What compression are these pistons (pic)

[My Black Beast]

Hey, I just took the heads off the car and I know the engine has been rebuilt before I got the car. I was just wondering if anyone knows around what compression ratio those pistons are giving me. I have stock heads on it also. Thanks, Mike

 

[Rick 91GT]

I would say with a stock head you would be in the 8.XX range. CC the reliefs, once you know how much volume they take up I could give you an accurate number. Do they have a PT# scribed in the tops under all the build up?

 

[My Black Beast]

Since they are domed pistons, wouldn't that raise the compression? Isn't the stock compression like 9:1. Mike

 

[poneypower89]

Yes, if they are doomed pistons the compression should raise. We (some buddies) built a 302 last year with some doomed pistions and stock heads.. compression was right around 11:1... but its hard to tell by just looking at ur pistons what compression you may be running.

 

[1SLO306]

but its hard to tell by just looking at ur pistons what compression you may be running.

I was thinking the same

 

[MadDAWG_zr2]

those look like the Keith Black pop up pistion. when I ran them with a 58cc head they were just short of 11:1 on a 0.040 over bore.

 

[retro50]

They look like the old TRW's to me! If they have a .440 dome there probably TRW Forged. If they have a .200 dome then there probably Keith Black Hyperutectic. If they are the K.B. pistons then You'll have high 9's-low 10's on the compression ratio with a 60c.c. head, uncut block and around a .042 gasket. I don't have a Federal Mogul Book in front of me to give you a round about figure on the TRW's.

 

[My Black Beast]

They look like the old TRW's to me! If they have a .440 dome there probably TRW Forged. If they have a .200 dome then there probably Keith Black Hyperutectic. If they are the K.B. pistons then You'll have high 9's-low 10's on the compression ratio with a 60c.c. head, uncut block and around a .042 gasket. I don't have a Federal Mogul Book in front of me to give you a round about figure on the TRW's.

Dude, right on the money!! TRW sounded a little familiar so I checked the pistons and one of them said TRW and they all said L2249N 030. Can anyone tell me anything about these pistons?

Somebody sure knows their pistons...

Thanks, Mike

 

[bill302]

.440 dome, Part #'s starting with "L" = Forged,bored .30 over

 

[bill302]

with a 60 cc head you have 10.3:1

 

[My Black Beast]

The previous owner said that the engine is a 306. Would that still be true if I have .030 pistons? I thought 306's would have .040, or am I completely off base here? Thanks, Mike

 

[mikemustang289]

.040 over is a 308

 

[bill302]

a 306 is a 302 bored over .030. without stroker kit you have a 306.

 

[retro50]

Pistons are L2249NF They made these in std.+.030. Bore sizes only. They have a 1.600 Compression Height and a .440 dome. The listed compression Ratio is anywhere from 9.91- 12.85 depending on the cylinder head c.c. (chamber size). With a stock 60 c.c. Head (69-70 351-w) the compression ratio is listed as 11.17:1 with a .036 gasket and the quench pad on the piston down in the cylinder .010. I'd say your compression is in the high 10's with a E-7 Head without knowing any specifics. I got these #'s out of an old 1989 TRW catalog I had Laying around. The ring grooves are listed as 1/16"x1/16"x3/16". Put on a good set of heads and match a cam and int/ex systems and the car will fly. The stock heads are not a good match for those pistons unless they are worked pretty good.

 

[My Black Beast]

a 306 is a 302 bored over .030. without stroker kit you have a 306.

Thanks a lot guys. I guess I got a little confused with the numbers. I am going to be putting the car up for sale since I just bought a house and I am going to focus on the 2.3T for now. This info will help in selling the car. Thanks again, Mike