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Were there "special XU1 pistons?


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#1 _xu1997_

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Posted 28 May 2009 - 07:54 PM

I had my JP motor reco'd, balanced and blueprinted by Barry Seton in 1982.He had trouble sourcing at the time what he described as XU1 "SLIPPER TYPE" pistons. He explained to me that they were lighter and stronger than std Holden 202 pistons and that the skirt to bore clearance was greater in these pistons to allow for expansion with the heat generated from higher revs. It apparently stopped the age old problem of holden pistons separating at the ring lands at high revs.

Has anyone else knowledge of this and are these or similar pistons still available?

Cheers
xu1997

#2 Bazza

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Posted 28 May 2009 - 09:17 PM

Hi xu1997

Both the LH and LX parts catalogues give the same part numbers as the early ''72 LJ parts catalogue for the 3300 cc engine pistons. There may have been a change with the '72 Bathurst - perhaps someone with a '73 parts catalogue can confirm.

The XU-1 bearings are different.

Cheers

Bazza

#3 _HQ SS_

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Posted 29 May 2009 - 01:33 AM

I think I still have a piston here somewhere out of a mates XU1 motor.
I will dig it out and post a picture of it if it is wanted, to show the difference on the inside of it.
Cheers Paul.

#4 _gtr-xu1_

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Posted 29 May 2009 - 11:26 AM

the LJ XU1 engine suffered from piston failure, as the standard 202 pistons wernt up to the task. the XU1 replacement piston part number is 991327.

#5 Bazza

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Posted 29 May 2009 - 11:49 AM

the LJ XU1 engine suffered from piston failure, as the standard 202 pistons wernt up to the task. the XU1 replacement piston part number is 991327.



Hi

My standard bore motor is fitted with pistons P/N 2824141. I can't find this number anywhere. Does anyone have any ideas?

Cheers

Bazza

#6 wingnut

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Posted 29 May 2009 - 11:50 AM

I had my JP motor reco'd, balanced and blueprinted by Barry Seton in 1982.He had trouble sourcing at the time what he described as XU1 "SLIPPER TYPE" pistons. He explained to me that they were lighter and stronger than std Holden 202 pistons and that the skirt to bore clearance was greater in these pistons to allow for expansion with the heat generated from higher revs. It apparently stopped the age old problem of holden pistons separating at the ring lands at high revs.

Has anyone else knowledge of this and are these or similar pistons still available?

Cheers
xu1997



Hi Glenn / Bazza et al

I have a set of those slipper pistons and starfire rods waiting to go into a spare 202 I'm building.
The pistons are old Repco / ACL part no. 6KRY 2585 - Piston crowns actually marked RA 2585X
They are + 60 thou. so not going into my JP block.
I think they would be hard to find these days - they have 2 mm thick compression rings whereas
I believe the modern ACL Race Series have thinner grooves & rings.
My engine machinist didn't want to use them in the motor I'm building for the very reason Glenn
mentioned - solid skirt and bigger clearances so lots of noise / rattling on start up until running
temp. reached - traditional XU1 charisma !!!

My LJ parts catalogue ( June 1975 green cover) indicates there were 2 distinct XU1 piston & pin
assemblies -

Standard high limit Regular # 2825761 ( sequetial numbers following for + 001" & + 002" O/S )
Standard Heavy Duty # 9931326
Standard high limit Heavy Duty # 9931327 and oversizes + 002" 020" 030" & 040"

Hope you all can make sense of this.

Cheers J R

#7 Bazza

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Posted 29 May 2009 - 12:06 PM

Hi all

I found another reference to pistons: From 1 July 1973 P/N 9930823.

Still can't find 2824141.

Cheers

Bazza

#8 Zook

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Posted 29 May 2009 - 06:40 PM

Bazza
2824141 seems to be like a cast number on Holden pistons. I have a set and that number is cast inside the skirt, as is 'Holden'. Mine have part number 9931326 stamped into the crown. These are standard size and came out of an XU-1 motor of some sort...if memory serves.

#9 Bazza

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Posted 29 May 2009 - 06:49 PM

Bazza
2824141 seems to be like a cast number on Holden pistons. I have a set and that number is cast inside the skirt, as is 'Holden'. Mine have part number 9931326 stamped into the crown. These are standard size and came out of an XU-1 motor of some sort...if memory serves.


Hi Zook

Thanks - I will have a closer look.

Cheers

Bazza

#10 Zook

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Posted 29 May 2009 - 07:28 PM

No worries. Just noticed that the number stamped in mine is the Standard Heavy Duty number provided by Wingnut. Where are you getting your number from Bazza?

#11 _aussie4speeds_

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Posted 29 May 2009 - 07:47 PM

the black efi motor in the vk commodore ran the xu1 pistons and rods so i have been told and the black motor runs a steel crank i think bnut only in the efi motors can some one confirm

#12 _scooter_

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Posted 29 May 2009 - 07:57 PM

I dont know if they are special but I think they might be...my 8/73 bathurst special(yes it's on the list) has Repco pistons.....

scooter

#13 _gtr-xu1_

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Posted 29 May 2009 - 09:31 PM

the LJ XU1 engine suffered from piston failure, as the standard 202 pistons wernt up to the task. the XU1 replacement piston part number is 991327.


oops left a 3 out

9931327

#14 _HQ SS_

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Posted 30 May 2009 - 12:46 AM

I have found the piston in the shed and have taken some pictures of it.
From memory as this was a while ago now, this piston was from a LJ Bathurst Torana engine that I overhauled for a mate.
I kept it because of what it was from.
At the time I was told the same thing as xu1997 that the pistons were lighter and stronger than std pistons.
Part of the reason I was told that they were lighter was that there was no steel reinforcing plate on the inside of the skirt where the gudgin pin goes through the piston.
If you look at this piston I have marked where I mean and also the casting details on the inside of the piston.

Posted Image

I remember comparing it to a std 202 piston and the std one had a steel plate cast in to the piston in that area.
I do not have a std piston out of a engine anymore to take a picture of it to show what I mean.
(From what I have seen newer aftermarket pistons do not have this plate either.)
The stamping in the top of it does not match any of the numbers that are posted above at all.
This is what is stamped in to the top of the piston and the 2585 is cast on to the inside of the piston too.

Posted Image

A side view.

Posted Image

and one of the Holden cast on to the inside.

Posted Image

I am interested to see if anyone else has seen this type of piston and the numbers that are on it.
Cheers Paul.

#15 _pacey1977_

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Posted 30 May 2009 - 01:46 AM

Hi guys I have these piston in my 202 they are repco xu1 slipper piston solid skirts with no metal inserts. the top of the piston is the same I had the head off about 8 years ago and still remember what they look like. the spec sheet I got with my engine also say the are xu1 pistons but I dont have a part number. my engine was built around 1993 so maybe these pistons where still around then. mine are also 30thou up but still going great. I will be selling the engine soon as am building a new 202 blue motor with 186 head and 202 black motor crank , soild cam and all the good gear. just put my new webber on today so I can make sure they are running good for the new donk. will post a pic when running cheers

#16 _irvingfj_

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Posted 30 September 2009 - 07:24 PM

I had my JP motor reco'd, balanced and blueprinted by Barry Seton in 1982.He had trouble sourcing at the time what he described as XU1 "SLIPPER TYPE" pistons. He explained to me that they were lighter and stronger than std Holden 202 pistons and that the skirt to bore clearance was greater in these pistons to allow for expansion with the heat generated from higher revs. It apparently stopped the age old problem of holden pistons separating at the ring lands at high revs.

Has anyone else knowledge of this and are these or similar pistons still available?

Cheers
xu1997


Hi,
I just pulled down a rare irving headed engine with the very type of piston you speake of, they are a repco/acl piston with no metal support inside and a part number RA2585, have you heard any more info on these items?

#17 _irvingfj_

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Posted 30 September 2009 - 07:31 PM

Hi guys I have these piston in my 202 they are repco xu1 slipper piston solid skirts with no metal inserts. the top of the piston is the same I had the head off about 8 years ago and still remember what they look like. the spec sheet I got with my engine also say the are xu1 pistons but I dont have a part number. my engine was built around 1993 so maybe these pistons where still around then. mine are also 30thou up but still going great. I will be selling the engine soon as am building a new 202 blue motor with 186 head and 202 black motor crank , soild cam and all the good gear. just put my new webber on today so I can make sure they are running good for the new donk. will post a pic when running cheers



Hi,
I have just came across the very piston you have in your shots, i bought a irving headed engine from my boss who had it in his race boat, it was built HUGHES&BROOKFEILD where the irvings were built and sold from and has that type of piston but my ones are 40 over, this company had very close relations with Harry Firth so no surprise it had this type of piston fitted.

#18 Zook

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Posted 16 November 2013 - 04:45 PM

Reviving an old thread I know but I am researching a JP block that I want to buy and in the course of that I have come across some new old information.

 

As I said earlier I have pistons with cast number 2824141 cast in and and part number 9931326 stamped in the crown. What is interesting is that on pg 161 of the Fiv book this part number is mentioned, and then on page 163 the piston is described. The description matches my piston. I'll get photos up shortly.



#19 _vin150cars_

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Posted 18 November 2013 - 07:10 PM

how are you going these days peter have you shill got the pistons

cheers vin



#20 rtorana1

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Posted 21 March 2014 - 02:14 PM

A MATE OF MINE HAD A GENUINE BATHURST LJ XU1. THE PISTONS IN THAT MOTOR HAD CUTOUTS IN THE TOP OF THE PISTONS TO ACCOMMODATE THE VALVES DUE TO THE EXTREMELY HIGH LIFT CAM.



#21 S pack

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Posted 21 March 2014 - 04:11 PM

A MATE OF MINE HAD A GENUINE BATHURST LJ XU1. THE PISTONS IN THAT MOTOR HAD CUTOUTS IN THE TOP OF THE PISTONS TO ACCOMMODATE THE VALVES DUE TO THE EXTREMELY HIGH LIFT CAM.

Not the original pistons (or they were modified) and possibly not the original camshaft either.



#22 crabba67

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Posted 21 March 2014 - 05:57 PM

a original late1973 9/2E piston which fits a 9/2E block......... no cut outs for large valves.

cheers



#23 _202DOHC_

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Posted 23 March 2014 - 09:39 PM

In the 1985 Repco engine parts catalogue the RP2585 is listed as a slipper type piston suitable for high speed engines.
Compression rings 5/64", wide oil control ring 3/16" wide.
Compression height 1.676" overall length 2.731"

Std 202 piston RP2506 Comp height 1.654" and overall length 3.020"

#24 N/A-PWR

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Posted 23 March 2014 - 09:49 PM

Hmm, good Information there Wayne, thank's. Dave I



and Anthony



I had 1/2 inch lift with a 41/78 Cam and 100 thou off the head, and the Valves didn't touch



#25 crabba67

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Posted 24 March 2014 - 01:47 PM

Dave, the rp2585 piston was used by RPM repco replacement motors west heidelberg factory until 1992 in reconditioned blocks,the measurement from gudgeon pin to the top of piston on a rp2585 to a 2824141 is about 30thou different can only be used in a 9/2e block  because of deck height.

cheers






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