Info about TRW pistons [Archive] - Team Camaro Tech

: Info about TRW pistons


GM man
Apr 4th, 02, 12:48 AM
A friend of mine has a set of TRW forged pistons and I'd like to buy them. However, eh doesn't have any printed material about the pistons.
They are TRW L 2304 030 oversize. I would put them into '79 350 cid sb Chevy with stock 76 cc iron heads, Crane 296 Fireball cam and stock rods. My friend recalls that the pistons are ment to use in an older 350sb and they will give a 11:1 compression rate. That is too much for me, allthough I'm able to use 98 octane gasoline.
Could anyone give me any infomation about those pistons and how much would the compression ratio be with them?

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PDQUICK
Apr 4th, 02, 02:19 AM
There's not much info on the web about these pistons, except that they are a good, forged piston, and have a .100" dome.

If you figure that the dome is worth 7-10cc (negative when you figure the CR), with a .039" gasket your CR will be approximately:

10.25-10.5 with 72cc heads
11.25-11.5 with 64cc heads

I would cc the domes to figure an accurate CR. But, ya might wanna shave the domes a little bit on these bad boys for street use!

joesmith69
Apr 4th, 02, 02:48 AM
According to what you just said, that 76CC head should keep compression under 10:1.

Should be fine, you may have to run premium or retard the timing slightly though.

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79' Z28 4-spd- built 355, TRW 10:1 forged flat tops, WP SportsmanII heads, Crane Energizer 228* duration .480" lift, Edelbrock Victor Jr., Holley 750cfm, Dynomax headers, dual 3" flowmasters :) 3.73 Posi 10-bolt

stingr69
Apr 4th, 02, 05:16 AM
Be careful when shaving those domes. I have some TRW/Speed Pro forged domed pistons and the domes are hollow on mine. The company was bought out by Federal Mogul and we realy got screwed in the process. They used to have a great web site with tons of useful information but that was taken down at some point. I had saved a copy of the info from the site that might be useful here. "Some domed pistons can be modified to a flat top, to lower compression ratio, but this is not a job for the home engine builder. A minimum head thickness of .180" for forgings, or .220" for hypereutectics must be maintained, with greater thickness required for endurance, nitrous, or blower use." Watch the underside of the piston and take careful measurements when you decide to have them milled.

I thought they also shut down the forging factory too. None of this is a good thing for our hobby.

I hope this is helpful.

-Mark.

GM man
Apr 4th, 02, 10:18 PM
Thank You very much! I think that was great news to me! I 'm gonna buy those pistons and put them into my Camaro.
Those web pages of Federal Mogul are just nonsense, no help at all! But luckily there are these Camaro pages, where all the best mechanics are.
Thanks!

secndgn
Apr 5th, 02, 03:48 AM
L2304's are the 1970 LT1/Z28 type piston, 11.0 to 1 with 64cc heads.

Lonnie67
Apr 5th, 02, 06:31 AM
Assuming you will get 11.0:1 with 64cc heads, you will have 9.6:1 with 76cc heads. Not the most efficient way to get there, but I guess it'll work. You might want to rethink that cam. What are the full specs on it?

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67 Camaro 410sb 11.63 @117.6
67 Camaro 388 12.10 @110.6, best MPH 112.96
website (http://www.geocities.com/lonnie67_1966)

SY1
Apr 5th, 02, 08:16 AM
Gman,
L2304 are forged .100 dome pistons for 350. With stell head gasket and 64cc chamber you get 11:1, 68cc chamber gets you 10.4:1 and 76cc gets you 9.75:1

Dave

GM man
Apr 7th, 02, 12:45 AM
<BLOCKQUOTE>quote:</font><HR>Originally posted by Lonnie67:
Assuming you will get 11.0:1 with 64cc heads, you will have 9.6:1 with 76cc heads. Not the most efficient way to get there, but I guess it'll work. You might want to rethink that cam. What are the full specs on it?

<HR></BLOCKQUOTE>

Here are the cam specs. What do you think of it, is it OK?


Crane Camshaft Specification Card


Part Number: 11X792
Grind Number: FIREBALL 296A
Engine Ident: 1957-1987 CHEVROLET V-8
262 THRU 400 CU.IN.
FAIR IDLE, MODERATE
PERFORMANCE USAGE,
GOOD MID-RANGE H.P.,
BRACKET RACING

VALVE SETTING: INTAKE .000 EXHAUST
.000 ----&gt; HOT

LIFT: INTAKE @CAM 303 @VALVE 455
EXHAUST @CAM 303 @VALVE 455
ROCKER ARM RATIO 1.50
ALL LIFTS ARE BASED ON ZERO LASH AND
THEORETICAL ROCKER ARM RATIOS


CAM TIMING
@ .0034 TAPPET LIFT
OPENS CLOSES ADV DUR
INTAKE 34BTDC 82ABDC 296 DEG
EXHAUST 82BBDC 34ATDC 296 DEG


SPRING REQUIREMENTS
TRIPLE DUAL OUTER INNER
PART NUMBER 99848

LOADS:

CLOSED 105 LBS @ 1.700 OR 1 45/64
OPEN 273 LBS @ 1.260
RECOMMENDED RPM
RANGE WITH MATCHING COMPONENTS
MINIMUM RPM 2500
MAXIMUM RPM 5500
VALVE FLOAT 6500

CAM TIMING
@.050 TAPPET LIFT
OPENS CLOSES MAX LIFT DURATION
INTAKE 2 BTDC 40 ABDC 109 ATDC 222

EXHAUST 50 BBDC (8)BTDC 119 BTDC 222

REMARKS: