Help ! '63 673 Thermodyne dry rockers

[Thor nogson]

OK Mack Gurus , heres one from a newbie in UK. A chance to display your tech savvy and experience.

Truck is a '63 B61T 673 non-TurboThermodyne, it is currently in refit , has been starting and running fine but began to sound tappety lately so I removed the rocker covers to find the rocker shaft dry.

removed the rocker shaft and found the oil hole dry too.

thought at this point the head gasket may have been fitted upside down so pulled the head to find the oil hole in the block dry too

engine has probably been messed with by previous owner , I bought it as a project . A friend of mine suggested a problem with Camshaft bearings.

Has anyone solved this problem before ?

Thanks

John

[alex g]

Pull pan check oil pump

[Freightrain]

I was curious about oil filter adapter plate or lines. Is the bottom end knocking?

[39 Baby Mack]

Sounds like cam bearings to me also.

Can't remember which number cam bushings they are for sure, but the two that feed the the rockers have slots machined in them

between two holes in the bushing.

Ron

[gearhead204]

if you have oil pressure on the gauge, I think Ron "nailed it" impropper cam brg. install!

[Thor nogson]

Thanks for your comments and ideas , I have made further investigations and find good pressure at the flexi into the oil filter but very little coming out the hose that goes back into the block.

Also took the adapter plate off and found a thread inside the hole in the block the oil comes out of , is there something that should be screwed into it ?

Also noticed o ring on oil filter can may be a bit small , it's not leaking oil but may be letting air pass , what is the effect of air in the top of the filter can ?

[theakerstwo]

The threaded tube should be in there because it goes down to oil pump and comes up and blocks the oil galley so it will not let oil go down the galley before being filtered.Oil comes thru that tube into the full flow oil filter which returns it to the oil galley thru the two oil in the block beside the threaded tube.You better do as been told and pull cam and check the bushings.Also show us a photo of the oil filter and hoses from the filter to block.

[Thor nogson]

I was curious about oil filter adapter plate or lines. Is the bottom end knocking?

Hi Larry , following your comments here , I came across your thread about adapter plates and have taken a better look at mine. Strangely it's the only part of the engine which is not painted which suggests it may have been swapped out. It has the part number 766GB37B on it but that doesn't match any in the PDF from your thread about them . It also seems to be fitted with the wrong gasket but in this case I don't think it affects it's working The pressure releif piston and spring seem to be in good order. I think I will make up a plate in 1/2 inch ally that connects the big hole (flow from pump ) directly to the two return holes either side of it and tap it for a gauge . With the heads off I can only spin it on the starter but I should see 5-10 psi ? Which should be enough to get oil to the top of the block ? Once I can see this , I can put the heads back on and refit the filter housing

No bottom end noise and there is oil on the bottom end of the pushrods

Edited July 24, 2015 by Thor nogson