3K Compression? ?

[rolla76]

hi guy just want to know what a good compression is for a 3k thanks

[altezzaclub]

Anywhere between 9.6 and 10 to one, depending on what you want to use it for, what fuel you're going to use and what cam you're going to run.

 

If you're talking psi on a compression test, then 130 would be the minimum for a motor that runs, 150 would be a good motor, and above that would be great. They should all be within 5 or 10psi.

[rolla76]

thanks for the info iv got a blowen head gasket but still got 150 110 150 155 so thats a good start apart from the 110 psi

[altezzaclub]

Head gaskets blow when the head gets warped between 2 and 3, so its probably dumping compression into the water from #2. I've got the same on my new car, but its not bad enough to panic over yet, just starts on 3cyl for 20seconds and bubbles come out the rad.

 

The big decision is, do you do any other mods while the head is off?? Skim for higher comp, fit extractors, fit twin carbs... which is what I'm thinking about now.....

 

Don't forget to solve the problem that caused it to overheat in the first place! You wouldn't want to blow a second gasket... The previous owner replaced the leaking radiator, but was ripped by a garage for new plugs, leads, dizzy and a stack of stuff chasing the very obvious head gasket misfire!

[rolla76]

The car didnt over heat or anything just took it around the block for a strap then i cheaked the oil cap later on that night and had the sign of milky on cap, but yea iv got motor out on stand getting ready to strip it down to put lumpy cam more compression and extractors, twin webber and a k50 box,

The car ran really smooth b4 that so hope to have some good luck with the old 3k motor. I'm just getting as much info as possible to help me on my way, still looking for the 3k engine repiar manaul .