115 recap comp question

[Benny1963]

1976 115 whent to run comp check. starter seemed to run alittle slow
battery was not hot or starter was draging . i got 60 psi per cyl across the board . does the battery have to spin a full capacity to run comp check these numbers were low but not sure motor turned fast enough
motor has sat should i spray some wd or deep creep and try again with good battery or can i get good reading with motor turning over slow
thanks bennyb

 

[guy74]

Re: 115 recap comp question

Needs to spin over good to get useable numbers. The fact that they are all the same is encouraging.
Goodluck,
Brian

 

[crb478]

Re: 115 recap comp question

That motor needs a fully charged battery to get the full compression numbers or to start. It takes somewhere around 300 rpm to start. Ideally you should get something over 100lbs on each cylinder and within 10 percent of each other.

 

[ezeke]

Re: 115 recap comp question

Keep all the spark plugs out, spray some fogging oil in the cylinders and run the test on jumper cables to get the speed. Test cylinders 1 to 4 and do it again 4 to 1 to give it a fair shot.