Crank turn over?

Can you turn the crank over by hand in these m20s? I need to change the rings and pulling the pistons isnt an option

Wicked Fast Entertainment

piston rings? you have to pull pistons to replace the rings. you can do say replace the bottom end without removing the engine, but your just causing more work and the possibilities of screwing the job up more probable.

I was thinking i could take the head off and rotate the crank to put new rings on

Wicked Fast Entertainment

negative. pistons dont raise high enough. they have to be unbolted from the crank then raised out of the block .

Not being disrespectful, but you obviously know so little about engine rebuilding that you have no business tackling ring replacement in your M20. All you're going to do is screw it up. Sorry man. I wish I could be more supportive. READ AND LEARN about basic engine repair, then work your way up to a rebuild.

+1 with HH. Piston removal is the only way to change rings. Pistons come out and are refitted from the top. You have to release the big end and remove the cylinder head to do this.

I think that if you want to learn the way to rebuild an engine (this is a seperate trade, where you can earn your master degree in Alemagná) first read, then ask if you may observe in a machine shop how they do it & then get a spare motor (like a M52) to attempt it yourself.
This will not be a cheap exercise ! But you will have learned something
Anybody can dis/assemble a motor, but to get it to last....
Otherwise pull your motor & give it to a machine shop to recon. When I used to do this, I gave 50 000 km's guarantee on any motor in its stock application & not raced

Hh ive never done it but my friend drives a racecar at the local dirt track and thats how he changes gis rings he wanted me to ask if it could be done on this since hes never worked on bmw's

Wicked Fast Entertainment

Maybe consider changing friends ?

Originally Posted by WickedFast.Inc

Hh ive never done it but my friend drives a racecar at the local dirt track and thats how he changes gis rings he wanted me to ask if it could be done on this since hes never worked on bmw's

Wicked Fast Entertainment

ive never seen a piston to where the rings raised above the deck, besides removing the pistons or the pistons being blown out the hood.

Keep your friend away from your Bimmer..

Originally Posted by downhiller

ive never seen a piston to where the rings raised above the deck, besides removing the pistons or the pistons being blown out the hood.

+1. its illogical anyway, why would the ring go across a groove that is inevitably created in the head/headgasket/block join. maybe in a race car where there is a rebuild every 5000kms anyway, but not in a production car. the friction would be massive, even normal driving at 2000rpm, thats 4000 times it moves across that gap per minute, and how many 100,000 if not millions of minutes does an engine operate for.

happy to be prooven wrong.

Originally Posted by WickedFast.Inc

Hh ive never done it but my friend drives a racecar at the local dirt track and thats how he changes gis rings he wanted me to ask if it could be done on this since hes never worked on bmw's

Wicked Fast Entertainment

You are either misunderstanding what he's telling you about what he's doing, or he's totally BSing you, because you cannot change rings without taking the rods loose from the crankshaft to allow the pistons to come out the top of the bores. It simply cannot be done.

Originally Posted by _Ethrty-Andy_

+1. its illogical anyway, why would the ring go across a groove that is inevitably created in the head/headgasket/block join. maybe in a race car where there is a rebuild every 5000kms anyway, but not in a production car. the friction would be massive, even normal driving at 2000rpm, thats 4000 times it moves across that gap per minute, and how many 100,000 if not millions of minutes does an engine operate for.

happy to be prooven wrong.

you got your revs wrong. 2000 rpms is 2000 rpms. its the cam that rotates 1000 rpms (2 crank rotations to 1 cam).

getting back on track, every motor has rings, if they raise above the deck, those rings will be destroyed which then, would start destroying the engine.

Originally Posted by downhiller

you got your revs wrong. 2000 rpms is 2000 rpms. its the cam that rotates 1000 rpms (2 crank rotations to 1 cam).

thought about it some more, pretty sure im right. once on the way up it crosses and once on the way down! either way, we are in agreement it would destroy rings

Originally Posted by _Ethrty-Andy_

+1. its illogical anyway, why would the ring go across a groove that is inevitably created in the head/headgasket/block join. maybe in a race car where there is a rebuild every 5000kms anyway, but not in a production car. the friction would be massive, even normal driving at 2000rpm, thats 4000 times it moves across that gap per minute, and how many 100,000 if not millions of minutes does an engine operate for.

happy to be prooven wrong.

You guys are absolutley right about the bore and the stroke. No engine unless O ringed N/A block will have a piston rise above the deck, and almost always the top ring is never exposed just about a .5-1mm of piston crown.

Originally Posted by hornhospital

You are either misunderstanding what he's telling you about what he's doing, or he's totally BSing you, because you cannot change rings without taking the rods loose from the crankshaft to allow the pistons to come out the top of the bores. It simply cannot be done.

Fact.


I would not attempt this with the block in the car that's just being a glutton for punishment.

Where in TX are you? McAllen? Harligen?

Originally Posted by _Ethrty-Andy_

thought about it some more, pretty sure im right. once on the way up it crosses and once on the way down! either way, we are in agreement it would destroy rings

Tachometers or rev counters on cars, aircraft, and other vehicles show the rate of rotation of the engine's crankshaft.

what i was taught, when your checking timing on the pulley, that mark is the location of the piston on the up travel before the combustion stroke, and only that stroke. and that spark/signal is normally whats used to send the signal to the ecu and tach.

Hi Downhiller, You've sort of got it. You will get 2 tdc readings per cylinder per cycle. One at the change from compression to power strokes and on at the change from exhaust to inlet strokes. This is how the 'experts' get the timing 180deg out. The ECU signal can be any point known to both the engine and the ECU. Case in point, my E23 sends a signal at 20deg BTDC but the rpm monitor for the service port is at TDC.

Originally Posted by BMWFatherFigure

Hi Downhiller, You've sort of got it. You will get 2 tdc readings per cylinder per cycle. One at the change from compression to power strokes and on at the change from exhaust to inlet strokes. This is how the 'experts' get the timing 180deg out. The ECU signal can be any point known to both the engine and the ECU. Case in point, my E23 sends a signal at 20deg BTDC but the rpm monitor for the service port is at TDC.

i remember that, just trying to make it short and sweet. the point is, the rpm reading is from the crank and the tach measures the crack rotation