Examine the case to determine if serviceable.
You are looking for stripped, broken, or missing bolts and studs, cracks in the case. Knowing the overall condition of your case is necessary so that you can make the correct choices to proceed.
Stripped case studs can be replaced with case savers.
For condition, you are primarily looking for cracks and corrosion
- Inspect areas that had a lot of sludge buildup for cracks.
- On the outside of the case, check the front of Cylinder 3 for cracks. Later cases usually have more magnesium or aluminum in this area so that a large vertical crack does not develop. This area is often welded in for performance applications.
- On Cylinder 1 head stud location there are often cracks radiating from the head stud hole to the case stud hole.
- Check the oil pressure sender hole for stripped threads or cracks.
- On the case nose, check the three oil galley plugs for leakage. The middle one may be drilled and tapped for a full flow oiling system, but the others must be plugged.
- The center main bearings journal is a common point of cracking through the center saddle.
- While not common, check the oil galley area behind cylinder 4. make sure there are no cracks from the stud hole to the oil passages.
- Heating areas with a propane torch will expand the metal and oil will weep out of the cracks.
- A common place for corrosion is the oil drain sump area. Make sure the corrosion is not so bad the drain cover cannot seal.
- Check the oil sump studs for any cracks radiating from the stud holes.
- Using your fingernail, check the bearing surfaces for stampings or ridges. Assemble the two case halves together and see if there is any misalignment of the bearing surfaces at the joints. If any of these conditions appear, an align bore is necessary. When in doubt, just get the case machined.
Check rod bearings for size stamps and possibly a date stamp. you will need to know the size to order new bearings, the date will give you a rough idea of when the engine was last rebuilt.
Measure bearings to get size everything last machined to. This is also confirms what you see on the bearing stamps. Do not rely on these bearing sizes alone however, as the incorrect size could have been installed. Measure camshaft and crankshaft bearing surface sizes as well to confirm.
Check the thrust surface to determine if a thrust cut is needed. Look at the smooth, shiny lip. If you can feel the inner lip around the thrust bearing surface with a fingernail it may need machining. Cases can have two thrust cuts before they are unusable. VW thrust measurement is 21.96mm or 0.8645″.
Check the lifters in their bore for lateral movement. It is best to use a new, or at least clean lifter for this. They should go up and down, not side to side. Lateral movement is bad. VW wear limit for the Type I is 19.05mm or 0.7500″. If the rest of the case checks out, you can save the case by having the bores sleeved.
Check all dowel pin holes. High mileage cases have oval holes that no longer hold pins well. Consider step dowels or another case if a bearing has been spun.
Check main bearing saddle. Put the case halves together and torque the six main nuts. Shine a flashlight behind the main bearing web and case main journals. Any gap between the main journals means the case is unusable. If you can see light discard the case and find a new one.
-List stock and serviceable numbers – If all else checks out, match the line bore and thrust cut with serviceable parameters and determine if the case is still to be used.
Remove galley plugs and clean the case. Install NTP plugs for full flow.
Crankshaft inspection. Measure the main and rod journals and inspect for cracks. If a rod has been spun the crank must be machined. Light scratches can be polished out with extremely fine emory cloth and WD-40 for lubrication. Also have the crank checked for straightness if it has been taken off a shelf and has been sitting around unsupported for some time.
Check the number 2 bearing for the type of oil hole drilled into the crank. If the crank is cross drilled different bearings are required. For non-cross drilled use a KS bearing. <show picture>
You should now have enough measurements to order your bearings.
*verify with align bore adjustments needed
Examine the Crankshaft
Examine the Rods
The size and date of the rod bearings are stamped on the back.
Check the rod color. Any discolored, and more specifically black rods must be discarded.
Reassemble and torque the rod bolts. Measure the big end in several places to identify if it is out of round.
Check the rod bushing clearances.
If you have any doubts, rebuilt rods are cheap and better than unknowns. New even better.
Examine the Camshaft and Lifters
- Measure the cam lobes and verify within specifications. Make sure there is a peak at the end of the lobe to promote smooth lifting.
- Check the lifters by rocking their heads face to face. The surface should be convex and they should not rock and not be flat against each other . If they do not rock they are too worn to use and must be replaced.
Examine the Cylinder Heads
Inspect the heads for broken studs and missing cooling fins. Studs can be replaced, but more than a few broken fins will compromise cooling. With the high miles on old heads that might have been rebuilt a few times already, new heads might need to find their way into the budge.
If you determine the heads look good so far: Clean. Clean. Clean.
Look for damage from something bouncing around in the head that will cause valve seating problems.
Now check for cracks. Specifically around valve guides and spark plug holes. Many of these cracks can be welded so if you’ve got old single port heads or 36hp heads that are hard to find it may be worth it. If the goal is reliability, you’ll need to spring for new heads.
Put a straight edge across the seating surfaces and see if machining is necessary.
If everything checks out so far, check for flycut. It may be acceptable.
Flip it over, check the valve springs for tension **
Check the valve cover seating surface for nicks and gouges that might be causing excessive oil leaks.
Examine the Oil Cooler
Examine the Cooling Fan
Examine the Cooling Tin
Printable checklist/PDF as attachment to this page ]