boostintsi Posted August 3, 2014 Report Share Posted August 3, 2014 (edited) So, while driving today I noticed a bit of a lifter tick and slight valve train noise. I pulled the valve cover off to check it out, I figured an oil hole was getting blocked or somthing. Well, come to find out cylinder 3 intake rocker arm had slid forward about 1/4 to 1/2 inch. Just enough for the lifter to catch on the retainer and stop it from causing serious damage. There's literally a mile on the car ran like this, I checked it out as soon as I heard it. To my surprise after pulling rocker shaft assembly off, the lifter still looks good as well as the valve and retainer. I'm thinking the bit of play in lifter saved me here. I'm going to replace the lifters regardless for peace of mind but everything else still looks great visually. My question, has anyone else had this happen? If so why and is this common? I'm going to be sourcing new rocker shaft springs and gonna mic the shafts themselves and check to be sure they are perfectly straight and replace if neccessary. Just looking to see who else has ran into this and the fix. Even if I replace everything I'll be inclined to pull the valve cover every time I drive this thing for a while just to be positive it's not happening again. the joys of old mitsubishis, oh well still love the car. Edited August 3, 2014 by boostintsi Link to comment Share on other sites More sharing options...
Funky Phil Posted August 3, 2014 Report Share Posted August 3, 2014 stronger springs or nylon spacer. Not all that common but happens on this style of rocker assembly Link to comment Share on other sites More sharing options...
boostintsi Posted August 3, 2014 Author Report Share Posted August 3, 2014 Thanks Phil, I was thinking the springs have probably weakened a bit over the years. My valve train was swapped over from my original head. Guess I should have replaced everything at the time. If the shafts check out ok maybe I'll just make up some delrin spacers for now. Link to comment Share on other sites More sharing options...
Funky Phil Posted August 3, 2014 Report Share Posted August 3, 2014 Only other thing i can think is valve float. Link to comment Share on other sites More sharing options...
boostintsi Posted August 4, 2014 Author Report Share Posted August 4, 2014 I guess I can see that happening although I haven't revved my motor high enough yet to float the springs in my motor. Also if they were floating and slipped off to the retainer I'd expect some damage. Everything checked out ok so I turned some spacers out of 6061 stock I had laying around. Definitely much stiffer I dont see them slipping off anymore although I will be checking the first few runs out with the spacers. Link to comment Share on other sites More sharing options...
tsi_tom Posted August 4, 2014 Report Share Posted August 4, 2014 I put a piece of paper towel down the mounting holes in the head to absorb the oil. This way when you torque the assembly it will be accurate. Did you use a torque wrench? Link to comment Share on other sites More sharing options...
Funky Phil Posted August 5, 2014 Report Share Posted August 5, 2014 I guess I can see that happening although I haven't revved my motor high enough yet to float the springs in my motor. Also if they were floating and slipped off to the retainer I'd expect some damage. Everything checked out ok so I turned some spacers out of 6061 stock I had laying around. Definitely much stiffer I dont see them slipping off anymore although I will be checking the first few runs out with the spacers. Well, I was floating valves over 5500rpm on multiple occassions (I thought it was something other than my springs) and when I checked the valve tip they were fine. But you ruled that out. Sooo since i helped you, where are MY spacers..........? Link to comment Share on other sites More sharing options...
boostintsi Posted August 5, 2014 Author Report Share Posted August 5, 2014 I guess it could be valve float, I just haven't taken this motor over 5000 yet with current setup due to timing and a couple other issues. If I remember right seat pressure on the springs was about 160 or 170 at .5. Nothing too crazy but at that seat pressure they shouldn't float, even at 5500. Definitely doesn't sound like they're floating but it is possible. What springs were you using when getting float over 5500 Phil? Let me see how the spacers work if it seems like it did the trick I'll send you some. Pretty quick and easy to make up I had some thick wall extrude honed .750 id tubing that I turned down a bit and parted at .5 inch. Definitely stiffer, I had to drop bolts in the caps to get it to stay together. Gonna install today and check to make sure the rocker arms are centered with the valve stems. I have a sneaking suspicion that possibly the cam caps may need some material either taken off or for the rocker to be shimmed against the cap to get properly centered. After looking at the rocker assembly it just seems like there's lots of room for improvement. I don't like the idea of only relying on a spring to hold the rocker arm in place when the results could be so catastrophic if it slipped out far enough. Maybe a circlip and shim setup might work, although there's not much shaft meat to work with. There's got to be a better way. Tsi tom, the cam caps were properly torqued. The cap torque really has nothing to do with the rocker arm though, the only thing holding the rocker arm in place is the spring tension against the rocker which is stopped by the cap, as bad an idea as that sounds( at least to me). I mean if a cam cap came off completely sure, but that would be a real mess. Link to comment Share on other sites More sharing options...
Tim_C. Posted August 6, 2014 Report Share Posted August 6, 2014 Some possibilities come to mind:1) Weak or damaged positioning springs. I would be very leary about running SST spacers against the aluminum rocker. You may need a bronze bushing on the end of the spacer to properly wear. However, from your verbiage, you seem to know more about metals than I do. My point here stems from an old school thinking that rigid spacers instead of soft springs may cause wear especially if they aren't very well calculated for length, etc... The springs should have enough tension to hold the rockers from slipping off under normal conditions. That's another reason I would not jump to spacers so fast. They should have enough tension to 'spring' (verb) the rocker assembly apart enough that you need the bolts in place in order for the bolt holes to stay lined up.2) Bad valve guides allowing the valve to wobble at the top and allowing the lifter to slip off of it. Once it slips off, there is no going back.3) Combination of things including the lifter got stuck, thus not providing the proper lash adjustment. A small mis-alignment problem is now magnified and can allow the lifter to slip off of the valve when it encounters the valve top again after lifting away from it.4) Worn rocker internal pivot hole diameter. The shafts are normally fine, but the aluminum rockers can be worn considerably. Again, this would allow the rocker to wobble on the valve end and or always run slightly crooked. This condition may not be so easily observed when engine is not running. You need to wiggle the rocker on the valve end to see if it allows much movement. Also, rockers get easily damaged when the untrained person tries to remove them from the shaft without properly cleaning the old varnished oil deposits from the shaft before trying to slide the rockers over it. They can also catch at the end of the shaft and a nasty gouge can occur if extra care isn't taken when pulling them off of the end. They **** awkwardly and very easily gouge the internal diameter of the rocker. Link to comment Share on other sites More sharing options...
Dad Posted August 6, 2014 Report Share Posted August 6, 2014 Cam or rocker worn to the side causing the rocker to "track" off the valve,, sort of like adjustment on a belt sander. Really never seen this happen.Dad Link to comment Share on other sites More sharing options...
tsi_tom Posted August 6, 2014 Report Share Posted August 6, 2014 Also, rockers get easily damaged when the untrained person tries to remove them from the shaft without properly cleaning the old varnished oil deposits from the shaft before trying to slide the rockers over it. They can also catch at the end of the shaft and a nasty gouge can occur if extra care isn't taken when pulling them off of the end. They **** awkwardly and very easily gouge the internal diameter of the rocker. Very true! Link to comment Share on other sites More sharing options...
Funky Phil Posted August 6, 2014 Report Share Posted August 6, 2014 the sakura head had either nylon or delrin spacers. But that was also regularly inspected. Link to comment Share on other sites More sharing options...
boostintsi Posted August 7, 2014 Author Report Share Posted August 7, 2014 (edited) Thank you all for the replies and knowledge it's very much appreciated. The engine was rebuilt roughly 4000 miles ago with the exception being I reused the rocker arms, shafts and springs. When I disassembled originally the first thing the rocker assembly got was a chemical bath before being disassembled. Not to say that I did not damage anything but care was taken. As it was when I disassembled a couple days ago. My rebuild included new non jet head from randy with new valves, guides seals etc. I am incrediblyjz always monitoring oil pressure and temp cooling temps, wideband etc. Every time I drive the car it is being logged and logs looked over afterwards. I would be surprised if my valve guides are worn but I did not think to even check because of low miles and care put into the build and every time it's ran. I'm about to pull the valve cover to inspect as I just we not for my first run with spring spacers in just letting her cool down a bit. You made some good points Tim C. 1. I was able to pull the rocker assembly out of the head and with no bolts in place it had not the slightest desire to pop out of place. Now maybe that's a tell in itself that possibly my rocker arms are binding as well and holding it together. But after a quick bath I easily slid everything apart. 2. I touched on the valve guides above but good point and I will inspect shortly. 3.the initial noise I heard was to my ears the definition of a dry lifter. It quickly pumped back up , but still had a bit of an odd noise hence my pulling the cover to inspect. Seems like a real good possibility. 4.the rockers, I definitely want to replace the rockers. They were not scored but did show a more polished witness marking on half the bore than the other half. Indicating to me out of round. This is very good possibility as well.5. What Randy mentioned about the uneven cam lobe, I will inspect shortly but by eye I don't think I'll be able to see that. The wear/witness on the slippers and the cam lobe looked uniform to me to the eye so I didn't put another thought to it. I am looking for a stock cam to put in the car for right now so I can have my unknown tep cam put on a cam doctor by a friend who has access to one, that will tell for sure. 6. As to the spacers I made up, I wasn't worried about wear because I installed them between the spring and cam cap where they shouldn't see much repetitive movement. I also installed a bronze shim between the spring and rocker arms for that purpose exactly so hopefully the spring won't move at all. Aluminum shavings from the spacers were a concern of mine but I plan on inspecting every run for a while. I just ordered a bunch of valve cover gaskets lol thanks again guys. I'll report back after another, closer inspection. Edited August 7, 2014 by boostintsi Link to comment Share on other sites More sharing options...
boostintsi Posted August 11, 2014 Author Report Share Posted August 11, 2014 (edited) Ok after multiple runs and inspections I have not had it reoccur. I'm going to leave the spacers for now. They are not moving I verified by marking indicating spring to spacer, spacer to cap. I purged the lifters in solvent and the number three intake lifter had some junk in it as well as number 1 exhaust, the bleed hole on number three intake rocker was also blocked. Checked out the valve guides and I'm confident that's not the issue. Rocker arm bores are slightly questionable as are the shafts but the tops of lifters and rocker arm lifter seats look perfect. There is wear marks on the bores and shafts but nothing crazy. I do want to replace arms and shafts but for now it seems to be working well and valve train is silky smooth. I'll be sending out the cam to be checked on cam doctor but other than that my diagnosis is a combination of a lifter possibly getting stuck due to contaminants and or not being able to bleed off and weak springs allowing it to jump over. Possibly the wear on rockers and shafts is not helping but with the pressure against them now I don't seem them coming back off. Gonna be checking periodically to inspect and make sure nothings wearing uneven before swapping the new stuff on to the setup though. Thanks guys for the help and Phil lmk if you want a set of these. Edited August 11, 2014 by boostintsi Link to comment Share on other sites More sharing options...
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