Stupid_fast Posted March 27, 2012 Report Share Posted March 27, 2012 Hello all, I've had lots of engine performance trouble that have not been fixed and there is one thing that I have noticed happening for a while. The motor is an L20b with A87(pretty sure..) head. Motor was bought as rebuilt, has about 4000 miles on it. I have adjusted the vavles cold, and hot to the on the specs from olddatsuns.com probably 30 times and I cant get them right. I'm taking the car to troy ermish shop in the next few weeks to have him sort out other running problems, but I'd like to have it running as best as I can get it when I take it there. It seems every time I adjust my valves, it goes out of spec just driving it once. Last night I set my valves to hot spec, set motor to TDC adjusted 4 valves, turned crank 360* and adjusted the other 4 valves. (0.010 int, 0.012 ex) I adjusted it so the (for example) intake 0.010 would fit in with little drag, but the 0.011 would not fit. Also I tightened down the adjusters quite well and verified the lash setting everything seems fine. After adjusting it, I take the car for a short drive about 1-2 miles up the roads around my house, when I left the valves made very little noise but when I came back after the drive they where making a ton of noise again. I really don't understand what could be causing this, could this be a problem with the valvetrain? Thanks. Quote Link to comment
datzenmike Posted March 27, 2012 Report Share Posted March 27, 2012 If while setting the lash the motor cooled down then the last valves (maybe more) set would actually be set too wide and would open up even more when it warmed up and start rattling. Try idling the motor for a couple of minutes between cylinders. Just slip the valve cover on loosely to contain the oil. Quote Link to comment
datsunaholic Posted March 27, 2012 Report Share Posted March 27, 2012 A lot of things can cause this. 1st, the hot spec means hot. The engine will cool off by the 4th valve, so you'd have to heat it back up again. 2nd, what are you using for oil? If you're using 10W30 (or worse, 5W anything) stop and get real oil. Modern 10W30 oil is for fuel economy and emissions, not actually oiling the engine. It's practically water. I run 15W40 diesel oil, but that's not a good idea on an old engine (it'll clean it up too fast), but on a "new" ish engine like yours won't be a problem. Some folks claim the high detergent is bad, but it's no worse than running synthetic. 3rd, to be sure you probably should check the wear pattern on the cam lobes and rockers. There are some really crappy aftermarket rockers that aren't properly hardened and they just get eaten to death, or worse are overhardened and eat up the camshaft. Try this- you know it's quiet when you first start out. Gets noisy after a couple miles. So, after having this happen, park it for an hour, and start it up. If it's quiet again, it's your oil choice OR you just aren't getting the readings when it's hot enough. If it's immediately noisy, your adjustments are not right to begin with (or backing off) or the cam/rockers are grinding apart. That could be bad parts, OR it could be a severe lack of cam oiling. Hopefully it's not a "solid" race cam that needs a spraybar. Quote Link to comment
banzai510(hainz) Posted March 27, 2012 Report Share Posted March 27, 2012 Genius!!!!!!!!!! I do .006 /.008 cold I have been running 15/40 Ford Motorcraft oil right now in my truck. YOu got aftermarket cam using taller lash pads and stock retainers?????? could be slighlty loose in retainer Quote Link to comment
Stupid_fast Posted March 27, 2012 Author Report Share Posted March 27, 2012 If while setting the lash the motor cooled down then the last valves (maybe more) set would actually be set too wide and would open up even more when it warmed up and start rattling. Try idling the motor for a couple of minutes between cylinders. Just slip the valve cover on loosely to contain the oil. A lot of things can cause this. 1st, the hot spec means hot. The engine will cool off by the 4th valve, so you'd have to heat it back up again. 2nd, what are you using for oil? If you're using 10W30 (or worse, 5W anything) stop and get real oil. Modern 10W30 oil is for fuel economy and emissions, not actually oiling the engine. It's practically water. I run 15W40 diesel oil, but that's not a good idea on an old engine (it'll clean it up too fast), but on a "new" ish engine like yours won't be a problem. Some folks claim the high detergent is bad, but it's no worse than running synthetic. 3rd, to be sure you probably should check the wear pattern on the cam lobes and rockers. There are some really crappy aftermarket rockers that aren't properly hardened and they just get eaten to death, or worse are overhardened and eat up the camshaft. Try this- you know it's quiet when you first start out. Gets noisy after a couple miles. So, after having this happen, park it for an hour, and start it up. If it's quiet again, it's your oil choice OR you just aren't getting the readings when it's hot enough. If it's immediately noisy, your adjustments are not right to begin with (or backing off) or the cam/rockers are grinding apart. That could be bad parts, OR it could be a severe lack of cam oiling. Hopefully it's not a "solid" race cam that needs a spraybar. 1, I have tried setting half the valves, driving, then setting the other half... never seemed to help much. I always check the valves against the other one I did so I take engine cooling into consideration. 2, I am using 10w30 Valvoline VR-1 ... non synthetic with ZDDP, my car runs in 30-60 degree weather at the moment. Is that REALLY too thin for this engine? 3, I will check over the valvetrain, I believe I measured the cam once and verified it was stock. It did have some wear on it even in the rebuilt motor, so maybe it was a used cam. I'll try it again with various methods and see if I can improve it. Genius!!!!!!!!!! I do .006 /.008 cold I have been running 15/40 Ford Motorcraft oil right now in my truck. YOu got aftermarket cam using taller lash pads and stock retainers?????? could be slighlty loose in retainer Hehe, I see what you did there! I was noticing when I set 0.08 int, 0.010 ex cold it was too loose when the engine was warmed up, I will also try setting it tighter cold. I don't think its aftermarket, but I don't really know anything about this rebuild... Is there something specific I can check over or measure? I am on business until the weekend, I will mess with it then. Thank you for the replies. Edit, just talked to the guy I got the engine from... Its an aftermarket cam! That's probably why I've had so much trouble... I'm going to measure it when I get back home on the weekend. Quote Link to comment
banzai510(hainz) Posted March 28, 2012 Report Share Posted March 28, 2012 get a photo up close of cam and lash pads retainers Quote Link to comment
Stupid_fast Posted March 28, 2012 Author Report Share Posted March 28, 2012 @Banzai, This is the only picture I have right now. its back when I first took the valve cover off to do the lash before starting it the first time. I'll get a better picture up on saturday. I can say... this engine feels like it hits its torque max at about 4k RPM. pulls nice to 6k .. Quote Link to comment
Sealik Posted March 28, 2012 Report Share Posted March 28, 2012 Edit, just talked to the guy I got the engine from... Its an aftermarket cam! That's probably why I've had so much trouble... I'm going to measure it when I get back home on the weekend. They look like stock lash pads.....??? If so....the cam is running off the edge of the rocker...pivot side, which will give you a "ton of noise" Wipe pattern.... Quote Link to comment
Stupid_fast Posted March 28, 2012 Author Report Share Posted March 28, 2012 @ Sealik, can that potentially cause other problems with the engine as well? How do I fix it? Get new lash pads? Motor is most likely completely stock besides the cam. Quote Link to comment
Sealik Posted March 28, 2012 Report Share Posted March 28, 2012 @ Sealik, can that potentially cause other problems with the engine as well? How do I fix it? Get new lash pads? Motor is most likely completely stock besides the cam. I think it would only wear the cam...after an extended period though. Before you consider lash pads....do a wipe pattern. If it's running off the side of the rocker.....then thicker pads are a given....you want the pattern centered. One .150 pad would be needed to calculate lash pads needed..... Quote Link to comment
Sealik Posted March 28, 2012 Report Share Posted March 28, 2012 Those look like after market valve springs...notice the coils are leaning the opposite way than stock. Need to see what pads are in there Stock on left.....aftermarket on right. Stock pads also have 2 groves on top...each side of where the rocker sits Quote Link to comment
banzai510(hainz) Posted March 28, 2012 Report Share Posted March 28, 2012 Before any body panicks here look at the cam close and see what markings are on there. Be honest most Pevious owners say there is a cam in there and its NOT. This Dont look like a regrind!!!!!!!! So its stock or a NEW cam. I have a Schneifder and a Webcamsahft and they have a CWC in the center. Maybe its the company thay cast these? also most new aftermarket cam will have writting onthe back of the cam so get a mirror and see what it says. If after market you can do a visual ck by pointing the lobe up and look wwhere it is shiny at by looking at both ends. If running off the edge of the rocker could be a proplem. also put a cam lobe on full rocker pointing down and look to see if the spring loots compressed all the way. Inner and outer! Maybe its a after market cam with stock everyhting else. Maybe its really stock????? Only you will know But if you could put a lash pad out these will give us a clue. as it loosk like stock retainers bUt the steel after market ones do look similar also. I buy alum ones and those are red which is EZ to see. Quote Link to comment
datzenmike Posted March 28, 2012 Report Share Posted March 28, 2012 Maybe just oil but those lobes look like the rocker has worn a groove in them... Quote Link to comment
Stupid_fast Posted March 28, 2012 Author Report Share Posted March 28, 2012 @Sealik, I will check the lash pads and see if they are stock or not. @hainz, the previous owner is a trustworthy guy. I just asked him and he says the only thing he remembers about the engine is that it was an aftermarket cam. I will look more closely and take some pics and measurements once I can. @Datzenmike, yes the cam is worn, that pic is from before I ever cranked the motor. I assumed he used a stock used cam, maybe he used something from another engine he had. I found another picture of the intake side. This is from before I even put oil in it... As I said before, I will look at it again over the weekend and get more information. Thank you all for the great info. Quote Link to comment
banzai510(hainz) Posted March 28, 2012 Report Share Posted March 28, 2012 THis previos owner, He put the cam in there? If so you think he would remeber the size of the cam. Not just its a aftermarket. I seen after market where they were smaller than the stock cam. I Usually remember cause they aint cheap Cam looks like a newer casting like a Scheider. Youll see a CWC casting in the middle soem where. just by the color of the springs they look aftermarket also Quote Link to comment
Stupid_fast Posted March 29, 2012 Author Report Share Posted March 29, 2012 @Hainz, he has not worked on his cars for at least 5 years... that's why he sold them. He just happened to have a rebuilt L20b he bought ... sold to me with the car. No idea who put the cam in, maybe he gave it to the rebuilder... If you zoom in on that pic and look in the middle of the cam you can see a C marking and what looks like a W before it. Now I just gotta get home and measure everything. Quote Link to comment
banzai510(hainz) Posted March 29, 2012 Report Share Posted March 29, 2012 there will be a number on back side of the cam Quote Link to comment
Stupid_fast Posted March 31, 2012 Author Report Share Posted March 31, 2012 OK the cam says this; D1-272-2-10-NC CRANE 162 18 88 the valves springs are double, I will get pics up in a few minutes. I adjusted the valves cold to 0.06 INT and 0.08 EX, it runs nicer now! Still, valves started making some noise after a drive... Quote Link to comment
Sealik Posted March 31, 2012 Report Share Posted March 31, 2012 OK the cam says this; D1-272-2-10-NC CRANE 162 18 88 the valves springs are double, I will get pics up in a few minutes. I adjusted the valves cold to 0.06 INT and 0.08 EX, it runs nicer now! Still, valves started making some noise after a drive... Most likely a 272 duration....who knows what lift. Measure and or check Cranes website. All 'springs' are double... Valve Lash is set at .006 and .008 cold .."I adjusted the valves cold to 0.06 INT and 0.08 EX, it runs nicer now!".... ???? Assuming a 'typo' error????............... :D Quote Link to comment
Stupid_fast Posted March 31, 2012 Author Report Share Posted March 31, 2012 cam int/ex lobes are the same... 40mm at longest point, 33mm at shortest point No not a typo, Olddatsuns says to set 0.08 INT/ 0.010 EX for cold specs. :confused: Quote Link to comment
datzenmike Posted March 31, 2012 Report Share Posted March 31, 2012 0.275" Same lobe lift as a stock L20B. L20B duration is 248. Quote Link to comment
Stupid_fast Posted March 31, 2012 Author Report Share Posted March 31, 2012 The question, is there anything wrong with my valvetrain? If there is, how can I fix it, and if there isn't then WTF. Thanks for help, now for some pr0n.... . Quote Link to comment
Sealik Posted March 31, 2012 Report Share Posted March 31, 2012 .407 lift.... from your measurements...worn cam ......couple of rockers look NFG Stock lash pads .008 or .006 for intake (cold)....NOT .08........too loose...wear/noise Quote Link to comment
Stupid_fast Posted March 31, 2012 Author Report Share Posted March 31, 2012 @Sealik, so NFG(not fucking good?), I should replace rockers and fit proper lash pads? :confused: Thank you... Quote Link to comment
banzai510(hainz) Posted March 31, 2012 Report Share Posted March 31, 2012 crane made camsare in the 272,282,292 duration and all were .450 lift at zero lash. Behonest the cam looks ok and if the lash pad is flat on bottom then i will assume the lash is the correct size and you have bigger steel retainers. .oo6intake/.oo8 try 20/50 oil Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.