A Z20Let Is Reborn (Pic Heavy)
#1
Posted 09 November 2011 - 09:53 AM
oil pickup, timing wheel, balancer shaft drive
#2
Posted 09 November 2011 - 10:14 AM
What's the plan for this? Standard rebuild? Simple mods to improve performance? mental overhaul to rival Nev's Nipper?
#3
Posted 09 November 2011 - 10:30 AM
Edited by Nev, 09 November 2011 - 10:41 AM.
#4
Posted 09 November 2011 - 10:41 AM
Wow, looks like a good one. The oil looks nice and clean and hardly any carbon build up (though the sump pan is the best indicator for this).
Cylinders are clearly burning evenly and perfectly. Maybe just change the rods and bearing shells for £350 and put it into your car. These engines/cars are a bloody bargain!
this is sort of the route that I think people would appreciate, leave engine insitu and rebuild it from the bottom without taking off head or turbo.
I'm not sure if the gearbox has to be detached to get to the lower sump after the oil pan is removed. But the idea is whilst removing the balancer shafts , to drop the crank out and then put in arp bolts, optional upgrade rods if going above 360lbf.ft , this would take you to stage4.9+ , pretty much a std engine and wallet friendly.
Ideally get the lot sent to vibration free.
#5
Posted 09 November 2011 - 10:44 AM
BTW, I know where you can get 1/2 decent forged rods for £250. Proven to 400 BHP and probably good a for more.
lithuania bloke (fcp-engineering) , seems to be able to make bespoke anything?
#6
Posted 09 November 2011 - 10:58 AM
#7
Posted 09 November 2011 - 11:22 AM
#8
Posted 09 November 2011 - 01:12 PM
Blimey, can't believe how clean the piston crowns are after 70k miles. They're properly filthy with carbon build-up on the Z22SE.
at 50k mine were cludged up compared to those
#9
Posted 09 November 2011 - 02:03 PM
Blimey, can't believe how clean the piston crowns are after 70k miles. They're properly filthy with carbon build-up on the Z22SE.
at 50k mine were cludged up compared to those
when we had the head off my car the pistons were almost black
can't believe how new that looks
#10
Posted 09 November 2011 - 02:13 PM
#11
Posted 09 November 2011 - 02:18 PM
Look like they've had a good old clean to me
I gave them a hoover to remove the bits of glass that got sucked in, and at best a light wipe over , considering this sat outside for over a year before I could get started on the project.
#12
Posted 09 November 2011 - 02:19 PM
#13
Posted 09 November 2011 - 02:21 PM
Does the Z20LET have an EGR system? I guess that makes a huge difference to the amount of sh!t that gets into the combustion chamber.
nope, and its pretty keen to fuel it lean when it can, judging by the LTFT trims
#14
Posted 09 November 2011 - 02:38 PM
Yep, exact reverse of the Z22SE that seems to over-fuel by default and also by preference.
Does the Z20LET have an EGR system? I guess that makes a huge difference to the amount of sh!t that gets into the combustion chamber.
nope, and its pretty keen to fuel it lean when it can, judging by the LTFT trims
#15
Posted 09 November 2011 - 03:24 PM
when we had the head off my car the pistons were almost black
can't believe how new that looks
Fueling isn't the only reason for carbon deposits in the cylinder. Other possible reasons are:
i) 1 or more failing stem seals allowing oil to seap down the valve and thus get burnt.
ii) Turbo seal(s) failing and letting oil into the inlet charge.
iii) Mild HGF allowing oil to seap into 1 or more cylinders.
HTH.
If you have a bore scope and inspect your engine and see loads of carbon on your piston crowns, the first remedial thing you can do is change your oil for some thicker stuff.
Edited by Nev, 09 November 2011 - 03:25 PM.
#16
Posted 09 November 2011 - 06:56 PM
This is very interesting as I was thiking of replaceing my engine because after replaceing the head when the valves were leaking I found it still not starting which now looks like bottom end problems as it ate the end of the crank sensor.So now I have seen that should be possable to strip the bottom end down with it in situ I may well have a go at fixing it rather than replaceing it.
Wow, looks like a good one. The oil looks nice and clean and hardly any carbon build up (though the sump pan is the best indicator for this).
Cylinders are clearly burning evenly and perfectly. Maybe just change the rods and bearing shells for £350 and put it into your car. These engines/cars are a bloody bargain!
this is sort of the route that I think people would appreciate, leave engine insitu and rebuild it from the bottom without taking off head or turbo.
I'm not sure if the gearbox has to be detached to get to the lower sump after the oil pan is removed. But the idea is whilst removing the balancer shafts , to drop the crank out and then put in arp bolts, optional upgrade rods if going above 360lbf.ft , this would take you to stage4.9+ , pretty much a std engine and wallet friendly.
Ideally get the lot sent to vibration free.
#17
Posted 09 November 2011 - 07:21 PM
#18
Posted 14 November 2011 - 10:06 PM
when we had the head off my car the pistons were almost black
can't believe how new that looks
Fueling isn't the only reason for carbon deposits in the cylinder. Other possible reasons are:
i) 1 or more failing stem seals allowing oil to seap down the valve and thus get burnt.
ii) Turbo seal(s) failing and letting oil into the inlet charge.
iii) Mild HGF allowing oil to seap into 1 or more cylinders.
1 and 3 have just been done so if thats the problem its sorted and i dont have a tubby
#19
Posted 20 December 2011 - 12:13 PM
standard Astra VXR z20leh piston , notice differences to LET pistons above ;
pocket cutouts for inlet cams
larger diameter domed deck profile
dish edge profile
z20leh standard rod (on the left) LEH piston and aftermarket rod (on the right)
#20
Posted 20 December 2011 - 12:41 PM
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