Cam freshen up

[Konradical]

As you may be well aware in recent past I have had a ton of trouble with my '89 RRC getting it to start and run, then the resulting carnival ride to sort the issue and have a happy and healthy roadable Rangie.

Since moving back to SA I have freshened up the front end, fitted new tyres and where money + weather allowed, slowly sorting out the little niggly things.

Well aside from a leaking power steering system and the engine fan exploding, it has been doing pretty well. For blocks at a time it does my 160km daily trek to work and home and still get the ugly tow jobs instead of the Disco. Whilst doing this, it has had a very thirsty appetite. Currently getting around 20-24 L/100.

I hope to reduce this by replacing the cam and using a 10W-40 HPR10 oil.

So over the last day, dodging this awesome temperature, I have removed the old cam. I found that there were no shims under the rocker pedestals, one of the followers didn't have a retaining clip and the distributor drive gear is worn again after only 10k km..

To note there was less wear on the cam than I expected and the followers weren't as concaved as I have seen on the web. From measuring the old and new cam lobes, there was on average 0.01" of wear. Randomly on No. 7 intake, there was 0.04" of wear. Working it out with the rocker ratio the valve is 0.064" (1.76mm) less open than it should be. The ideal outcome would for the car to have more torque than it has and make cruising at 100kmh a little less arduous.

My plan is to fit the 3.9 EFi cam and degree it in properly to gain a bit more of that bottom end. I don't have huge expectations though, just want a little more smoothness.

Oddly, the cam I pulled out has HRC 1619 on it, which research leads me to believe is the 3.9 cam already.. maybe I won't get too much change at all...

[PhilipA]

Yes IMHO don't go trying after market cams.
Even "towing" cams can be too radical for a RRC. The 3.9 EFI cams are about the best grind.

You only need shims if the preload on the lifters is out. This usually happens if the heads have been shaved .

Also check your rocker shafts and rockers for wear.

Regards PhilipA

[Konradical]

You only need shims if the preload on the lifters is out. This usually happens if the heads have been shaved .

You are right about the cam, from all that I have read here and other places the std cam is probably going to be the best, considering the rest of the engine is pretty well factory. As long as it is dialled in correctly, it should work well.

The reason I mentioned the shims, is because I have been reading various articles on the subject and how it effects the valve opening and rotation of the followers/push rods. Before I loosened everything I tried to rotate the pushrods and even on TDC combustion, they were pretty tight.

The rockers feel tight, but Il be sure to dismantle them and check properly. I was hoping to have it running tonight, but I have had to order a couple of bits that I didn't think I needed, so may be the weekend after new years. This gives me a chance to clean everything properly and thoroughly.

Also gives me a chance to memorise the Rave Section..

[Pedro_The_Swift]

The only good thing about the 3.9 cam is, well it fits.
The bad thing is dont expect any change in its longevity. [bighmmm][smilebigeye]

are you going to use new valve springs?

[Konradical]

Does any body know what or how the cam is kept in place? Is it voodoo or from the tension on the drive chain that hold it there. There aren't any retaining plates, so what stops it trying to drive out?

The reason behind this question is because I am trying to figure out why I am on my second dizzy drive gear and the weird lobe wear tend to point at the cam trying to push its way out..

I noticed today that some of the lobes have more wear on the rear edge.

Be interesting to know..

[Bradtot]

Hi...I also wondered about this many years ago and was told the the Cam lobes are ground in such a way as to push the cam backwards when hitting the lifters when rotating. This is also why the lifters should also spin/ rotate when working so they don’t wear in one spot.
When I have removed the rocker covers on a carby rover V8 and started the engine, on a engine that has a worn cam lobe I have seen the pushrods not rotating..symptoms of a new cam required. Many years ago there was a cam called WL9 from memory, it was an experimental cam grind used by the independents here in Perth when they were modifying the Rover V8 using 3.9 liners in a 3.5 also using holden 186 flattops pistons and this Cam....I had this done to my Rangerover and it was great...the current 3.9 Cam has almost the same specs as th the WL9 so it was never continued with. In those days 84/85 it cost a bomb to do. There was even 5 litre Rover V8 with different cranks. That motor is still running today after around 300k and the Rangie has just been sold again to someone who I believe is going to rebuild it from scratch.....It was the best car I have ever owned..1982 4 door with Holley 350 and Webber conversion block..when I sold it it had done 525000kms and that was 9 years ago..l loved that Rangie...I like my 89 vogue as well but this one was the best!!!
Brad

[PhilipA]

You used to be able to get cam buttons that screw into the front of the cam and stop it from moving forward, but a bugger to fit as had to assembled by trial and error. They were a LR part at one stage.

The slope on the cam lobes keep the cam in place. I also think the timing chain helps so if worn will reduce the help.

I fitted a double row timing chain to mine, but this necessitated grinding quite a lot off the timing cover where the dizzy shaft comes down.
Regards PhilipA

[Konradical]

So I thought I'd update and share how this process has gone.

After having to wait for a few more parts, I managed to get the engine back over the course of a few days and evenings here and there for the last couple of months. This culminated this week when I took it off to get my life in gear and get stuff sorted.

Aside from having the power wire connected to the wrong terminal on the coil, she fired first time and spent the next 15mins at high idle to bed the cam in.

All was well!!

Was...

After a quick tidy up, I took her for a drive. First thing I noticed was it started missing slightly when in gear and foot on the brake. Then it missed/hesitated slightly as I slowly accelerated, but once past that point it was smooth. This continued as the test drive got more brave. The only other thing to noted was again a slight miss/hesitation at about 60kph, but went away with more accelerator or backing off.

When home I rechecked the timing and made sure everything was connected properly. Even readjusted idle. It remained the same.

Next day I replaced the plugs and rechecked it all again. Seemed to run better but still had a hesitation once warm. Took it for another drive and it felt good, so good in fact I took it up into the hills. Still had a flat acceleration similar to before the new cam, but was more willing than before.

It appears that was mistake for some reason.

On the way back from the town I turned around in, on a down hill run, it just randomly started backfiring. Then no power. Just backfired like crazy every time I tried to accelerate.

Found a place to pull over and it was fine idling, but didn't like revving. Somehow I managed to get it to the next town (including ****ing a bunch of people off) where I stopped in the shade. Had a check and adjust of a few things and after 10mins it was back to the way it was.

I managed to get home. When idling it started the hesitation again and not in drive this time.

Thinking it could be a coil I replaced it with a spare I have. Straight away it was better. I even went out, drove near the city and then back out along the expressway, traveling at least 30km and it felt good. After I got home though it started hesitating at idle again.

I left it till this morning, where the hesitation has gotten worse. It's now at a point where when it is at operation temp it stumbles until it just stops.

It's not fuel. Plugs aren't wet from over fuelling. It's doesn't cough or splutter when it stalls. It isn't showing the symptoms it did when I was having ecu issues.

All the usual suspects have been tested and adjusted to where they should be. I even pulled the dizzy apart, cleaned and adjusted before resetting the timing.

If the rpm at up around 1000, it doesn't stumble, but there is a slight miss.

I even resealed the manifold incase the was an air leak. The vacuum gauge I have fitted indicates no air leaks or other symptoms. It sits steady at 17 in/hg and only moves when it hesitates. And then only down to about 12 in/hg.

The timing also stays steady.

The only things I haven't changed with spares are the leads and ignition module.

To note I have started it on Diesel HPR15 just to help clear the muck out of it. Have not wanted to carry out a proper service until it is running right.

I am hoping someone could have a different suggestion to get it going. Im right at the end of my patience and it's getting harder to justify to my partner why I want to keep it. Really right now I am at the stage where I just want to drive it and not play around, just can't work out what is going on.

[DoubleChevron]

sounds like its leaning out .... fuel pump. There is an internal hose on the fuel pump that can leak and circulate the fuel within the tank.. You may have changed to coil, what about the igntion module ? Try heating it with a hair drier and see if you get the poor running and cutting out again.

As soon as you talk heat soak issues I go straight for electronic bits under the bonnet (for example if it was my Citroen CX ..... I'd go straight to the flywheel/TDC sensors which are known for going open circuit when hot as they age). On a a range rover classic, the only real electronics under the bonnet is the ignition module.


seeya,
Shane L.

[PhilipA]

Check that you have not got the ECU temp sensor wire and the adjacent injector wire mixed up.
Check that you have the plug wires correct.

regards PhilipA
another thought is that it is something unrelated like a exhaust valve sticking which is common with these.

[Konradical]

Check that you have not got the ECU temp sensor wire and the adjacent injector wire mixed up.
Check that you have the plug wires correct.

regards PhilipA
another thought is that it is something unrelated like a exhaust valve sticking which is common with these.I have done that before, the thermotime and ecu temp are right next to each other. This time I made sure they were marked so they couldn't be mixed up.

I might borrow a laser temp gun and see what the cylinders are doing. Should be able to narrow it down to a set area and work from there.

Still not sure that a oil change will change much, but it's something I could try.

[BigJon]

Have you updated to a Bosch BIM024 module? If not, do so post haste. Cures all manner of ills. There is a good how to thread started by bee utey if you haven't seen it.

Lucas ignition amplifier replacement by Bosch 024 (https://www.aulro.com/afvb/technical-chatter/96950-lucas-ignition-amplifier-replacement-bosch-024-a.html)

[Konradical]

Have you updated to a Bosch BIM024 module? If not, do so post haste. Cures all manner of ills. There is a good how to thread started by bee utey if you haven't seen it.

Lucas ignition amplifier replacement by Bosch 024 (https://www.aulro.com/afvb/technical-chatter/96950-lucas-ignition-amplifier-replacement-bosch-024-a.html)Yeah I did that a couple of years back and to be honest, didn't really note too much of a difference afterward.

With that, one of my tests were to get it doing the hesitation and sprayed the ignition module with freeze spray. If there was a heat problem there, that test would have shown it.

[Meccles]

i've just fixed a vibration in the dizzy caused by worn drive gear on cam. After replacing that dizzy now runs smooth no vibration BUT i've picked up a miss when accelerating. i suspect distributor cap the rotor button was wobbling with vibration but now its smooth i wonder if gap between rotor and cap is just a bit big? Runs perfect at cruise idle etc just a miss accelerating under a bit of load