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cyl. pressure psi ? #773656
08/14/10 05:20 PM
08/14/10 05:20 PM
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earthmover Offline OP
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earthmover  Offline OP
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Hay guys I ran a comp. Check on the old 340 and I got some diff. Reading and want your thoughts on what I got. I got 1 cyl at 160 the lowest and few at 175 and everything else on 185 is that to bad to keep running or is it time to spend

Re: cyl. pressure psi ? [Re: earthmover] #773657
08/14/10 05:28 PM
08/14/10 05:28 PM
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emarine01 Offline
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If you post more info like what the testing order was and haw you did the test, all plugs out with engine hot .... ect, sometimes the cranking speed will effect the #s, a leak down test might be next

Re: cyl. pressure psi ? [Re: emarine01] #773658
08/14/10 05:35 PM
08/14/10 05:35 PM
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earthmover Offline OP
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Ok sorry I had motor at 180 temp. All plugs out carb open and turn motor same #s of turns. I tried 1 cyl on leak down but never did it before so I stopped.how is it done thanks mike

Re: cyl. pressure psi ? [Re: earthmover] #773659
08/14/10 06:11 PM
08/14/10 06:11 PM
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emarine01 Offline
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Were you charging the batt during the test? Some times the last few cyls will read low on compression as the batt fades, What type of leak down tester are u using

Re: cyl. pressure psi ? [Re: earthmover] #773660
08/14/10 06:12 PM
08/14/10 06:12 PM
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Romeo MI
MR_P_BODY Offline
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Quote:

Ok sorry I had motor at 180 temp. All plugs out carb open and turn motor same #s of turns. I tried 1 cyl on leak down but never did it before so I stopped.how is it done thanks mike




Next thing to do is squirt some oil in each cyl and
re test the compression to see if its valves or rings
(have a battery charger on it)... the one cyl is low
in relation to the highest... 10% is suppose to be the
max difference

Re: cyl. pressure psi ? [Re: MR_P_BODY] #773661
08/14/10 07:22 PM
08/14/10 07:22 PM
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earthmover Offline OP
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Thanks guys yea I had the batt charger on and the lowest 1 is the 1st to be checked #1 but could the val. Lash have a affect on this cause I did it last time and never did it before so I'm gonna check all that as well. Car has been a best of 7.44 in the 1/8 mile last night was a best of 7.70 with 1.70 short times and 90 mph people told me the car pick the wheels up a little and went bout 5ft with them but something is going on here I changed jets cause lean cond. And the front got worst don't know how but did. Just trying to get this thing back where it was or close. I made some changes since it ran the best in this order I moved muff. Back 18 inch from coll. Got fuel system up to par adv cam 4 deg and moved timing to 34 from 38 so help please I will shoot oil in and report back thanks mike

Re: cyl. pressure psi ? [Re: earthmover] #773662
08/14/10 07:31 PM
08/14/10 07:31 PM
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emarine01 Offline
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The valve lash being too tight can drop cyl pressure, valve not sealing, Your #s spread is showing some things up, If its a ring seal issue I would just wait till winter and over haul

Re: cyl. pressure psi ? [Re: emarine01] #773663
08/14/10 08:03 PM
08/14/10 08:03 PM
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earthmover Offline OP
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Yea. I don't want to rebuild right now plan to build something new next year so want to get by but man . Anyway could adv. The cam make this happen where I lost 3ths with all the mods I did would have thought that I help with the verta at lease buyt dunno

Re: cyl. pressure psi ? [Re: earthmover] #773664
08/14/10 08:23 PM
08/14/10 08:23 PM
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY Offline
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Quote:

Yea. I don't want to rebuild right now plan to build something new next year so want to get by but man . Anyway could adv. The cam make this happen where I lost 3ths with all the mods I did would have thought that I help with the verta at lease buyt dunno




Have you checked to see if you have a lobe on the
cam going south(check the cyl that is low)

Re: cyl. pressure psi ? [Re: MR_P_BODY] #773665
08/14/10 08:33 PM
08/14/10 08:33 PM
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earthmover Offline OP
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Ill check that mr.p never thought bout that good to know







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