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Discussion Starter #1
Hi All,
Although this is my first thread, I have been scouring through all of yours for quite some time now.

I picked up a 71 142s back in November of last year that is in fairly good shape with 165k miles on the clock. This is the third early 70's Volvo I have owned since my mid teens but my first with carburetors (SU’s). It’s been 20 good years since I have turned a wrench on B20, but I have always had a soft spot for these early 70 Volvo's.



When I bought the car the motor was not running the best and the PO thought it just needed a tune up. It needed a lot of revs just to take off (M40 trans) but at speed was not too bad. I did a complete tune up (using great guidance from the green book, Phil's papers, and others) and it ran much better, but still not nearly close enough to how it should, and it still had some noises at idle which I presumed to be the timing gear needing to be replaced.

I noticed that there seemed to be a very thin layer of oil on top of the coolant in the pressure tank, which I removed and cleaned. While there was no water at all in the oil, this made me think that a head gasket was probably in order. Next I did a compression test and came up with 165lbs for cylinders 2, 3, 4, but around 90lbs for cylinder 1 (and a little squirt of oil in the cylinder did not change a thing). Now I knew the head had to come off and since the only other thing I planned to do was the timing gear, I decided to do this without pulling the motor. (at least that was the plan)

So off came the timing cover which revealed a fiber timing gear that was actually in pretty good shape, definitely not the original one. There was a good (actually bad) amount of axial play of the camshaft and gear which may have been making the “noises” I was hearing which were exaggerated by the rough idle.



When I adjusted the valves during the tune up, I could tell by eye that not all the valves were opening with the same lift, so decided to measure these before removing the head. Results were as expected, several, including the #1 exhaust valve were opening less than .200 – camshaft/lifters were added to shopping list.



I went ahead and pulled the head with the engine in the car just to see what I might be in for. What I found was a very burnt and receded #1 exhaust valve which was probably leaking all the “bang” from that cylinder into the exhaust. (Now I know why the exhaust had a funny sound to it) Also, although the cylinders were very smooth, there was almost no lip at the top.





It was at this time that I debated doing the (uncomfortable) cam install with the engine in (mostly in) the car or just remove it. After pulling a few lifters out for inspection and imagining what kind of metal particles have caused this wear and cycled through the engine, I was running for the engine hoist!





Besides that it was oily, and really needed to be re-sealed, my father always said "new parts always work better with new parts"

So the head went to the machine shop, and the engine was put on the stand for tear down.
I referenced Phil’s great article for the tear down and all was going smoothly until time came to remove the distributor and oil pump drive gear.

What I expected was to have the timing marks aligned on the gears, #1 piston at TDC AND the rotor position at firing hole #1. What I got was the rotor 180 degrees from #1, with the marks aligned or the opposite, camshaft gear 180 degrees out with the rotor at #1. Here is the latter.





I am still miffed by this, could the engine even run at all like this? I know a SBC will run like this, albeit very poorly.

I went ahead and pulled the distributor out with the timing marks aligned, and snapped a (not so great) pic of the shaft orientation.



Off came the gear, and out the cam. – Added cam bearings to the shopping list.

Here is where some of the axial movement of the cam is, the brass retaining plate. About a .010 deep groove.



I think I am going to mount the cam on the shop wall and give it a purple heart. (Also, see the wear on the fuel pump lobe – fuel pump was added to the shopping list accordingly)





Well, this is the most I can post today.

I apologize for any UN-orthodox method in my writing, this is not my forte’ and I wouldn’t even write this except that having gained so much from what others have posted here (and other forums) I feel it’s only respectable to give back any lessons I have learned through this experience.

I am further along with this build, as I delivered the block to the machine shop last week. I will however pick up where I left off in the next day or two and explain what I found in the rest of the tear down.

Thanks for any and all help.

Best regards,
 

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If you turned the crankshaft 360° the timing marks would line up and the distributor would be pretty close. And you can put the distributor in almost any old way and if you put the wires on correctly for the orientation, and then time it properly, it will run fine.
Can you give us the motor type number, on the driver's side of the block near the top, first 2 or maybe 4 numbers cast and the rest stamped on a rectangular boss. First 2 digits will be 49, USUALLY followed by 69 for earlier models and the next 2 digits and we can tell you how it was originally equipped.
 

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Discussion Starter #6
Really? I thought the SU's were original, so someone replaced the HS6's with HIF6's in the past. Interesting - Thank you
 
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