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420A 420a Headgasket Replacement

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Nova95

Proven Member
57
5
Jul 7, 2022
Kirbyville, Missouri
Hey guys. I'm in the middle of a head gasket replacement on my 96 RS. I've got most of the tear down around the engine done and I'm down to the timing components and finishing the intake manifold which has been the most pain in the a$$ so far. I've cracked the top bolts loose but I have literally no wiggle room so I figured I'd look around and see if there were any tricks online. I Read that if I unbolt the two stays, that the head and intake will come off as one, so I don't need to even bother with the intake manifold bolts. What?! Is it really that easy?!
 
Phew okay. So after pulling the spark plugs I can turn the crank perfectly with no issue. I rotated the crank 4 times and the timing marks come out to this. Is this acceptable?

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Phew okay. So after pulling the spark plugs I can turn the crank perfectly with no issue. I rotated the crank 4 times and the timing marks come out to this. Is this acceptable?

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Those looke fine. But what about the ones on the crank sprocket and oil pump?
 
Hey man, I just noticed the seal for your intake cam popped out. You need to reinstall it or else it will leak like hell LOL

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Ha wow thanks I fixed them 😂 So all the timing marks line up. And she still sounds like she's dragging her a@@ on starting. She gave me a good two seconds where she sounded like she was going to start, then she let out a little bit of backfire and then back to just cranking over. I rechecked that I didn't miss any connectors, I can smell gas, and I made sure I'm getting spark. My battery doesn't seem to have the juice it did before I parked the car a week ago, could it potentially be the problem?
 
Low battery charge could be the issue. Although it doesn't really take much juice to crank a 420a, it's still wort recharging the battery and trying again. Also check the ground strap that goes from the intake manifold to the firewall. Although it's small, it will cause issues if left loose
 
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is that the sound of my valves slapping?...
 
It's hard to hear much but to me it sounds exactly like the timing is off...

I don't doubt you, but if you can post a picture of all the timing marks lining up at once then we can rule that out.
So just took the crank back off and took new pictures. This is how they are sitting

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Your timing marks need to be lined up at exactly half height on the cams gears like the line I drew. You have them slightly too low and angled as I illustrated. It was hard to tell from the perspective of your previous image. So you're probably 1 tooth off on timing.

The best way I know to describe it is imagine a straight line between the center of each cam bolt, that's where your timing marks need to sit for proper timing.

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So Can I just line up crank then pop the belt off and bump the cams up/down a tooth or do they need to do a full rotation around clockwise and meet up higher?
 
So Can I just line up crank then pop the belt off and bump the cams up/down a tooth or do they need to do a full rotation around clockwise and meet up higher?
Don't fully rotate them. Cylinders 1 & 4 will have piston to valve contact since the engine is at TDC. Just rotate the exhaust cam clockwise and the intake cam counterclockwise until those marks line up at half height. One way you can do it if you're not sure is hold a ruler or straight edge across, being centered with each cam bolt. The marks should also line up with that edge.
 
Okay readjusted timing and she started right up and sounds better than she did when I bought her! Thank you so much! One last thing, her idle sits at like 1100. Is this where she should be? If not, where should she be?
 
Okay readjusted timing and she started right up and sounds better than she did when I bought her! Thank you so much! One last thing, her idle sits at like 1100. Is this where she should be? If not, where should she be?
I believe the base idle speed was 850 rpm. Might have a small vacuum leak or it's just not warmed up yet.
 
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