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120 Posts
S3 block with S4 head?
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Aren't the timing marks on the cam caps different?
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120 Posts
Now that I've slapped things together it seems to be idling a little high, 1000-1100 instead of 900-950. Theres also a noticeable miss every few seconds. It revs freely and I cannot hear any missing off idle.
Plugs are 1 day old and gapped to 0.025, wires/cap/rotor are a year/5000mi. old.
Temp gauge stays @ 175 with no signs of smoke out the tailpipe and no bubbles in the overflow when revved.
I checked the VVT and it is not stuck on. TPS was out of adjustment but a readjustment had no effect on idle quality.
I poked a propane torch around and didn't find any vacuum leaks. I couldn't get to the underside of the intake but teed a vacuum gauge into the MAP sensor line and saw 16.5" at idle.
On my old head the vacuum gauge needle would flicker 1" at idle from what I assume was valvetrain waer. On this new head the reading is dead steady except for when it misses.
I assume the next step is a compression test followed by shaking Greg Gordon's L-jet guide at it?
Plugs are 1 day old and gapped to 0.025, wires/cap/rotor are a year/5000mi. old.
Temp gauge stays @ 175 with no signs of smoke out the tailpipe and no bubbles in the overflow when revved.
I checked the VVT and it is not stuck on. TPS was out of adjustment but a readjustment had no effect on idle quality.
I poked a propane torch around and didn't find any vacuum leaks. I couldn't get to the underside of the intake but teed a vacuum gauge into the MAP sensor line and saw 16.5" at idle.
On my old head the vacuum gauge needle would flicker 1" at idle from what I assume was valvetrain waer. On this new head the reading is dead steady except for when it misses.
I assume the next step is a compression test followed by shaking Greg Gordon's L-jet guide at it?
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Joined
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120 Posts
My old head had no oil drainback holes in it so I hope I'm good there.
I took the Alfa out to run a few errands. Throughout the entire drive it seemed to be idling worse every time I came to a stoplight. I had teed in a vacuum gauge earlier and when I pulled into my driveway I almost had a heart attack when I saw the vacuum gauge was reading 5".
One of the vacuum lines I had teed off of had split and opened up as I was driving. After replacing that line the idle is back to 950rpm instead of 1000-1100 and the vacuum readings are back to normal.
While the idle does not fluctuate anymore it does still miss (at idle only). My tach has also been acting funky ever since I swapped heads. It sometimes will conk out completely or flicker.
I'm going to attack the fusebox and coil connections with a can of contact cleaner, a toothbrush and some holy water. Wish me luck.
I took the Alfa out to run a few errands. Throughout the entire drive it seemed to be idling worse every time I came to a stoplight. I had teed in a vacuum gauge earlier and when I pulled into my driveway I almost had a heart attack when I saw the vacuum gauge was reading 5".
One of the vacuum lines I had teed off of had split and opened up as I was driving. After replacing that line the idle is back to 950rpm instead of 1000-1100 and the vacuum readings are back to normal.
While the idle does not fluctuate anymore it does still miss (at idle only). My tach has also been acting funky ever since I swapped heads. It sometimes will conk out completely or flicker.
I'm going to attack the fusebox and coil connections with a can of contact cleaner, a toothbrush and some holy water. Wish me luck.
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