Misfire after doing pushrod tubes (Aircooled 2 litre)

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jospanner
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Misfire after doing pushrod tubes (Aircooled 2 litre)

Post by jospanner »

Hi
Got a misfire and no idle after doing the pushrod tubes on my 2.0 CU (hydraulic lifter) engine.
I adjusted the valves as per the manual, turn until just touching, then tighten +2 turns.

I'm fairly certain everything is back as it was before in the correct order! No weird noises either.

Where should I start with this?
'81 2.0 Aircooled CU with 4 speed box

davidoft1
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Re: Misfire after doing pushrod tubes (Aircooled 2 litre)

Post by davidoft1 »

Incorrectly seated push rod or you may have set the valves incorrectly, look at the valve gear and see if everything looks similarly adjusted

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jospanner
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Re: Misfire after doing pushrod tubes (Aircooled 2 litre)

Post by jospanner »

Had another go from scratch. I'm sure I'm doing it right, but it won't get compression unless I set the rockers "too loose". Just tried contact + 1/2 a turn on the adjuster and it was happy but that might cause float?
'81 2.0 Aircooled CU with 4 speed box

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jospanner
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Re: Misfire after doing pushrod tubes (Aircooled 2 litre)

Post by jospanner »

Let me run you by exactly what I'm doing:

Insert push rods back in the same order they came out. They feel like they slide up slightly like they're locating into a divot in the lifter.

Loosely put the spring back in.

Rocker arm assemblies go back in, same side they came out. Pushrods are located into the cups and the rocker assemblies are hand tightened to keep light tension on the rods.

Wire is located into the cut out part in the rocker assembly.

Rocker assemblies are torqued to 15nm.

Engine is rotated so that the distributor arm faces the small 1 shaped mark (tdc cyl 1), which matches the position of the #1 spark plug lead.

Arm tension is adjusted by screwing the screw in just until there is no slack in the arm, then +2 turns to tighten it further. They are then locked in place with the 14mm nut.

Rotate engine to -90° from cyl 1 tdc on the distributor, which should be cyl 2 tdc. Repeat tightening process.

Button everything up. No compression, misfires.

Am I doing something wrong?
'81 2.0 Aircooled CU with 4 speed box

davidoft1
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Re: Misfire after doing pushrod tubes (Aircooled 2 litre)

Post by davidoft1 »

My guess would be perhaps it’s not a hydraulic follower set up anymore, try setting them to solid lifter spec

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Re: Misfire after doing pushrod tubes (Aircooled 2 litre)

Post by Stesaw »

Shouldn't the engine be rotated CCW 180 degrees for each cylinder, so your timing marks are on the bottom of the pulley if you want to be adjusting your tappets for no 2? then 180 again for no 3 etc
1985 LeisureDrive 2.1DJ 5 Speed syncro conversion project.
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davidoft1
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Re: Misfire after doing pushrod tubes (Aircooled 2 litre)

Post by davidoft1 »

Stesaw wrote: 20 Jun 2022, 19:11 Shouldn't the engine be rotated CCW 180 degrees for each cylinder, so your timing marks are on the bottom of the pulley if you want to be adjusting your tappets for no 2? then 180 again for no 3 etc


Yes ,I should have read to the bottom

Set number both valves on number 1 cylinder

rotate anti-clockwise 180 , set both valves on number 2 etc

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jospanner
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Re: Misfire after doing pushrod tubes (Aircooled 2 litre)

Post by jospanner »

The distributor does 0.5x revolutions per engine revolution so both these approaches do the same thing.

I'll check the lifters tomorrow... That's really all it can be, right? It's clearly not taking the pre-load and it would make sense if these are solid.
'81 2.0 Aircooled CU with 4 speed box

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sarran1955
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Re: Misfire after doing pushrod tubes (Aircooled 2 litre)

Post by sarran1955 »

Hello,

I think you are being a bit optimistic at contact plus 2 turns... especially if you have been turning the engine over a lot.

Go back to contact plus 1/2 turn.. and then see how you go...

Cordialement,

:ok

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