Hi there. I've got a 52 Special with the 263 in it. I'm pretty new to the Straight 8s, so I've got a couple questions for the veterans out there:

I did a series of tests to determine the condition of the motor. All in all, it runs well. I've never driven another Buick with a straight 8 in it, so I really have nothing to compare it to. I did a vacuum test and it came out satisfactory. No leaks anywhere and the reading was high enough to not sound off any alarms. After that, I did a compression test with the following readings:

No 1 @ 110 lbs
No 2 @ 110 lbs
No 3 @ 100 lbs
No 4 @ 110 lbs
No 5 @ 110 lbs
No 6 @ 123 lbs
No 7 @ 110 lbs
No 8 @ 110 lbs

Now my gage isn't the highest of quality, so give or take 2 lbs on each of those would be a pretty safe tolerance. Obviously the number 6 cylinder is throwing me. It may have had a sleeve job in the past, or maybe someone just replaced just that piston, but who knows? Now my general rule of thumb doing a compression test is that all the cylinders being within 90% of each other is excellent. 75% being okay but getting bad. I fall in at about 85%. To me that's okay, but I noticed the tune up specs on this site state that they should be at 140 and within 10 lbs of each other. Should I be overly concerned here?

The second question I have deals with carburetion. I've got a brand new carb and its working great. Starts easily while cold. It'll also start easily while hot provided I start the engine right after I've shut it off. If the engine is hot and I shut it off and leave if for several minutes than try and start it again, it acts as if it's flooding out. I've checked all the adjustments to the manual and everything appears to be okay. I suspect the choke unloader is kicking in too soon. Does anyone have any suggestions?

Any help/advice would be greatly appreciated.

-Brad

I wouldn't worry about the 140 spec too much. The rule is withing 10% of each other. Your engine high and low is 123 and 100. That is more than is should have to be considered good. That doesn't mean it doesn't seem to run well enough and may give many more satisfactory miles.

What was your vacuum reading?

Hey Bob,

Thanks for the reply!

Yeah I was pretty happy until I hit cylinder 6 at 123. I don't know what's up with that one. The other 7 cylinders and pretty consistent. I'm guessing someone probably just swapped out that one piston or something.

My vacuum reading was a steady 17 HG. I had a very slight needle fluctuation of less than 1. I figured that was an ignition deal and wasn't too worried about it. Setting the timing was a chore as the flywheel had 3 different timing marks that were put on it over the years. 1 red and 1 white in addition to the factory yellow. I ended up setting it to the factory yellow marking. It seemed to run best there over the other two.

Like I said, the engine seems to be running pretty well. I've got a steady idle at about 550 RPM. Anything set lower than that and it starts to choke up a bit. I'm not burning oil and my fuel consumption is what I would expect it to be. Something like 15 MPG. My valves are pretty noisy, so I took a look under the valve cover. To my surprise the rocker arm assy was pretty clean. I was expecting to see years of sludge in there, but the previous owner must have done pretty regular oil changes. 8 of the 16 pushrods were pretty sloppy. I'm sure the lifters need to be reconditioned, but I didn't get that far into the inspection. I haven't checked valve lift yet, but based on the clatter, I'm sure they aren't where they're supposed to be. Based on the vacuum readings I got, I'd say the valves are okay.

Like I said in my first post, I don't know anyone else that runs a straight 8, so I'm in uncharted territory here. I don't know what they're supposed to sound like, how they're supposed to run, etc. Mine could run like a champ for all I know. I'm trying to determine the current reliability and whether or not I should consider a rebuild. Any suggestions?

The 263 has hydaulic lifters, so the valves should not be noisy. It may be that you have some sticky lifters.

Yeah, I figured the noise stemmed from the lifters due to the slop I found in the pushrods. There was a significant gap between the pushrod and rocker arm and it quieted down a bit when I slid feeler gauges between the two.