The 'E' Type Forum

Hi,

When I restored my e-type a few years ago I didn’t touch the engine (other than carbs etc) as the car had been an abandoned project and I was under the impression the engine had already been done (it has these ‘warranty void if removed’ tags in several places). Anyway it turns out that the gearbox is very noisy in first (probably laygear bearings) and I am thinking about pulling it to get it sorted during the winter. The other thing is that the rear left core plug blew out recently on a track day. I’ve replaced it but clearly not very well as it blew out again. I’ve done it a second time but now have limited confidence in taking the car on long trips or giving the car some beans. Anyway I’m also thinking I should get the engine rebuilt when it is out although it does seem a bit crazy to spend £5k+ when the engine otherwise seems to run well. The only other visible issue is brown staining on the side of the block where water appears to be weeping between the head and the block - no water in the oil so gasket seems to be good? So the question I am asking is what tests I can do on the engine to ascertain whether a rebuild is worth the expense? I’m guessing oil pressure (gauge maxxed out so will need to check with a wet gauge) and compression? What readings should I expect and what other tests should I do? Any advice gratefully received!

Thanks

Myles

Hi a lot of people on jag-lovers like the Dorman style core plugs,I think Ray Livingston did a write up on them a few years back,he had the same problem as you.
Regards Gerry 62 Ots.

Check you have the correct rad cap - originally 4lbs but most people use a 7. (We took a 13lb one from a 3.8 that was causing a core plug to weep).

Things to look at:

• how many miles are on the engine?
  do you trust the people who did the rebuild?
  does the engine have good oil pressure?
  does the engine use oil?
  what compression does it have, and are they even between cylinders?
  does it make horrible noises?
  odd vibrations?
  does it leak oil or coolant excessively, or from places it shouldn't?
  does it overheat excessively despite a known good radiator and fan?

If all of the above are OK I probably wouldn't strip the engine. While the engine is out it is easy to drop the sump and have a look at the bearing shells. This won't disturb the front or rear crank oil seals so it is a fairly low risk procedure.

I would have a good look at your water leak from the head. This could be the head gasket, or the manifold gaskets if it's on the inlet side. I would address this, even if the head has to come off. It's just possible that your core plug problem could relate to the coolant being pressurised by a small leak between a combustion chamber and the water jacket. If the leak doesn't involve the oil passages you won't get oil in the coolant.

If you do change the head gasket it's not enough just to do so. You need to work out why it failed. So check the deck and the head for flatness and look at the water passages for excessive corrosion in both block and head. Spend money and buy a good head gasket. Brand names like Payen, or even the fancy Cometic MLS gaskets are worth the extra.

When you address the core plug, get a wire brush on a drill and remove every skerrick of rust and paint from around the hole. Then gently take a dremel to smooth any roughened bits on the inner rim. I use Devcon epoxy sealant and these watchglass shaped core plugs. https://www.sngbarratt.com/uk/#!/Englis ... e592d09cee I do not use the dish shaped ones.

To fit the plug, first put a good bead of Devcon right around the inside of the hole. Then tap the plug conical side outwards into the hole and gently snug it down into the bottom of the hole. Then put a flat ended 1/2" drift in the centre and hit it with a hammer until it has a decent dent in the centre. Smear more Devcon around the edge with your finger. If one core plug has come loose the others are potentially suspect. They are cheap and I would remove the lot and replace them all. Best removal method is to drill a hole in the centre and use a screw on the end of a slide hammer. Otherwise use a small cold chisel.

For completeness, if you wish, you can fit a core plug hold down kit. I have no experience with them, but Rob Beere make one. http://www.rob-beere-racing.co.uk/cooling.html#core

Dear Myles,
What you are telling us is that the water finds it easier to blow out a core plug and weep out of the block than it is to circulate back around. Then that was still true after a core plug was replaced. With the benefit of hindsight, the weeping is probably a milder symptom of the same thing that led to the core plug blowing out.

I'd ask myself whether the normal route back is partially obstructed or why the pressure is so high.

kind regards
Marek

Thanks for all your advice. You may have a point with the rad cap for the first core plug blow out and the weeping from the head gasket. The car has a Ron Davis radiator and header tank (came with the car) and I was using the cap that I also inherited. I now have a new 7 psi cap but comparing the spring pressure on the new with the old it looks like the old cap was much higher. In fact I seem to remember the Ron Davis website recommending a cap pressure somewhere near 20 psi for their system. That doesn’t explain the core plug coming off the second time which was probably because it’s hard to get the hammer square on the plug as the engine frames are in the way, even with the heater and washer bottle removed.

Myles

I'm struggling to find Devcon Gel in the UK (I'm thinking the Gel is the one to use due to its filling properties and ability to adhere to vertical surfaces). Any other recommendation on what to use to seal the 3.8 dome shaped core plugs?

Thanks

Myles

Anything epoxy should do. JB Weld or similar. It just needs to stick well and set rock hard.

I just had a look at the Devcon site; I had no idea they had such a range. We don't use gel, just the normal pale grey stuff and it is more than thick enough to do the job and not run. If you were concerned you could put the plugs in with the engine on it's side but I haven't found this necessary.

What did you end up doing with your engine and gearbox?

If you go the JB Weld route, use the slowest-setting formula available. The five-minute stuff is nothing more than five-minute epoxy with metal filler and will not hold up to continuous submersion, and you'll probably see the leak return in short order.

Is oil consumption a reliable way of gauging how worn an engine is ? Mine has 90 k on the clock but doesn`t seem to use much oil.

max-it-out wrote: ↑

Fri Sep 06, 2019 3:38 pm

Is oil consumption a reliable way of gauging how worn an engine is ? Mine has 90 k on the clock but doesn`t seem to use much oil.

Oil gets consumed if it goes past the rings or the valve stem seals, or out the breather pipe, so yes.

It doesn't get consumed if the bearings are worn though, so no.

The XK engine will continue to perform well even when worn. I recall an engine we did for a customer that was running fine but was completely shot when we stripped it during a resto.

My view is if it runs OK and doesn't make horrible noises or lots of smoke then leave well alone until you need to take it out for some other reason, like a new clutch or gearbox rebuild. At that point you can then decide if you want to spend $10k and rebuild it as well.

Re core plugs:

“ Then put a flat ended 1/2" drift in the centre and hit it with a hammer until it has a decent dent in the centre.”

I would not use a half-inch drift unless it was a 5/&” core plug. The idea is not to get a decent dent in the centre it is to flatten the plug overall. Of course the act of denting it somewhat spreads it out but only flattening it gives full edge pressure around the circumference for it to deform to seal against the cast iron.

The later cup type plugs are more secure and more forgiving, needing only a suitable socket slightly smaller than the cup ID and a soft hammer to save the socket from damage. But for the dish type plugs if you haven’t got a suitable diameter piece of bar it’s better to turn the socket back to front to flatten across the plug, not just dimple the centre.

PeterCrespin wrote: ↑

Sat Sep 07, 2019 10:24 am

I would not use a half-inch drift unless it was a 5/&” core plug.

Each to their own Peter. It's not astrophysics.