Broke a rocker arm, replace the springs?

[CrazyJew89]

So I broke a rocker arm the other day and I am taking the head off to replace all of them, seeing as this car was abused in the past. However I am not sure I am not sure if I should be replacing the springs as well. The reason I am questioning the springs is b/c everyone seems to like to bring up valve float all the time. The car has 180K and was running perfectly fine before the rocker arm broke. What do you guys think?

[SmokeE30]

stock i springs are fine till like 7200rpm you should have no issues with valve float as you shouldn't be reving that high in a street m20. also make sure you adjust your valves thats probably the reason it broke do that and you should be fine.

[jlevie]

If you are going to remove the head and replace rockers it would make sense to complete the job by having new guides installed, valves ground, new seals, and springs checked. You should have have the cam gaged to see if it is worn below spec.

[lennon]

I would at least get a standard valve job and have the head checked out like J Levie says. The machine shop will probably recommend you replace them. If they have 180k and were abused like you say, they are probably tired. Then again if you just need this car to get you from A to B and don't care about keeping it, maybe don't bother.

[StereoInstaller1]

I think it is silly to pull your head to replace all your rockers. I think if you have a good 180K motor, just fix it and drive it until it wears out, THEN pull and apply the love.

[monkeytaco]

So I broke a rocker arm the other day and I am taking the head off to replace all of them, seeing as this car was abused in the past. However I am not sure I am not sure if I should be replacing the springs as well. The reason I am questioning the springs is b/c everyone seems to like to bring up valve float all the time. The car has 180K and was running perfectly fine before the rocker arm broke. What do you guys think?

replace worn part #m20 with freshly rebuilt part #m50 or higher.

[StereoInstaller1]

replace worn part #m20 with freshly rebuilt part #m50 or higher.

blah blah replace motor blah blah

[CrazyJew89]

stock i springs are fine till like 7200rpm you should have no issues with valve float as you shouldn't be reving that high in a street m20. also make sure you adjust your valves thats probably the reason it broke do that and you should be fine.

I assumed the stock springs would be good a little past red line but i guess my question is does that 7200rpm drop w/ age, and if so is it enough to justify buying some cheap newer springs from someone on the forums? Actually I checked the valve lashings a couple days before this happened.

I would at least get a standard valve job and have the head checked out like J Levie says. The machine shop will probably recommend you replace them. If they have 180k and were abused like you say, they are probably tired. Then again if you just need this car to get you from A to B and don't care about keeping it, maybe don't bother.

I am not going to take it to the machine shop b/c it is currently a really fun A to B car, I'm a college student that doesn't have a huge budget, and it ran perfectly fine before the rocker arm broke.

I think it is silly to pull your head to replace all your rockers. I think if you have a good 180K motor, just fix it and drive it until it wears out, THEN pull and apply the love.

I think it is too but unfortunately it was on cylinder 4 and from what I have read you can't easily fix that without pulling the head. Besides, I already took it off.

[wakeboardr42393]

Do valve springs wear out over time? That is my question. I've heard people say they will be fine, and I've heard others say they won't. Who is right?

I am replacing my FOURTH rocker arm on my m20b25. The engine is stock for all I know. The same one has not broken twice so maybe the rockers are just old. But then again, only the intake rockers have broken so far. and I know the intake valves are bigger, therefore heavier, then exhaust valves. are they floating? could they be floating bad enough that the valves would be hitting the piston, sending a shock back to the rocker, breaking it? if so, I don't want to just replace rockers to risk messing up the way the valves seat. like i don't want to ignore the real problem by just replacing rockers.

I beat the crap out of my car and frequently bounce off the electronic rev limiter. All four times a rocker has broken, the engine was at 6500 rpm at the time of breakage.

I plan to race my car within the next year (stage rally), and I figure if something can't handle "spirited" street driving, it will not handle racing. kind of working the kinks out lol.

the engine has unknown mileage (bought the car with non-working speedo/odo, since fixed.). If the rockers are breaking consistently, I don't think it is a fluke. It seems like something is wrong. I thought these engines should be able to handle being at the redline often? The reason I bought an e30 is so i could run it hard? (well, there were more reasons, but this is just one of of them ;] )

I have not pulled the head, it is not too bad of a job with the head on the car- takes me a few hours by now lol. i have a thread with some photos of me doing the rocker while the head is still on the car, if anyone is interested haha.

So, can the valve springs be so worn that it would be worth replacing? I really don't know about the properties of springs and metal etc.

[Mossman]

Yes the springs like all things steel will experience fatigue/creep. The spring rate will be lower as the springs wear as well, raising the chance of valve float occurring. That being said I romp on my 200k mile valve springs to redline all the time and don't worry about it. I've never had a rocker randomly break unrelated to a timing belt snap, but I know it does happen. If it was me I would have yanked the head the 2nd time a rocker broke, and rebuilt it. Definitely wouldn't have swapped single rockers 4 times that sounds miserable. Granted, valve springs aren't an item I would normally replace in a stock rebuild, but a capable machine shop ought to have a way to easily test spring rate of your springs. Without an acceptable stock range to compare it to, that doesn't mean much, but buying one new inner and outer in order to compare is pretty cheap.

TLDR: Make sure you're adjusting your valves properly and often enough, your timing is correct, and if another one breaks get some new springs.

[CrazyJew89]

I second making sure your valves are adjusted properly. I'm pretty sure when I snapped my rocker arm it was from making them too tight. From the issues your having, and my assumption that you're on a budget, I would suggest getting some used low mileage springs and rockers, and look into cam side valve adjustments. Your valves probably have enough miles that they have developed a dish in the top of the stem making it impossible to get the right adjustment from the valve side.

[wakeboardr42393]

I wonder how much lower the spring rate is then stock at this point. If it is a significant amount.

I just don't get why I seem to be the only one having this problem so consistantly (i've only had the car for about 7k km; less then 1 year). I have searched and have found zero cases where people have experienced 4 subsequent rocker arm breakages.

If this happens again, maybe I'll get springs for a single valve and have a shop measure differences between old and new spring rates. I'd post results. If pressures are significantly different between new vs old, buy a new set of springs. Valve springs are much cheaper then I thought they would be haha.

I just replaced the timing belt about 3k km ago. Today I double checked the timing, and it was ok. (the mark was like 2mm off but i suspect that's acceptable ;) ) I set the clearances a week before this arm broke to .010" on the valve side. I looked up cam side adjustment and I'm going to try it when this rocker arm comes in. makes plenty of sense. just seems like it'd be more awkward to get a feeler in there haha.

Would having excessively worn rocker contact pads do anything negative?

[digger]

Would having excessively worn rocker contact pads do anything negative?

yes, the valve motion wont be controlled as intended which can lead to you know what if bad enough.

[jlevie]

I am replacing my FOURTH rocker arm on my m20b25. The engine is stock for all I know. The same one has not broken twice so maybe the rockers are just old. But then again, only the intake rockers have broken so far. and I know the intake valves are bigger, therefore heavier, then exhaust valves. are they floating? could they be floating bad enough that the valves would be hitting the piston, sending a shock back to the rocker, breaking it? if so, I don't want to just replace rockers to risk messing up the way the valves seat. like i don't want to ignore the real problem by just replacing rockers.

Intake valves are smaller than the exhaust valves.

From what I've seen, my theory on broken rockers is that they fail due to a history of improper clearance (too loose). The repetitive impacts cause the rocker to eventually fail.

[wakeboardr42393]

my rocker arm pads are pretty badly worn-



Yeah I don't think the previous owner kept the clearances set. It was pretty bad when I got the car.

Intake valves are smaller than the exhaust valves.

unless they are smaller in overall mass, which they may be for all i know lol, intake valves are larger at least in diameter then exhaust valves: