How to... Choose and install Type 4 pushrods tube seals

Discussion in 'How To' started by Joker, May 16, 2014.

  1. There are numerous posts around regarding installation and choice of pushrods tube seals, where to buy them from, which type, which colour, do I use a sealant, do I install them dry or with oil.

    Here is what I do, I see this as tried and tested because once I've installed them I've yet to have a leaky one.

    First, which seals?

    Well, it's very well known that the green seals for the head end are the best type because they are made from Viton, but typically they are only available in the Victor Reinz kit which costs about £50, a lot of money for 8 seals. The usual suppliers sell single seals off the shelf but this is what I've found...

    The pictures below show a green Viton seal, and a black and red seal I've bought and trialled in the past.

    [​IMG]

    [​IMG]

    As can be seen there is not only a difference in diameter of the seals overall, but there is also a difference in the overall thickness and sheen if the seals. What can't be shown is the 'feel' and texture of the seals.

    The green Viton seal is by far the largest in diameter and thickness. I haven't put a gauge on it but the difference can be measured in mm as opposed to microns. The green seal feels 'plump' and has a rubbery bendy feel to it. It can be squeezed and compressed but it retains it's shape. The finish is dull.

    The black seal in the middle is smaller in diameter and thinner over all. It has a harder more plasticky feel to it, hard enough that it can't be compressed between your fingers, and when it's bent out of shape it retains it's new shape be that oval or twisted. I've demonstrated this below, I squeezed both of these oval at the same time, as you can see the black seal retains it's oval shape to a degree.

    [​IMG]

    The finish on this seal is very shiny, more in keeping with some of the other 'rubber' products available from the 'scene' I haven't gone so far as having its chemistry tested at work but may do this at a later date. This seal is also susceptible to easy damage from the push rod tube itself or any tool.

    The red seal is the smaller of the 3 and appears to have a similar make up to the Viton one, however, being smaller it doesn't provide the same surface area for sealing as the green one.

    Below are 2 examples of the smaller diameter seals.

    [​IMG]

    The one on the left I sourced from Viton, a pack of 16 for me to conduct a trial. The one on the right came from a Usual Suspect, Kaiser Soze I think?

    As can be seen from the pic, the Viton seal is 'plumper' and it has the same feel and quality to it as the green Viton seal. The one on the right has the same feel and look to it as the large black seal with the same plasticky feel and glossy sheen to it, although the size is much closer to the Viton seal so overall would provide a better seal than the large black seal. This is what most people actually find, that their leaks are at the head end not the engine end.

    I trialled these on the engine I blew up, still they didn't leak! So I've stripped them off, cleaned the permatex off them and am about to install them on the 2 litre engine which I stupidly didn't do before I installed it so it's leaking like a sieve.

    So, installation.

    Sealant or no sealant? I was warned many years ago to stay away from the instant gasket and hylomar type sealants and I see why. They create a mess, often bits of it are found inside the engine risking blockages, and the things just don't work. I followed Jake Raby's advice and uses clean engine oil smeared on the seal which is good, but if for any reason you knock or dislodge a pushrod tube, through fitting an exhaust for example, this method can see a leak form. Once it starts to leak it won't stop. So from my second build onwards I started to use a small smear of Permatex 3h. This is the brown gooey stuff with the odd smell which looks a bit like marmite. This stuff remains ever so slightly tacky and puts up with being moved around when installing the push rod tubes. The method I've used is to apply a smear to the tube, install the seal then apply a small smear to the outer seal, then push the tube home with a final little twist to seat it home. I've used this method now and have yet to experience a leaky pushrod

    Hope this helps point some on the right direction


    :)
     
    Pickles likes this.
  2. I think the red seals are for the earlier smaller pushrods tubes
     
  3. Sold in a pack of type 4 seals recently by a well known vendor I won't name
    :)
     
  4. The red ones are also in the Elring gasket set , not 100% but early type 4 engines had a smaller tube ?
     

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