Afshin
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Posts posted by Afshin
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Sounds good, I think I can make it.
Sorry Dale, my turbo S30 has been guted and fully rusted out in some junkyard back east (after being rear ended by a Ford F150). As they say: dust to dust or would it be mineral to mineral ?
However, still got a sweet turbo spooling
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I would also go with the grainger valve (ball and spring) for the reasons outlined by Bastaad. I does help the turbo spool up faster. However, I imagine the would be less spiking with the actuator rod length controling boost. I prefer to have quicker spool up. Also it is easier to adjust the grainger valve, specially if you get a cockpit adjustable one which are still relatively cheap and work as well as most electronic boost controllers.
This link is to a nice sports compact review on the electronic controllers and one grainger type valve.
http://www.sportcompactcarweb.com/tech/0207scc_boostcontrol/
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OK, OK I was being a little unfair and harsh to say the least (what's the male equivalent to PMS anyway), I've had my coffee now took the kids out to the park had some food and feel better
. But seriously, how could the turbo seal go the second you put the rebuilt head on and then foul the spark plugs with oil and the J pipe be completely dry ?. I know there is a thin film of oil now, which is unimpressive and the problem was there before the oil. Also failed turbo seal typically do not cause start up smoke which goes away when you rev the engine and comes back when idling for a while. When turbo seals leak, there is less smoke at first when the engine is cold as the oil is thicker and smokes more as is warms up, you have the opposite.
In terms of the rings, how could all 6 collapse simultaneously without good reason (i.e. overheating engine). It is certainly true that if the oil rings fail as opposed to the compression rings, compression values will be normal. The main reason for checking compression is to get an overall picture of the "health" of the engine. It should be checked anytime before the head comes out to evaluate if the bottom end seems OK. why fix the head if the bottom end is faulty....
Finally to answer you last question, the reason the car will start to smoke more when contaminated with fuel is that it decreases the viscosity (thins out) of the oil which both leaks thru seals and looses it's effectiveness in protecting the engine. And yes, it will get recontaminated as you use it again, but at least it will take a little while. Sorry about the tone of my last post, I really am trying to help you out and minimize the amount of work you do so you can keep the car and enjoy it.
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Hi Bastaad. In a N/A car when vale seals go bad the car makes more smoke when you start it (as I explained previously) and when the car is idling for a few minutes( I can't remember the exact reason for this, but I was told by outstanding master mechanic). In a turbo car it will additionally smoke under boost because of the higher pressure causing more oil to leak. To answer your previous question, when under boost there is more pressure in each cylinder Only when the intake valve is open (so during that cycle more oil does not leak) but the pressure under the valve cover will be constantly elevated causing more oil to leak.
What I'm trying to say is that the symptoms are Classic for bad valve seals, the problem happened after you rebuilt the head and initially the spark plugs were soaked with oil and the turbo pipe was clean. This is the valve seals, why spend the time swapping turbo's which does not cause smoking at start up or after idling (if it's the turbo then it will smoke more when driving without boost than at idle). Each time you look at something that's not the main problem, you waist time and effort resulting in more frustration. You need to be more systematic by which I mean first address the most significant problem. Why play with the TPS or clamping the fuel return line and turn the boost up to 13 when the car is leaking oil and running like shit, you will only do more damage and then complain that everything goes wrong. I'm sorry if I'm coming down hard on you, but I get the feeling that you keep working sub optimally on multiple problems instead off focusing 100% on the main one (maybe I'm wrong).
Please check the compression; it helps all many of us think about the problem more clearly. Also did you change the oil? if not buy now it is so contaminated with fuel (if oil leaks in then usually fuel leak out as well) and thinned out that it would smoke in any car and risk mechanical failure to the engine and turbo.
Off course I could be wrong, (since it happens often enough) but you still need to tackle it in the most logical way. there was oil on all 6 plugs when the pipe was clean, it happened the second after you put the rebuilt head on, and the pattern of smoking is consistent with faulty valve seals. Boy, am I grumpy this morning
I guess I will go have my coffee now (before I sound like even a bigger jerk, if possible). -
Hi, I found this site a little while back, they have a great variety of pyrometers, some very cheap along with a lot of nice technical info related to them. Considering the low cost you may consider one for your next outing to the industrial estate.
http://www.longacreracing.com/articles/art.asp?ARTID=16
Also can you give some more info relating to your current suspension set up i.e. tire type and size, control arm bushings new, old, strut bar?...
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You can check the compression by yourself, I have done it many times. Take out all the plugs, check all of them, disconect the coil, screw in the compression gauge and crank about 7-10 turns and then take the reading. You can also very easilly place an alligator clip or any wire on the starter solenoid and connect to + power (on starter or at battery) and the engine will crank with you at the bay and watching the compression gauge. Make sure you check the compression Without the oil first, if low, then check it after squirting the oil in (5-10cc). The compression may read a litlle higher with oil in even a good motor. As you know, the test is too see if you get a big improvement in compression in a engine with low compression. I'll keep my fingers crossed.
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Why did you also specify to change the oil before revving too high or boosting?
because you oil is contaminated. after any rebuild and assembly there is always some fine metal and non metal particles that make there way into the engine. Also there is some potential slight grinding as the valves, valve reground seats... break in. Furthermore, you used some solvent to clean your piston and you where leaking plenty of oil in the chamber, which means that you also leaked fuel into the oil which thins out the oil. So as a easy protective measure just flush out the oil with clean oil and a new good quality filter.
About retorquing the head, I thought I read somewhere that you're not supposed to retorque it when you use a felpro gasket?the reason for retorquing the head is that with the initial torquing of the head and the first few times that the head heat and cools (expands, constricts,expands...) the head bolts may losen. Retorquing has been recommended by many engine builders. However I don't know why felpro says not to do it (I was not awar of that). Perhaps out of concern for the metal rings/seals to fail/collapse if the retorquing causes the head to reseat slightly differently. Maybee someone else knows the answer. I guess you should hold off on the retorquing for now.
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I have been trying to think a little more about the oil problem. As we all seem to agree It really doesn't make sense that all rings would collapse at once and I also thought about the solvent issue I brought up earlier (it makes no sense either) and that should not be able to do it. Rings collapse because of rapid temperature change (hot then cold). SO I keep getting back to the valve seals, which typically cause smoking when you start the car. the reason is that as the engine sits. oil on the valve stem leaks down into the cylinder, and when the car is started the excess oil burns and smokes. this is not the case with rings. faster RPM would not effect the amount of oil leaking in from the seals that much, however under boost the positive pressure would cause more oil to leak in and cause smoke. I know you said you checked the seals but are you able to tell if they are truly fully clipped in place and making a PROPER seal without taking the springs off ? I know this does not explain why the problem seemed to get better (off course the engine will smoke plenty when you start it right after a rebuild for the first few minutes).
In the end only 2 things can soak all of your spark plugs with oil:
1)six simultaneous collapsed rings (for no apparent reason) or
2)leaking valve stem seals after a head rebuilt . It can be either wrong size such as wrong part put in and leaking from the valve stem or valve stem seals that are not properly in place and sealed over the guides.
ALso why don't you recheck the spark plugs to see if there is still oil on all 6.
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1) unfortunately it's hardly ever that easy (or cheap)
2)yes, resticting the fuel return line will increase fuel pressure. But it's not a good idea and will be inconsistent. If you want higher fuel pressure, you adjust it with the pressure regulator, if yours is stock, buy an adjustable one. There are previous post discussing rising rate fuel pressure regulators (RRFPR), they increase fuel pressure during boost by restricting the fuel return line. Can work, but not the best way of getting more fuel. you can find more details by doing a search in the fuel section.
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hey, I think your last post came up while I was replying to the previous one. If valve seals seem to be in place, you should definitely check compression. I agree if the problem is getting better maybe it is the rings, did you use any cleaners or solvent in the cylinders when the head was off? I wonder if something like that could cause the rings to collapse ( I heard that it can, but I don't know for sure if it's true). Also try not to push the engine rpm or boost until every thing is fully ironed out, you change the oil and re-torque the head. it's also not bad to give the head rebuit a little break in time, specially if each lifter is not in the same location as prior to the head rebuilt, since the wear pattern on the cam lobes and lifters can be slightly off from one location to another.
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Sorry to hear that you are having so many problems in a row. I'll try to think about the TPS problem later. Meanwhile did you check the compression in all cylinders. My guess is it is OK, but it would be nice to confirm. sometimes rings can collapse, but I can't see how all six would. The only thing I can think of for now is the valve stem seals as already mentioned by Doug. You need to make sure that they clip fully in place or they do pop up and leak. Let us know after you check.
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Well I certainly know where you are coming from. i used to have a couple a Z's about ten years ago than felt the need to get another one as a hobby I could seriously enjoy. Off course now I have a wife, two wonderful little kids, busier at work.... So I kept debating about getting a newer fun car (practical and still fun) or another Z (less practical, much more fun and true to my heart).
Well here I am with another one. Am I glad now that I'm back into it, absolutely. However with the wisdom of age, more money and mostly much less free time I decided to spent less time saving money buy not buying cheaper parts, used parts..., and just buy (within reason off course) what I want for the car. So my advice if you are to keep the car is to spend a little more money and a little less time on it. I would also consider having some of the less fun jobs such as replacing suspension bushings done by a mechanic. You should even have the mechanic swap the motor/tranny and you do the harness yourself... And while it feels better to do all of it yourself, it does not seem to be the better choice considering your family needs. A compromise is needed, this will save a whole lot of time, and will still cost a lot less than getting the new mustang, specially if you consider the depreciation on the new car. This way you keep your personal toy/hobby and don't neglect the more valuable family. So scale back on the time as you suggested, but I would scale up on the $$$$ as opposed to scale back, otherwise it will never get done and continue to drag on and cause further distress. So spend all the money upfront as you would when getting a new car, it will be done much faster and make everyone happier. That's my two cents.
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You bring up a very good point about the degree of hygroscopic affinity in race vs non race fluids. However, while motul 600 is clearly a racing brake fluid, it is also designed to be a street fluid. Indeed it is commonly used as such and is recommended by many aftermarket brake upgrade manufacturers for "daily use", these would include comptech and m2 performance which had it's WRX cars features in car and driver and turbo magazine. I also believe that stillen was/is using it for many of the high performance street and track kits. Furthermore its wet boiling point still exceeds the dry boiling points of many other fluids. Finally Dave Wolman one of the VP's of motul also recommeds it for certain street cars (well maintained/enthousiates cars that get reasonably frequent brake fluid flushes)
However, your point is well taken and I should consider this aspect in addition to just dry and wet boiling point in the final recommendation, so here is an addendum after doing some more research for daily vs track applications (which I should have done from the beginning).
New and improved personal recs:
Castrol SRF. amazing fluid, very low hygroscopic affinity (does not absorb much water) and the highest boiling points, and the most expensive by far (actually it is a silicon ester not a glycol based fluid, but it is not the same as the dot 5 plain silicon which can't be contaminated with glycol based fluid)
Castrol LMA. (LMA=low moisture affinity) cheap, available at most stores, not race fluid but very good as low maintenance and high performing fluid and is actually suitable for most aggressive street applications and can still handle a track or two (wet/dry boiling 325/490)
Motul 600. one of the best race fluid, can be used for daily street/track cars. Does absorb more water (more, but not extremely hygroscopic).Great choice if car goes to track often, if you don't leave fluid in over 8-12 months and if live in a dryer climate.
Ate type 200 also known as super blue and super gold. Outstanding fluid good for race and street, can last for two years (not racing off course). This fluid is possibly the best for aggressive street as well as track use type of car/driver.
One last point, while technically the different non dot 5 fluids are all compatible, it is not advisable to mix them since people have reported poor performance, spongy pedal feels and so on when doing so. It is best to flush the system when upgrading to a better and new fluid.
I just summarized my research from various brake related web sites. It would be nice now to get some personal preference from those with extensive track experience on the different fluids (since I'm clearly not one of them, at least not yet
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Well here is one very long answer/summary:
DOT 3,4 and 5.1 fluid are all glycol based and generally compatible. However one may offset the benefit of the better fluid if mixing it with lower grade, so it’s always better to flush the whole system with the newer fluid. Also some are more different than others despite the same DOT rating, ie synthetic, different viscosities and different amount of hygroscopic (water absorbing) properties causing them to absorb brake system moisture, and over time the boiling point is gradually reduced.
The Dry Boiling Point is the temperature at which a brake fluid will boil when new in its non-contaminated state and the wet boiling Point is the temperature a brake fluid will boil after it has been fully saturated with moisture. The requirement for wet boiling point minimum for DOT 3 is 284F, 356F for DOT 5.1 and 311F for DOT 4. These numbers are the minimum and many of the better brands far exceed the minimum requirement (e.g. castrol SRF has wet boiling of 518F, dry boiling of 590F).
Difference between Dot 4 and 5.1:
DOT 5.1, albeit confusing in designation, is effectively a lighter viscosity synthetic poly glycol fluid with DOT 4 performance parameters. It was developed for use in mechanical ABS systems that require a higher cyclic rate. It is not a “higher “performing fluid.
DOT 5 is a silicone based synthetic fluid originally designed for use in military and government vehicles where regular maintenance could be problematic. It is non corrosive and is marketed as a “lifetime†fluid often used to preserve brake systems in antique vehicles and those that sit for long periods of time between use. It was never intended for high performance application. DOT 5 fluid is not hygroscopic, so it does not absorb water and may be useful where water absorption is a problem as one of the reason for its development (military equipment and tropical environment..). However and perhaps ironically this brings up another serious concern as moisture enters the system (can not be prevented), it is not absorbed by the fluid, and can result in moisture collecting in the calipers which can very easily boil causing vapor lock and system failure or can cause corrosion where the water collect (it has to collect somewhere since it is not absorbed). DOT 5 fluid is now most used/best suited for show car applications where its anti-corrosion and paint friendly characteristics (does nor ruin paint) are important. DOT 5 is not compatible and can not be mixed with other fluids since it can result in slugging.
I think previously some race teams used to use DOT 5 it because of it’s higher boiling point, however the new poly-glycol synthetic fluid have the same or even better boiling point along with better pedal feel (dot 5 is more compressible and has spongier pedal feel) so DOT 5 has fallen out of favor.
Personal recommendations:
DOT 3 is outdated and not suited for aggressively driven cars, dot 5 is problematic and should be avoided. dot 5.1 is good and best suited for ABS systems which leave us with dot 4.
I think that motul 600 is probably the best for most of us since its performance is second best (based on wet/dry boiling point of 421/585F) along with Neo (identical) but is also very well priced. Castrol SRF is the highest performing (wet/dry 518/590F) that I could find but it is also about 3 times more expensive.
Finally the best high quality and cheap fluid seems to be the Ate type 200 fluid (wet/dry of 392/536F) which is very cheap has a wet boiling point of 100F greater than for Ford HD or AP 550 fluids (AP 5.1 matches the Ate but is much more expensive). I hope this helps
(this info was pooled from various brake related web sites and from a nice summary by Jeff Lucius)
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In terms of 6 cylinder engines some of the more commonly talked about are from the 280ZXT(l28et),the 84-89 300ZX V6, supra machIII (7mgte), supra mach IV (2jz-gte)and skyline cars(rb26) (there are obviously more). The last two choices provide absolutely amazing engines, and off course are anything but cheap. I personally find the 300zx engine unimpressive for the amount of work required to do the swap and I have always been biased towards staight six configurations (the newer nissan V6's are much nicer). The 7mgte engine from the supra is a great and cheap straight six turbo engine which can easilly put out 300 hp (with stock motor, computer, injectors..) in a very reliable smooth manner, it revs nicely and breaths well (as long as you don't use the factory intercooler for higher boost). The only problem is that the swap is not a very easy one, so it takes time, skill and patience, but not that much money (relatively speaking). This brings us to the 280zxt/l28et swap which is by far the easiest swap since it bolts right in. Adapting the harness from the 280zxt into the 240 is also relatively easy and many of us have experience with it. If you add an intercooler you will be able to get into the 250-300hp range easilly(you get get much more, but it will require some more money since it would have to be reasonably modified from stock injection system..). the engine is not as smooth and does not have as broad a power band as the supra one (and the supra engine is more powerful for the same amount of mods as the ZXT), but it will be much much easier to do and should be able to put a grin on your face every time the boost goes up and up and up
So, I cast my biased vote along with sleeperZ and Eric-Z for the l28et as the best cheap and reliable way to achieve the250-300hp range with a 6cylinder engine.
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Nice numbers, time to plan for a LSD if you don't already have one
What did you exactly do since the last dyno that resulted in the approximately 30hp and 40ft/lb torque gain? More boost, cooler weather, different timing...? Also how do you like the Z31 ECU set up?
Thanks
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I'm planning to go with option 1 for my own set up. I already have the hardest part set up, which is a good muffler shop that charges reasonable/cheap rates (hard to find these days). I figure I will get the piping from JC witney or alex costa at precision machines (he is a hybridZ member). I see no reason to have the shop do crush bending only to decrease efficiency and cause more turbulence.
With my non existent welding skills I figure it would take me longer, cost as much or more (getting/renting welder, redoing the work over after ruining the mandrel bent pipe I just bought or only to find a leak in my crummy weld later....)and certainly won't come out as nice as the work from my skilled mufller shop guy.
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Yahooo! Triple congratulations after all that work
This yellow is in the same plug as the CAS and TPS wires. I have no idea why it only needs crank only 12v, but it does and when i re-wired it correctly...LED started flashing - adjusting injectors and timing advance started workingAs I mentioned in my previous post the ECU operates in open loop mode during start/crank (and cold engine, high load and RPM>3600)and hence bypasses the O2 sensor at that time. Since you were providing a crank signal at all times, you could not get into closed loop mode. My guess is that timing is also fixed during crank time.
Well you certainly made all of us think hard. I hope you have a blast during the holiday weekend, and watch out for the oh so so many cops in NJ (I used to leave there for many years)
Enjoy the drive
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Oddly enough, the 240Z was tested in wind tunnels, at least from what I can tell. I have a coffee-table book on Z history, with several pictures of wind tunnel tests
I just rechecked my Z books, in Brian Longs book on the ZX there is only mention of the ZX being tested in the wind tunnel and in Millspaugh's book Z car a legend in it's own time he specifically says the the 280ZX was the first Z to be tested in a wind tunnel. I know the Z has been in wind tunnels, that's how we know how poor the CD is. So I think it was tested after it was produced and the info might have been used for racing modifications as opposed to during the development of the production car.
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i just cant understand why with either ECM plugged into my Z, they dont adjust for the O2 value
During start up, cold engine when O2 sensor not heated, during heavy load and when rpm is over 3600 the ECCS is in open loop mode and bypasses the O2 sensor input for fuel mixture. During this phase there is no oscillation of voltage. However, if the car is running rich for over 6.4 sec or lean over 10 sec the O2 sensor input will override the open loop and adjust mixture best it can (e.g. running lean under load)
The voltage fluctuating between .3-.6 is because of the back and forth response in fuel mixture made by the ECU in response to the O2 sensor input, which happens during closed loop operation. My understanding is that in closed loop mode, the O2 sensor overrides most other info in determining fuel delivery (injector pulse..).
The reason your voltage and led are not fluctuating is that the ECU is not able to get into closed loop mode. Faulty O2 sensor or circuit can cause this, but it should not cause the timing problem (by faulty I mean broken wire, not short, who knows what that can do).
Timing, closed vs. open loop mode determination and fuel mixture all depend on input from engine temp (head temperature sensor) and engine load (determined mostly by AFM flap opening and RPM and vacuum). So perhaps you can check for shorts in these shared circuits while looking for an ECCS analyzer or other ZXT harness.
You already checked all the actual components. Next I would check the head temp circuit for short, then the AFM circuit, then O2 sensor circuit and finally the dizzy circuit(since it provides RPM measurement to the ECU) .
Best of luck
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Wow! I can't believe how difficult this problem has been to solve. At this point you have checked every sensor at the sensor and at the ECU, you have swapped all the major EFI and ignition components and also checked for broken wire to ECU, ruled out vacuun leaks, checked fuel delivery and all is still negative.
Considering this and that both your timing advance and fuel mixture are off my best guess is a short which is throwing off the ECU which would acount for both fuel and ignition problems.
Since you already swapped ECU's, dizzy and AFM, it seems most likely that the short is in the harness itself. Checking resistance in each wire end to end obviously won't let you know about any shorts.
You could check resistance between each wire/pin at the ECU end and the body for a ground short, since they are the most common type (on non ground pins off course).
If all is OK you could then check for resistance from pin to pin, but that is a pain in the ass specially since some of them (i.e. comming from the same sensor) should have some continuity.
At this point I would check for a ground short first, if negative I would call every nissan dealership in NJ and find one that has the factory ECCS analyzer which can check for proper input to the ECU as well as proper output from the ECU. Of course you could also try to locate another zxt harness, it would be relatively easy to install.
I just can't think of anything else since you have been so thorough in checking all individual systems components. The only thing left is a short
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I'm so sorry and absolutely embarrassed, that was a big slip (I was picturing a different non ZX rear suspension set up in my easily confused mind), the ZX rear strut assembly clearly does not affect camber since it has a pivot point at the bottom...
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Hi Jon, the car does use a strut, so moving the "top" via a camber plate would change the camber as would moving the trailing arm. The camber is set based on the relative angle between the strut top and the trailing arm.
The MSA camber kits works by sloting the bushing middle hole and as such allows one to change the pivot points on the bushing end. the saw hole kit is to slot the bushings, the washers will hold it in place. This will give some adjustability for both camber and toe. This should work, however i don't know how durable it is or how good of a job it does at maintining any new angle that you may set.
The MSA guys claim that it works very well, so far my experience with them has been very good. I will hopefully purchase and install the kit later this year. Please post an update to provide some feedback on the kit if you end up using it.
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Hi Jersey, have you had the chance to do any more diagnostic work on the car? I'm really curious as to your progress and finding what is causing all of your problems. Also did you say that after resetting the timing it always goes back to 20 after you run the car ?
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I guess I will go have my coffee now (before I sound like even a bigger jerk, if possible).
8)
Bay Area Z meet 9-19-03 Union City
in Non Tech Board
Posted
Hi Len, all is well on my end. I just ordered JSK's brake kit, can wait to get it. Did you just move into a new house ?
Also see if you can bring Fru this Friday.
Hey Alex are you out there ? any progress on the rotary swap?