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MG MGB Technical - WHAT IS A GF ENGINE AND HOW IT COMPARES WITH A 18V

I HAVE A GF ENGINE WITHOUT A TACK DRIVE. IS THIS A 3-MAIN OR A 5-MAIN. hOW DOES THIS COMPARE WITH A 18V ENGINE. I AM GOING TO USE THIS ENGINE IN A MAGNETTE WITH A 5-SPEED TRANS AND GOING TO TRY TO USE AIR CONDITIONING
JEFF BECKER

Jeff,

the 18GF is a 5 main bearing engine. Although some (interchargable) internals are different, con rods, cam followers and pushrods, the engines can be used to substitude each other. All external dimensions are the same.

Ralph

Ralph

Jeff-
The 18GF engine has the earlier "closed" heart-shaped combustion chamber, while the 18V engine has the later, more efficient "open" kidney-shaped design. The 18GF engine uses barrel tappets and short pushrods, while the 18V engine uses bucket tappets and long pushrods. Early 18V engines (18V 581, 18V 582, 18V 583, 18V 584, 18V 585, 18V 672, and 18V 673) had a larger intake valve. The 18GF engine has a hanging oil filter that has a felt filtration element, while the 18V engine has an inverted catridge-type filter. The 18GF engine has an oil separator incorporated into the front cover of the tappet chest, while the 18V engine has a cylindrical oil separator. The 18GF engine has obliquely-split connecting rods, while the 18V engine has horizontally-split connecting rods. The 18GF engine has 8.8:1 compression ratio pistons with slip-fitted wrist pins, while the 18V engine has 8.0:1 compression ratio pistons with press-fitted wrist pins. The 18GF engine has closed-circuit crankcase ventilation while the 18V engine has carburetor ventilation. The 18GF engine uses SU HS4 carburetors, while the 18V engine uses SU HIF4 carburetors, although these may be interchanged with appropriate changes to the fuel-metering needles. Other changes include the oil dipstick and its seal, ignition curve of the distributors, and different intake and exhaust manifolds. The rocker arm covers, timing covers, harmonic balancers, and camshaft timing are also different.
Steve S.

What I have is only the block with pistons, rods and pan. I will have to come up with a head, distributer ect. Would I be better off to get a 18v engine with a head as the block will have the cuts for valve clearance. I am trying to build a dependable engine( STOP LAUGHING) as I know it is a british engine.
JEFF BECKER

Jeff-
No reason to laugh. The B Series engine can be remarkably reliable if properly built. I personally prefer the 18V engine because it is more developed and refined than the earlier G-GK engines.
Steve S.

"can be remarkably reliable"

Can be? What are you on about? They *are* very reliable - unless poorly built, poorly maintained or over-modified.

The difference between the 18GF and 18V is relatively marginal, even the carbs aren't an issue, the UK stayed with HSs on the 18V for some time.
Paul Hunt

Paul-
You should have continuued reading- "If properly rebuilt".
Steve S.

It was the 'can be' I was referring to. If properly built they *are* reliable, and it isn't remarkable but normal.
Paul Hunt

This thread was discussed between 05/07/2008 and 07/07/2008

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