Been having a bit of trouble getting my Z up and running. The engine that we put in is blowing smoke from the dipstick, so I've worked out that somehow there is too much air pressure building up in the sump Today I had a compression test done on the engine to check things out and the results were fairly dismal. Here they are anyways.. (Looking at the front of the engine 1 is on the left toward the front, two is at the front on the right) 1 - 5 psi? 2 - 50 psi 3 - 150 psi 4 - 70 psi 5 - 155 psi 6 - 140 psi So firstly I'm confused by the cylinder that's got 5 psi. That's horrible.. Could it be that maybe an intake or exhaust valve is stuck open or broken? Or not sealing properly for some reason? I've inspected inside the cylinder with a boroscope that came up as 5 psi, there's wet oil on the piston and spark plug, though the piston itself hasn't got any holes in it, but even still... if there were blow-by it still should be showing more than 5 psi.. You would assume so anyway.. Anyway, my question is, do you think it's possible to save this engine by looking over the valves, and fixing them up? Or is the compression so much up s-creek that I should just get a used engine from UAS that I've been eyeing off?
What you describe is indicative of broken Piston-rings or a holed Piston(or both) and suggests that your current engine is "toast". Buying another engine is also somewhat risky(unless you have a "cast iron" guarantee that it is 100% serviceable). It may be advisable to do a complete re-build of your current engine, as you will have a complete idea as to what has been done to it (and less chance of getting unpleasant surprises later on). Buying a second-hand engine is NEVER a guarantee of everything being in acceptable condition(and can frequently lead to considerable unforeseen expense). Hope everything works-out OK for you....:zlove::br:
Lloyd's on the money. You could leakdown test to further pin point the cause of your low compression but it's academic at this point. Your engine, most likely bottom end, is ****ed. Given the damage that has likely occured you're in for a re-bore. If you buy a second hand engine make sure it is leakdown tested before you purchase, otherwise you may be buying into more problems. Ask for specific results per cylinder.
Thanks guys, pretty much confirmed what I'd suspected.. it's toast. My next question is, does anyone know of a reputable engine builder in VIC that would be able to do a rebuild if I look to go this direction? I've noticed you're all from NSW, though you might know of someone through the forum that could help out. And what would something like this end up costing? The two second hand engines I'm looking at are both for sale by Unique Auto Sports, one of them (the more expensive of the two) is supposed to have 55,000k's on it and it's been compression tested, and the other one they couldn't tell me how many K's it had for some reason.. though they said it had also checked out fine on a compression test.. But I'm always a bit skeptical about buying a used engine, cause you never know what else could be hiding in it. I've got two busted blocks now just sitting around in my shed hah.. This one that I put in, the one that blew smoke from the dipstick has pretty much had everything except the insides of the engine itself replaced. New turbos, exhaust manifolds, all new sensors, new fuel rails, injectors, timing belt, PTU, brand new EFI harness, etc etc.. I spent a lot on it.. but was too young and naive at the time to have doubted the engine itself not being solid before I did all the work So I'm absolutely kicking myself at the moment, I've owned it 7 years and never driven it!
You should investigate the condition of any suspect valves(bent or broken) and/or the probability of broken Piston Rings(both of these conditions could result in what you are experiencing). What(if any)warrantee/guarantee are UAS offering on these S/H engines??:br:
Do the turbo's etc come on the TT engine UAS are selling? $2,900.00 would be what a GOOD complete TT engine would be worth these days. You'll obviously have to add freight on that to get it to Victoria. Questions to ask would be: What did it come out of, a manual or an auto? What year model? What was the VIN? How can the 55,000km be verified, has the engine been rebuilt? What is the engine number? What were the compression figures when tested? How much warranty is included on the engine? What does the warranty cover? If there aren't any compression figures available, or no written warranty, look elsewhere.
If you're buying an engine from a shop you're in a much better position if it's knackered. They have an obligation to refund, though you obviously don't want to deal with that. 2.9k is a hilarious price. I am friendly with someone here in Syd who had a healthy engine that just had a full 100k kit put through it for sale for 1k for a year before it went, and it still didn't pull 4 figures. Get a better deal.
No $2500-3000 is pretty fair if it is from a business and comes with a warranty. Id expect to pay $1750-2000 for a really good proven motor with figures and a personal guarantee, good motors are bloody thin on the ground. Best bet is rebuild youra locally or look at nizpro wreckers add on gumtree, $2999 for a rebuilt motor on exchange, probably work out around the same
Something to keep in mind. If you get a warranty on an interstate engine, how would you make a claim? Imagine you get the engine shipped, have it installed & the engine has, or develops a problem within the warranty period. What happens next? Obviously you wouldn't be able to drive the vehicle interstate. Do you have to remove the engine & freight it back? Probably. When it arrives at the place of purchase, you are contacted thereafter to be told it wasn't installed correctly, or such & such was the cause & it's outside of warranty, do you want us to fix it? See where this is going? tuff's suggestion has merit.
So the engine they had with 55000k's on it was sold already. The engine I'm looking at now they couldn't tell me how many K's it had on it, though they did run a cold compression test and told me the numbers were between 130 and 160, that it ran quietly and blew no smoke. I've followed East Coast Z's advice and asked a heap more questions. Hoping to get answers tomorrow. What do you guys make of those compression results? Do they seem in the ballpark?
29 max I'm pretty sure Nissan specs are maximum of 29psi difference between cylinders but that is on a hot test. Should be a bit better if the engine is warm but of course that is just another unknown, like the km. I would tread with caution. Could always tear both your engines down and see whats happening inside. Might be able to do just rings and bearing if your lucky.
The compression figures on a TT are as follows: Standard 171psi - This is the pressure you would see on a new engine. The minimum pressure is 128psi. The maximum difference between cylinders is 14psi. The figures on the engine you are considering purchasing has pressures ranging from 160psi to 130psi. You could argue the point these figures are within specification as they fall between 171 to 128psi, & you'd be correct on that point. However, the difference in pressure between the highest & lowest cylinders is 30psi. The specifications indicate the maximum difference should be no more than 14psi. This engine is suitable as a potential rebuild, it is not suited as a viable engine replacement. Don't you currently have two engines that require rebuilding? Why would you want a third? It's your call........
It all comes down to price and ability. If you have the time and ability to strip an engine and refresh all the gaskets, bearings, seals and rings, rebuilding one of your existing engines is probably the best option. You could probably do it for a bit over a grand. Any used engine will be questionable, especially if you can't hear it running and do a warm compression test. A cold compression test is not going to be very reliable. A leak down test cold would be much better, a leak down test period would be recommended as well as the warm compression test. But again comes down to price. If the used engine with 130-160 compression cold is only $500, probably worth the gamble. Again pending ability, if you can do the engine swap yourself. If $2-3K, pay someone to rebuild your own engine. Or look for a running half cut ex Japan.
Most second hand engines are going to show some degree of wear. I think you need to decide if your budget allows for a rebuild, or if not how much wear is acceptable on a second hand motor. A stock rebuild is not hugely expensive but still into the thousands when you start to consider machining, head service, gasket kit, timing kit, assembly etc. In your case I'm almost certain (given the symptoms) that you'll need to overbore, so add aftermarket Pistons and balancing to your cost sheet...
