04-17-2006, 05:31 PM
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#1
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AF Regular
Join Date: Jan 2006
Location: Indianapolis, Indiana
Posts: 63
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Compression
I have completed a compression check and I have made peace with the findings.
#1 = 155, #3 = 40, #5 = 55
#2 = 125, #4 = 162, #6 = 175
So as I tear down to do my first head & intake gaskets which looks like an engine rebuild to me, I will be cruising along asking for tips along the way.
1st ?
Asside from the obvious gaskets and machine shop sevices, any other repairs or replacements I should do along the way.
thanks in advance
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04-17-2006, 07:16 PM
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#2
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A990 racer
Join Date: Mar 2002
Location: Chestertown, New York
Posts: 12,373
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Re: Compression
What engine, what general condition, what mileage?
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04-17-2006, 08:36 PM
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#3
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AF Regular
Join Date: Jan 2006
Location: Indianapolis, Indiana
Posts: 63
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Re: Compression
Quote:
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Originally Posted by maxwedge
What engine, what general condition, what mileage?
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Oops, sorry, My '95, 3.1, APV, w/115,000. It was an ebay purchase 3 years ago and after research discovered it was a repo and possibly spent some time partially submerged in water. None of this showed up on carfax. I have spent the last three years doing routine maintenance and replacing electrical components as they malfuntioned. Changed water pump and T-stat upon delivery.
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04-18-2006, 12:50 AM
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#4
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AF -Advisor
Join Date: Nov 2003
Location: Maple Lake, Minnesota
Posts: 4,437
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Re: Compression
could bad head gaskets really cause compression readings that low? sounds almost like a valve not opening right to me.
__________________
2000 Pontiac Grand Prix GTP
(3.4" Pulley, DHP 1.5 Powertuned PCM, ZZP 2.5" High Flow Downpipe, MMS Ported and Polished Lower Intake Manifold, ZZP Stage 1 Ported Throttle Body, 180° Thermostat, NGK Iridium TR6IX)
1997 Chevrolet Silverado K1500 4x4 350
(soon to come,true dual exhaust, roll-up access tonneau cover, light bar)

Check this out! (Good Stuff)
Honda Cog Commercial
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04-18-2006, 12:51 AM
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#5
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AF -Advisor
Join Date: Nov 2003
Location: Maple Lake, Minnesota
Posts: 4,437
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Re: Compression
i see now, if 3 and 5 cylinders are leaking into eachother.
__________________
2000 Pontiac Grand Prix GTP
(3.4" Pulley, DHP 1.5 Powertuned PCM, ZZP 2.5" High Flow Downpipe, MMS Ported and Polished Lower Intake Manifold, ZZP Stage 1 Ported Throttle Body, 180° Thermostat, NGK Iridium TR6IX)
1997 Chevrolet Silverado K1500 4x4 350
(soon to come,true dual exhaust, roll-up access tonneau cover, light bar)

Check this out! (Good Stuff)
Honda Cog Commercial
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04-18-2006, 10:16 AM
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#6
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parts monkey slayer
Join Date: Aug 2004
Location: Flint, Michigan
Posts: 9,456
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Re: Compression
Yep, you have a head gasket leaking between 3 and 5, or a cracked head. Definitely take the heads in and have them pressure tested and resurfaced. Make sure you do both, not just the one. Replace the t-stat, while it's down, it's due. I believe while tracking this down, you tuned it up, so those parts should be ok to re-use. Change any filters you haven't already done, and make sure you have a good torque wrench for re-assembly.
__________________
Would you drive any better with that cell phone up your ...?!
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04-18-2006, 03:07 PM
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#7
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AF Regular
Join Date: Jan 2006
Location: Indianapolis, Indiana
Posts: 63
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Re: Compression
Quote:
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Originally Posted by richtazz
Yep, you have a head gasket leaking between 3 and 5, or a cracked head. Definitely take the heads in and have them pressure tested and resurfaced. Make sure you do both, not just the one. Replace the t-stat, while it's down, it's due. I believe while tracking this down, you tuned it up, so those parts should be ok to re-use. Change any filters you haven't already done, and make sure you have a good torque wrench for re-assembly.
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Thanks Rich, I am planning on doing both sides, I have always done things in pairs. Especially here since working from the easy side to the back will make doing the backside easier. I also am replacing most vacuum lines as I rebuild and will probably add a reman'd T-body. The radiator also has a leak so it is coming out to be repaired or replaced. I should have plenty of room to work and hopefully have a well running van after this. Been saving egg cartons and cardboard to stay organized and have some bus tubs for holding/cleaning large parts.
When the heads go to the shop, does the intake also benefit from going to the shop?
By good torque wrench I hope both current ratcheting Craftsman (inch #s & ft. #s) qualify. I did have to special order a set of female torx sockets.
Thanks again
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04-18-2006, 05:29 PM
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#8
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Lactose the Intolerant
Join Date: Aug 2004
Location: Arnold, Missouri
Posts: 5,910
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Re: Compression
Also remember if any coolant went into the combustion chambers, either from the leak or from the repair, the o2 sensors will get crapped up, if it's running silicated (old style) anti-freeze.
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You made three mistakes. First, you took the job. Second, you came light. A four man crew for me? F**king insulting. But the worst mistake you made...
...empty gun rack.
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04-19-2006, 12:08 PM
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#9
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parts monkey slayer
Join Date: Aug 2004
Location: Flint, Michigan
Posts: 9,456
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Re: Compression
Craftsman definitely qualify as good ones. Good luck, and don't forget to ask for help if you run into any issues as you go. After all, that's what we're here for. Good suggestion Jeff, o2's and antifreeze don't play well together.
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Would you drive any better with that cell phone up your ...?!
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04-19-2006, 02:47 PM
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#10
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AF Regular
Join Date: Jan 2006
Location: Indianapolis, Indiana
Posts: 63
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Re: Compression
Thanks to both Rich and Jeff, I was planning on replacing all sensors especially the ones that are hard to reach.
? for Rich in Parts  . Is it possible to order the complete set of vacuum lines from GM. I like the preformed a/k/a idiot proof way they are molded to where they go. Of course if I run flexable line they won't be so brittle in winter.
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04-19-2006, 03:10 PM
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#11
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parts monkey slayer
Join Date: Aug 2004
Location: Flint, Michigan
Posts: 9,456
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Re: Compression
The emissions control vacuum harness is GM part #10146885 and is still available. Dealer retail is $40, and it includes everything but the tube to the PCV valve, which is part #10065462, and runs $6 at the dealer. Since these parts aren't Delco (they're dealer only), I couldn't sell them to you any cheaper once you factor in shipping.
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Would you drive any better with that cell phone up your ...?!
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04-19-2006, 04:39 PM
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#12
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AF Regular
Join Date: Jan 2006
Location: Indianapolis, Indiana
Posts: 63
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Re: Compression
Thanks dude, That is good to know, Just need to decide if idiot proof is worth the winter brittleness that has some lines broken and repaired w/heatshrink.
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04-19-2006, 04:39 PM
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#13
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AF Regular
Join Date: Jan 2006
Location: Indianapolis, Indiana
Posts: 63
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Re: Compression
Thanks dude, That is good to know, Just need to decide if idiot proof is worth the winter brittleness that has some lines broken and repaired w/heatshrink.
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