broken intake rocker the cause of all the problems???

[C Murda]

so i had posted up a while ago about buying an 88 325is auto with 97k original miles on it and how it felt like it had no power at all felt as if the little 2.5 was trying to push a 5000lb car... and how the car would blow a decent amount of blue smoke (very light blue not dark) but still a lot of smoke whiteish with a hint of blue... ANYWAYS i did a compression test and for some all the cylinders were in range of eachother except for cyl #5 and #2 for some reason i could not get any reading on them????

i decided to take off the valve cover to take a look at the valve train and to my surprise cyl #2 intake valve rocker arm was broken so for who knows how long this car has been running with a cylinder not being able to suck in air and squirting fuel washing the cylinder walls.... could this one problem be the cause of my car blowing smoke??? it definatley must be the reason why the car is running like garbage...

[C Murda]

oh and also i noticed one CLEAN rocker arm on the exhaust side of cyl #5 it deffinately wasnt OEM and was replaced at one time...could that be causing any problems for that cylinder? maybe the original one had broken at one time and the constant use burned the exhaust valve but only rockers was replaced so thats why the cyl#5 isnt getting much of a reading??

EDIT: i did a leak down test on this cylinder and it was like 100% leak and i could hear it coming out the exhaust...

[e30rapidic]

you most likely will need to pull the head off to assess damage in the chambers...

[jlevie]

The low compression on the cylinder with a broken rocker could be expected. The replaced rocker on cylinder 5 could be as a result of a timing belt failure (as could the broken rocker on cyl 2). If that happened in the past, the cyl 2 rocker might have been damaged and later failed. The valves could also be bent. I'd pull the head, tear it down and see if there is damage deeper than the rockers.

[riceh8r]

2 and 5 fire at the same time, bet the belt broke, and someone just let it ride. really surprised it didn't break more, it may have been idling. but, mine was idling at dairy queen drive thru, and i lost 6 intake rockers, and a bunch of valves. could your belt maybe have skipped a tooth ?

[C Murda]

ill have to pull it off to assess the damage but i actuall notice when listening for the leak from the leak down test that air was seeping in to cyl #4 and the exhaust valve was open in that cylinder too so thats why i heard it coming out the tail pipe.. that being said cyl 5 is leaking into cyl 4 so cracked head or gasket ill have to rip it all off anyways

[StereoInstaller1]

Pics of the E31, STAT!

then we can talk about rockers and shit

[riceh8r]

misread. i thought you already had the head off. i bet when you pull the head off, you have several bent valves. that's why you are leaking 4 to 5. don't mean to be a "doom" prophet, but a broke belt is gonna do damage no matter what the rpm's are at the time. 2 of my valve heads were bent @ 30'. i had to break the head off 2 others just to get the retainers off. i was lucky, found a good parts head, minus the cam for $50. ended up buying 2 intake valves and 1 exhaust valve. 12 guides. that's about $100. $100 to the machine shop for shave, install guides and regrind seats. so...$250 materials, maybe, and a bunch of time. i wish you the best.

[C Murda]

misread. i thought you already had the head off. i bet when you pull the head off, you have several bent valves. that's why you are leaking 4 to 5. don't mean to be a "doom" prophet, but a broke belt is gonna do damage no matter what the rpm's are at the time. 2 of my valve heads were bent @ 30'. i had to break the head off 2 others just to get the retainers off. i was lucky, found a good parts head, minus the cam for $50. ended up buying 2 intake valves and 1 exhaust valve. 12 guides. that's about $100. $100 to the machine shop for shave, install guides and regrind seats. so...$250 materials, maybe, and a bunch of time. i wish you the best.

how would a bent valve from one or two adjacent cylinders cause a leak from one to the other? each cylinder should technically be sealed and the valves only control what goes in and what goes out to the cylinder they are "working" for. anywayy im hoping the issue is ONLY top end i can replace a head easily... dont want to have any internal block issues... not with a car with such low mileage..

stereoinstaller1: ill get some pics up soon... car is in storage along with the race car for winter

[riceh8r]

you are correct...my brainfart.

[scottinAZ]

if the #5 exhaust is bent (and therefore stuck partially open) and #4 is slightly open, then you will get leakage back through the exhaust manifold. I wouldnt condemn the casting just yet