overhauling/inspection questions [Archive]

Robyn

12-13-2007, 09:23

Hello

Any and all techniques to enhance airflow are a good thing.

Keep in mind that these engines are a midrange unit and max at 3500 RPM

The porting and such will not hurt at all. If you are running the turbo diesel the tops of the pistons are finished with a heat rejecting material so be careful not to nick it.
I have used a not so sharp putty knife and then finish with a soft wire brush. Dont use a wire wheel over the ring lands at all. Keep the grooves sharp and use a suitable tool to clean out all the crap in the grooves before installing new rings (very important)

As far as cleaning the engine out with components still in, ????????

I would not. I prefer to remove everything and steam clean the little creatures out totally with high pressure hot water and the nastiest soap I can find then rinse and blow dry.
Once dry I lightly oil the machined surfaces to prevent rust, (Cylinder walls, bearing bores (mains)
Another good thing to do is to break all the sharp corners (stress risers) on the main bearing parting lines) one does not need to get crazy with this but just get rid of the sharp corners. Also a tiny little break on the bolt holes is good too. (a countersink just lightly touched to get rid of the sharp corners)

Any time one of these engine is down the main webs on the 3 center ones need to be checks around the outer holes for cracks. Now cracks here many times are not visible to the naked eye and may need to be searched for carefully.
( I use a propane torch and warm the webs around the outer holes until they are very very warm and then look for oil bubbling out on the verticle surfaces.)

I will also wash the crank and the cam and then spray with a rust preventive and wrap up until ready to reinstall. Cams and cranks in these engine can routinely run well into the 200K arena and still be very serviceable with little no no work other than a pollish on the rod and main journals. If the cam lobes look good and have do damage they can go right back to work. I do however recommned a fresh set of lifters as these little beasts can decide after a teardown (high mile) not to work again due to being disturbed.

Remove the soft plugs unless the engine is very new as these will eat out from the inside and can be very thin and ready to go away on an engine with 75000 + on it.

The water jacket can also be flushed very well with the hot washer under pressure to get rid of the crud in there too.

All oil passages should be flushed and blown dry.

Be sure to bag the lifters so they go back on the same lobe they came from. The rockers and such need to be kept on the same spot they ran so when changing the plastic guide buttons just wash the shaft/rockers as a unit then replace the buttons one at a time and leave all the components where they sit.

The push rods go back in with the copper colored end (ball) up to the rocker as this end is hardened.

Another area that can be nasty is the rear cam plug, if this is removed and many times mechanics will, especially if bearings are to be replaced. (most 6.2/6.5 cam bearings will be fine even with mega miles on them unless the engine has lost oil pressure.
**When replacing the cam plug** be sure that when the cam is in and the retaining plate is on that the cam does not hit the plug. The plug needs to have a sealer installed and I usually place a nice bead of JB weld all around the part line of the plug and the block when Im done. (If the plug leaks this will be followed by a long period of tools flying about and not so polite language issuing forth from the area. :(

As far as any other air flow items, almost any flow enhancing work wont hurt. Matching the exhaust ports to the manifolds.

Anything that promotes flow and decreases turbulence is a good thing.
Any work that helps the exhaust flow out of the heads is also good.
It will not be of great value to get really wild with porting but some basic work will certainly be of value and can possibly help make a smoother running and better performing engine when combined with other mods.

If you are running an N/A engine all the above still applies.

A good pollish job on the ports to get rid of unwanted roughness is always helpful. The exhaust especially can be helped by a pollish as this will eliminate the little places for carbon to build up and interfere with flow.

The 6.2/6.5 are just basic V8 engines and will respond to most all performance work.
These are however mid range grunt engines so one needs to think in those terms and not be looking towards high flow rates and super sonic flow speeds.

A good ballance job on the rotating assembly is a very good step with these engines.
When doing this procedure all the parts that bolt to the crank need to be ballanced (Including the ballancer and the pulley and the pulley should be witness marked) the flex plate must also be included as these are an externally ballanced engine.

I hope this material helps answer your questions

Robyn