Engine oil leak tube push rod

[Reinaldo]

Hello,

 

Looks like I got a significant oil leak in the area close to the spark plugs (engine tr4a).

After cleaning, adding some white powder it is clear that the oil comes from the pushrod tubes. From all of them, but looks like a bit more on cylinder 4.

Complete engine restoration was done 15 years ago and car has run less then 15 thousand miles since then. I guess it is about time to show some deterioration.

Looks like the remedy being head removal and proper reassembly of the tubes in a new gasket (drawing attached).

I have a 694-510 head gasket from Mossmotors US and there is a note for new tubes: "swag ends in head and seal with blue locktite" which is not quite clear to me.

Also , the same 694-510 head gasket is for 83, 86 and 87 mm cylinders (?). Moss Europe has different gaskets for different cylinders dimensions.

I also read somewhere in this forum a palliative solution of using locktite externally without removing the head.

Any tip or recommendation? Any help will be appreciated.

Regards,

Reinaldo Morilha

TR4A 1966

TR3A 1959

[RogerH]

Hi Reinaldo,

This has come up a few times and a couple recently.

 

To sort the leak properly you need to remove the head, remove the tubes and refit using a quality sealant between the tube and the seat in the head.

 

The ends of the tube are swaged into place.

Using two large ball bearings (either end of the tube) and squishing the whole lot on a vice should sort it.

 

External repairs have been mentioned but nobody has come back with any good feedback.

 

The head gasket will have no effect on sealing the tubes.

The leak is caused by low crank case pressure and capillary action.

 

Roger

[LGFromage]

If removing the old push rod tubes plan on re-using them as the new ones sold by Moss and others are +22 thou oversize on diameter. In consequence they too big to fit into the head, unless of course the the head is machined to suit at extra expense.

 

Tim

[RogerH]

Hi Tim,

is it possible to remove them without damage and then re-use.

 

Roger

[Geko]

The leaks are due to the different thermal/expansion properties of the head and tubes (iron/aluminium). With my cast iron head, 2/8 of the new aluminium tubes are leaking again tho sealed with Loctite. Using another material than aluminium but allowing swaging and a bit thicker would probably solve the problem. Machine job. Also, there's no way to remove the tubes without damaging them.

Edited October 28, 2014 by Geko

[RogerH]

Hi Stef,

using another material sounds sensible.

Good ol' mild steel to the rescue. Expansion similar to cast steel.

Easily fabricated into a correct size tube.

Many people paint the tubes black or they could be chromed, Zinc or Nickel finish.

 

Roger

[AlanT]

Anybody know the dimension of these tubes?

 

There is a nice Youtube video of a guy rebuilding a Vintage Rolls engine and swaging in a load of similar tubes.

I think these are water tubes and this would be even harder to seal.

 

I would think that corrosion from dissimilar metals is at the bottom of this problem. The engine oil will be a little acidic and have some water mixed in it. I'm pretty sure the Rolls guy reams the head out.

 

This maybe why the tubes you can buy now are too big.

[LGFromage]

Hi Tim,

is it possible to remove them without damage and then re-use.

 

Roger

Hi Roger

 

It is possible to remove the tubes and re-use them but you have to be careful both in removing and replacing. I should have been a bit more careful as I managed 6 out of 8 OK but replacements had to be found for the other 2. (Thanks Darryl)

 

Oil leaks from the tubes can result from the removal of significant amounts of material from the cylinder head face in order to improve compression ratio. This can lead to the flare on the bottom of the tube being removed thereby making the tube loose. In order to stop this the chamfered holes in the head should be re-cut so that a new bottom flare can be created.

 

As a matter of interest I have been doing some research into the availability of aluminium tubing (as it happens to repair my Peter Powell stunt fling kite in order to impress my grandchildren) and happened to notice that 0.750 in dia tubing, as required for a 4 cylinder TR engine, is reasonably available on the internet. So in future if I need some for my TR I now have an alternative source of supply.

 

Tim

[Reinaldo]

All of us are very fortunate to have such a deep and knowledgeable guidance available at this forum.

Thank you guys for the help.

Now that the most obvious parts are available for removing and putting back the head (during the work they never are enough but lets us believe they are !) , we will remove the head and decide at the machine shop what course of action we will take. Either having the ends of the tubes swaged into place using large ball bearings as Roger said, or removing them. If we remove them looks like we might have to machine new ones (thanks LGfromage for the warning). Using aluminium or steel is a sort of challenging decision. As Geko said different materials might be more prone to fail, but I guess we should also pursue originality.

Thanks,

Reinaldo

PS.: I found one video at youtube that might be the one that Alan has referred to (look at around 1:40 min):

[AlanT]

I hope this convinces you to find someone who knows how to do this.

 

[Reinaldo]

Very convincing Alan !

Thank you very much !

Reinaldo

[AlanT]

I think this confirms that you need a soft, ductile material. So you probably stay with aluminium.

But you want the right grade of aluminium. And you need to anneal it.

 

Aluminium is not like steel to anneal and re-hardens as time passes!

 

Rolls probably has tapered holes in the block and the TR holes are probably parallel.

Check this!

 

Getting these to seal looks a bit more tricky than a bang on the end.

[Geko]

The below detailed instructions are drawn from the workshop manual of the Fergusson TE20 which has a similar head as TR4

 

 

[Reinaldo]

This is great Geko. Thank you very much !

[AlanT]

3/8in all-thread and two custom turned bushes.

 

Beats hammering.

[Besalu]

On 10/27/2014 at 5:50 PM, RogerH said:

Hi Reinaldo,

This has come up a few times and a couple recently.

 

To sort the leak properly you need to remove the head, remove the tubes and refit using a quality sealant between the tube and the seat in the head.

 

The ends of the tube are swaged into place.

Using two large ball bearings (either end of the tube) and squishing the whole lot on a vice should sort it.

 

External repairs have been mentioned but nobody has come back with any good feedback.

 

The head gasket will have no effect on sealing the tubes.

The leak is caused by low crank case pressure and capillary action.

 

Roger

Good clear advice Roger.

Tim mentions about the new tubes from Moss being 22 Thou too big on the diameter. Has any reader had problems with this?

Also which sealant would be the best? I have read suggestions of Loctite 648 and also Loctite 574. Excuse my ignorance but what is the difference between these two?

Thanks, Richard

[Rob Salisbury]

Hi,

           648 is a liquid, 574 a paste, I'd use 574 if fitting new tubes, but the 648 is thin enough to run down the joint between the fitted tubes and the head.

Chers Rob