Cant find post about sealing & compounds

[miked]

There was a posting about the above. I meant to print it but cant seem to find it. As I recall it was from one of our Australian members.

Could someone point me at it?

Mike

[stuartgb100]

Mike,

I'm still having problems with the Search function, but I did copy it when it first posted (ex Rohan).

Glad your wishbone problems are (fingers crossed) over. What rear camber and rideheight do you now have?

Here's the thread:

My $0.02 worth on sealing twin cams

1. Take the time to clean and ensure all the sealing surfaces are flat and
free of major defects if possible. If you have a major problem here then
the standard sealing approaches wont work. Also make sure your engine does
not have excessive blow by or poor venting which is pressuring it up at high
revs and blowing oil out the seals, gaskets, filler cap or dip stick

2. Ensure when you assemble all the joints that you actaully get the gasket
and sealing material properly placed and you torque the joints evenly. Its
very easy to displace some of the gaskets such as the ones around the front
and rear main bearngs and the sump as you tighten the joint down. I did not
get one of these right once after a rebuild and ended up getting black
flagged during a race as oil came out under hard cornering and high engine
speeds. It did not leak during normal driving just at race speeds. Try to
find the formed rubber seals for this sealing of the sump as they are much
easier to fit than the cork bits you have to try to get to bend around the
bearing housings.

3. I try not to use silcones except in 4 places

a.On the half moon cam cover plugs where you need it to fill up the
clearance gaps
b. In the corners where the gaskets join around the sump to block seal.
c. On the bore of the water pump housing to help the O rings to seal
d. Under the cam cover nuts and washers

When you use it then ensure you use a proper engine sealant type which is
suitably oil resistant ( I use Loticte Blue or Copper). Recognise, it oozes
everywhere and you risk getting it inside the engine and into the oil system
so use the minimum amount possible.

4. I use a locally made head gasket made by a one man company called HJ head
gasets ( you can get them through the Elan Factory). These are made using
the same materials as Ford in Australia use for their modern cars. It is
made of a composite material reinforced internally with a wire mesh and
coated on the outside with something that looks like aluminium paint !!!.
It seals very well but is hard to get off the block and head, as has already
been commented on. I use a spray on gasket stripper to remove it. The bores
and oil passage in this gasket are sealed with a sheet metal ring of u
shaped crossection formed around the edges of the holes in the composite
gasket. The guy makes the gaskets in thicknesses from 0.8 mm to 2.2 mm to
any bore you want so you can use them to tailor to your engine bore and
compresion ratio wanted. I have used these in engines with 13.5 comp ratios
with no problems and never a blown head gasket or oil or water leak despite
other major engine trauma over the years ( dropped valves, cracked bores,
broken rods). If you use the thicker head gasket you need to ensure you get
a thicker cork gasket for the head to chain cover seal as you will not get a
good seal with some of the thinner ones I have seen.

3. I seal the cork and paper gaskets using Loctite aviation gasket cement
No. 3. This a black tacky goo that dries semi hard and helps stop the cork
gaskets extruding if you let it go off after you paint it on before
assembling the joint due to its adhesive properties. ( I have never seen an
aviation gasket cement No. 1 and 2 so I dont know where the 3 comes from !).
I only put the No.3 gasket cement on the bottom of the cam cover gasket so I
can easily remove the cover without disturbing andneeding to replacing the
gasket.

4. For the metal to metal joins in the front cover I use the Loctite
anerobic gasket former range ( 510, 515, 518). This forms a semi flexible
gasket and what squeezes out stays liquid. It is available in a number of
grades to suit various degrees of sealing surface gaps, pick the one that
matches how badly corroded or warped your front cover to back plate joint
is. I have also started using this on the oil pump without the orginal paper
gasket. I was suffering cracking in the oil pump mounting flange due to a
resonance around 8000 rpm and removing the gasket and going to a metal to
metal join has moved this resonance above the engine speed range ( cut out
set at 8300rpm ).

5. Press the front and rear crank seals in place with a loctite thread
locker such a 243 to ensure a good seal and positive location especially if
any damage or corrosion on the alloy housings.

6. A washer welded onto the top of the dip stick with rubber seal and a
spring to hold the dip stick down also helps stop oil coming up the dip
stick.

7. Even with all of the care in the world I still get a small leak out the
front crank seal at high revs due to crank shaft vibration and flexing, the
steel Datsun cranks appear to cause less leaks than the orginal cast iron
cranks here despite running them at higher revs again. Be careful to ensure
these seals are centred on the crank shaft even if it means their housing
are not quite flat with the bottom of the block. The sump gasket will take
up the difference easier than running the crank seals eccentric.

8. I use Loctite 567 pipe thread sealant for the threaded plugs and other
similar items in the oil and water systems. Loctite also have a 569 grade
for sealing high filtration zero contaminant oil and air systems but I have
never used it but it would proably work fine also.

9. I epoxy in the core plugs to ensure no leakage. No freezing problems here
in Australia so you dont need to worry about them not pushing out if you
freeze the block.

10. I use conventional sodium silicate based exhaust gasket sealant with
conventional metal reinfoced composite material exhaust gaskets. I prefer
the type with the perforated metal outer layer and the composite material
sandwiched in between. These appear to be more flexible and forgiving of
misalignment than the composite ones with an innner metal mesh reinforcing.
I have seen people use the high temperature Loctite copper silicone sealant
on the exhaust mamnfold joint both with and without a gasket but I am not
sure how long this would last as it gets very hot even with the head cooling
the join itself down compared to the exhaust pipe an inch away from the
head.

11. Replace the mechanical fuel pump with a blanking plate and a suitable
electric pump. Oil leaks out the vent hole in the pump body under the
diaphram at high engine speeds. Altenatively seal the hole up if you really
want to keep the mechanical pump. I dont see any real functional need for
it. Maybe someone else knows why it is there apart from lubrication for the
starter motor underneath it?


Once you have got all the leaks in the engine fixed then you can start on
the gear box.

regards
Rohan

[rgh0]

I wrote that post a couple of years ago now and the only change I would make to it is say that high temperature silicone sealant ( eg the loctite copper silicone) on the head to exhaust manifold gaskets has worked well for the last couple of years on my Elan with no problems at racing temperatures.

Another article to refer to on this is on the Elan Factory web site which is generally consistent with what I wrote.

http://www.elanfactory.com.au/pdf/techn ... alants.pdf

regards
Rohan

[miked]

Rohan & Stuart,

Thanks very much for info'. I will print and save.

Stuart, I will find out what you asked about camber and ride height but am away with work a couple of days. I only have some model car camber gauge effort but should be able to glue some bits onto it and get some reading. Got carried away on ebay and then realised it was for a model car.

thanks Mike

[stuartgb100]

Mike,

No rush. Just interested and wanted to compare.
I will start a new thread in the Elan forum.

Regarding the model camber kit ...........


By today's standards, some would maintain that we do indeed have model-sized cars (particularly those of us with the baby Elan) !

Regards,
Stuart.