Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Rocker Cover Sealant

TMers

.A few weeks ago i noticed oil leaking out from the Rocker cover. At first I tightened the screws up. At first all seemed well, but it started leaking again. So i replaced the cork gasket and it still leaked. Spoke to 'Burton Power' who told be that Kent engines are notorious for leaking. I've had my MOG since 2001 and it has never had a leak before! I saw on line that some people use a rubber gasket. Tried that, and unfortunately its still leaking.
A mate of mine has suggested that i use some gasket sealant. I have never used this. Couple of questions, 1. Is it safe? 2. Is it easy to take off as well as put on and 3. If TMers have used it, what brand is good?

The Book on rebuilding Kent engines have suggested that even the Author has used it on the Rocker cover. Can i please ask for you thoughts.

Regards

If it's a pressed steel rocker cover Dave, with thick gasket these have a habit over the years of distorting around the screw down holes. This means it becomes increasingly difficult to get an even pressure on even a new cork gasket with further tightening in an attempt to stop leaks exacerbating the situation. Put rocker cover on flat surface and look to see how it sits. It may be possible to carefully tap back metal around holes with a support the other side, but take care as you may make the situation worse. Once done be careful not to overtighten although I admit you will probably need to use non-hardening sealant as well.

The trick is to use the holding down tab washers from the later Pinto engine under the rocker box screws.. These prevent the rocker box distorting.

A smear of gasket sealant will do it no harm and there are no oil ways nearby for it to clog up.

I use Hylomar Blue and apply it sparingly with a kiddies paintbrush. Comes off easily with cellulose thinners or scraping with a Stanley knife blade.

Ultimate way around this would be to move to an alloy rocker cover but they are pricey - but they do reduce the clatter from the valve gear!!

Arwyn

Another 👍 for blue Hylomar ... I've used it since I grew up and stopped throwing gobs of red Hermetite at oily things! 🙂

K

Yep I'm a Hylomar blue man too! It's very sticky and won't set beyond a gel like finish and it really seals. As Richard V6 said though, re level the rocker box cover. They are always being over tightened and drag the area around the hole into a funnel shape. From my Ford days I have a tool I made to level them off. It's a cut down brick bolster with the sharpe edges just softened. I put the cover correct way up on a surface block, hard surface will do and slowly tap it back into shape. The bolster is 2 1/2" wide so flattens it perfectly. Use the cork gasket and Apply Hylomar blue, first to the rocker cover, here its fairly generous , 5mm centrally applied bead,then seat the cork gasket into it enough to just stick and position it. Now sparingly apply the Hylomar blue to the head surface..... Why not the cork I hear you ask! Well you don't want wodges of it squeezing out and finding its way into the oil with the obvious results. so a light smear here, start with a 3mm bead then smear it evenly on the surface. Now position the rocker cover onto the head.

Tighten down the cover, you may have to manipulate the cork gasket to align the holes with the rocker cover. Use a small screwdriver with gentle pressure applied downward on the cover and then fit the screw and engage the threads.... don't compress the gasket yet! When all screws are in, starting at the centre and much like tightening a head down, wrap the cover on evenly from side to side and diagonal to diagonal firstly just about finger tight then progressively tighter. You will not need more than a screwdriver type tool to achieve a tight enough fit! I Know Hylomar blue doesn't technically set but it does set up! If you can leave it over night before starting the engine then so much the better. That should sort your problem Dave.

If you find you still have a problem PM me and I have a few more suggestions for you to try!

Look for these at your local car parts store. They distribute the force better than the screws alone.

Richard V6, Arwyn, K, Sewin and PaulyG
Many thanks for your replies and the suggestions of using Hylomar blue sealant. Paul, I have those types of washer already, although those look longer in length. Arwyn, I take it when you state ' holding down tab washers from the later Pinto engine' you mean the type that Paul has suggested?

Regards

Used Blue Hylomar since 1970s. Still the best.

BTW is your engine breather clear of gunge?

Absolutely, we should have mentioned that. Also when the engine is warm at tick over remove the oil filler cap and see if you have excessive piston blow-by. Should be some noise and a little air movement but no wooshes when you remove the cap! Are you, the car using oil, more than it did anyway. If so valve stem oil seals have hardened. If that's the case I would check compression levels start with a compression test to all cylinders and see what you have. simple test and cheap tool! Should give you a clue as to what might be amiss. youtube it and you'll see how its done!

Chris and Sewin
This is what i like about this Forum, people out in MOG land happy to answer questions and suggest ideas. I will check both next time that I'm doing stuff with the MOG.
Many thanks