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Author Topic:   no compression on a fresh sbc350
posted July 26, 2003 12:54 PM
ok i tech ? i just rebuild a sbc 350 with double hump heads, i put 11:5:1 pistons. well with the 64cc heads its 11:5:1 i checked the compression before actually fire the engine. it was around 180 psi, and now i finally got all my stuff installed and ready to start it. did another compression test and all the cylinders are below 100 psi ., is this at all common ? any help appreciated thnx

jhon hollomon
posted July 26, 2003 01:42 PM
The rings probably haven't seated good yet.

rico 08
posted July 26, 2003 08:42 PM
If you put oil in the cylinders when installing the pistons this will bring up the compression,then after turning over the motor a few times it will go down.Also make sure the carb is wide open,this will lower the readings also.

posted July 26, 2003 08:49 PM
that does not sound right. similair motor this year with 10.5:1 , was 170 in dry dock, after break in 175, and after seating pistions with a few laps around the track, 180.

maybe compression tester gone bad?

[This message has been edited by avila (edited July 28, 2003).]

posted July 29, 2003 02:01 PM
Well finally fired engine, ran it about 2 hours, runs great and now carring a steady 189 psi compression on all 8. fires the 112 octane good. sounds great ., gonna finish scaling the car out and see how it does this sat.. thnx

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