New 6.2 owner, various questions

[MLind]

Hello, just purchased a new to me 1989 1 ton 4x4 with utility box. Rather tired truck here and there, but that is how I buy them. Then I work on them. It should work well for hauling my tools and muddy boots to geothermal drilling sites.

Questions that have come up in the first week of examining the new truck and as I put in a new radiator, replace the oil cooler and leaking lines, etc.

1. Metric or standard? Where and why did GM use metric vs SAE bolts and nuts? Seems to be random, but perhpas there is some small logic to when and where. Also, the bolts on the oil pan seem to be 9.5mm or 13/32 (or worse). Do I have to add to all my x/16 inch size sockets to work on things?

2. Turbos. The VW diesels I am familiar with (I am new to the GM diesels) the heads, pistons, and valves are "upgraded" for the turbo engines. What are the pertinant issues if I decide to add the Banks turbo system? Why doesn't intercooling seem to be important as people upgrade these engines? Can the piston squirters easily be added? All reports I have read about the banks upgrade seem to be very positive, but I am used to having the turbo components being more robust than the NA components.

3. Passenger side CV axle is new, I am replacing the driver side. However, on the driver side of the fixed axle assembly, there is 1/4 inch or so of play where the axle mounts to the CV assmebly (where the 6 bolts are. Not sure what to call all these pieces). No leakage. Is this side to side play going to be a problem? Should it be addressed soon or can it be ignored until it gets worse? This is my first 4x4.

4. From staring at the engine compartment most of the afternoon, it appears that the PS pump is also the vacuum generator for the brakes. Interesting. Besides diesels not producing vacuum naturally, is there any other reason to do this?

Any thoughts, partial replies, opinions welcome.

Thanks
Myron

[DmaxMaverick]

Welcome to the forum. Hope you find the answers you seek.

Most of your answers can be found, in depth, using the search feature of the forum. Not raggin'. Just informin'.

I'll offer some answers. Much of what you'll find here is based on opinion, but most end with the same result. Try to bare with the content and boil it down.

1. I don't think there is a standard answer here. GM may have a grand plan, but didn't inform any one entinty of all the facts. It seems that over the years, less SAE is used, but still exists to this date.

2. The stock form of the 6.2L is very durable and can handle surprising power levels. There really wasn't much "upgrading" done to accomodate the increased boost levels of the later 6.5L TD's. Perhaps they should have done more, but in most cases, they handle modest power/boost increases. Adding oil "squirters" is not an option. If it didn't come with them, it's not practical to add them. Early 6.5L's had them. Later models did not. Seems that the oil channels weakened the block enough to cause problems that exceeded the gain. Piston cooling really wasn't a serious issue, IMO. Piston crown temps would be secondary to other problems by the time the temps get high enough.

3. Play is normal in the front diff. This is the end play of the spline coupling. It is a non-thrust coupling. The play actually helps to reduce seal failure, usually caused by seal to shaft friction. The play allows the seal to "wear" on a larger area, rather than grooving the shaft in one place, like can happen on cranks or pinion seals.

4. The brake booster system is called "hydroboost". It does not use any type of vacuum. The booster is powered by hydraulic pressure provided by the PS pump. Many GM Diesels are equipped with a vacuum pump to operate HVAC (early models), turbo boost control, and EGR (if so equipped). EGR and turbo boost control can be modified to operate without vacuum (usually improving performance), eliminating the need for a vacuum pump.

Enjoy your GM Diesel. Treat it right and it'll return the favor.