3 1/2 Litre, water in cyl. 6

Pre-XK
1

Hi,

Yes, a bad subject I guess, but it now happened to me!

Just after we did a record run, of 282 miles in one day in Southern Finland, in nice summer weather, the hood down all the way! :slight_smile:

But the next day, at first a fuel leak (yes, I had to fill her up with 98E5) and then I ran out of fuel, but in our yard, so no problem. But then I am not sure what were the symptoms and what was the real issue, it ran strangely, like with only a few cylinders…then after it got really hot, I notice the coolant fumes in exhaust! Oh, oh! Shut off, allow to cool, take off the rocker cover, the rocker mechanism, tighten the 14 head nuts, all is well, except that after a test run, even more coolant in the exhaust, I shut off and check the plugs, at first they are fine, except nr. 5 has a huge gap, looks like the center has pulled in, and when I had nr. 6 out, coolant started pouring out!!! :-o

Sooooo, please Ed don’t tell me I need a new cylinder head?!?

Any other way to get coolant into cyl nr. 6?

I was thinking of pulling the carbs and the coolant rail to see what I can find, but I would like to first figure out what the options are.

I do think I may have to pull the head anyways. :frowning:

The positive think is that it will probably be a lot simpler than pulling the head(s) on a V12 E-type or even the XK engine. The XK could have a simple timing cover problem with similar results, but on the pushrod engine the waterpump can not leak into cyl. nr. 6 or the inlet manifold, as there is none, it’s all inside the cylinder head!

Any good ideas???

Cheers,

Pekka T. - 647194
Fin.

Ps. Like can a head gasket fail so, that coolant will continue to pour into a cylinder, even when the engine is standing still? And shouldn’t an inlet valve also stop the coolant pouring into a cylinder if the engine is turned by hand? (Now it did not. It continued to pour in even if I turned the engine by hand so all valves into cyl. 6 were closed…oh, grief!)

2

Hi Pekka, sorry to hear of malaise in engine. One immediate suggestion is to plan and take useful measurements before any further taking apart. Compression and leakdown could aid diagnosis, if still safe to do so. Number 6 (front of engine) and number 5 sound compromised. What was source of overheating, was waterpump and thermostat operation correct? It is possible to have incorrect water flow going back to water pump via bypass and not giving much radiator flow if incorrectly plumbed. Is water flow forced correctly through the engine when cold and at operating temperature ?

If water flow to engine is proper, flow within the engine can have clogs, deposits, inside the castings. Headbolts can let coolant seep through, acorn nuts can be incorrect inside depth and bottom out without good head gasket seal. Headbolt can pull block deck up slightly, if block deck and head not flat then poor seal can result, perhaps temperature dependent leak or not. Head gasket can be blown for one reason or another, reading the gasket carefully may help diagnosis when head is pulled. Doug and Ed Nantes know how to specify and provide head gaskets which work well.

Water in the oil system can clog and reduce lubricant needs elsewhere in the engine, clean/flush oil system until you are comfortable all passages are okay. There are several techniques for this depending on the condition and your courage.

When pulling the head from an S-series engine, keep in mind the pushrods may be attached rather than free to pull out the top like the T- and Z-series. You also may find the head will not quite clear the back end of the radiator by 1 cm when pulling, radiator may need movement.

I helped a friend deal with a similar scenario on an S-engine, his turned out to be improper water flow. Damage minimal with oil system flush, new head gasket, and custom plug inside thermostat housing bypass which was missing the thermostat entirely.

Good luck!

3

Hi Roger,

Thanks, yes I should have given more information.

No the cooling system was working well, as verified by an infra red camera on my cell phone. I have an XK engine thermostat in a slightly modified thermostat housing (as per Ed’s instructions) that completely closes the by-pass.

I am sure my problem was fuel related, 98E5 probably dissolved something and caused starvation in the front carb, and thus the engine ran properly only with the three rear cylinders and the front got very hot.

BTW I did have some “dieseling” before, a few puffs after the ingnition was off after a long run, but now that was cured after the 282 mile run. But then there was first the starting carb leaking, and when I fixed that I had the poor running, now with coolant getting into cylinder nr. 6.

No other issues, no water in oil, no oil in water, only coolant into combustion chamber nr. 6.

So what’s the best place for shopping head gaskets? And new head bolts? IIRC some of the bolts go through coolant passages which will probably mean they need to be replaced with new ones.

And what is the “dressing” the ROM suggests putting on the water passages of a new head gasket? Just Hylomar? Something else?

Cheers,

Pekka T. - 647194
Fin.

4

Head bolts are studs, they do go into the water jacket and sometimes corrode. But it’s also the thread in te deck of the block that corrode s as well The fix s to use recoils to replace the femaile thread m but really this needs to be done with the block in a ill, to get the threads square with the deck. Otherwise, the studs will lean over at different angles and you won’t g et the head on The blocks were a bit weak at the RH front and rear corners . later casting had a bit more metal stick out at those points . And on some the water jacket holes in those corners did not line up well between head and block. There are endless possible causes for a lucky owner. Cracked head. Head gasket, they can be made [ for a small extra charge] with crushes around the water an oil holes. But this won’t be a fix if there is something else wrong

Was the tension wrench recently calibrated.?
Was the inlet tract through the head cleaned out so a piece of carbon wouldn’t get dislodged and drop onto the gasket when refitting the head?
if you take the head off , it would be wise to have it crack tested.

5

The one time I had a blown head gasket, back in the summer of '88 when my XJ12 was down and I was using the Mark V as my daily driver, I got oil in the water, it was bubbling out around the leaping cat’s feet, and he glared at me as if to say, “Unlike most cats, Jaguars do like water, but you’re boiling me in oil!” I changed it in about 8 hours.

In addition to the good advice so far, I would add to be aware of bottoming out the head nuts on the studs. The studs were sized for use with the decompression plate, which mine does not have, so to make up that 1/8" I added 1/8" thick flat washers.

6

Hi Ed, and Rob,

I am glad to hear there are endless possibilities! :smiley:

No, the wrench was not calibrated, AFAIK the previous head job was done in 1976 in Oklahoma or Colorado, or even earlier. I had no trouble before, at least not like this. I suspect fuel starvation and ethanol contained in the fuel may have caused some extra hot conditions and blew the head gasket.

Did you replace a blown head gasket in eight hours Rob? Pretty fast.

I was able to make it worse, now for the first time ever, after I did my round of “tightening” of the 14 head nuts, I also found water in oil for the first time! :-o So I guess I also now have a truly blown gasket. (And not a blown engine? :wink:

Drained the oil and took out the filter immediately. Took off the bonnet, air silencer and exhaust manifolds. Tomorrow I’ll pull the carbs and the water rail and see if I can also get the head off, as per the factory ROM intructions of course, carefully and only open the head nuts in sequence 1/4 of a turn at a time until they are free.

I just don’t have a head gasket at hand, so I will need to get some. I do have core plugs and a bunch of seals and gaskets for the manifolds, exhaust pipes etc. I am afraid some of the studs may be in such condition it would be good to replace them with new ones. But where should I get them from to be safe?

I have not exactly calibrated my torque wrench, but the “clicking” one I have I have always bench tested on a vice with a cheap spring scale that also gives me an idea on the big torque values as how much my arms will shake when I apply that much force. :slight_smile:

And the base reference is pretty simple, 10 kgs in a 1/2m long shaft hanging for instance is easy to duplicate in my simple garage and do the maths.

Lets see what the head and gasket look like once I get them off the block.

And no, my SL series engine does not seem to have a compression plate either, so I better check the nuts and stud lenghts before putting everything back again.

Cheers,

Pekka T. - 647194
Fin.

7

And important, use a long series socket when tensioning the head nuts, the standard sockets are too short to cope adequately with the domed chromed nuts which result in the socket only operating on the top section of the nut. It doesn’t make for an accurate reading and is also one of the primary causes of those nuts being damaged.
Leave the water rail on , it’s handy to have something to hang onto when lifting up the head.
I also would think that if lean mixture had been a cause, it would have Bruny out the ex valve.

8

Hi Ed,

Thanks for the hints, I try to do just that. Ok, there was some back firing etc when the poor running occured. Too bad that even when I got everything running fine again the damage was already done. :frowning:

So I will carefully examine the exhaust valves and clean everything, grind and lap the valves as per factory ROM and see if the valves are ok, true and not pitted, the same regarding the inlet tracts and valve seats ang guides.

Cheers,

Pekka T. - 647194
Fin.

9

Hi,

Ok, it’s off with her head!

Now that I can see it all, it looks good. The reason is a blown head gasket, one corner of the gasket around cyl. nr. 6 has melted. Yes it’s a metal only gasket with rings around all openings and passages and has imprinted the cyl head surface, so I take it that the surface would need a small smoothing with some mill.

All the pistons are ok, nr. 1 shows signs of pinking, nr. 2 & 3 have a lot of deposits, nr. 4 & 5 are fine, just a bit stained, nr. 6 is k, but shows some signs of the water in the combustion chamber, in other words, it’s somewhat cleaned now.

IMG_0184.JPG480Ă—640 103 KB

That is cyl. Nr. 6. Look at the lower left corner.

Now I need a new head gasket, any recommendations on where to buy from?

Cheers,

Pekka T. - 647194
Fin.

10

What strange place for it to burn. I could understand melting as the gasses exited into the push rod voids but you’d have thought the presence of water at that little water passage would have prevented melting at that point.

I wonder if the relative height of your cylinder liner and the top deck might be a factor but strangely the gasket appears to be outside of the liner top lip.

Peter

11

Hi Peter,

Sure, I found it strange too, but then again, like you said, if the combustion burst into the pushrod void and the metal was close to melting point and/or the coolant was boiling locally, AFAIK the steam pressure can also be very high! :-o

But a good thing I did not get hydro lock in that cylinder afterwards, like I wrote when I took the spark plug out, coolant started pouring out from cyl. nr. 6. :frowning:

Btw thanks again for all the good advice, the cyl. head is quite heavy, I was standing inside the engine room when we lifted it out. It was much lighter to lift out once I disconnected the (forgotten) acc. return spring! (I ruined it) and the distributor vacuum line! (I still had the carbs on the head) :smiley:

Cheers,

Pekka T. - 647194
Fin.

12

The pistons are hi comp , not a ratio that jag supplied. But they should not be too bad depending on how much has een taken off the head. It may be worth calculating the comp ratio as the pistons which appear to be XK will also have abigger bore. and timing and mixture would need to be appropriate

It looks like one of the original shim gaskets used originally . Always check with over bored pistons that the crush around the combustion chambers don;t intrude into the chamber and burn.
You could check the threads on the head studs, perhaps the one near the burnt gasket could have the thread on stud or block corroded and not tensioned properly.

13

Hi Ed,

Ok, that’s great info. I thought the pistons did not look standard. That might also explain the pinking and dieseling.

But I think once I have all the deposits out the combustion chambers it should run just fine. Maybe I need to start adding an octane booster. It did always feel like there’s some grunt. :slight_smile:

But it looks as if the top surface of the block has never been touched and the same with the bottom surface of the head. The “CORRUJOINT” text and circles around all passages and cylinders have been impregnated on both surfaces and the block has all other cylinders marked “G” except nr. 2 & 3 which have been marked (with a stamped letter) “F” which I think would originally have refrerred to piston clearance, no?

I got a response from Simon, saying that the composite head gaskets are made in NZ and should be pretty good. So I am getting that and maybe just having the head checked, planed and clean the valves, passages, combustion chambers and valve seats and put it all back together, ASAP. :smiley:

Cheers,

Pekka T. - 647194
Fin.

14

Pekka

I would suggest firstly , measure what size the bores are.

15

Original bore was 82 mm, and F and G refer to piston sizes originally fitted, page B42 in the Service Manual, though now irrelevant if you have 83mm XK pistons. They appear to be what in an XK engine would have been 8:1 compression ratio, though something different with a pushrod engine having a larger combustion chamber in the head. Maybe you’d better measure the height of the head to see if it has been shaved off. A composite gasket reduces the compression ratio.

16

Rob , I was meaning that if a block has been over bored to a non Jaguar size[ often done, a special head gasket will be needed to make sure the crushes aren’t in the combustion chamber. I’d have a guess that the engine now has an effective CR of more than 8:1.

17

is having a copper gasket made for an overbore engine viable to compensate for overbore and possible head shave?..a guy I know has made them up custom from copper sheet, he is a metal worker with access to all machinery, but I dont know how long it takes him

18

Hi,

Oh, oh! I was about to order the gasket (made in NZ) from Simon together with other parts, but Now I guess I should go and measure the bores first! (the car is at the summer cottage garage and I am in the city)

Or could I just have someone mill/laser/modify the gasket in case the edges end up being 0.5 mm inside the bores?

I do see a problem there as although the gasket would be firmly against the head, it’s not perhaps a good idea to have part of the gasket be inside the combustion chamber, regardless if it’ some composite material or copper. It would burn and melt anyways for sure.

Thanks all for you input!

Cheers,

Pekka T. - 647194
Fin.

19

Pekka

You can’t modify th e gasket once it is made.If the crush is inside the combustion chamber it will only last a very short time [ A cameo appearance. so to speak]
I think Simon is referring to the gaskets being made in New Zealand\s west island … Australia.

20

Hi,

Ahh, I see Ed! :smiley:

Yes, I believe a composite gasket can not be modified. But a metal CORRYJOINT or copper gasket could be laser cut, right? Just take out 0.3-0.5mm away from the radius.

Cheers!