QUESTION
I have just been looking at your breather tubes and note the press fit required in the block.
I note peoples comments that some holes are as cast and others are reamed.
I have a 120E block the engine having been supplied to the previous owner by an engine rebuilders that Club Lotus do not recommend following very bad reviews.
I would therefore be grateful if you could advise what diameter my block hole should be.
S.B. - UK
ANSWER
Lotus Marques manufactures a variety of alloy breather tubes to suit the Ford 120E, 711M and Lotus 701M cylinder blocks etc.
The spigot end of the breather tube needs to be a light press fit and be installed with Loctite 620.
The Loctite compound acts as a lubricant during installation but then cures to prevent the breather moving in the cylinder block.
Unfortunately it is not possible to provide a consistent breather hole diameter for every type of cylinder block.
From experience, it would appear that Ford experienced problems in maintaining the tolerance on this breather hole in any given cylinder block.
If you are anticipating fitting an aluminium breather tube, then its best to measure the bore size before ordering.
Over the years Lotus Marques has manufactured custom breather tubes to accommodate the various breather hole sizes discovered in customer cylinder blocks.
The later 711M 1600cc Kent blocks appear to have been manufactured with a much larger diameter breather hole.
If you purchase one of our alloy breather tubes, then there is a revised/simplified head gasket installation guide supplied with the alloy tube.
If you are contemplating using a 120E cylinder block to build a Lotus twin cam engine then it would be wise to get the block ultra-sonic tested BEFORE commencing building.
The cylinder walls should be checked to see if there is sufficient thickness to build a reliable engine without the risk of wall flex.
Ultra-sonic readings should be made at every 90 degrees - at the top, the middle and at the bottom of all 4 bores (a total of 12 readings per bore).
This is a useful check for internal corrosion and core-shift that takes place during the casting process.
There is no point re-boring a second-hand block that has inherently thin cylinder walls - say just in one spot.
From experience it is possible to still find 120E blocks really thick cylinder walls.
Five years ago customers cracked 701M block was sucessfully replaced with a 120E block that had thick cylinder walls 0.250" ++
If you do use a 120E block for your Lotus twin cam engine then you may need one of our custom oil pick-up pipes.
Copyright © 2019 Lotus Marques
I have just been looking at your breather tubes and note the press fit required in the block.
I note peoples comments that some holes are as cast and others are reamed.
I have a 120E block the engine having been supplied to the previous owner by an engine rebuilders that Club Lotus do not recommend following very bad reviews.
I would therefore be grateful if you could advise what diameter my block hole should be.
S.B. - UK
ANSWER
Lotus Marques manufactures a variety of alloy breather tubes to suit the Ford 120E, 711M and Lotus 701M cylinder blocks etc.
The spigot end of the breather tube needs to be a light press fit and be installed with Loctite 620.
The Loctite compound acts as a lubricant during installation but then cures to prevent the breather moving in the cylinder block.
Unfortunately it is not possible to provide a consistent breather hole diameter for every type of cylinder block.
From experience, it would appear that Ford experienced problems in maintaining the tolerance on this breather hole in any given cylinder block.
If you are anticipating fitting an aluminium breather tube, then its best to measure the bore size before ordering.
Over the years Lotus Marques has manufactured custom breather tubes to accommodate the various breather hole sizes discovered in customer cylinder blocks.
The later 711M 1600cc Kent blocks appear to have been manufactured with a much larger diameter breather hole.
If you purchase one of our alloy breather tubes, then there is a revised/simplified head gasket installation guide supplied with the alloy tube.
If you are contemplating using a 120E cylinder block to build a Lotus twin cam engine then it would be wise to get the block ultra-sonic tested BEFORE commencing building.
The cylinder walls should be checked to see if there is sufficient thickness to build a reliable engine without the risk of wall flex.
Ultra-sonic readings should be made at every 90 degrees - at the top, the middle and at the bottom of all 4 bores (a total of 12 readings per bore).
This is a useful check for internal corrosion and core-shift that takes place during the casting process.
There is no point re-boring a second-hand block that has inherently thin cylinder walls - say just in one spot.
From experience it is possible to still find 120E blocks really thick cylinder walls.
Five years ago customers cracked 701M block was sucessfully replaced with a 120E block that had thick cylinder walls 0.250" ++
If you do use a 120E block for your Lotus twin cam engine then you may need one of our custom oil pick-up pipes.
Copyright © 2019 Lotus Marques
