What is the difference between a JDM engine and a UKDM engine
Former Moderator
Joined: Jan 2004
Posts: 24,771
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From: Stanmore
Chris/RWD Lover/anyone else.
Do either of you guys know of a site similar to Lings where the parts diagrams are given along with part numbers, but for the Japanese versions?
If such a site exists, the that would be a great solution.
Ray, Lings site has all the UK parts numbers, so it may be easier to copmare what's stamped onto your engine with those listed.
Here's an example of the cylinder head: http://www.lingshondaparts.com/honda...block_03=23874
And the Pistons: http://www.lingshondaparts.com/honda...block_03=23874
You get the idea.
Do either of you guys know of a site similar to Lings where the parts diagrams are given along with part numbers, but for the Japanese versions?
If such a site exists, the that would be a great solution.
Ray, Lings site has all the UK parts numbers, so it may be easier to copmare what's stamped onto your engine with those listed.
Here's an example of the cylinder head: http://www.lingshondaparts.com/honda...block_03=23874
And the Pistons: http://www.lingshondaparts.com/honda...block_03=23874
You get the idea.
Former Moderator
Joined: Mar 2003
Posts: 4,176
Likes: 11
From: MUGEN 無限 POWER
Originally Posted by chrisr111' timestamp='1441496570' post='23738315
[quote name='RWDlover' timestamp='1441492531' post='23738271']
[quote name='chrisr111' timestamp='1441483733' post='23738190']
The increased compression of the JDM F20C (11.7:1 c.f. 11.0:1) is as a result of the use of a thinner head gasket
HTH
Chris.
[quote name='chrisr111' timestamp='1441483733' post='23738190']
The increased compression of the JDM F20C (11.7:1 c.f. 11.0:1) is as a result of the use of a thinner head gasket
HTH
Chris.
The part number stamped on Daves piston (13010-PCX-A00) is not exclusive to the JDM engine--it was also use in early USDM engines.
The USDM engine was never available in the JDM high compression state.
The conclusion being that the -A00 pistons do not raise compression ratio; it's the head gasket
Chris.
[/quote]
OP said that his pistons are stamped PCX-00, not A00.
Part numbers for JDM pistons :
00-02 13010-PCX-010 (A) , 13020-PCX-010 (B)
02-03 13010-PCX-020 (A) , 13020-PCX-020 (B)
04-06 13010-PCX-040 (A) , 13020-PCX-040 (B)
EUDM pistons :
00-02 13010-PCX-A01 (A) , 13020-PCX-A01 (B)
02-03 13010-PCX-A03 (A) , 13020-PCX-A03 (B)
04-09 13010-PCX-A04 (A) , 13020-PCX-A04 (B)
There is no difference in the head gasket, it's the pistons.
[/quote]
You are still wrong
13010-PCX-000
13010-PCX-010
13010-PCX-020
are also USDM part numbers and have since been superceeded by 13010-PCX-305
I don't think the US ever got the high comp engine so these piston must not be responsible for the increase.
If you reckon it's not the head gasket, maybe the cylinder heads are different?
Chris.
Edit: I am right that the US never got the HC engine??? I doubting myself now.......
Thread Starter
Joined: Sep 2012
Posts: 2,908
Likes: 56
Originally Posted by RWDlover' timestamp='1441499805' post='23738333
[quote name='chrisr111' timestamp='1441496570' post='23738315']
[quote name='RWDlover' timestamp='1441492531' post='23738271']
[quote name='chrisr111' timestamp='1441483733' post='23738190']
The increased compression of the JDM F20C (11.7:1 c.f. 11.0:1) is as a result of the use of a thinner head gasket
HTH
Chris.
[quote name='RWDlover' timestamp='1441492531' post='23738271']
[quote name='chrisr111' timestamp='1441483733' post='23738190']
The increased compression of the JDM F20C (11.7:1 c.f. 11.0:1) is as a result of the use of a thinner head gasket
HTH
Chris.
The part number stamped on Daves piston (13010-PCX-A00) is not exclusive to the JDM engine--it was also use in early USDM engines.
The USDM engine was never available in the JDM high compression state.
The conclusion being that the -A00 pistons do not raise compression ratio; it's the head gasket
Chris.
[/quote]
OP said that his pistons are stamped PCX-00, not A00.
Part numbers for JDM pistons :
00-02 13010-PCX-010 (A) , 13020-PCX-010 (B)
02-03 13010-PCX-020 (A) , 13020-PCX-020 (B)
04-06 13010-PCX-040 (A) , 13020-PCX-040 (B)
EUDM pistons :
00-02 13010-PCX-A01 (A) , 13020-PCX-A01 (B)
02-03 13010-PCX-A03 (A) , 13020-PCX-A03 (B)
04-09 13010-PCX-A04 (A) , 13020-PCX-A04 (B)
There is no difference in the head gasket, it's the pistons.
[/quote]
You are still wrong
13010-PCX-000
13010-PCX-010
13010-PCX-020
are also USDM part numbers and have since been superceeded by 13010-PCX-305
I don't think the US ever got the high comp engine so these piston must not be responsible for the increase.
If you reckon it's not the head gasket, maybe the cylinder heads are different?
Chris.
Edit: I am right that the US never got the HC engine??? I doubting myself now.......
[/quote]
This is the info i have found that 1 piston now supersedes all the older piston's so from that i thought they must have being the same, i can't find any info on a Piston PCX-00
Joined: Feb 2009
Posts: 194
Likes: 1
Originally Posted by RWDlover' timestamp='1441499805' post='23738333
[quote name='chrisr111' timestamp='1441496570' post='23738315']
[quote name='RWDlover' timestamp='1441492531' post='23738271']
[quote name='chrisr111' timestamp='1441483733' post='23738190']
The increased compression of the JDM F20C (11.7:1 c.f. 11.0:1) is as a result of the use of a thinner head gasket
HTH
Chris.
[quote name='RWDlover' timestamp='1441492531' post='23738271']
[quote name='chrisr111' timestamp='1441483733' post='23738190']
The increased compression of the JDM F20C (11.7:1 c.f. 11.0:1) is as a result of the use of a thinner head gasket
HTH
Chris.
The part number stamped on Daves piston (13010-PCX-A00) is not exclusive to the JDM engine--it was also use in early USDM engines.
The USDM engine was never available in the JDM high compression state.
The conclusion being that the -A00 pistons do not raise compression ratio; it's the head gasket
Chris.
[/quote]
OP said that his pistons are stamped PCX-00, not A00.
Part numbers for JDM pistons :
00-02 13010-PCX-010 (A) , 13020-PCX-010 (B)
02-03 13010-PCX-020 (A) , 13020-PCX-020 (B)
04-06 13010-PCX-040 (A) , 13020-PCX-040 (B)
EUDM pistons :
00-02 13010-PCX-A01 (A) , 13020-PCX-A01 (B)
02-03 13010-PCX-A03 (A) , 13020-PCX-A03 (B)
04-09 13010-PCX-A04 (A) , 13020-PCX-A04 (B)
There is no difference in the head gasket, it's the pistons.
[/quote]
You are still wrong
13010-PCX-000
13010-PCX-010
13010-PCX-020
are also USDM part numbers and have since been superceeded by 13010-PCX-305
I don't think the US ever got the high comp engine so these piston must not be responsible for the increase.
If you reckon it's not the head gasket, maybe the cylinder heads are different?
Chris.
Edit: I am right that the US never got the HC engine??? I doubting myself now.......
[/quote]
The USA/EU never got any pistons without the A in the part numbers, where do you get this info?
Joined: Mar 2001
Posts: 31,181
Likes: 58
From: Hertford
JDM slugs on Hondaparts now with no area reference
AP1 KA-spec ones with pretty diagram
Maybe that is the source of the confusion.
BTW - I was always told it was the HG, which proves what a load of old bollocks is abound.
PS - What is the K-code for a JDM AP1? It's KE in the UK and KG in EU.
AP1 KA-spec ones with pretty diagram
Maybe that is the source of the confusion.
BTW - I was always told it was the HG, which proves what a load of old bollocks is abound.
PS - What is the K-code for a JDM AP1? It's KE in the UK and KG in EU.
Former Moderator
Joined: Mar 2003
Posts: 4,176
Likes: 11
From: MUGEN 無限 POWER
Having looked into this some more, I now agree with RWDlover
I was sure there were multiple part numbers for the head gasket, but it appears there's only one (12251-PCX-004) for all S2000s irrespective of the intended market
The conclusion being that the increased CR of OEM JDM engines is not as a result of a thinner head gasket
I can make enquires for a definitive answer on the pistons, but it may take some time....
Chris.
I was sure there were multiple part numbers for the head gasket, but it appears there's only one (12251-PCX-004) for all S2000s irrespective of the intended market
The conclusion being that the increased CR of OEM JDM engines is not as a result of a thinner head gasket
I can make enquires for a definitive answer on the pistons, but it may take some time....
Chris.
Joined: Feb 2009
Posts: 194
Likes: 1
Having looked into this some more, I now agree with RWDlover
I was sure there were multiple part numbers for the head gasket, but it appears there's only one (12251-PCX-004) for all S2000s irrespective of the intended market
The conclusion being that the increased CR of OEM JDM engines is not as a result of a thinner head gasket
I can make enquires for a definitive answer on the pistons, but it may take some time....
Chris.
I was sure there were multiple part numbers for the head gasket, but it appears there's only one (12251-PCX-004) for all S2000s irrespective of the intended market
The conclusion being that the increased CR of OEM JDM engines is not as a result of a thinner head gasket
I can make enquires for a definitive answer on the pistons, but it may take some time....
Chris.
The JDM cams are also a myth, there is no such a thing on the F20C, JDM and EU/US have the same part number cams.
Joined: Mar 2011
Posts: 853
Likes: 2
From: Amersham, Bucks
when looking to replace HG on my old car, they found a couple of different thickness HG's from honda, no idea if it was or wasnt the reason, but that was on my 99 import... ended up fitting a cosworth gasket!
Joined: Jul 2012
Posts: 254
Likes: 0
From: Peterborough
Not sure if this helps with the quest for an answer but my '03 (UK spec) engine has piston part number PCX-A01 stamped on the top. My new Spoon F22C short block also has this PCX-A01 piston set. Happy to supply pictures if required.
This short block came straight from Japan. I do know that this engine has an 11.8:1 CR when used with the Spoon HG, I think that is what takes the CR from 11.7:1 (JDM standard) to 11.8:1. The engine is standard, taken from AP1 JDM, then stroked up to 2.2L with AP2 crank and rods (bore x stroke = 87.00 × 90.7mm).
It could be that the AP2 pistons are used may explain why pistons are the same, but then where does the raised CR come from? As I see it (please feel free to correct me), this rules out the pistons since the PCX-A01 came on my UK spec AP1 and stroker JDM AP1 and the same bore/stroke is seen when comparing this stroked JDM AP1 to the AP2 (with 11.1:1 CR).
It's probably dangerous bringing an aftermarket modified engine into the equation but it may help since we all know Spoon have only mixed up and modified standard components.
This short block came straight from Japan. I do know that this engine has an 11.8:1 CR when used with the Spoon HG, I think that is what takes the CR from 11.7:1 (JDM standard) to 11.8:1. The engine is standard, taken from AP1 JDM, then stroked up to 2.2L with AP2 crank and rods (bore x stroke = 87.00 × 90.7mm).
It could be that the AP2 pistons are used may explain why pistons are the same, but then where does the raised CR come from? As I see it (please feel free to correct me), this rules out the pistons since the PCX-A01 came on my UK spec AP1 and stroker JDM AP1 and the same bore/stroke is seen when comparing this stroked JDM AP1 to the AP2 (with 11.1:1 CR).
It's probably dangerous bringing an aftermarket modified engine into the equation but it may help since we all know Spoon have only mixed up and modified standard components.
