opened a can of worms

seanmull · Jul 4, 2013

doing a head gaskett on my dse and noticed that the top of the block and one cylinder is badly pitted and the top of the piston is also badly pitted . im assuming that with a previous owner the head was off and it got wet for a while. also 3 pistons have valve marks on them , also noticed that all the pistons are protruding above the top of the block. i have an engine that boiled badly and cracked the head,so im planning to build one good engine out of the two

wammers · Jul 4, 2013

Someone had the cam off and did not wait long enough for the tappets to settle before starting or turning over. Or valve timing grossly out. Pistons are supposed to protrude from bore. On initial assembly they are measured and a suitable thickness gasket fitted. ALWAYS fit the gasket with three thickness indicating holes in it for safety. Follow the torquing instructions to the letter. Pitting is cause by water and heat it has had water intrusion into that bore at some time.

jamesmartin · Jul 4, 2013

seanmull said:
doing a head gaskett on my dse and noticed that the top of the block and one cylinder is badly pitted and the top of the piston is also badly pitted . im assuming that with a previous owner the head was off and it got wet for a while. also 3 pistons have valve marks on them , also noticed that all the pistons are protruding above the top of the block. i have an engine that boiled badly and cracked the head,so im planning to build one good engine out of the two

if its water damage it wiould be cracked head or gasket issue

seanmull · Jul 4, 2013

wammers said:
Someone had the cam off and did not wait long enough for the tappets to settle before starting or turning over. Or valve timing grossly out. Pistons are supposed to protrude from bore. On initial assembly they are measured and a suitable thickness gasket fitted. ALWAYS fit the gasket with three thickness indicating holes in it for safety. Follow the torquing instructions to the letter. Pitting is cause by water and heat it has had water intrusion into that bore at some time.

the gaskett coming off and new one going on are both 3 hole gasketts. i would love to know what muppet torqued the head down, or did he use the same bolts twice

seanmull · Jul 4, 2013

jamesmartin said:
if its water damage it wiould be cracked head or gasket issue

im assuming the head is ok as it was pressure tested, eventhough i did have one pressure tested about 3 yrs ago and it turned out to be cracked after i was told all was good

jamesmartin · Jul 4, 2013

seanmull said:
the gaskett coming off and new one going on are both 3 hole gasketts. i would love to know what muppet torqued the head down, or did he use the same bolts twice

why were bolts loose ?has head been previously skimmed as well as piston protrusion there is valve head depth

seanmull · Jul 4, 2013

i think the bolts were loose because the person i bought it off thought he was a brilliant mechanic but looking around his "garage" i did see hammers chisels and 2 broken vise grips. so i think he didnt torque down tight enough or used the same bolts again. the head was ok to be skimmed the man who skimmed it said it was ok to do so. it was a new head at some stage the vehicle is 96 and the head is 00. to be honest im at a loss as to the piston protrusion, i know pistons protrude but this was crazy protrusion , i cant imagine the protrusion with engine running

wammers · Jul 5, 2013

seanmull said:
i think the bolts were loose because the person i bought it off thought he was a brilliant mechanic but looking around his "garage" i did see hammers chisels and 2 broken vise grips. so i think he didnt torque down tight enough or used the same bolts again. the head was ok to be skimmed the man who skimmed it said it was ok to do so. it was a new head at some stage the vehicle is 96 and the head is 00. to be honest im at a loss as to the piston protrusion, i know pistons protrude but this was crazy protrusion , i cant imagine the protrusion with engine running

BMW M 51 heads must NOT be skimmed under any circumstances, according to BMW. If they are warped they are scrap. But what do BMW know, obviously the guy who skimmed it knew more than they do.

Pistons can protrude almost a 1 mm in which case the three hole gasket MUST be fitted.

seanmull · Jul 5, 2013

wammers said:
BMW M 51 heads must NOT be skimmed under any circumstances, according to BMW. If they are warped they are scrap. But what do BMW know, obviously the guy who skimmed it knew more than they do.

i heard that today ..... considering i have it skimmed now , gaskett and headbolts got and i have a good block to use and a heap of parts if i need them i will give it a go. im not saying it will be a sucess but i am curious to see if it will work

jamesmartin · Jul 5, 2013

seanmull said:
i heard that today ..... considering i have it skimmed now , gaskett and headbolts got and i have a good block to use and a heap of parts if i need them i will give it a go. im not saying it will be a sucess but i am curious to see if it will work

you need to measure valve depth then ,not enough and they will hit pistons

seanmull · Jul 5, 2013

jamesmartin said:
you need to measure valve depth then ,not enough and they will hit pistons

the valve depth is going to be measured

opened a can of worms

seanmull

Active Member

wammers

No longer with us, RIP

jamesmartin

Well-Known Member

seanmull

Active Member

seanmull

Active Member

jamesmartin

Well-Known Member

seanmull

Active Member

wammers

No longer with us, RIP

seanmull

Active Member

jamesmartin

Well-Known Member

seanmull

Active Member

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