Hey fellas, hope your labor day was nice!

I finally got my valve covers painted and back on the engine. It took longer than expected 'cause of rain but we're in business. I got a few questions for you engine savvy folks:

On the right valve cover, there is a 'breather hose' that comes from a stem on the cover and attatches to the plenum chamber. Before my valve job, I noted that there was a hole in this hose and it was sucking air. I made a mental note to fix it while I did the valve cover job. While the cover was off, I realized that the stem for this hose had been intentionaly blocked using a tire stem cap! I freed the blockage before reinstalling the covers.
The question is, what exactly does this hose accomplish? Where will I see a difference if there is one?

I also changed the plugs and wires while at it, and now I have a real change in performance. My RPM's run a bit lower at speed but my trans. seems to switch at different RPM's than before. For instance, the tranny switches from 2nd to 3rd and from 3rd to 4th gears at about 3000 RPM's. Normal? I don't know. But I run 55-65 mph at about 2300 - 2500 RPM's; sometimes lower.

I would like any comments you can offer. This was my first time working on this rover engine. It was a real pleasure! I'm looking forward to investigating a persistant power steering leak as well as a brake job, but I'll save those questions for then. As a side note, just to express some excitment, after the covers were on I took it on a trail for the first time! It was great! More fun than I expected!

Thanks for your help!
Cheers!

 

The hose in mention is designed to suck off blow by and reburn it thru the manifold, what people used to call a PVC hose, Positive Crank Case Ventilation.
As for the improvement in performance, to be expected. Normally don't see the idle go lower, could be related to fixing the hose.

 

Thanks Mike,
The idle hasn't changed. The only difference in RPM is on the highway at speed.

As regards the transmission, the switch from 2nd to 3rd and from 3rd to 4thgives a pretty big jolt! The RPM's jump down from 3000 to just under 2000!I've only driven the truck 6 or 7 months or so, but I don't recallthe engine joltingthat much before this cover job. Just curious if thePCV tube had anything to do with it. Why would someone block that tube anyway? What's the point?

 

Check your kickdown cable. I adjusted mine out and it held the shift longer, making it shift harder. Mine had been adjusted so far out that the kickdown wasn't actuating. I lubed it, ran it like this for a little while, then adjusted it back down. Shifts great now. If you messed with your throttle cables at all, this might be the culprit. If you have a D1, the retaining nuts are 13MM.

I run 70 @ 2500RPM, stock tires. My shift points under normal load are around 2500....

Might want to add your truck specs to your sig so people know what you have. Easier to give advice.

 

Hey thanks discoguy!

You know, I did remove the throttle body along with the plenum chamber and I bet that's it! When I reinstalled I wasn't sure where the retaining nuts should sit so I just guestimated. Thanks for the tip.