New Hampshire CMP Barn 2011- 2012 HUP Overhaul

[Bob Carriere]

Granted there seems to be a large amount of oil flow on the rockers....


..... but let's go back to the beginning of the oiling system.....

The rockers are the lasts step in the oiling process...... first the crank, camshaft and then to the top of the engine where it eventually get dumped in the return channels/holes in the head back to the crank case.

If all the other bearing clearances are tight or at least according to specs. the oil pressure doesn't really start to fall until it reaches the loose rockers...

.... the oil pressure sensor is located early in the oil galleries... then why would it be so drastically affected by a leak further down into the system....

Is there anyway that you can reduce the flow to the rockers to confirm that the looseness of the rockers are in fact affecting the overall oil pressure??? some kind of temporary restriction inside the line...?

If you can confirm that the rockers are at fault it would be relatively easy at this stage to correct before installing into the truck.....

Now some rockers can be bored out and brass sleeves installed... not sure if that is feasible on the 216..... so rocker tubes are new and rockers as is.... it would not be too complicated to measure for clearance.....

When you got your NOS head did it have the full valve train or was it bare....?

If you need rockers I may be able to help you out...... how similar are they between 216 vs 235 vs 261...... 235 and 261 are usually interchangeable but not sure if low pressure 235 would interchange with high pressure 235 rockers

Keep us posted...

Bob

[Phil Waterman]

Hi Bob

Good idea about isolating the rocker arm assembly to see what it does to the oil pressure. Think it can be done fairly easy, if that makes the pressure jump up then that is fairly easy to rectify.

Couple of choices, as you suggested, I've got the bushings to bore and bushing the rocker individual arms, but a complete new replacement is $250. Plus I've got another used assembly that I think is good condition.

I'll try isolating the supply today, if that identifies the problem then great, if not then I think the next step will be to drop the oil pump, or brink the 216 that came out when I swapped over to the 261. I kept it complete so it would be a half days work to get it all set up again.

Don't think there is a suction leak because there doesn't seem to be any air bubbles showing in the oil. Just the normal air bubbles as the last of the air is pushed out of the oil filter even with filling the filter body with 2 quarts of oil before putting the cover on.

By the way I recovered all the oil from the oil change into clear bottles and there doesn't to be any large chunks of stuff.

Cheers Phil

[Phil Waterman]

I'm now to the point in the reassembly of the HUP that the wiring harness, fuel lines, break lines have been all installed. One small weeper leak in the brake system of course it is the big fitting on the master cylinder which should seal OK just needs to be tightened but of course will mean bleeding the entire brake system again.

In painting small parts to reinstall I came across one brass marker light I'd heard that these existed but this is the first one that I actually seen.
HUP May 2012- 007.jpgHUP May 2012- 008.jpg

Cheers Phil

[Bob Carriere]

...... you should save that brass marker light a wall mounted plaque/trophy....

Reminds me of the lower rear axle shock absorber bracket, the one that bolts on the diff. cover....... Rob found one made of cast brass....even had proper GM part numbers on it....... go figure !!!

Curious to hear what you find about the oil flow when a restriction is applied to the oil flow of the rockers.

Bob

[Phil Waterman]

Hi Bob

Well it's not the rocker arm assembly spent an hour this morning testing the theory that it was excessive flow from the individual rocker arms that was causing the low oil flow from the rocker arm bypass or over flow.

After bring the engine up to temperature and basically stabilize at 1500 RPM here are the results the end result was with the oil line to the rocker assembly disconnected and blocked there was no difference in oil pressure. Also posted a really dull video http://canadianmilitarypattern.com/R...%20Flow%20.wmv

So spent the rest of the day working on reassembly of the HUP pretty much decided that I'm going to concentrate on getting the HUP completely reassembled. Tomorrow I plan to bring the other 216 engine down from the loft and set it up to run. That way I'll should be able to get the HUP on the road for the 25 Anniversary Weare Rally end of July.

Should take me about 3 hours to set the other engine up and test it. I'll come back to this engine once everything else is done.

Cheers Phil

[Bob Carriere]

Hi Phil

How frustrating......

How did you block the oil flow to the rockers...?

... thinking out loud..... the oil comes out of the block underneath the carb inside that little cover ( the oil distributor valve assembly ) on the side of the block.....

Could a blown gasket on that small cover cause it.... could the line running inside the block be opened....

From the previous video it seems you have a high volume flowing but no pressure..... so the pump flows good quantity... in fact large quantity..... but there is nothing ( as in tight cleanrances ) in the oiling system to hold it back and build pressure...

So once out of the pump the oil goes into the main gallery some of which is directed to the rockers the rest goes to the crank and cam shaft...... something as to be opened either in a bearing clearance or a leak as occurred from the oil gallery...... has to be inside the block as nothing is leaking out or oil level going down...... can't be leaking at the pump or you would not have the high volume......

Intriging to say the least....

Being desperate I am now looking at the MB C2.....

What about the Timing gear oil nozzle.... inside the timing cover...?

Hummm have you read page K 28 ....which describes the oil flow in the block.... under Connecting Rod Bearing Lubrication...

...what if the "oil distributor valve" .... was stuck open ..instead of opening up when pressure builds up..... maybe toooo much oil is going to the six oil nozzle pipes....???

....on page K 30 ... some caution about the sequence of the 2 dist. valve body gaskets....!!!!!

and the pipe nipple is "calibrated" to deliver the proper amount of oil to rockers.....

...top of K 31....." Substituting a standard nipple will permit too heavy an oil flow and will interfere with the oil pressure in the entire oiling system"......

is that it ????

Bob C

[Phil Waterman]

Hi Bob

Blocking of the oil feed to the rock assembly was easy just unscrewed the line from the fitting in the middle of the assembly and replace it with a union fitting that had the end soldered up.


You can just see it sticking up between the push rods in the center of the picture.

Yes I had taken note of the instructions about the gaskets on the oil pressure relief on the side of the engine. Took it apart and checked that I had assembled it correctly. As to the restrictive orifices yes I've learned to look at the fittings on the Chevy both in the oil system and vacuum system. When I find them I tag them, made a number of replacements over the years by soldering the replacement closed and then drilling it with a matching size drill.

Your suggestions and comment have been very helpful as the process of communicating back and forth helps the diagnostic process. As does making incredibly dull videos because that way I can refer back to the video.

I'm pretty sure that I have exhausted the easy things to check and that what ever it is going to take some real time to find.

Cheers Phil