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Old 02-25-2007, 12:29 PM   #1
meathead95
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engine guru's

i think the engine in my k20 is junk when i got it it ran rough. so i replaced the quadrajet and points with a new hei and edelbrock 600cfm carb and it ran a little better but i still had never taken it on its maiden voyage as i was waiting on brake parts and now it will not start at all and i still have spark and fuel so i ran a compression check on the cylinders and this is what i got


1-70 2-90
3-80 4-110
5-70 6-60
7-95 8-75

i would say it needs a rebuild but do you think these low compression numbers is why it will not run?
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Old 02-25-2007, 12:52 PM   #2
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Re: engine guru's

Generally, any compression pressure under 100 will be a dead cylinder- and you have plenty of them. Most likely tapered cylinders & worn rings. Squirt 3-4 shots of oil from an oil can in each spark plug hole & retest compression. Any cylinders that come up considerably are ring/ cylinder wear. Any that don't are worn valves/ seats or a blown head gasket.
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Old 02-25-2007, 01:25 PM   #3
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Re: engine guru's

5, 6, 7, and 8 already had oil in them lol.........
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Old 02-25-2007, 01:37 PM   #4
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Re: engine guru's

INO, you cant rely on those numbers as the car was cold. Get it to fire up and once warm recheck. Then you have solid numbers to work with.
Did it work after the HEI install?
s/t
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Old 02-25-2007, 01:56 PM   #5
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Re: engine guru's

yes i installed the hei and carb and it ran great in the garage for a few weeks and it got really hard to start and then it wouldnt start and i noticed the rh intake gasket was leaking a little so i took it apart again and replaced the gasket and now it wont run at all.
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Old 02-25-2007, 04:37 PM   #6
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Re: engine guru's

Keith, check and make sure that the distributor didn't get installed wrong. Yes it has low compression but if it ran before you pulled the intake it should still run. Just double check everything and make sure you didn't let it slip a tooth or two.
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Old 02-25-2007, 05:01 PM   #7
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Re: engine guru's

sounds like you got a big combination of stuff fighting against you. if the plugs are oil soaked they are fouled and need replaced.it sounds like its very worn engine but it should still start up. after you get some decent plugs in there make sure you have the distributor in the right place and the correct timing.also you could have a massive vaccum leak if the intake gasket isnt properly seated which will also cause it to not start. recheck everything and make sure the bolts are tights on the intake as well as the carb
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Old 02-25-2007, 05:39 PM   #8
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Re: engine guru's

definitely check the valve seats on the heads when you rebuild it. they are probably non hardened seats made for back in the day when people ran leaded gasoline... they will sink into the head and you wont get a tight seal from the valves. but it sounds like you have piston ring problems to begin with anyways
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Old 02-25-2007, 09:24 PM   #9
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Re: engine guru's

Double check that you didn't get the distributor 180 out. Engine will crank but definitely not sound right. You can also rule out a fuel problem with a little starting fluid, if it will fire on it then it is fuel.
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Old 02-25-2007, 10:09 PM   #10
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Re: engine guru's

i put new plugs in it and i took the dizzy out and redid it 3 times and still cannot get it to start im gonna go get the module in the dizzy tested tomorrow it is a brand new summit hei but i guess that doesnt mean anything
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Old 02-25-2007, 10:21 PM   #11
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Re: engine guru's

My .02 - look at the compression. Tapered holes is what I'm throwing at it here. Hard starting because it takes a bunch of moving air to create useable compression, the only way to off-set that is to pump like hell on the throttle while cranking, to make good on the fuel ratio.
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Old 02-25-2007, 10:24 PM   #12
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Re: engine guru's

when it did run before i had to pump it like hell to get it started. and now nothing
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Old 02-25-2007, 10:36 PM   #13
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Re: engine guru's

I don't think it is ignition related here, especially a new dizzy module, you don't have enough heat in it to make a new one go bad. If you have set the dizzy right as much as 3 times, don't seem right that it would be 180 out. I just think you are out of compression. You may want to try advancing the timing a bunch. If it gets running agin, drop some Rislone or an additive in her to help short term with combustion ratios. Bad compression sucks.
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Old 02-26-2007, 02:32 AM   #14
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Re: engine guru's

well all i can say to rebuilding your engine to buying a new one at the GM dealer might be worth checking into here in calif to have a eng rebuilt will cost you 1300.00 1100.00 if you do some short cuts Now GM goodwrench has a deal out for a std bore 350 4 bolt main 240 hp 300 pounds of torq or is it 350 pounds of torq for 1400.00 out the door

this is not a rebuilt or recondtion engine its Brand new nothing inside this eng is used so you get a 350 std bore with valve covers and a oil pan and timeing cover olready installed

all you have to do is put intake water pump and HEI in and bam your ready i've done 1 so far no problems and they give a 1 year 12k warrinty with it and if you put it in and you have a problem with it youcan got back to the dealer ship where you bought it from and most of the times they will take your old one out and drop the new one in as long as you did not modifye it in any way like adding a cam or putting roller lifters in they will replace it

and plus there is NO CORE your buying a brand new engine GM dose not want a Core

Last edited by stsalvage; 02-26-2007 at 02:34 AM.
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Old 02-26-2007, 07:56 AM   #15
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Re: engine guru's

i also forgot to mention the strangest thing ive ever seen was after carnking it to try and get it to start plugs 2,3, and4 where gas soaked 5,6,7, and 8 where gas and oil soaked but #1 was completely dry?
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