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  #1  
Old 04-10-2009, 12:37 AM
Tarrbabe Tarrbabe is offline
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Question Question on compression..........

We all run into things we aren't sure about and this is one for me. I have a 80 step-side with a 318 from another year. The engine is a newer model with roller lifters but not a magnum so it would be from between 86 and 91. It has a flutter in the exhaust on both sides but worse on the pass side. You know what I'm talking about, where the exhaust seems to suck back in. Motor seems to be stock except for MSD/Edie 600 and Headmans.
Because of the flutter on the pass side I decided to run a compression check to see if I had valves starting to burn. The following are the numbers I got.
Pass side front to rear. : 150 - 140 - 160 - 150
Driver side front to rear: 135 - 145 - 130 - 140.
The flutter on the Pass. side doen't make since as the compression is higher on passenger side.
What are your opinion's on this? The engine was started and ran for about a minute before the compression check but was not up to temp. It had been setting for about a week before check.
Engine has 20 lbs oil pressure at idle when up to temp of 190 and 45 lbs when running at 3000 rpm.
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Old 04-10-2009, 12:56 AM
TK TK is offline
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I wouldn't think that is low enough to hear it....... It may just be the really mild cam, and dual exhaust messing with you.
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  #3  
Old 04-10-2009, 04:02 AM
TeamDart TeamDart is offline
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Compression is decent.... could be more even.... but not enough to hear a problem like TK said....
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Old 04-10-2009, 09:40 AM
chirorod chirorod is offline
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I just wonder if it's actually a miss you're hearing. Might be an ignition problem.
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Old 04-10-2009, 02:13 PM
TK TK is offline
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I think it is the very mild cam........... They kinda sound like they are missing, hell, a non HP 70 318, that runs good, you can cut the muffler off and not hear the exhaust at idle.
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  #6  
Old 04-10-2009, 02:22 PM
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cageman cageman is offline
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I think it is the heat crossover in the intake messing with ya.
I have a roller 318 in this truck out of an 88, it makes funny noses out of the straight pipes. No mufflers at all and you can barely hear it run. It does run good though and gets great mileage.
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Old 04-10-2009, 04:43 PM
Tarrbabe Tarrbabe is offline
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Lightbulb Thanks for the feedback.....

I think I need to pull the intake. It has a 68 340 cast intake on the 318 heads. Had to retorqe them already and it ran better but I suspect the damage was already done. I was worried about the drivers side being somewhat weaker in compression than the pass. side. A little more cam equal to the 340 cam would be nice too. I already have a 340 tc that stalled 2300 on my 340.
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Old 04-10-2009, 06:19 PM
TK TK is offline
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Doooo iiiiit!

It will run sweet!
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Old 04-10-2009, 06:20 PM
TK TK is offline
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Nice truck Cage, it looks kinda gloomy outside tho........
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  #10  
Old 04-11-2009, 12:48 AM
Tarrbabe Tarrbabe is offline
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Question Anyone know a cam...............

That is close to the stock 340 cam, but fits the roller cam block of my 318? Can the stock rollers be run with a replacement cam? I am already suspect of any timing chain that I haven't installed so I'm thinking of that already.
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  #11  
Old 04-17-2009, 02:04 PM
Brian Mills Brian Mills is offline
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If you re-tourqued the heads and it ran better , I will throw in my .02 and suggest head gaskets . I have a 360 getting both for a more advanced case of the same symptom .
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Old 04-17-2009, 08:45 PM
valiant64 valiant64 is offline
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Well, if you're gonna pull the heads to replace gaskets, you might as well have the valve job checked out @ the machine shop & get the springs replaced to match whatever cam you choose. The stock hyd roller lifters will probably work o.k. with a mild cam. Comp & Crane both make cams for this app. Double roller timing set for sure on the sb mopar even if bone stock.
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