Welcome to the North American Subaru Impreza Owners Club Thursday March 28, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Built Motor Discussion

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 12-15-2009, 02:46 PM   #1
hobbesnapoli
Scooby Newbie
 
Member#: 221436
Join Date: Aug 2009
Location: PA
Vehicle:
02 WRX vf39

Default Torque Plate vs Non Torque Plate Motor

Some people claim that the EJ257 will go out of round unless it is bored/honed with a torque plate. However- judging by the information i've gathered around here, many people build 100mm bore motors without issues and presumably their machine shops (random local ones) did not use a torque plate. I need my block bored/honed and I really hate to get it done and then have excessive blowby, anyone have experience with or without a 'torque-plate-bored' motor?
* Registered users of the site do not see these ads.
hobbesnapoli is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 12-15-2009, 05:21 PM   #2
EMS
Scooby Newbie
 
Member#: 14116
Join Date: Jan 2002
Default

Measure the bores without torque plate and measure them again with torque plate fitted. After this you know there is only one RIGHT way to do a bore/hone job!!!

Mark.
EMS is offline   Reply With Quote
Old 12-15-2009, 05:23 PM   #3
2milehi
Scooby Specialist
 
Member#: 81633
Join Date: Feb 2005
Location: Dillon, CO
Vehicle:
'98 RS-T
Blue

Default

Factory doesn't use a torque plate.
2milehi is offline   Reply With Quote
Old 12-15-2009, 06:05 PM   #4
integroid
Scooby Specialist
 
Member#: 49222
Join Date: Nov 2003
Location: Atlanta, GA
Vehicle:
2005 Legacy GT Wagon
Limited 5MT 580whpQ16

Default

Mine was done with a torque plate. The motor is going in tomorrow so I will let you know the outcome.
integroid is offline   Reply With Quote
Old 12-15-2009, 09:44 PM   #5
nitro1956
Scooby Newbie
 
Member#: 230682
Join Date: Nov 2009
Default

....Anywhere I can find description/definition of a torque plate ? Already on a link somewhere ?
nitro1956 is offline   Reply With Quote
Old 12-15-2009, 09:52 PM   #6
Crystal_Imprezav
Scooby Specialist
 
Member#: 84105
Join Date: Mar 2005
Chapter/Region: SCIC
Location: I'm a Newbie
Vehicle:
2005 Super Slow STi
CGM

Default

The only test I know of for a suby motor:

http://www.cosworthusa.com/blog/default.asp?idpage=18
Crystal_Imprezav is offline   Reply With Quote
Old 12-15-2009, 10:39 PM   #7
reddevil
Scooby Guru
 
Member#: 64673
Join Date: Jun 2004
Chapter/Region: NWIC
Location: portland
Vehicle:
1990 Legacy wagon
goes 12.387 @ 116.5

Default

I have bored about 3 motors so far WITHOUT plate, just for myself. NO blowby. The motors I have had bored and sold have had NO blowby.\

However,none of these motors are seeing more than 400whp.
reddevil is offline   Reply With Quote
Old 12-16-2009, 12:05 PM   #8
kay95
Scooby Specialist
 
Member#: 45494
Join Date: Oct 2003
Location: glen rock, pa
Vehicle:
95 impreza L awd
green

Default

Well did they try and measure that with the block at temp? The way the sleeves are supported would allow the bore to expand where it wasnt support by more than where it is. Not to mention the factory pistons have a VERY small clearance IIRC it is .001. So going by that the factory pistons would seize correct? I mean correct me if I am wrong in my thinking.
kay95 is offline   Reply With Quote
Old 12-16-2009, 07:52 PM   #9
WrXtaCy2003
Scooby Specialist
 
Member#: 85036
Join Date: Apr 2005
Chapter/Region: MWSOC
Vehicle:
2013 PBP sti ltd
05 LGT 35r 30psi..busted

Default

Quote:
Originally Posted by Crystal_Imprezav View Post
The only test I know of for a suby motor:

http://www.cosworthusa.com/blog/default.asp?idpage=18

I did this!

http://forums.nasioc.com/forums/show....php?t=1659712


Since the end of this thread, I built three customer cars. Two of them opted for the torque plate. One did not. The two that got torque plated, like my motor, are SIGNIFICANTLY quieter (piston slap) both cold and hot, than ones that are not torque plate. This is the only "experimental" evidence I have using torque plates, other than when my machinists measured the bores with and without a torque plate. That info should be in my thread.



DK
WrXtaCy2003 is offline   Reply With Quote
Old 12-17-2009, 05:59 AM   #10
Marnix
Scooby Specialist
 
Member#: 51480
Join Date: Dec 2003
Chapter/Region: International
Location: The Netherlands
Vehicle:
1984 AM5, 1984 AF1,
1994 BC4, 2015 Outback

Default

Useless to do with a torqueplate when you don't know what the bores are doing when the engine is getting hot. So either bore/hone 'as is' or use a torqueplate with the block heated up to 85 degrees. Does anybody do that? I guess not...
Marnix is offline   Reply With Quote
Old 12-17-2009, 10:58 AM   #11
FuJi K
Scooby Guru
 
Member#: 3687
Join Date: Jan 2001
Chapter/Region: MWSOC
Location: St. Paul, MN
Vehicle:
MY99 GF4 JDM 6spd
NF Performance

Default

This only applies to EJ257/EJ255 motors huh? if so.... i'm sorry for you 2.5L guys
FuJi K is offline   Reply With Quote
Old 12-17-2009, 11:48 AM   #12
hobbesnapoli
Scooby Newbie
 
Member#: 221436
Join Date: Aug 2009
Location: PA
Vehicle:
02 WRX vf39

Default

Well it seems like torque plates are the way to go... but certainly not for any sort of *budget* build. Has anyone experimented with a slightly tighter piston-wall clearance on a non-torque plated motor?
hobbesnapoli is offline   Reply With Quote
Old 12-17-2009, 01:03 PM   #13
2milehi
Scooby Specialist
 
Member#: 81633
Join Date: Feb 2005
Location: Dillon, CO
Vehicle:
'98 RS-T
Blue

Default

Quote:
Originally Posted by Marnix View Post
Useless to do with a torqueplate when you don't know what the bores are doing when the engine is getting hot. So either bore/hone 'as is' or use a torqueplate with the block heated up to 85 degrees. Does anybody do that? I guess not...
85°C I guess you mean or 185°F in the USA
2milehi is offline   Reply With Quote
Old 12-17-2009, 01:29 PM   #14
Marnix
Scooby Specialist
 
Member#: 51480
Join Date: Dec 2003
Chapter/Region: International
Location: The Netherlands
Vehicle:
1984 AM5, 1984 AF1,
1994 BC4, 2015 Outback

Default

Eh deg C but it is an intersting discussion; so far I've never used a torque plate and on EJ20s it doesn't have a big impact, on EJ25s it could be, but still, measuring at room temperature - how does the roundness of the cylinders change when the engine gets hot?
Marnix is offline   Reply With Quote
Old 12-18-2009, 07:16 AM   #15
EMS
Scooby Newbie
 
Member#: 14116
Join Date: Jan 2002
Default

Will check soon on a heated block! On a non heated block the bore is getting ovalised with the torque plate fitted quite a lot... Don't see that it will get better when heating...
EMS is offline   Reply With Quote
Old 12-18-2009, 09:13 AM   #16
SBW
Scooby Specialist
 
Member#: 38469
Join Date: Jun 2003
Chapter/Region: NESIC
Vehicle:
07 LGT spec-b
Crystal Grey Metallic

Default

Quote:
Originally Posted by Crystal_Imprezav View Post
The only test I know of for a suby motor:

http://www.cosworthusa.com/blog/default.asp?idpage=18
Would this apply to closed deck blocks as well?
SBW is offline   Reply With Quote
Old 12-18-2009, 11:32 AM   #17
Marnix
Scooby Specialist
 
Member#: 51480
Join Date: Dec 2003
Chapter/Region: International
Location: The Netherlands
Vehicle:
1984 AM5, 1984 AF1,
1994 BC4, 2015 Outback

Default

Quote:
Originally Posted by EMS View Post
Will check soon on a heated block! On a non heated block the bore is getting ovalised with the torque plate fitted quite a lot... Don't see that it will get better when heating...
Mark, when you are going to try this, heat the block with torque plate fitted; I'm very interested in the results as I will have to bore and/or hone an EJ25 for a German customer in January...

Marnix is offline   Reply With Quote
Old 12-18-2009, 05:23 PM   #18
EMS
Scooby Newbie
 
Member#: 14116
Join Date: Jan 2002
Default

Quote:
Originally Posted by Marnix View Post
Mark, when you are going to try this, heat the block with torque plate fitted; I'm very interested in the results as I will have to bore and/or hone an EJ25 for a German customer in January...

Of course I will heat it with toque plate! I don't have such a big oven, so I think we will use the engine washing machine from my engine shop.
EMS is offline   Reply With Quote
Old 12-19-2009, 12:06 PM   #19
sama lama
Scooby Newbie
 
Member#: 136231
Join Date: Dec 2006
Chapter/Region: South East
Location: Lebanon TN
Vehicle:
95 LX Impreza
blue

Default

Torque plates should not matter as much on an ej engine because the head studs or bolts pull from way down in the block. Most engines the head bolts pull from the deck surface and deforms the bore at the top of the cylinder where most of the compression happens. At bottom dead center compression loss is minimized. At most shops they only hone the last few thousandths with torque plates.
sama lama is offline   Reply With Quote
Old 12-20-2009, 01:06 AM   #20
2milehi
Scooby Specialist
 
Member#: 81633
Join Date: Feb 2005
Location: Dillon, CO
Vehicle:
'98 RS-T
Blue

Default

Quote:
Originally Posted by sama lama View Post
Torque plates should not matter as much on an ej engine because the head studs or bolts pull from way down in the block. Most engines the head bolts pull from the deck surface and deforms the bore at the top of the cylinder where most of the compression happens. At bottom dead center compression loss is minimized. At most shops they only hone the last few thousandths with torque plates.
+1, one of the muscle car rags in the 90's did a honing comparison with and without a torque plate. The magazine showed the difference in honing around the head bolts at top of the cylinders.

Last edited by 2milehi; 12-20-2009 at 09:20 AM.
2milehi is offline   Reply With Quote
Old 12-20-2009, 10:40 AM   #21
modaddict
Scooby Guru
 
Member#: 95840
Join Date: Sep 2005
Chapter/Region: NWIC
Location: Pasco, WA
Vehicle:
sold to a good bud
awaiting next car

Default

There is also this thread:

http://forums.nasioc.com/forums/show....php?t=1431376

1st post. "machining" section.
modaddict is offline   Reply With Quote
Old 12-20-2009, 12:50 PM   #22
06STi
Scooby Specialist
 
Member#: 97561
Join Date: Oct 2005
Location: GT30R Cosie-Hybrid
Vehicle:
2006 Widebody
WRB/Carbon/Primer

Default

Quote:
Originally Posted by 2milehi View Post
Factory doesn't use a torque plate.
Which is why the bores are square.

Also it comes down to what type of rings are used. Some rings are able to deal with a non perfect bore. Some rings need it.
Talk with your engine builder about what piston and rings your running. Then see what he thinks about boring.

I myself have seen the square bores, So I would never not use a torque plate.
06STi is offline   Reply With Quote
Old 12-20-2009, 12:58 PM   #23
06STi
Scooby Specialist
 
Member#: 97561
Join Date: Oct 2005
Location: GT30R Cosie-Hybrid
Vehicle:
2006 Widebody
WRB/Carbon/Primer

Default

Quote:
Originally Posted by sama lama View Post
Torque plates should not matter as much on an ej engine because the head studs or bolts pull from way down in the block. Most engines the head bolts pull from the deck surface and deforms the bore at the top of the cylinder where most of the compression happens. At bottom dead center compression loss is minimized. At most shops they only hone the last few thousandths with torque plates.
They still have a slight compresion of the block materal. Which can and does cause block distortion.

Have you ever read the cosworth outline for installing their heads? They set the shim lash when you get them. Then they have to be adjusted when they are bolted to the heads. They go off a few thousands..
06STi is offline   Reply With Quote
Old 12-20-2009, 01:02 PM   #24
06STi
Scooby Specialist
 
Member#: 97561
Join Date: Oct 2005
Location: GT30R Cosie-Hybrid
Vehicle:
2006 Widebody
WRB/Carbon/Primer

Default

Quote:
Originally Posted by Cosworth
understand that the EJ257 cylinder block is more of a "case" than it is a block. Because it is virually hollow and its walls are quite thin, it is subject to severe distortion when head and block fasteners are torqued. Here are some tips for honing a Subaru engine block.
Taken right from that posted link. The subaru motor is no different then the ducati racing spec motors I build.
06STi is offline   Reply With Quote
Old 12-20-2009, 02:34 PM   #25
EMS
Scooby Newbie
 
Member#: 14116
Join Date: Jan 2002
Default

Quote:
Originally Posted by 2milehi View Post
+1, one of the muscle car rags in the 90's did a honing comparison with and without a torque plate. The magazine showed the difference in honing around the head bolts at top of the cylinders.
Very nice and useful information...

If you had measured a Subaru with and without torque plate fitted, you would know that the cilinders will be compressed when the head (or torque plate) is fitted. This causes the bores to be ovalised and getting bigger especially in the middle.
EMS is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
WTT: My RCE lowering camber plates for your non-lowering plates Jard Suspension/Brakes/Handling 6 04-29-2008 11:09 PM
WTT: RCE Lowering Camber Plates for Non-Lowering Plates Jard MAIC Private Classifieds 7 09-27-2007 03:35 PM
Tilton Twin Plate VS. Exedy Twin plate majunche66 Transmission (AT/MT) & Driveline 6 03-08-2006 12:35 PM
Pillow Balls vs Camber Plates vs STi Strut Tops vs Stock Tops Bob O Brakes, Steering & Suspension 5 09-17-2005 11:58 PM
Primitive Racing skid plate vs Subaru OE plate remarcable Interior & Exterior Modification 8 04-26-2001 12:02 AM

All times are GMT -4. The time now is 10:27 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.