MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - cyl head bolts

While checking the stretch of the cylinder head retaining bolts I noticed that several bolts “bottomed” at 60mm instead of the expected 92/97mm. All bolts are the same length.
Can someone please explain the difference, as I’m not planning on opening up the bottom end.
The head has been removed while under a previously owner (Japan). We’ve owned it for the past 5 years.
’97 MGf with 51K kms on the clock – stripped down because a cam pulley bolt let go.

Thanks in advance.
Dennis Montgomery

Inspection of cylinder head bolts.
With head removed, Clean bolts and assenble by hand into block/oil rail. Distance from block to under head not to exceed 97 mm. If greater, replace bolt.
For my car, it gets best engineering practices so they are a 100% replacement item.
Geoff F.
G. Farthing

Thanks, however new or old it does not explain why several of the bolts are about 30mm lower.
Dennis

If they are bottoming at 60mm without the head in place then you are screwing them in to far. It is possible that the front(exhaust side) bolt between bore 3/4 can bottom on the sump, to cure just remove 2 mm from the tip.If the bolts do not screw in freely then replace the oil rail. If in doubt and the head has been off before the replace the bolts.
mike

Thanks Mike - exhaust side between 3 & 4 bore is OK, most are on the inlet side, the exception is exhaust side in front of bore 1. There are a total of 4 bolts that screw (hand tight only) down to 60mm - without the head in place. All threads are clean and free running. I assume there are no blind threaded bolt holes?
Dennis

Dennis, without the head in place ,which has a approx thickness of 100mm , then the bolts should screw down till they run out of thread, which will be around 60m from the block face.So unless you are meeting any resistance from the threads then you don't have a problem and you dont need to screw them in that far.You only have a problem if they will not screw down past, say 90mm.ie 90mm plus and the bolt stops you got a problem.if they are not all the same height it doesn't matter as some may bottom on the sump, especially if you are taking down as far as you have..
mike

Got it - thanks Mike.
Dennis

This thread was discussed between 30/10/2005 and 31/10/2005

MG MGF Technical index

This thread is from the archives. Join the live MG MGF Technical BBS now