15 Most Common Mistakes

15 PLUS Most common mistakes We get lots of phone calls and emails everyday, Here are the most common mistakes done by builders and machinists. Number one is valve guide clearance too tight, the new stainless valves require .002-.003 on intakes and .0025- .0035 on exhaust valves or you will have serious problems. Number two, trying to install hardened seats and ruining the heads, Buick's don't need them. Number  three is leaving out the oil galley plug in front of the distributor on the end of the oil galley that stops inside the block, loosing oil pressure. Number four is bolting the flywheel/flexplate on wrong causing the engine to be out of balance, ALL Buick's are externally balanced, line up the index hole. Number five is buying a cam designed for a Chevy engine,all the camshaft companies just want to sell what they have in stock, you could easily loose 100hp!. Number six, not degreeing a H.P. cam in, ALL custom camshaft grinds must be degreed. Number seven, using F-E-L-P-R-O head gaskets that always cause oil leaks. Number eight, using intake spacers (15 HP loss) and or Offy intakes (75 HP Loss), costing torque and HP. Number nine, Modifying the heads for non-Buick type springs, that will put the spring in the push rod hole, distroying push rods.. Number ten, installing any distributor in without re-curving it correctly, especially the MSD units! Number eleven, not tightening the balancer bolt on the crank to 220 lbs, damaging the crank and cracking the balancer. Number twelve, listening to Chevy builders and using too small of a carburetor,. Number thirteen, mixing up 1953-55 and 56 and later lifters and push rods. Number fourteen, using gaskets on the exhaust manifold to head, causing manifold cracks, Buick did not use them. Number fifteen, mixing up water pumps with the wrong timing covers, three different gasket surface shapes.
More problems we are hearing about !!
Broken inner valve springs, caused by using the wrong outer valve spring shim with too small of a hole in the center so the inner spring can't fit down in it's own seat. Causes coil bind and breakage.
Broken rockers.. most common causes are exhaust valve guides too tight, locking up the valves, if a intake rocker breaks most common cause is bad gas, old fuel turns to glue and locks up the intake valves in the guides.
Reproduction rocker arm failures.. some of the 1953-59 iron repros have push rod holes machined incorrectly breaking the push rod tips off! We always recommend our bronzed bushed rebuilt assemblies.
We are getting reports of cheap overseas and Mexican lifters chewing up camshafts. We sell only made in USA.
Failing water pumps! The new 53-55 264-322 water pumps (we sell rebuilt ones only) have plastic impeller vanes that spin on the shaft! stick with high quality rebuilts.
Remember to check your carburetor jetting, most performance cams require richer mixtures, don't ruin the engine running it too lean!
CAM WILL NOT FIT WITH NEW CAM BEARING....
It is very rare that camshaft will slide right in, maybe in one out of 50 engines that will happen. When these engines were new, cam bearings were undersized and line bored in the block..The machinist should always check cam fit before the block leaves the shop. The cam must be the first thing you install in a block. Scrapping the bearings with be necessary to fit the cam, someone with experience will be best and only a small amount in the correct places to make the camshaft fit. One of the reasons we grind casting flash from the lifter area when rebuilding these engines is so we don't cut our hands fitting the cam in the block. Front cam bearings can also be put in wrong.
Not installing the distributor all the way down into the block so the oil pump shaft will not engage.
 Installing the intake gaskets wrong! the 1957-66 engines have ports that are offset with the bolt holes, there are flags or tags on the ends of these gaskets, they must face toward the other gasket, NOT outboard toward the valve covers. If you see the intake gaskets when you look between the intake and the valve cover they are on wrong causing a vacuum leak! This should be one of the first on the list.