R Cubed

If its any help my hose is straight but has a little dog leg in it and roughly 6" long end to end. All I know of the history is that it was imported from France in 1995 then sold to the guy who I bought it off, he kept it for a couple of years before I bought it and had it ever since. In re-spraying it a couple of years ago found a French flag painted on the back left hand rear mudguard !!

Yes of coarse I can Ian, what I will also do is take some pics too for you.

Hi there, if its any help the one on my truck is straightish, no loops in the flexible hose, looks like the steel tube from the oil pressure gauge needs to be a bit shorter.

You are sooo right, maybe a blessing in disguise. The piston ring issue was well worth doing as in the stripping down several of the pistons just slid down the cylinders of their own accord :shocked: and after checking the ring gaps of the old rings found them to be over 50 thou gap so needed doing.

All very much appreciated, thanks. Well, I am not all that inexperienced with engines, however the sound it was making in my opinion did sound like a "banging futt sound" you could say it was a knock which is what I thought, suspect this is because the size of the cylinders and the resultant combustion volume made a larger sound than I am usually use to with playing about with Rover 3.5 Ltr V8's and 2 Ltr 4 pots. In hindsight though having stripped the engine and not found anything except worn piston rings and pitted big end bearing shells the search continued, to the point I am at now !!! Yes reckon you are right.:blush: I think the gaskets on the inlet were fine until I disturbed them all when I cleaned the loose bits off the exhaust ports, this then lead to the inlet not pulling up tight to get the exhaust manifold to seal ( sort of ) at that time did not want to get into the situation of replacing both the manifolds, but there you go maybe I should have changed them years ago !!!! You live and learn...... Since putting the engine back together the first time the knocking was as bad, coupled with the massive lack in power, due to the two end inlet ports leaking lots, I now know they were leaking lots as when I wiped grease round them when the engine was ticking over you could see the grease being pulled in through the gasket joints, this would account for the loss of power as these two end inlet ports each serve 2 cylinders so 4 cylinders were running very weak :shocked: Note Richard, please do not think this is a moan at you I am just trying to tell everyone my errors in diagnosis of the fault was and how you can get side tracked into thinking it is something more serious than it actually is..

You are sooooo right there is NO mistake looks like I am the nooob :blush: 15 years of having the truck and I am still learning.

Yes your translation is quite right.

Ok to clear up the confusion, Deadline you are right about the valve this is the one I am referring to. The "deliberate mistake" I was lead to believe there should have been a steel ball in there to act as a valve but investigating it more I now see that it IS a restriction and NOT a non return valve, as Deadline points out with his pic of the TM page. It can pass air either way but in its installed position there is a vacuum caused in the rocker cover due to this connection to the inlet manifold and with the oil filler air filter this allows air in to the crankcase and flows up through the cylinder head into the rocker cover and then in to the inlet manifold taking with it blow by gasses and oil mist in the process. So there is no deliberate mistake everything is as it should be. There is a right and wrong way for it to fit ( the threads are also different ) the inner valve and spring must face towards the inlet manifold for it to work correctly.

If you see my post with the pics today you will see that I have explained that the hydrovac non return valve is fine its the valve for the crankcase breather from the top of the rocker cover to the inlet manifold which I am talking about.

You just stay down there I am getting it sorted now and I dont want to add your electrical problems to it as well.

How do we know if our on-line booking form has worked ? Could there be a locked thread that the mods could post people and vehicles who have been confirmed as booked in.

Well I have been also going thorough the bits and bobs connected to the inlet manifold. I have checked the hydrovac non return valve, which was fine holding good vacuum some time after the engine had been stopped. The steel pipe from the rocker cover to the inlet manifold via a metering valve can quite often get gummed up with oil and carbon deposits, my one was un blocked and the valve inside was free to move. Below are some pics of the valve unit this is detailed in the TM to be regularly checked to ensure it does not get blocked up. NOTE: the thread on the right hand side in the pic screws into the elbow on the inlet manifold, the thread on the left hand side ( Brass ) screws to the steel tube with the other end screwing to the elbow on the rocker cover. This is the complete valve removed from the inlet connection and the steel tube to the rocker cover. This is how it splits in half. This is what is inside it. Here is the main valve part and return spring. There is a small hole in the centre of this valve and can sometimes get gummed up with oil deposits. ( in TM for regular cleaning ) There is also a larger hole in the side of the valve to allow more air to pass under higher vacuum loads. Here is a view of the back of the valve and spring. Here is the inside view of one half of the valve housing, (this is the half which screws into the inlet manifold connection) where the valve and spring in the pic above go in spring first. Last of all the other side of the valve housing.

If the truck re assembly goes well and it behaves its self, might drive it there but depends on how much its going to cost in fuel :shocked: Looks like its about 400 miles from Calais so at 8 to the gallon its going to be roughly £200 each way.... Plus the UK bit.... What are peoples suggestions on a sensible route to take for driving a GMC? Dover to Calais as the ferry crossing ?

whats the deal with this event for 2012 ? does anyone know the dates and where it starts from........

errrrrrr stay " tuned".............

In the top link ww2talk what's the Sherman doing there ? Still in use ?

I am very surprised with how bad the inlet air leaks were and considering this how well the truck went even with the gun on !!! good old GMC...

I am still a little aprehensive about the Knocking sound but we shall see on that point. With what I have found the exhaust manifold definatly needs replacing, the inlet I am going to check for flatness, although it should be ok as it does not suffer with the heat that the exhaust manifold does. The broken studs are all in easily accessible places so will be done in-situ.

Over the weeekend I have removed the two manifolds and split them appart, of the four fixing bolts one came undone due to the threaded hole in the inlet manifold being cracked, one was corroded so badly there was only about 5mm dia of stud left, and that sheared off, the other two sheared off, yes level with the manifold. The last two exhaust ports nearest the firewall both are corroded beyond use ( no more material to machine off to create a flat level surface) and can be seen to have been blowing badly ( this I susspect is the knocking noise ) ...... Also the exhaust manifold casting between ports 3 and 4 has a crack in it about a inch long although there is no sign of black exhaust soot from it. Due to the fact that both manifolds have been bolted together for many many years the corrosion on the exhaust ports has now meant that when they were pulled up tight it distorted the inlet ports so would not seal properly (now proved before stripping down) both end ports of the inlet manifold had air leaks, these of course feed two cylinders each (the squeeking / weazing sound) so this has had an effect of weakening the fuel / air mixture to cylinders 1, 2, 5 and 6 so out of the 6 cylinders only 2 were getting the correct mixture, no wonder it seemed sluggish :shocked:

Thanks very much for the measurements I will now check my one, sorry to hear of your breakdown woes, Makes me think I must check my oil line flexie hose.

Yes its a real pain, more so it now looks like its only an exhaust blow but I am holding my breath.... we shall see soon.

I think so also another item which goes hand in hand with these filters is an "S" at the end of the USA bonnet number, refering to the vehicle is Suppressed.

Can people measure their dipsticks please........ What I would like to know is the length of the outer tube from the point it enters the fitting on the sump ( please only need people with double / deep sumps ) to the top of it, and on the actual dipstick the Low mark to disc up by handle and also High mark to same place.

Just looking through my TM 9-801 for another reason and came across a pic of the oli filler breather filter, which has a transfer on it is this the orange couloured one on your set ?

Mmmmmmmmmm HST....................