Author Topic: M42 Durability (Read 3319 times)

BlueBMW · « **on:** May 18, 2010, 11:01:55 PM »

Just how durable are these motors? Can we drive them hard all the time and expect them to just keep coming back for more? Or is there a limit? I know mine see's redline at least once a day (usually 4 or 5 times)... while it seems to take it fine, am I risking blowing the darn thing up way sooner rather than later?

Just curious since I drive my poor old car pretty darn hard every day. I keep it maintained with proper fluids etc, and I fix problems when they arise but still, how much abuse can these motors really take?

rob_e30 · « **Reply #1 on:** May 19, 2010, 01:28:15 AM »

A lot, but you do need to be careful about over-revving it. If you rev it too high and the lifters start to float, you'll be in trouble as your pistons may strike the valves. You also need to be sure that your timing chain tensioner has been replaced. One problem is that as your timing components wear you get less precision which can cause a host of problems.

bmwconnect · « **Reply #2 on:** May 19, 2010, 05:34:52 PM »

IMO anything over 7000rpm is a bad idea. Like rob says the timing components wear. I have basically beat the shit out of this motor and with 230,000kms+ using 20w50 non synthetic and she still go's like hell without burning any oil. One of the most impressive and reliable motors I have come across in my time

Romrog318is · « **Reply #3 on:** May 19, 2010, 05:46:25 PM »

well like i said in my forsale thread i beat the shit out of mine and was at 7100 everyday NEVER did my lifters float but i mean my timing components were already done so yea
i can always take the valve cover off and see how the 207,XXX mile motor looks.

Jorgeconrico · « **Reply #4 on:** May 19, 2010, 06:13:33 PM »

Quote from: rob_e30;92616

A lot, but you do need to be careful about over-revving it. If you rev it too high and the lifters start to float, you'll be in trouble as your pistons may strike the valves. You also need to be sure that your timing chain tensioner has been replaced. One problem is that as your timing components wear you get less precision which can cause a host of problems.

In some cases if you change the tensioner can't it put more stress on the already worn timing components and cause failure??

Romrog318is · « **Reply #5 on:** May 19, 2010, 06:41:52 PM »

umm all of mine were replaced lol
the chain, tensioners, sprockets, idler gear (or whatever its called) ALL of were changed

Jorgeconrico · « **Reply #6 on:** May 19, 2010, 07:09:03 PM »

Quote from: Romrog318is;92648

umm all of mine were replaced lol
the chain, tensioners, sprockets, idler gear (or whatever its called) ALL of were changed

Thats swell that you changed everthing but thats not what I was asking. If you put a new tensioner on will it cause premature failure of older timing components?

Romrog318is · « **Reply #7 on:** May 19, 2010, 07:30:12 PM »

ohhh i thought u were stating something hah
and im not sure really it just depends on the condition of the teeth on the sprockets i guess lol

BlueBMW · « **Reply #8 on:** May 19, 2010, 09:30:44 PM »

A new tensioner was put on mine... but I know my other components are worn. I'm kind of gambling right now as I save up for either new timing components or romrog's motor (if he still has it!) I dont have any noise or anything even on cold start, but I'm just waiting to hit 7K one day and have it explode.