compression ?
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Freshman User
Joined: Jan 2003
Posts: 38
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From: morris USA
compression ?
Hey fellas- I performed a compression test the other day and I would like the highly aclaimed expert opinnion of the FTE guru's
please. I averaged a low of 60 and a high of 120. It took two to three strokes to build to 60 and any where from five to eight to get to 120. However it did hold the high compression well. I've been haveing some performance problems as of late. All the usuall tune up components are new along with a new timming set (done correctly I might add.) I put a holley for motorcraft off a 85 Ford truck with unknown engine size. I'm wondering if I should kit the old carb that was on it when bought it. It apears that it was the original carb. The engine is out of a galaxie 500/ 390 with c4ae heads stock manifolds and no performance additions that I know of. YET!!. Please help. I would like to get running smoothly before I start working on the steering and suspension.
please. I averaged a low of 60 and a high of 120. It took two to three strokes to build to 60 and any where from five to eight to get to 120. However it did hold the high compression well. I've been haveing some performance problems as of late. All the usuall tune up components are new along with a new timming set (done correctly I might add.) I put a holley for motorcraft off a 85 Ford truck with unknown engine size. I'm wondering if I should kit the old carb that was on it when bought it. It apears that it was the original carb. The engine is out of a galaxie 500/ 390 with c4ae heads stock manifolds and no performance additions that I know of. YET!!. Please help. I would like to get running smoothly before I start working on the steering and suspension.
Hotshot
Joined: May 2003
Posts: 11,141
Likes: 25
From: south louisiana
compression ?
You mentioned having problems but didn't specify what they were. First thing to do is get a set of headers on that thing. Put a Pertronix unit in the distributor. Get a Holley in the 650 - 750 cfm range.
Posting Guru
Joined: Oct 1999
Posts: 1,188
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From: yes
compression ?
Originally posted by clods64fe
Hey fellas- I performed a compression test the other day and I would like the highly aclaimed expert opinnion of the FTE guru's please. I averaged a low of 60 and a high of 120.
Hey fellas- I performed a compression test the other day and I would like the highly aclaimed expert opinnion of the FTE guru's
please. I averaged a low of 60 and a high of 120.
more than 20% variation calls for rebuild time
Senior User
Joined: Mar 2003
Posts: 231
Likes: 0
From: Utah
compression ?
Too much variation in compression. Maybe rings, valves guides, etc...... Oh hell, just do it all. IMHO the autolite 4100 carb that came on the motor is a better carb than the emission version holly. However that autolite is small, I think around 480cfm, but they're simple and work quite well. I wouldn't worry about headers, but ignition is important.
Cargo Master
Joined: Aug 2000
Posts: 2,931
Likes: 12
From: SW Michigan
compression ?
You might like to start with a valve job. The C4 heads that your engine is wearing were never meant for unleaded fuel. And unleaded is all that has been available for many years. My guess would be that the valveseats have receeded and thats why you're losing compression. You'll need to have hardened seats installed under the exhaust, and maybe some new valves. Plan on spending around 400$ to do it properly. When the heads are off, you can look at the bores and see if they are okay. Let us know. DF
