Another problem: overheating

[qim]

Forgive my ignorance... but is the cylinder head the same as the engine block?

 

Please, don't laugh!!!

[RogerH]

Not laughing - honest.

 

The cylinder is attached to the block by 10 big bolts. The block and the head are separate items but share the coolant

The coolant goes into the block and comes out of the head via the thermostat housing and into the radiator.

A blockage in the head would also cause heating problems (but isn;t common as the silt will go to the bottom)

 

Roger

[qim]

Thanks

 

I found the invoices dated 1987

 

They changed the "Short engine". I assume this is what contains the cylinders and comes under the head with the valves, right?

 

In my limited knowledge, I see the engine in THREE parts: the head (valves); the short engine (cylinders) and the sump beneath.

 

When I took it back because it was overheating they told me that they replaced, again, the "Short engine" (may be they did not), but I have an extra invoice for the oil cooler and an exchange fan (I assume this is a larger one).

Edited August 14, 2016 by qim

[qim]

One thought...

 

What spark plugs should I use? (Tr3A 1959, 2200cc)

 

Thanks

[RogerH]

I use NGK BP6HS or BPR6HS if you do not have suppressed caps.

 

Roger.

[qim]

I use NGK BP6HS or BPR6HS if you do not have suppressed caps.

 

Roger.

How do I know if I have supressed caps...?

 

PS: have done some reading. From what I understand if I have suppressed caps (in order not to disturb radios and the like as you pass houses) I also need special ignition leads. Is that right?

Edited August 14, 2016 by qim

[iain]

Hi Again Qim

If you send me a p.m. with your e mail address I will send you the same pics that I sent Lebro (Bob) and Yves.

 

Iain

 

Does your ducting have a top plate as well? mine does, as I thought that with the side plates only in position the air might be forced over the top of the radiator being the least line of resistance. Also do you have pipes to take cold air to the carbs direct?

 

Dave

Hi Dave.

The deflectors do not have a top but are a very close fit to the shape of the apron. Air can only escape over the top of the radiator width.

I did have issues with over heating years ago, mainly I think caused by a poorly timed cam,poor fuel mixture that was leaning out at higher rpm and a poor rad.

I have just refreshed the engine and so far it runs just below the 185 mark in running in type motoring. Fingers crossed this continues :-)

Iain

[RogerH]

How do I know if I have supressed caps...?

 

PS: have done some reading. From what I understand if I have suppressed caps (in order not to disturb radios and the like as you pass houses) I also need special ignition leads. Is that right?

 

Hi ,

if you have suppressed caps they may well have 5K moulded in them. If there is nothing then they are probably not suppressed.

In which case get the plugs with an R in the part number.

It is also possible to have suppressed leads - usually carbon based. Not sure how you would tell these apart.

 

You probably would not notice much difference if you had suppressed caps and plugs together.

 

Roger

[Don H.]

...It is also possible to have suppressed leads - usually carbon based. Not sure how you would tell these apart...

Resistance or supression leads often have that moulded into the insulation covering.

[Lebro]

It seems fairly clear to me that QIM does not have any ducting in front of the rad, & this surely is the problem ??

 

Bob.

[yaya]

I have mounted a Volvo radiator in my TR3A, I got the idea from members of the TR Register Australia. I have mounted a fan that sucks behind the radiator, the fan is controlled by a thermo switch. I've cut the neck of the old radiator and made a remote reservoir that is attached to the tie member for the front apron. It works very well in hot climate and in city traffic

Edited August 14, 2016 by yaya

[qim]

It seems fairly clear to me that QIM does not have any ducting in front of the rad, & this surely is the problem ??

 

Bob.

Hi Bob

 

The car heats up (boils) during normal running along an empty motorway. It should not and did not in the past (before the short engine change.

 

Yes, it got hot in traffic but not running along a motorway.

 

Now, I can only drive it with the electric fan on.

 

qim

[rhino_mac]

QIM, I'm no expert but in my experience you must have the cardboard ducting in place.

 

It's very cheap and just fits with a few self tapping screws inside the grill so I would get that first. From memory you will need to remove the front bumper stays if you have a front bumper before you can remove the grill.

 

Even I could fit that and I don't know one end of a screwdriver from the other.

 

I don't think this will fix your issue, but it will help. You will need one regardless of how efficient your cooling is as Triumph fitted them from new because of cooling problems without.

 

I would be looking at a new radiator as the main culprit which is a time consuming to fit as you need to take the front apron off. While that is being done, fit a new thermostat (make sure it's a bellows type, not a cheapy waxstat which won't work correctly).

 

Just a thought, if it didn't boil up before the new short engine was changed, could it be overheating because the head gasket is leaking. Maybe it wasn't torqued correctly when the head was fitted (your short engine would have been the block and sump - your old head would have been fitted on this). I might be miles out on this - I'd be looking at the cooling system first.

[Don H.]

rhino_mac, you bring up an important point about head torque.

 

Not only does the cylinder head have to be correctly torqued, it as to be correctly retorqued within the first 500-1000 miles.

 

One of our members here may have had to redo a head gasket because the a new head gasket wasn't retorqued.

[rhino_mac]

Indeed Don, Stuart rebuilt my engine recently and Chris retorqued the head after about 700 miles. It was surprising how much he got on some of the studs.

[qim]

rhino_mac, you bring up an important point about head torque.

 

Not only does the cylinder head have to be correctly torqued, it as to be correctly retorqued within the first 500-1000 miles.

 

One of our members here may have had to redo a head gasket because the a new head gasket wasn't retorqued.

Good point, but I am not losing oil and there is no visual evidence of oil leaks.

 

Slowly, slowly I will fix this even if I have to take the short engine out!

 

Many thanks, everybody.

 

qim

[rhino_mac]

Not sure you'd lose oil but again, I'm no expert. I would check for milky gunk around the oil filler cap or "Mayonnaise" in the oil. Are you losing water and need to top up regularly?

 

If your TR doesn't lose oil I'd like to know your secret!

[Lebro]

+1

I was suffering from a slightly leaking head gasket in my 1968 ST built engine. re-torqued the head - tappet clearances went down to zero (or less), after resetting all was back to normal again. So it's worth doing several times over the life of an engine.

 

By the way one reason that the short engine gets hotter than the original is that it will be tighter, & so generate more heat.

Fit that cardboard ducting, & I think all will be well.

 

Bob.

Edited August 15, 2016 by Lebro

[qim]

Is it possible that the engine is not correctly torqued causing overheating, and yet there are no oil leaks?

 

Thanks

[Motorsport Mickey]

Is it possible that the engine is not correctly torqued causing overheating, and yet there are no oil leaks?

 

Thanks

Yes, the main force upon the join between the cylinder head and the top of the cylinder block (your short engine) is the compressive forces around each cylinder liner, holding back the compression of each piston. There's only the small oil feed hole between the block and the head and it's situated away from any edge of the block or cylinder and so seals pretty well even if a head gasket gas blown. The top of the cam follower galleries in the block (the large bath tube shaped cut outs) only has the block internal compressive forces (from the bottom of the piston up and down movements) is well placed to the side and so doesn't leak oil unless the head is about to fall off !

 

Bob is quite correct regarding a rebuilt engine running hotter. If the engine has received new or rebored cylinder liners and pistons or even just new piston rings in new liners the clearances between the components will be at the very minimum and so the "drag" of the piston rings will be at it's highest and the engine would be referred to as being "stiff". I wouldn't be doing anything to this engine until:-

 

1) Run the engine until it's hot, then drain the water from the engine to empty the cylinder head and then straight away whilst it's hot retorque the head to make sure you know what the situation is. To retorque the head first UNDOE the cylinder head nuts just one flat (this is to ensure there is no sticking of the nut in it's current position),and then following the cylinder head torqueing sequence torque the head back up to 105 lb ft in smooth movements. Don't be surprised if the nuts travel past the one flat position you've already undone them by, you are now reapplying the correct torque upon a partially compressed gasket and it's normal to gain a few thou in better compression (that's why you are doing this) on the gasket.

 

2) As many of the previous posters have said the radiator needs it's cardboard shroud .

 

Lets make this easy, if there isn't a FULL and comprehensive air duct or shroud in place in front of the radiator that is SEALED to the sides of the radiator shell (it doesn't have to be stuck on just fitted right up to the radiator shell with out any gaps) the engine will run hot, sometimes enough to overheat.

Air and water share many similarities, if there is any unobstructed opening or gap it dives through it like a wombat up a drainpipe ! Air doesn't want to go through the radiator because the fins and radiator vanes block up between them maybe 50% of the gaps and so the pressure in front of the radiator builds up (even if nominally) and it seeks out any easier opening it can go down, don't give it a chance to escape, force it through the radiator.

 

3) Make sure the electric fan is as close as you can to the radiator core vanes and fins. If there is any more than about 5mm gap the air travelling through loses it's speed (it's only a poxy electric motor sucking or blowing it thgrough after all) because the vanes and fins are blocking the flow of air some of it bounces back and "stalls" the airflow. If you keep the fan blades within the 5mm of the radiator it will overcome the blockage and push the air through.

 

4) THIS HAS BEEN ASKED 4 TIMES AND SO FAR WITHOUT A REPLY, DOES THE FAN PUSH THE AIR IN THE CORRECT DIRECTION ? YES OR NO.

As has been said by myself and others make sure the fan is pushing the air through the rad and it's not trying to "pull" the air back out of the engine compartment, it will still have some cooling affect but it will be much reduced against pushing the air through from outside. If it's in the wrong direction reverse the wires on the motor which will turn the fan in the opposite direction.

 

5) Drive a 1000 miles and see if the "bedding" in process as the piston rings and the cylinder walls of the engine smooth the high spots off each other reduces the internal friction which reduces the engine heat and the engine runs cooler.

 

Then consider how the engine is performing and report back.

Note: All of these processes are far easier than removing engine or cylinder heads or any of the other cures which have been suggested above (they are all valid but possibly not required until these other easier and quicker items above are carried out).

PS: the above suggestions are cheaper also which will save your chequebook.

 

Mick Richards

[qim]

Hi Mick

 

many, many thanks for your explanations and suggestions. I will deal with the torque as soon as my mechanic has the time.

 

I had better get some needed spares. Do I need a new head gasket, or anything else?

 

In fact, I wonder if this would be a good time to adapt the engine to unleaded fuel. Is that a good idea, and what parts do I need? Rimmer Bros mentioned valve seats and guides but they don't supply them. I wonder why... and where can I get them.

 

 

 

Thank you again

 

qim

Edited August 15, 2016 by qim

[Motorsport Mickey]

No, the head isn't to be removed, so the original head gasket should be fine being left alone as long as it hasn't blown.

 

It's important to undo and slack off the head nuts the one flat so as to prevent "stiction" ( a mixture of sticking and friction). When the nuts were originally torqued the threads will have leaned and deformed upon the studs and nut, this needs resetting which helps stop the fastenings sticking, of course there is also an amount of friction between the stud and nut surfaces which needs to be overcome also. If you don't undo the nut the one flat you can't tell whether the torque you are applying (105 lb ft) has been reached or if the nut is sticking.

 

The retorquing of the engine used to be quite common maybe 50 years ago (when these engines were in use) and should normally be carried out after about 500 miles of running, (not critical on mileage as long as it's done thereabouts, I often do it after a couple of hundred miles). This running allows the components to be warmed and cool a good few times which helps relieve the stresses within them and they relax, the retorque just takes up any slack and brings the fastenings back up to the correct clamping forces.

 

Don't forget to find out and confirm with us whether the fan is pushing the air into the rad and towards the engine bay which is correct, if it's "pulling" the air forwards out of engine bay it won't work very well.

 

Mick Richards

[Lebro]

Just this:

 

http://www.moss-europe.co.uk/duct-panel-radiator-803440-8.html

 

Bob

[qim]

the stresses within them and they relax, the retorque just takes up any slack and brings the fastenings back up to the correct clamping forces.

 

Don't forget to find out and confirm with us whether the fan is pushing the air into the rad and towards the engine bay which is correct,

Mick Richards

It must be correct because when the engine heats up and the fan is turned on the temperature falls. But I will check it again next time the car goes to the "doctor"

 

Thanks

[qim]

If your TR doesn't lose oil I'd like to know your secret!

How about not driving it?... It hasn't had much use since I changed the short engine: because the fuel consumption doubled (and so did the cost of petrol...); because for 12 years with the arrival of a daughter I could not drive it with her and her mother; and because work kept me busy.

 

Now, I want to sort out the problems and put it back on the road.