Surf alloy head

[Tono]

Just wandering, when these fragile heads let go, and replaced with the steel/cast heads (and I asume they are off UK variants) does this cure the overheating problem ?


Cheers and merry xmas from the south

[Guest]

Just wandering, when these fragile heads let go, and replaced with the steel/cast heads (and I asume they are off UK variants) does this cure the overheating problem ?


Cheers and merry xmas from the south

All the Surf 2.4 heads are Cast Iron, even the old ones. The new ones are supposed to be redesigned to move the waterways further from the surface of the head and seem to cure the problems. I've had 2 new heads on mine however the second time was not due to head cracking but due to a valve breaking and damaging the head. When the head was removed there was no evidence of any other problems like cracks and that head had done nearly 20K miles so I think it is reasonable to say that the new heads cure the problem. The new design ones are not off the UK variant as the UK vehicles with the same engines (only the Landcruiser 11 2.4 had the 2LTE engine in the UK) have the same problems as far as I am aware.

Also it's not all 2.4s that seem to have the problem, some go on for ever. Not sure if it is down to where the engine was built - Toyota Diesels are built by Toyota, Daihatsu and Hino Heavy Industries as the age and type of 2.4 (2LT or 2LTE) doesn't seem to matter. also both the 2LT, 2LTE and the newer 2L2T have the same head.

Cheers

[Tono]

Thanks for that - therefore if my head were to go what would be the best choice ??


Regards

[TonyN]

An alloy head would be good, they only warp, quick skim and your away with higher compression!

[Guest]

Alloy head, Cast Iron Block, not always a winning combination - ever remember the Triumph Dolomite Sprint, First car I ever new that had a tendancy to eat more heads than I eat meals. Then there was the Hillman Hunter 1750. (Just showing How old I am).

Alloy Head - Alloy Block
Cast Iron Head - Cast Iron Block - just make the Bl**dy Head properly.

[laser_jock@work]

Alloy head, Cast Iron Block, not always a winning combination - ever remember the Triumph Dolomite Sprint, First car I ever new that had a tendancy to eat more heads than I eat meals. Then there was the Hillman Hunter 1750. (Just showing How old I am).

Alloy Head - Alloy Block
Cast Iron Head - Cast Iron Block - just make the Bl**dy Head properly.

Yup- both parts ought to be the same material otherwise there is a galvanic potential between the differening metals resulting electrolytic corrosion of metal at higher potential (the alloy in this case). Thats why boats for instance have sacrifical anodes made from a big lump of zinc bolted to the hull.

http://www.corrosionsource.com/handbook/galv_series.htm

Nevillef

[UKWolf]

Yup- both parts ought to be the same material otherwise there is a galvanic potential between the differening metals resulting electrolytic corrosion of metal at higher potential (the alloy in this case). Thats why boats for instance have sacrifical anodes made from a big lump of zinc bolted to the hull.

http://www.corrosionsource.com/handbook/galv_series.htm

Nevillef

I knew we had to get to the elecy bit somewhere otherwise this wouldn't be in this section.

I trained as a marine engineer and when at cooage had to do sacrifical anode calculations in electrotech - Buggered if I can remember it all now (long time ago)

Ali

[jet1749]

Galvanic corrosion rates depends on the distance apart on the galvanic tables between the respective metals and also the strength of the electrolyte connecting the two materials, metals reasonably close in the table will be largely unaffected. Temperature also plays a part as corrosion rates increase substantially as temperatures rises. Although as modern antifreezes contain effective anti corrosion additives the problem is likely to be largely historic. Also bear in mind that an accidental anti-corrosion property was introduced in the 1960's when most remaining car manufacturers changed over to negative earth polarity (running a negative earth voltage reduces the effectiveness of any electrolyte on the surface of metals)

errr.......I think

[laser_jock@work]

Galvanic corrosion rates depends on the distance apart on the galvanic tables between the respective metals and also the strength of the electrolyte connecting the two materials, metals reasonably close in the table will be largely unaffected. Temperature also plays a part as corrosion rates increase substantially as temperatures rises. Although as modern antifreezes contain effective anti corrosion additives the problem is likely to be largely historic. Also bear in mind that an accidental anti-corrosion property was introduced in the 1960's when most remaining car manufacturers changed over to negative earth polarity (running a negative earth voltage reduces the effectiveness of any electrolyte on the surface of metals)

errr.......I think

You must also throw into the equation the conductivity of the electrolyte (engine coolant) as this will also affect the corrosion rate. De-ionised water has low conductivity so lower corrosion might expected compared to say standard tap water, sea water being full of ions is way more conductive and therefore more corrosive.

Modern antifreeze coolants contain some corrosion inhibters (probably some kind of pH buffer??) but these generally only last about 2 years- hence the need to coolant flush & change regularly- prefferably using de-ionised water (but I don't think it makes that much difference).

Nevillef

[TimberSurf]

Alloy head, Cast Iron Block, not always a winning combination - ever remember the Triumph Dolomite Sprint, First car I ever new that had a tendancy to eat more heads than I eat meals. Then there was the Hillman Hunter 1750. (Just showing How old I am).

Alloy Head - Alloy Block
Cast Iron Head - Cast Iron Block - just make the Bl**dy Head properly.

I had a Triumph Dolomite Sprint, between skimming Ali heads, and loosing wheels held on by Ali nuts on steel studs,

NOT a good combination!