Compression test ??

[777stickman]

Compression test during plug replacement on the "57 3CAR".

High=125 (3, 7 & 6) Low 115 (8). The rest in the 120 range.

Specs: SBC 355. 12k miles. Edelbrock RPM heads (70cc). Edelbrock RPM cam. Flat top pistons, Edelbrock Pro-Flow Injection system.

Plugs 2 & 8 were darker than the rest (maybe injectors), otherwise good tan color.

Compression test done with motor at room temp (85 degs), throttle body wide open and all plugs removed. I did not do an oil squirt into the cylinders. (probably should have).

Question is, with the Edlebrock RPM cam profile is the 120 average psi ok.

The cam timing is advanced 2-4 degs for better low end.

The motor runs great with some oil consumption depending on how hard I abuse it.

[maxwedge]

What are the cam specs at .050 lift? What is the engine's static compression ratio?

[777stickman]

Compression ratio approx 9.5:1.

Duration @ .050. Int=234 deg------Exh=244 deg
Lift @ valve Int=.488----------Exh=.510
Timing @ .050
Int= open 10deg BTDC----------close 44deg ABDC
Exh=open 59deg BBDC----------close 5deg ATDC

These specs are for "straight up" cam timing. The cam is advanced 2-4 degs for better low end................Steve

[maxwedge]

That compression seems low with your set up, a leak down test should be done to really check things out, how does it run?

[777stickman]

Max: Motor runs great. Good power and response. Recently "street" raced a buddy with a modified 440 Dart. Uphill passing lane 30mph rolling start (just past the CHP office). When we shut down at the top (95mph) he had about 2 cars on me. He had a great smile 'cause he beat me and I had a great smile 'cause he didn't beat me as bad as I thought he would. He's 62 and I'm 65. I love being young!!!

Leak down test will have to wait until after the snow flies. Lots of shows and "Hot August Nights" next month.

Thanks again Max..........Steve

[maxwedge]

2 young guys huh, I am 69!!