TheNeedForZ Posted November 7, 2005 Share Posted November 7, 2005 Hi, I finally received my L28ET engine in a crate. Here are some questions : 1) The seller said it is an 81ZXT, but when I checked the distributor, the dizzy has a cable leading to a round plug(4 connectors inside). There is also a shiny disk(CAS disk?) inside the dizzy. Result of searching says the dizzy is a later/better dizzy with CAS inside the distributor. One of the FAQ thread mentioned that 81ZXT harness has "dropping resistor plugs" but no picture of the plugs is shown. How do I tell whether my ENGINE is 81 or later, and is there any disadvantages compared to 82~83 engines. I ask this because the seller may have upgraded to a 82~83 dizzy and this engine is indeed an 81. 2) The seller gave me 2 turbos, with one attached to the complete engine and one spare. On the spare turbo, there is no longitudal play (shaft doesn't move in or out) but there is some sideway play, about 0.5mm~0.75mm (0.020"~0.030"). The compressor fins look perfect and there is no damage in the compressor housing. What is the acceptable specs for stock turbo shaft play? If I need a rebuild kit, where is the place to get one(I live on the west side of the continent). Thanks in advance. Quote Link to comment Share on other sites More sharing options...
Metro Posted November 8, 2005 Share Posted November 8, 2005 I don't believe there are any differences between the '81-83 engines, other than the '83 might have the P90a head with hydraulic lifters. From the s130 to s30 guide.. a picture of the dropping resistor plug: You should also have a big metal box plugged into that if it is infact a 81 harness. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted November 8, 2005 Share Posted November 8, 2005 the motors are the same accept the aforementioned different head, many '83's (not sure if it was all or not) had the hydraulic lifters. Better if you like a quiet runnign motor and never adjusting the valve lash, worse if you like to rev high. But yeah, from your description of the distributor, that motor came out of an '82-83 Quote Link to comment Share on other sites More sharing options...
GrayZee Posted November 8, 2005 Share Posted November 8, 2005 the motors are the same accept the aforementioned different head' date=' many '83's (not sure if it was all or not) had the hydraulic lifters. Better if you like a quiet runnign motor and never adjusting the valve lash, worse if you like to rev high.[/quote'] I have a P90a head and I can rev up to 6K, what about you? Perhaps you are talking about building up the engine to allow 7 or 8k? Not sure if that would be of much advantage on a turbo L28 though. Quote Link to comment Share on other sites More sharing options...
Thumper Posted November 8, 2005 Share Posted November 8, 2005 Also some 82' models came with a p90a head. He could have just thrown the first available distributor on the engine though. I would guess you could look down at the crank pulley and see if their is CAS down there. If so then 81. About the turbo some shaft play is acceptable. No too much though. You can go ahead and run it and have the other turbo rebuilt/modified. Good luck Quote Link to comment Share on other sites More sharing options...
Thumper Posted November 8, 2005 Share Posted November 8, 2005 I have a P90a head and I can rev up to 6K, what about you? Perhaps you are talking about building up the engine to allow 7 or 8k? Not sure if that would be of much advantage on a turbo L28 though. Yes up to 6k the hydraulic lifters are fine. I have even heard they can handle 6500 but most say that is the limit. But that is if they are in perfect condition. Alot of the not so good condition hydraulic lifters will bleed down at high rpms. Most noticed around 6000-6300rpms My old 280zx had this problem and on the dyno the hp dropped significantly. Quote Link to comment Share on other sites More sharing options...
GrayZee Posted November 8, 2005 Share Posted November 8, 2005 Yes up to 6k the hydraulic lifters are fine. I have even heard they can handle 6500 but most say that is the limit. But that is if they are in perfect condition. Alot of the not so good condition hydraulic lifters will bleed down at high rpms. Most noticed around 6000-6300rpms My old 280zx had this problem and on the dyno the hp dropped significantly. Interesting.. so you are saying that the regular P90 allows higher revs? How much higher? I can't see it being much.. The L28et seems to get its power from torque at lower rpms. Quote Link to comment Share on other sites More sharing options...
Thumper Posted November 8, 2005 Share Posted November 8, 2005 Yeah with non-cross flow head, 2 valves per cylinder, and t3 turbo the l28et makes no power past 6k. Actually not much power over 5500 either. With a cam and better turbo then yeah it would make more power up top. From what I read p90 head with solid lifters with a stiffer valve springs can go up to 7k maybe more not to sure. But this was always in relationship to an n/a motor. But my opinion for hp below 350hp and less than 6300rpms the hydraulic lifters are fine. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted November 9, 2005 Author Share Posted November 9, 2005 Thanks for the responses. The head says P90 and block number is L28 700459, I didn't find any sensors near the crank pulley. But then again all electronics were taken off the engine. HERE'S THE BAD BAD NEWS The turbo on the engine is totally dead, the fins are completely ground FLAT to the base. The compressor housing is scratched big time. This is probably not rebuildable. The main concern is the engine internals. Is the engine damaged? I checked several cylinders from the spark plug holes by shining a bright beam into it while making the piston near TDC. I can only see black oily surface on the pistons, so I cannot tell whether they are damaged. The backside of valves look ok, so are the bore walls : the criss-cross honing marks are still visible. Once the pistons moves down, the bore walls are really clean and shiny without oil streaks, maybe the rings are not damaged. The oil is already drained prior to shipping, but I suspect there's still some oil left. Perhaps I can coax some oil out to check for metal bits once it is on engine stand. The damaged turbo rotates freely and has little shaft play just like the spare one. Perhaps one catastrophic failure due to foreign object hitting the wheels? Is there any other way I can check for engine damage? Quote Link to comment Share on other sites More sharing options...
GrayZee Posted November 9, 2005 Share Posted November 9, 2005 Buy a engine gasket kit for a L28et and take it apart. With the head and oil pan off you will be able to see alot more. If for nothing else, having the head/manifolds/oil pan off will give you the chance to clean it all up nicely. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted November 10, 2005 Share Posted November 10, 2005 Never said that a non hydraulic head would be better or preferred. I dont know what his intentions are for the motor, maybe he's making a full blown race motor with huge turbo that will ONLY make power in higher rpm? I just stated what I know to be facts, the hydraulic head is better for quiet operation and not needing adjustment, and worse if you want to build a high revving motor. As far as what it takes to make a whole L28 engine make power at higher revs... um, not that much as far as I know? A big cam, some good head work, very free flowing intake and exhaust. As far as the turbo... we all know bigger turbos move the power band up the rpm range... a monster turbo would have no problem making power above 6000rpm. Again, I dont know what HIS intentions are for the motor, just stated what I understand to be the pertinent info. No need to get argumentative or defensive about it. If it were me I would actually prefer the hydraulic head. I'm only on the stock turbo so yeah I have no need to rev past 6000rpm anyways, and would love the quiet valve train and adjusting valves is a pain in the butt that I'd be happy to never do again. Quote Link to comment Share on other sites More sharing options...
frank280zx Posted November 10, 2005 Share Posted November 10, 2005 I am aiming for 400HP, and i think it will be sience fiction, so i would have to see at least 300 ( reality kicks in there ), and i think it is doable with my set up, and this all will be on a P90A.. ( BEWARE not all p90a's are Hydrolic!!!) Id say the l28 has enough potentential to pull under 6K and even to make the 300 benchmark hopefully more. WHo here made in excess of that with a p90a ??? My set up is a 440 or 480 cc injectors t3/4 will be set at max 20PSI for the stock HG 3"exhaust custom manifold IC, MsS , stock internals for now ( if the HG goes ill go o ring orso) however back on track , the discription you give sounds like a turbo that could have been run WO an aircleaner, but a worn turbo does not mean the engine is bad aswel. shutting the engine when how will ruin a turbo, not an engine. There are so many things that will ruin a turbo fast ... But yeah buy a gasket set, and rings and main bearings, replace them all so you'll know it is good... This will give peace of mind, and a solid base Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted November 10, 2005 Share Posted November 10, 2005 sure you can make huge power w/o revving past 6000rpm. Lots of guys do it with big turbos (T3/04 typically) on stock head/cam. Which means yes you CAN make big power on a hydraulic lifter head. I never said you couldn't do that either. For most applications and guys on this board, the hydraulic head will work just fine, actually better considering you dont have to adjust the lash. I often wish I had the hydraulic lifter head. Quote Link to comment Share on other sites More sharing options...
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