Rebuilding engine, machine shop questions
 

I'm rebuilding an '03 engine with 115K.
What's the typical work you have done on the block and heads at a machine shop?

Depends on how much you are rebuilding.
New valves and valve guides, valves seats, heads planed...
As for the block, clean it up good, hone the cylinder walls...
The heads will need more work than the block.
Make sure the crank is in spec.
Same with the cam.
New timing set.

The engine is completely stripped and I'm doing new bearings, rings, cam, lifters, push rods, rockers, rocker shafts and timing set.
The crank is in spec and the journals are nice and shiny, no scoring or marks anywhere.

IF the oil pump failed on you or you had a ticking at idle to 2000 rpm....YOU MUST REPLACE THE CAM BEARINGS!!

since they are hard to find finished ....some shops leave them alone if they look okay....dont let your shop do this....insist that the cam bearings are replaced also otherwise your rebuilds wont make oil pressure!!!!!

ask me how i know!!!!!

if your lucky...maybe your engine guy will catch your tuck on fire like mine did!!!!

those were the days :0

No oil pump failure, oil pressure was very good. Cam bearings are good and they have nothing to do with oil pressure.

cam bearings have everything to do with oil pressure!!!!

try running a engine without 1 cam bearing.....you will get little or no oil pressure!!!!

apparently your rebuilding for other reasons....good luck....

btw heres a final word on oil pressure and cam bearings...FYI

http://www.mgaguru.com/mgtech/engine/of102.htm

Based on that statement my advice is to have someone else rebuild your engine.

I'm rebuilding my engine, so I cannot get someone else :).
OK how did this turn into a pissing contest about my cam bearings?
Everything in the engine was checked and measured and compared to the specs in RAVE, then checked and measured again. The cam and cam bearings fall into spec. My oil pressure is very good and my cam bearings are good. I understand the relationship between oil pressure and resistance to oil flow through bearings and oil passages through the engine.
I'm replacing the cam because I'm putting in new lifters, you don't put new lifters on an old cam. I'm not replacing the cam bearings because they are not the issue here, and neither is oil pressure.

First, is it on Rovers hit list for a bad oil pump/engine failure?
Second, why are you wasting so much money rebuilding that low a mileage engine?

Just Some Observations
 

Machine Work typical for a production engine...

1) Totally disassemble the engine inculding removing the freeze plugs and any screw-in plugs. Cam bearings are encouraged to be removed to assist in the cleaning process, and to bring the camshaft clearances/alignment back into spec (assuming no core shifting of the block. One of the biggest issues that I saw with an aluminum block was the extraction method used for the freeze plugs - depending on how this is accomplished, gouging the aluminum makes the new plugs almost impossible to reseal (use brass).

2) With a clean and prep'ed block, check crankshaft alignment (no more than .001-.0015 runout in the main webbing), cylinder deck alignment/height, and reinstall cam bearnings according to maunfacturer spec. Sounds fancy, but can all be accomplished pretty easily using a rotation method in the case of the crankshaft - I can explain in greater detail.

3) Check crankshaft runout (.0005-.001) at the middle journal. Check main/rod journals for tolerances and runout. Many times, I see people mic the journals and say "viola" it's great...yet they might egg shape by .001-.002, or more...journals wear around the oil passage opposite the direction of rotation...be careful and check roundness at least 3 different places then average the readings.

4) Check the big end of the rods for same, then check for squareness (centerline of big end aligned with center of small end)...again fairly easy using the wrist pin crank pin centerline method.

5) Spec the new pistons and assemble on the rods. Watch for L & R bank labeling...many engines have the wrist pin offset by a few .000's to assist in piston slap, plus the valve notching.

These steps with new timing pieces should get the rotating assembly is pretty good working order (remember, this thing will turn many millions/billions of revolutions).

OIL PRESSURE...life blood of any engine, can be summarized as follows:

Pressure is built from the clearances (all of them...cam, crank, lifters, and rocker shafts w/this style engine). All equally important!!! I have seen many engines reuse cam bearings with little to no issues, I have seem some "softened" by the cleaning process and fail 10-30K into a new rebuild, I have seen "NEW" ones installed improperly and fail, I have seen new ones installed and work as designed...so, what to do???

My personal opinion:

Given this is an aluminum cylinder case assembly (block) - they "move-around" A LOT, from a machinest standpoint (several thousandth's)...put in new ones and fit them by hand...you should be able to turn the camshaft freely by hand, if not find out why...then continue with the rebuild.

Enjoy, and best of luck!!!:D