hi, im writing bout my brothers tt, it recently had a oil leak, well spirted oil out around battery / dipstick area but could tell where exactly it had come from, the oil pressure also dropped. the car as not been driven since, before this happened there was some popping from exhaust when coming off revs at bout 4500rpm. the car as had a aftermarket manual boost controller fitted by previous owner but no ecu chip which would most likely cause too much air at high revs and not enough fuel? causing the popping.

 

it was pointed out that the oil is likely to have come from dipstick under pressure quite likely related to faulty pcv valves, also recommended to check was oil leaks on cam seals at rear of cam belt cover which was present. this apparently points to pcv valves.

 

his car as been to a specialist in our part of the world, we would rather it go to one of the better places but time and distance and finances did not allow. They have come back and said that on cylinder 6 there is 100% leakage meaning cracked piston and 45% on another and 5% on the rest. however i also have a 300zx and the car as always seemed very quick to me, and no power loss as been noticed, if a 3rd of the cylinders were not working should we have not noticed major power loss and missiring???

 

also they say it is a 3k rebuild to put new pistons in, surely the sump and crank can be dropped and it done from bellow???

 

are they ripping us off????

hi, im writing bout my brothers tt, it recently had a oil leak, well spirted oil out around battery / dipstick area but could tell where exactly it had come from, the oil pressure also dropped. the car as not been driven since, before this happened there was some popping from exhaust when coming off revs at bout 4500rpm. the car as had a aftermarket manual boost controller fitted by previous owner but no ecu chip which would most likely cause too much air at high revs and not enough fuel? causing the popping.

 

it was pointed out that the oil is likely to have come from dipstick under pressure quite likely related to faulty pcv valves, also recommended to check was oil leaks on cam seals at rear of cam belt cover which was present. this apparently points to pcv valves.

 

his car as been to a specialist in our part of the world, we would rather it go to one of the better places but time and distance and finances did not allow. They have come back and said that on cylinder 6 there is 100% leakage meaning cracked piston and 45% on another and 5% on the rest. however i also have a 300zx and the car as always seemed very quick to me, and no power loss as been noticed, if a 3rd of the cylinders were not working should we have not noticed major power loss and missiring???

 

also they say it is a 3k rebuild to put new pistons in, surely the sump and crank can be dropped and it done from bellow???

 

are they ripping us off????

 

the cars performance would of been down on power if cylinders were badly down on compression get a 2nd opinion and do a dry and wet test,wet test would show up in more detail if the rings or ring lands are damaged

 

you can remove the rods and pistons from below with sump removed,but you wont be able to refit,as a ring compressor is needed to put rods and pistons back in,besides the engine needs to be removed as more damage to the block may be present!

 

could always drop ryan @ztech a call 07968166640

 

all the best greg

cheers, they said they didnt pressure test they did a "leak test" instead, whats the difference? have spoke to ztech regarding price of rebuild, prob best to fit second hand lump though as never know what find when take it apart, but then dont know what you getting with second hand engines.

cheers, they said they didnt pressure test they did a "leak test" instead, whats the difference? have spoke to ztech regarding price of rebuild, prob best to fit second hand lump though as never know what find when take it apart, but then dont know what you getting with second hand engines.

 

a leak test is normally to check for head gasket :confused: that would not be accurate enough to show which piston has failed,it MAY show up if the head was warped and possible if two cylinders were down next to each other then it will show warping againpossibly

 

only real test is a compression test if that hasnt be done then id suggest you have that done before you start weighing up new engines as that will give a more accurate sign to engine damage

 

theres a risk with a 2nd hand engine even with a warranty,if you just swap and drop a new engine in,how long does it last,wheres the guarantee of all the seals gaskets lasting,where as an engine rebuild with warranty will cover that,pay your money take your chance i guess!

 

good luck

 

as for any free advice your always welcome to give ryan a buzz,he will always help if possible

a cylinder leakage test is a very accurate way of diagnosing.

 

each cylinder is pressurised independantly following a compression test.

 

% leakage is then recorded, excessive leakage on a cylinder can then be traced - you will hear air escaping through the inlet manifold if the inlet valves are leaking & through the exhaust for the exhaust valves. bubbles or dumping of the coolant out of the rad cap indicates the head gasket has blown accross a water way. excessive blowing out of the oil filler cap shows worn pistons/bores.