JJM
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| posted on 1/2/06 at 11:38 AM |
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XE forged pistons
Can anyone tell me how to identify the Mahle forged pistons from a C20XE? Can i tell by looking-or is there an easier way?
Cheers, John
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NS Dev
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| posted on 1/2/06 at 11:46 AM |
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All the Mahle pistons fitted as std to all 20XE and C20XE engines are forged, there's nothing to identify really.
They all say Mahle on them underneath and all have the OD dimension and orientation markings on top.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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JJM
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| posted on 1/2/06 at 11:53 AM |
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Thanks NS-i'll get him to check for the Mahle markings-just needed to know if they are cast or forged before parting with cash.
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ned
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| posted on 1/2/06 at 11:56 AM |
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yup they say mahle underneath and you can also see the casting lines on the underside of the later cast ones iirc..
Ned.
beware, I've got yellow skin
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NS Dev
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| posted on 1/2/06 at 11:56 AM |
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Ahhh!!
Is this an ebay buy?
I have seen "forged Mahle pistons" advertised on there loads of times going for silly money, but they are just std pistons, as I say they
are all forged on these engines as std.
Bear in mind there are 3 different "standard" bore sizes (3 different graded piston diameters)
These pistons are worth £40 for 4 tops.
If they are any more than that, I have several sets available, £10 per piston. (secondhadn but good condition)
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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ned
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| posted on 1/2/06 at 11:57 AM |
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I once sold a set for £100!!! but basically agree with what Nat said 
beware, I've got yellow skin
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JJM
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| posted on 1/2/06 at 11:59 AM |
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Right i thought some engines had cast not forged pistons as standard-not sure where that came from but i'm sure i read it somewhere? I probably
have them in my block but havent had the head off yet-need a special torx bit or something lol.
Thanks again guys.
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NS Dev
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| posted on 1/2/06 at 12:07 PM |
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Whereabouts are you, if you are near Leicester you are welcome to borrow any tools you need. If you take the sump off the engine, remove the windage
trayu and shine a torch up under the pistons you should see if they say Mahle on them. If they do then they are forged.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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ned
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| posted on 1/2/06 at 12:09 PM |
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later engines had cast pistons, earlier ones had mahle forged jobbies.
you don't need a torq socket, you can get away with an imperial 12 sided regular socket (7/16 rings a bell) instead. I've torqued head
bolts up with one of these and it fits fine.
Ned.
ps might be too oily, but what about whipping the sump and windage tray off and having a look up the cylinders from underneath, otherwise having the
head off won't help unless you're planning on removing the pistons completely which will still require sump and big ends off.
[Edited on 1/2/06 by ned]
beware, I've got yellow skin
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NS Dev
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| posted on 1/2/06 at 12:09 PM |
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quote:
Originally posted by ned
I once sold a set for £100!!! but basically agree with what Nat said
flipping hell!
JJM, get in quick!! I'll be sticking on ebay I think.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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NS Dev
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| posted on 1/2/06 at 12:14 PM |
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quote:
Originally posted by ned
later engines had cast pistons, earlier ones had mahle forged jobbies.
you don't need a torq socket, you can get away with an imperial 16 sided regular socket (7/16 rings a bell) instead. I've torqued head
bolts up with one of these and it fits fine.
Ned.
ps might be too oily, but what about whipping the sump and windage tray off and having a look up the cylinders from underneath, otherwise having the
head off won't help unless you're planning on removing the pistons completely which will still require sump and big ends off.
[Edited on 1/2/06 by ned]
How late an engine Ned? I thought all the XE's had forged pistons, and the ecotecs had cast ones.???
Certainly my 1992 C20XE had forged pistons when I checked.
Heh heh, post overlaps on the bore peeping!
[Edited on 1/2/06 by NS Dev]
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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ned
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| posted on 1/2/06 at 12:29 PM |
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not exactly sure on dates, i was led to believe (not confirmed) that the astra gte engines (with the extra webbing on the block by the starter) had
the lighter crank and forged pistons. that said i have seen some blocks with the extra webbing in calibra's and scrappy's but they could
have had transplants or replacements at some point.
Ned.
beware, I've got yellow skin
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NS Dev
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| posted on 1/2/06 at 12:38 PM |
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I have 4 engines, all have forged Mahle pistons, not sure on the blocks,
but two are 1988 and 1989 Astra GTE, one Coscast head one not,
one is 1992 Calibra, but strangely it's a 20XE with Coscast head so I think it may have had an engine change,
and the other is 1991 Cavalier GSI, with GM head and which was definitely the original engine (low mileage one owner salvage car)
They all have the same cranks and pistons, as I say, I'm not sure on the blocks, would have to double check on that.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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JJM
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| posted on 1/2/06 at 05:21 PM |
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Ah good tip on the sump removal-i'll have a look tomorrow thanks guys. The engine has a GM head-its had a porous fix done, round tooth cambelt
from a Cav GSi.
Cheers, John.
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NS Dev
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| posted on 1/2/06 at 05:53 PM |
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Let us know what you find!
Round tooth belt I thought was another indicator of the earlier engine, but then who knows!!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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Stu16v
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| posted on 1/2/06 at 06:46 PM |
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OK. I too have read that early engines have forged pistons, and later ones cast. But the bit I have trouble with, is why folk rave about fitting
otherwise standard forged pistons. They are probably heavier! Piston failure isnt high on the list of common issues associated with the XE - so why
bother?
Dont just build it.....make it!
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ned
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| posted on 1/2/06 at 08:31 PM |
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For info I have heard of cast ones disintegrating on race engines (200bhp+), but then hardly the same as road use.
Ned.
beware, I've got yellow skin
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Stu16v
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| posted on 1/2/06 at 09:07 PM |
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Fair comment, but unless restricted by regulation, any XE attempting to make serious power will have intruder pistons fitted anyway...
Dont just build it.....make it!
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NS Dev
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| posted on 2/2/06 at 12:08 AM |
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the std pistons in my grasser haven't broken...............yet!...........
Maybe I shouldn't have extended the rev limit to 8000 revs on std unbalanced bottom end???????
PS, stu, must apologise! Remember the discussion ages ago on the sputter bearings..........well it turns out you were quite right, looks like I was
spun a yarn before! They were for the diesel engine just as you said, and they are narrower like the 8 valve ones!! Got the verniers on them this
time! Looks like the only "wide" bearings for the XE are the gen OE white metal ones, everything heavy duty is 1mm narrower!........ah
well, live and learn eh! engine's in now!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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ned
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| posted on 2/2/06 at 07:23 AM |
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quote:
Originally posted by NS Dev
PS, stu, must apologise! Remember the discussion ages ago on the sputter bearings..........well it turns out you were quite right, looks like I was
spun a yarn before! They were for the diesel engine just as you said, and they are narrower like the 8 valve ones!! Got the verniers on them this
time! Looks like the only "wide" bearings for the XE are the gen OE white metal ones, everything heavy duty is 1mm narrower!........ah
well, live and learn eh! engine's in now!
glad my engine man was right on that then i've got the lead copper ones
[Edited on 2/2/06 by ned]
beware, I've got yellow skin
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Stu16v
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| posted on 3/2/06 at 07:17 PM |
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quote:
Originally posted by NS Dev
the std pistons in my grasser haven't broken...............yet!...........
Maybe I shouldn't have extended the rev limit to 8000 revs on std unbalanced bottom end???????
PS, stu, must apologise! Remember the discussion ages ago on the sputter bearings..........well it turns out you were quite right, looks like I was
spun a yarn before! They were for the diesel engine just as you said, and they are narrower like the 8 valve ones!! Got the verniers on them this
time! Looks like the only "wide" bearings for the XE are the gen OE white metal ones, everything heavy duty is 1mm narrower!........ah
well, live and learn eh! engine's in now!
No worries mate. I was only relaying info I had from Steve @ SBD, so wasnt in position to confirm or deny what you were saying...
Dont just build it.....make it!
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