Technical Pushrod tube seals will be the death of me.

[allyl90]

Hello all... again!

I've had nothing but oil leak issues from my 650cc engine. I rebuilt the engine using these nice springs pushrod tubes. They came with silicone seals but from day 1, have caused a leak. Upon investigation I realised due to my own fault and one was a little mooshed.
I replaced them, all fine. But the leaking continues.

I then gave up and handed the car to a local italian specialist to replace them. They did this, and it was still leaking. So it was suggested we try the original rubber seals.
They then swapped out the silicone ones for rubber.
I collected the car and done 0.4 miles before pulling over due to the sheer amount of oil that was being pushed from the seals!

So that's 4 lots of tube seals my engine has been through and it still leaks like a colander.

Has anyone got a solution?
Many thanks,
Alex.

 

[Toshi 975]

Never had a problem with original push rod tubes.

 

[fiat500]

Has anyone got a solution?

I'm with Dave on that one.

Never had a problem with original push rod tubes.

The version fitted to the original 500 engine has a weakness because of the concertina ends to the tubes, which can misalign and even lose their springiness. But the solid tubes of the 650, with the deeper sealing-rings, when fitted with care and a tiny amount of sealant are a positive fit.

I've never used the spring-loaded tubes, so I don't know what level of pressure they apply at the seal. But they seem to me to be a superfluous fashion item. The fact that you don't need to remove the cylinder-head in order to extract them is offered as their USP. But if they weren't prone to leaking in the first case, this "advantage " would be neutralised.

I would refit the originals forthwith.

 

[allyl90]

I think I'm with you guys on this one... I stupidly binned them when dismantling my engine, so I'll have a look on fleabay tonight to order some.

Many thanks chaps!

Alex.

 

[fiat500]

I think I'm with you guys on this one... I stupidly binned them when dismantling my engine, so I'll have a look on fleabay tonight to order some.

Many thanks chaps!

Alex.

Good idea; but I would wait for alternative takes on this and then weigh it up.

 

[the hobbler]

I use the 'spring-loaded tubes, and have never had a problem with them. I would suggest that you check on the underside of the head and make sure that there are no small pieces from the original seals stuck in the taper thatthe seal beds into. Also, check that the tops of the tubes are not distorted.
Yes, you can (just!--but the oil-tube cover-tube can be a bugger) fit the spring-loaded tubes into place with the head in position, but my normal proceedure is to fit the head in position with the head nuts JUST 'started', then fit the spring-loaded tubes. They don't cost much, so I never re-use seals---and I always use the red 'silicon' seals.

 

[AndrewHarvey]

I used the VW aftermarket tuning adjustable ones and have no issues

 

[the hobbler]

What seals did you use Andrew---because the diameter of the VW adjustable tube ends are not the same as the Fiat ones

 

[AndrewHarvey]

Ill dig out the spare one's Tom and measure.
I'm at rallycross at Lydden for my 42nd year in a row right now..

 

[JumpJet]

I used these spring-equipped ones with the regular black seals and they have been leak free (for at least the ~600km since the rebuild), even with full synthetic oil.

 

[Franko500]

I have used the new concertina tubes and never had an issue.
Only used the standard rubber seals that come in the gasket kit.

Have you made sure that you extend the tubes to longer than required before fitting them? Then when you tighten the head down this will compress them to the desired length under tension.

As Tom said make sure the seats are clean and not distorted.