Technical Oil leak

[doc18015]

Hello all, I am new to forum and do need advise on oil leak. On running , oil seems to be coming from the forward most cylinder ...between the cooling fins near the top. At first we thought it was a oil tube seal...but it is not. Almost looks as though there is a hole in the cylinder head fin area. How can we diagnose this leak? Is this a gasket leak or cylinder head? Thanks for the help. BTW, this car has been bored to 750 cc/ w/ Abarth cam and other changes by the previous owner.

 

[Bambino]

Hi Doc,
I've attached a picture of the standard oil lubrication system in these air-cooled engines.
The system is fairly simple with the head having no formal oil galleries. Oil is delivered under pressure up the oil tube and thence to the rockers. It returns passively via the push rod covers and the seals along the way are apparently notorious for leaking. Difficult to see sometimes and difficult to fix properly with the engine in the car. The other place where oil may leak out is around the valve cover seal. This is an easy fix.
I've no idea what the PO may have done to the head during the rebore and rebuild and I guess the only way you'll find out is to strip the engine. If you do, fit spring tensioned push rod covers - they seal very well.
If you can, post some photos - they may help diagnose the problem.
Regards,
Chris

 

[oopsadaisy]

Hello all, I am new to forum and do need advise on oil leak.

Hi Doc and welcome to the forum!

I can only echo what Chris says - the push rod tubes and rocker cover are the favourite culprits for top end oil leaks.

Good luck, and keep us posted!

 

[doc18015]

hi and many thanks.... I will run the engine today and try to isolate the leak. Cleaned the entire area last night. Almost looks like it blew the head gasket. Will keep all informed. This is my winter project.

 

[doc18015]

Hi, just in from isolating the leak. We wrapped the pushroad tube w/aluminum foil. Clearly showed that the leak is from pinhole in pushrod tube. We will try to sand/silver soldier the area . Will keep advised.

 

[Bambino]

Doc,
Glad to hear you've found the problem.
The hole you report may be the special hollow bolts that hold the left and right halves of the tinware together at the top. There is one on each side of the head. The bolts also connect with a groove in the head and, in the event of head gasket failure, vent exhaust gases to the atmosphere rather than into the cabin air. I've got an old head at home so I'll take a photo and upload it if you wish.
Post some pictures sometime and yeah as Oops said, welcome to the forum.
Merry xmas,
Chris

 

[doc18015]

Hi and thanks to all esp. Bambino! It was in the center portion of the tube. I silver soldered the hole BUT....went to start the car and .....no start!! I traced no start to no spark. This car has been changed to Marelli magnetic electronic distributor. The pick-up wire was not very sound so I will try to re-solder it to the pick-up in distributor. Fingers crossed! Will stay in contact. I am loving this car! Funny thing I have many other cars but this one grows on one. I want to get over these problems and take it out for a drive. Has converted 5 speed, many ABARTH goodies, Weber, Konis, etc..... Will forward pictures when I get some. I have no idea where to set timing either . Any suggestions? Also , any , shop manuals on these cars? Thanks again for your help!!

 

[Bambino]

Hi and thanks to all esp. Bambino! It was in the center portion of the tube. I silver soldered the hole BUT....went to start the car and .....no start!! I traced no start to no spark. This car has been changed to Marelli magnetic electronic distributor. The pick-up wire was not very sound so I will try to re-solder it to the pick-up in distributor. Fingers crossed! Will stay in contact. I am loving this car! Funny thing I have many other cars but this one grows on one. I want to get over these problems and take it out for a drive. Has converted 5 speed, many ABARTH goodies, Weber, Konis, etc..... Will forward pictures when I get some. I have no idea where to set timing either . Any suggestions? Also , any , shop manuals on these cars? Thanks again for your help!!

Doc,

There was a thread posted here about February this year explaining the method for setting the static timing. It's called "Setting the timing on a 500F" or something like that.

Manuals for these cars are readily available and there is an electronic one on this site in the 'stickies'.

The 123 ignition is very easy to set up and so far mine is very reliable. The only problem may be if you have a tacho in your car. The mechanical tacho adapters I've seen for the 500s go between the distributor dog and the distributor gear drive replacing the part that is already there. The 123 ignition is supplied as a complete unit down to the gear drive (similar to the Fiat 126 distributor) so you may have to remove the tacho drive to fit it. I have seen 123 kits that use the existing distributor but am not sure of there availability. I've attached a photo explaining what I mean. The distributor on the left is out of a 126 (and is the same as the 123 drive) while the one on the right is a standard 500F distributor and both are made by Marelli. It is the part on the lower right that is replaced by the mechanical tacho drive.

Regards,
Chris

 

[doc18015]

Hello all, I have read both the timing articles/posts. I now know #1 cylinder location, timing marks. I am confused w/the Marelli electronic ignition in car. It has just a magnetic pick-up in distributor. Does just one of the points (2) on the dist. shaft have to line up w/the pick-up blade? Which one or does it not make a difference?
Did resolder the wire(s) on the pic-up and now have spark @ plugs. Now to get the timing correct. The Haynes manual should be re-written by Bambino.....does a much better presentation and w/more clarity.