What exactly are TRW Forged pistons - Team Camaro Tech
Engine General Engine Discussion.

 
LinkBack Thread Tools Display Modes
post #1 of 10 (permalink) Old Jul 23rd, 03, 06:41 PM Thread Starter
Senior Tech
 
Join Date: Dec 2001
Location: The Mighty Midwest
Posts: 2,522
Post

What are these and how are they any different from any other type of pistons

[ 07-24-2003, 12:59 AM: Message edited by: garfield ]
garfield is offline  
Sponsored Links
Advertisement
 
post #2 of 10 (permalink) Old Jul 23rd, 03, 07:13 PM
Senior Tech
 
Join Date: Jan 2001
Location: skiatook, ok
Posts: 3,692
Post

Why, they are a forged piston made by TRW (now federal mogul), of course Years ago if you wanted an affordable forged piston, TRW was about the only option.
travis is offline  
post #3 of 10 (permalink) Old Jul 23rd, 03, 07:53 PM Thread Starter
Senior Tech
 
Join Date: Dec 2001
Location: The Mighty Midwest
Posts: 2,522
Post

How are they any better (different) from stock?
garfield is offline  
 
post #4 of 10 (permalink) Old Jul 23rd, 03, 09:32 PM
SY1
Senior Tech
Dave
 
Join Date: May 2001
Location: Michigan
Posts: 2,920
Post

The vast majority of GM pistons were cast. As far as forged pistons that GM used in high performance motors they were made by TRW and do not have the vertical ribs inside the skirts. TRW replacements have these. Supposedly they are stronger with the extra material. There are sometime other differences as well. For example 69 Z28 forged pistons carrying the part number 3927172. I have had several sets of these and have noticed differences in some of them. Ring land sizing and spacing, oil control hole diameter and number of holes have sometimes been different on some sets, even though they had the same GM part number. I've got one of the above part number pistons in front of me, it doesn't have the ribs, uses the larger ring sizes and larger, but fewer oil control holes. The reason I never used this piston is they did a poor job machining one side of the wrist pin retainer grooves. A good machine shop can fix that.

I said they are supposedly stronger because I purchased a set from Yunick's that Smokey had modified extensively. They were the GM part 3927172. I would think if there was a significant difference in strength he would have selected the TRW replacement over the GM part. With the amount of material he had removed from these pistons it doesn't appear strength is a big concern.

I've run both types of piston and haven't had a problem with either style.

[ 07-24-2003, 10:01 AM: Message edited by: SY1 ]
SY1 is offline  
post #5 of 10 (permalink) Old Jul 23rd, 03, 10:59 PM Thread Starter
Senior Tech
 
Join Date: Dec 2001
Location: The Mighty Midwest
Posts: 2,522
Post

Oh, Thanks [img]graemlins/thumbsup.gif[/img]

When you buy an American car, you provide work for a man and his family for three months. -Jay Leno
garfield is offline  
post #6 of 10 (permalink) Old Jul 23rd, 03, 11:26 PM
Senior Tech
Mark
 
Join Date: Feb 2002
Location: LR AR
Posts: 2,372
Post

They are heavy. That is why Smokey milled so much off of them. Strong but heavy. I milled mine down to get the C/R where I wanted it and they ended up being slighly less wt than a stock TRW slug.

-Mark.
stingr69 is offline  
post #7 of 10 (permalink) Old Jul 24th, 03, 01:47 AM
Senior Tech
 
Join Date: Sep 2001
Location: Elizabethtown, PA
Posts: 980
Send a message via AIM to Spames
Post

I thought cast meant cast in a mold (like jello), and forged meant forged, like taking a piece of metal and pounding it into shape
Spames is offline  
post #8 of 10 (permalink) Old Jul 24th, 03, 08:05 AM
SY1
Senior Tech
Dave
 
Join Date: May 2001
Location: Michigan
Posts: 2,920
Post

Mark you're probably right on the weight. It is kind of scary though how much material he removed. The pads below the wrist pin bores were gone. It's a straight line across the base of the piston, the skirts were intact though. It's surprising to see how little material was left below the wrist pin bores.

"..............what, and get out of aviation??"
SY1 is offline  
post #9 of 10 (permalink) Old Jul 24th, 03, 04:50 PM
 
Join Date: Apr 2000
Posts: 21,341
Smile

Spames,

You have it just about right except they hydraulically warm press a slug to make them so they flow better instead of hot hammer forge them like a hunk of steel.

As for cast, I think they still do sand cast some pistons as well as use permenant free flowing molds and die cast like pressure cast again in permenant molds.

It's the silicon content of the metal that still confuses people...

Like hypo-eutectic, or below the eutectic point, eutectic or at the mix point where the metal upon setting won't lose any silicon alloy due to extra silicon grain growth and hyper-eutectic or over the saturation point of metal such that too much is in the aluminum so that it has to be mixed to keep it in suspension and when cooled makes a fine silicon grained wear matrix sorta thing...

pdq67



pdq67 is offline  
post #10 of 10 (permalink) Old Jul 25th, 03, 01:51 AM
Senior Tech
 
Join Date: Sep 2001
Location: Elizabethtown, PA
Posts: 980
Send a message via AIM to Spames
Post

That makes sense to me!
Spames is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome