Overheating Traction 11B

[Rich MiddletonParticipant]

I had new pistons and liners last year, when I took it for a drive a couple of times (both on hot days) the car was overheating and blowing out water through the expansion pi

Regards

Rich Middleton

 

[BernieParticipant]

I would suspect the head gasket is not sealing and therefore allowing combustion gasses to escape aross the gasket faces and pressurise the water ways.

I assume it was not overheating before the pistons and liners were changed and a new head gasket was correctly fitted and torqued down.

If so, and nothing else has been changed, I would suspect iicorrect liner stand-off.

Did you verify the liner stand-off height?  If the liners do not protrude above the block surface as specified they cannot “dig into” the gasket to create the necessary load and the seal around the bores will be lost.

A compression test should reveal which, if not all, bores are failing.  The solution will be to remove the head and check the liner heights above the block face.  If that is the problem, correction will require liner removal and insertion of suitable thickness seals under each one to achieve the correct liner protrusion.  Then reassemble with a new head gasket.

B…….

[Larry LewisParticipant]

I have to ask- are the gaskets that go below the liners available in different thicknesses? Aren’t the liners supposed to be machined to make them the proper height? I’ve always understood that you install the liners in the block without the bottom gaskets and then measure and machine the liners accordingly and then install them with the gaskets. Or am I wrong?

• This reply was modified 3 years, 2 months ago by Larry Lewis.

[BernieParticipant]

Larry and Rich,

‘Fraid not.

Workshop manual operation 103.25(d) says…

Use only Hugo-Reinz joints stocked by our Spare Parts Department. Choose joints of a thickness that willl MAKE BARREL FACES STAND ABOVE UPPER CRANKCASE FACE BY 0.05 to 0.10 mm.

BEFORE TIGHTENING. Carefully measure the heights of barrel faces above crankcase face by the use of instrument MR.3377. Place the barrels together in pairs, give H-R joints a thin coating of linseed oil end place them on barrels. Place barrels in pairs in cylinder block.

The barrels must go into position under their own weight and without hindrance from barrel joint.

The Reinz gaskets referred to were a woven wire reinforced material with graphite coated soft facings and were considerably thicker than the modern “paper” replacements.  They were cut in pairs, like spectacles, hence the instruction to fit the barrels in pairs. The paper gaskets were introduced with the “D” engine in the mid 50’s and, since the ‘60s, are the only parts available.

New liners do partially take the reduced gasket thickness into account but it is still essential to ensure correct stand-off, especially if other work (such as block surface skimming) may have been done to the hardware.

As modern head gaskets no longer contain asbestos they tend to be less conforming so I recommend aiming for the top end of the stated stand-off range to ensure the necessary clamp load is achieved around the bores.

In 2017, when Phil and I rebuilt our two 6s, we had both block surfaces skimmed with new liners securely fitted in place but without any gaskets under them.  We then knew there was zero stand-off and subsequently fitted 0.10mm thick gaskets to achieve the correct final assembly height – easier than faffing about measuring heights with MR.3377 (and probably far more accurate!).

B…

[Richard LarterParticipant]

I recently rebuilt the engine of my Light 15 and found one liner was slightly longer than the rest and had to be machined down to match the rest. Having rebuilt a number of Triumph TR engines, a copy of the Traction engine I know the importance of deck heights. Another possibility is heat from friction if the piston rings were not gapped correctly.

Cheers Richard

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