Ok so basically i did a full rebuild a bit over a year ago due to piston number 6 having its side blown out! I now have lost compression on cylinder 6 yet again The reasons for it this time (i believe) are 1, i had an electrical short in the wiring loom which caused injector on cylinder 6 to stay open, which hydrolocked the piston. I believe this caused the major damage. 2... I also had a solenoid as part of my blitz ebc fail which caused it to over boost, hitting 20psi. Either way cylinder number 6 is down to about 100psi with all the others up about 160 psi. So, time to rebuild again and do it properly to prevent another repeat! parts replaced/upgraded last rebuild included... ACL 20 thou OS Race forged pistons, rods and bearings ARP head bolts etc cometic head gaskets new oil pump, water pump complete new gasket kit KOYO 60mm radiator Also had the heads and block professionally machined etc and bottom end balance. So this time i have 3 weeks to hopefully complete a second build. To start with i wanted to run my parts list past people. I'm trying to keep costs to a minimum considering the circumstances but i want to do it right. so this is what im about to order from COZ, because as far as im aware, thats where i'll get the best prices. I already have a set of Nismo yellow top injectors. list: Silicon brake booster hose $16.99 Silicon heater core hoses $25 CZP ECU upgrade (chipped pre tuned) $169 This ecu option seems to be the most cost effective at this stage. and i'm hoping to find someone to give it a custom tune once back on the road. Any other suggestions on this? Aeromotive 340LPH in tank fuel pump $160 reason for fuel pump is that i had the car dyno'd 3 months ago and it was running very lean over 4000rpm. CZP early to late style injector adapter kit $120 Tomioka fuel pressure regulator with gauge $125 NGK iridium spark plagues heat range #7 $50 JWT aluminium NA fly wheel $ 375: will i need a new bottom end balance with this new fly? Nissan OEM wiring harness $419 So far US$1460 I will also need to source ACL race forged piston rings from somewhere, not sure where, any ideas? At this stage im keeping the standard turbos but im considering a FM intercooler. Currently running a turbosmart bleed type boost controller since my ebc died. So... any comments??
Before getting too ahead of urself and planning a rather expensive rebuild, You may find that there is nothing wrong with the bottom end at all and more than likely a burnt valve suddenly dropping cranking pressure off. First thing would be do some leakdown tests to determine exactly where the loss of compression is happening. Just do the old compression stroke and attach a compressed air line to a plug hole adapter (gut out an old plug and weld on some pipe and an airline fitting) and have a listen around with a length of tube as a stethescope. It will become apparent very quickly where the air leak is. If its down into the crankcase then its grenaded and youll have to suck it up but It might just be a burnt/sticking valve You might find its nothing more than a quick head reco and your on your way for another 200,000 clicks of fun. Finding out you stripped and built the engine just because of a dodgey valve will really annoy!!!!!! Flywheel and engine balance? No not necessary. However, "IF" you have to strip it then have a balance done anyway with ur new fly AND clutch. Cheers E
why would you balance the clutch? wouldn't the mass of the clutch be reducing over time due to the loss of friction material
cheers tassuperkart, good idea! ill do this. not sure how obvious i'll find where the leak is, but ill give it a crack and see. as for the balance, i think ive decided to stick with the stock fly wheel so i probably wont need to do another balance at all.
While you have the engine stripped down, have the injectors checked, buy new o-rings and ensure they are fitted back into the rail using some vasoline, change your ecu just in case its fried a circuit and the causing the injector to stay open... The last scenario is highly unlikely but for the sake of $100 for another ecu, worth changing just to be sure.
Yep mate already sorted, but thanks i have a new set of nismo 550cc injectors to go in as well as a 340lph fuel pump and im getting a nistune board from you! haha. i had the car dyno'd a while ago and it was running lean too so i'll have to check the fuel pump erg out too i guess. new fuel pump is just to play it safe.
Finally got the engine stripped, and have pics of the damage! So i've finally had the chance to strip the engine back while ive had some holidays with the family over chrissy. Decided it was time to dig this old post up. So yes i have another damaged cylinder #6 Just to recap... likely causes were a faulty injector that stayed open, flooded the cylinder and caused it to hydro-lock. other reason was a faulty electronic boost controller allowing boost to reach 22psi on my standard turbos Ok so here are the pics of the damage... Bent rod, and gudgen pin pushed out side of piston as the cir-clip broke. Shows the broken and shitty quality cir-clip, and the broken oil squirter from the piston hitting it Shows the 2 grooves left in the bore by the gudgen pin that popped out the side of the piston. So yes some pretty significant damage here! Now what to do... i rang a local engineering shop this morning and they said that they could either re-bore or re-sleeve the cylinder depending on how bad the damage was. BUT, the said that either way i would need a complete new set of pistons to go in is this true?? i thought there must be a way around that, considering that these pistons are ACL race forged and cost me about a grand less than 2 years ago! i know i'll need new piston rings of course and maybe even a replacement for that one piston, but a whole new set! Not keen on that, especially because i might like to go with forged rods now too. Any ideas, suggestions??
youll find it hard to just buy one piston ay. Your best bet is to start again with new pistons and rods and try sell your old pistons to the sr20 guys. You might even be better of finding another block to it will save you having to get yours re sleved. Then look for what's caused the problem, I doubt hi boost would of caused it. Was it making any noise before it let go.
yeah, the thing is that there is no damage to the pistons at all, they are all fine. the only reason to go to new pistons would be because of the over sized re-bore on the cylinders. but i would have thought that if they were going to re-sleeve that one bore, that they could bring the bore size back to match tohe old size and thus i could still use the same pistons with new rings. thats my thought pattern anyway. i dont think the boost was the cause of it either mate, i think it was the hydro-locking that caused it. That and i really don't like the type of cir-clips that ACL supplied with these pistons and i think that there is a posibility that the cir-clip let go early on and started the chain of problems. Oh yeah and there was some noise but it was hard to tell if it was just noisy lifters or not. So the sound wasn't anything outstanding. the car was still running when i decided there was something wrong, so it never completely 'let go' Thanks for your input buddy
Unlikely a "walking" pison pin would be the beginnings of that issue rather than the result of the circlip breaking. Those type of circlips are the ducks guts and virtually refuse to rattle out unlike a plain "e" type of circlip which can flex at the eye (you grab with pliers) and at extreme rpm, can simple unclip from its groove. There will sitll be plenty of piston pin left in the other pin bore to support the piston and rod. Had the pin walked far enough to slip right out of the opposite side pin bore, id say that entire assembly would be cactus and go bang after a very short time. Severe detonation due to overboost is un likely to result in a bent rod like that. Im going with the flooded cylinder theory. Id say that rod is bent in both planes resulting in a lot of sideways movement of the rod during its cycle and repeatedly impacting on the clip has eventually broken the clip allowing the pin to walk out. Those scores from the pin/remains of the clip indicate to me that pin has been in contact with the cylinder for quite some time. Another thing to check for would be strange wear patterns on the corresponding crankpin. Unlikely, but worth checking. The bearings might show some peculiar wear marks indicating sideways or twisting loading on the big end pin. Realistically, your best bet with that engine is to simply junk that block. There are enough used blocks around to justify junking yours given the cost of having that single cylinder bored, sleeved and then bored and honed to size. Im not a big fan of reconning blocks with a single sleeve. id accept do all of them in the case of something really rare or old but VG's in pieces are pretty common now. Re-using that piston will be dependant on a number of things and will require a very thorough inspection and crack checking around the pin bosses and pin bores. Id say its unlikely theres much damage to the actual bores but...............errrmmmm. Your call. The easiest way out is to just grab another block and a rod, hot tank, deck, and bore/hone it to suit those lightly used pistons which is perfectly acceptable practise. 50 bucks a hole, 70-80 (whatever) bucks to deck, hot tank and a handful of new brass welch plugs. 500 bucks. Add rings, bearings and a full gasket set and your set. Bolt it up and hold your breath for a while when you rev the tripe out of it in case one of those pin bosses on the offending piston was actually cracked and the dye penetrant missed it....... For me, at the very least, Id be seeing if i could source another new single piston, check the chamber cc's and match up (if needed) and throw this combo at another prepared block. Basically a new short engine but at least grand cheaper than last time! I feel your pain M8 as I grenaded one of my fast Pulsar turbo ET engines recently and fried a single piston. The rest of the engine is pristine but trying to find a single +020" ACL Duralite piston was more or less an exercise in futility given ACL has not actually made pistons in some years. In the end, I sprang for a new set of high silicon CAST HypaTec pistons/Hastings chrome rings and I had another old block decked and bored/honed as outlined above. Sadly, in your case, as was in mine, you cant really get away with this on the cheap. Good luck E
LOL at M8's engine failure 'analysis'. A con rod can bend in any plane simply from hydraulicing and without any other contributing factors. In so doing it can cause secondary damage or wear which of course is irrelevant as to the primary cause. Engine building is quite simple but requires the appropriate tools and mindset. Do it all according to the book, patience and a methodical approach are crucial.
Yeah not too sure whats funny about it either? Seems 260 hasn't said anything different to tassuperkart anyway. Anyway I'm going to get new pistons and rods again.
The shopping cart So here's the shopping cart i just ordered from CZP for anyone interested... There was also another order from CZP a couple of months ago in which i got a new wiring harness, some oil hoses, fuel pump, fuel pressure reg. and i also have a Nistune chip. SKU: 300-TBK213_263X8 Item Name: Breeze T-Bolt Clamp Set for Boost Hoses - 8pc - 300ZX Cost: $30.00 Tax: 0.00 Quantity: 1 Total Cost: $30.00 SKU: 300-50304-3PACK Item Name: Red Line MT-90 Manual Transmission Fluid (3-Pack) - 300ZX Cost: $32.40 Tax: 0.00 Quantity: 1 Total Cost: $32.40 SKU: 300-15198-S8000-S Item Name: CZP 300ZX Turbo Oil Return Oil Resistant Silicone Hose Cost: $16.00 Tax: 0.00 Quantity: 2 Total Cost: $32.00 SKU: 300-28931-30P00_28932 Item Name: Nissan OEM 300ZX Windshield Washer Nozzle Front Set, 2+2/95+ Coupe Cost: $21.07 Tax: 0.00 Quantity: 1 Total Cost: $21.07 SKU: 300-15208-RN020 Item Name: Nismo Veruspeed 300ZX Oil Filter Cost: $14.95 Tax: 0.00 Quantity: 1 Total Cost: $14.95 SKU: 300-2667 Item Name: NGK 300ZX Iridium Spark Plugs, Heat Range #7 Cost: $49.99 Tax: 0.00 Quantity: 1 Total Cost: $49.99 SKU: 300-4M2737H Item Name: ACL 300ZX Race Series Main Bearing Set .25mm Cost: $80.00 Tax: 0.00 Quantity: 1 Total Cost: $80.00 SKU: 300-6B2390H Item Name: ACL 300ZX Race Series Connecting Rod Bearing Set .25mm Cost: $60.00 Tax: 0.00 Quantity: 1 Total Cost: $60.00 SKU: 300-CZPRBLTKTC Item Name: CZP 300ZX Wiseco, Eagle Engine Rebuild Kit C 87.5mm Cost: $1329.00 Tax: 0.00 Quantity: 1 Total Cost: $1,329.00 SKU: 300-11560-45 Item Name: Nissan OEM 300ZX Oil Jet Squirter - Non-Turbo or Upgraded Pistons Cost: $33.00 Tax: 0.00 Quantity: 3 Total Cost: $99.00 SKU: 300-49725-30P03-S Item Name: CZP 300ZX Silicone Power Steering Return Hose, Tank Side - Fluid Resistant Cost: $8.99 Tax: 0.00 Quantity: 1 Total Cost: $8.99 Subtotal: $1,757.40
