...
Ah, gudgeon pin that's the correct name!
Cheers,
David
 
Thomas (Gordini)--if you carry out those mods you will definitely improve the standard 500 engine. When you 'port' the head, don't forget the ridges in the inlet tract just behind the inlet valves--these can be softened quite a bit. Try and reduce the depth that the valve-guides stick into the inlet and exhaust tracts. Gasket-match the exhaust outlet in the head AND the little manifolds, and the inlet port into the head. I would have the head skimmed just enough o ensure flatness and then use a thin (0.5mm) copper head gasket. With these mods, a 'sport' cam and a good exhaust you will have effectively re-created a '500 Sport' engine.
thumb.gif
smile.gif
 
fiat500 said:
I have a spec. sheet that says there was a slightly different distributor type-number on the Sport. It results in the advance curve extending further in the rev range. I'll dig it out and scan the page next week.
Click to expand...

We live and learn as they say :)
I sat down the other day and went through the original Fiat 500 workshop manual looking for any references to the 500 Sport and how it may differ from the standard models. I missed the ignition specs on page 243 and of course you are right. Do we have the same spec sheets I wonder? I was a little surprised at what I saw.
 
Hi Chris,

Well, I used to live in Auckland and I bought the car in Napier. It was an Italian 500 made after they stopped assembling in NZ. I shipped it to the UK in 2013 when I moved back to Wolverhampton(!). I took back a P-class, jollyboat and 67 minivan too but that's another story! Yes, I would have liked to have stayed!

Cheers,

David
 
You must log in or register to reply here.

Similar threads

R
Technical Foreign Object Damage
2 3 4
Replies
60
Views
3K
the hobbler
T
M
Technical Piston Ring Gap
Replies
4
Views
926
myoshik
M
MotoLojo
Technical Rocker Arm Removal
Replies
8
Views
397
MotoLojo
MotoLojo
M
Technical Brake Pedal Removal from Brake/Clutch Pedal assembly?
Replies
1
Views
329
Mferg
M
I
  • Question
Technical 500F Rear Axle Stub Removal
Replies
6
Views
375
Italino
I
Back
Top