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cranking compression check #1460562 06/30/13 09:34 PM 06/30/13 09:34 PM
Joined: Jan 2007 Posts: 8,067 Mt Morris Michigan mopar dave OP master
mopar dave OP master Joined: Jan 2007 Posts: 8,067 Mt Morris Michigan	408 roared back to life today after the cam swap. did a cranking comp. check with engine cold about 190avg. I think the old avg with the other grind was 175. so picked up atleast another 15psi. my question is when checking the cranking comp. is it recommended the engine be hot or does it not make any difference? ran out of time or I would have tried it hot. still need to check lash hot and retune carb mixture screws. I did notice the vacume reading was about 3" higher in gear. http://www.youtube.com/watch?v=aIxaesJ190U http://youtu.be/lCZAaN7fFLg

Re: cranking compression check [Re: mopar dave] #1460563 06/30/13 09:40 PM 06/30/13 09:40 PM
Joined: Jan 2003 Posts: 11,657 Fitchburg,Massachusetts MPerry Mopahts memba'
MPerry Mopahts memba' Joined: Jan 2003 Posts: 11,657 Fitchburg,Massachusetts	Yes engine at operating temperature is what is recommended.

Re: cranking compression check [Re: mopar dave] #1460564 07/01/13 10:34 AM 07/01/13 10:34 AM
Joined: Oct 2003 Posts: 7,506 Az Crizila master
Crizila master Joined: Oct 2003 Posts: 7,506 Az	Quote: 408 roared back to life today after the cam swap. did a cranking comp. check with engine cold about 190avg. I think the old avg with the other grind was 175. so picked up atleast another 15psi. my question is when checking the cranking comp. is it recommended the engine be hot or does it not make any difference? ran out of time or I would have tried it hot. still need to check lash hot and retune carb mixture screws. I did notice the vacume reading was about 3" higher in gear. Doesn't make any difference if you do it hot or cold as long as you do it the same way every time - same gauge, temp, # of pumps, battery fully charged ( I do one bank and then recharge the battery before I do the other bank ). You are really referencing between holes and the previous comp check. One check, by itself, only gives you limited info. A string of them, all done the same way, will be much more informative. Fastest 300

Re: cranking compression check [Re: Crizila] #1460565 07/01/13 10:40 AM 07/01/13 10:40 AM
Joined: Jan 2007 Posts: 8,067 Mt Morris Michigan mopar dave OP master
mopar dave OP master Joined: Jan 2007 Posts: 8,067 Mt Morris Michigan	when I did it I had bat. charger on bat. and when it read 13.3v I would crank 6 times each cylinder. didn't sound like it cranks as fast as it used to. maybe bat. getting tired. http://www.youtube.com/watch?v=aIxaesJ190U http://youtu.be/lCZAaN7fFLg

Re: cranking compression check [Re: Crizila] #1460566 07/01/13 11:07 AM 07/01/13 11:07 AM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Doesn't make any difference if you do it hot or cold as long as you do it the same way every time - same gauge, temp, # of pumps, battery fully charged ( I do one bank and then recharge the battery before I do the other bank ). You are really referencing between holes and the previous comp check. One check, by itself, only gives you limited info. A string of them, all done the same way, will be much more informative. Yep... I do it cold just so I dont burn myself..its just a reference to look back at

Re: cranking compression check [Re: mopar dave] #1460567 07/01/13 11:31 AM 07/01/13 11:31 AM
Joined: Mar 2008 Posts: 5,746 Ontario, Canada Dodgem master
Dodgem master Joined: Mar 2008 Posts: 5,746 Ontario, Canada	I've done them cold and hot (well warm by the time you can work on it) not much difference often seems to be 2 to 5 lb lower warm heard that is as the oil film on the cylinders is thicker cold??

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