Rocker torque on aq205a

cptbill

Senior Chief Petty Officer
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Oct 6, 2012
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Torque Rocker Arms to 20 ft/lbs. far as I know no special procedure
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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You have adjustable value train. So 1/2-3/4 turn past zero last
 

QBhoy

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looks like you've got the answer above...just thought id add a little. Had one of these for years. Amazing engine. Mine was driving a 290DP on a 23ft 2000kgs cruiser. Incredibly surprising, how powerful these wee engines are. the same era had a 5.0/305ci v8 in the AQ range. That one of them was actually less powerful than the AQ205/4.3 and one of them was only about 6hp more.
The 205 managed to push that cruiser of mine along at mid 30's, no problem.
Only complaint Id have and many others I've seen have had, was the bloody belt on them being infamous for squealing and needing constant tinkering. I eventually made a more suitable spacer for the back of the power steering pump. Seemed to straighten things up a little and allowed a better adjustment to be achieved.
Originally the water pump housing cover plate had brass screw/bolts. These can be easily snapped or damaged, if not careful and kept greased and in good order. Not unusual for some guys to snap off one or more bolt heads, requiring the pump to be removed, in order to remove the sheared remains of the bolt....can be a pain. Since then, VP saw sense and improved/changed the type of head.
 

Lou C

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Nov 10, 2002
Messages
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You need to get each cyl that you are adjusting on TDC for the compression stroke, that ensures that both the intake and exhaust for that cyl are closed, then you go past zero lash by 3/4-1 turn depending on whose manual you are reading. In my OMC factory shop manual it said 1 turn.
Later models have the non-adjustable valve train, I actually prefer the older ones that can be adjusted.
 

Lou C

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Nov 10, 2002
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Yep your Volvo A205A is actually a garden variety Chevy 4.3 V6, pre-Vortec....
no balance shaft, but roller cam and hydraulic lash adjusters
same as mine....
When I replaced the cyl heads on mine I followed the procedure from my OMC manual, there are different ways of doing this and different degrees of turning the rocker nut after zero lash is obtained, but this worked for me....
I looked this up in another factory GM manual and they used 1 turn after zero lash but this has been debated since about oh 1955 when the small block arrived on the automotive scene...

 
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Lou C

Supreme Mariner
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Nov 10, 2002
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12,653
Another tip if you’re doing this for the first time mark the rocker arms as either I for intake or E for exhaust so you don’t get mixed up…
 
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