Compression test values
Discussion
What cam was the worn one and what did you put in Martin? That 3rd lobe is really bad... 
to be honest that looks like the type of wear I found on the 500 HC as was due to those bad casting spurs above the cam where the oil runs down the valley
Lets hope it last a bit longer otherwise it looks like a very expensive service item!!
to be honest that looks like the type of wear I found on the 500 HC as was due to those bad casting spurs above the cam where the oil runs down the valleyLets hope it last a bit longer otherwise it looks like a very expensive service item!!
I'm not unduly surprised about the cam. It was one of the freely available aftermarket cams at about £120 for the cam and followers; moral of the story is that you gets what you pays for. OE Land Rover cams are £400+ as are Piper/Kent etc alternatives (with the followers). Real Steel offer cheaper ones but you don't know the quality until you try them, I might try that at some point but I'm not holding my breath! I've put back in a 'high compression' cam from Rimmers which I don't think was available a couple of years ago (and it does look better quality); I didn't want to put an expensive cam in as after I've fitted megasquirt I can't guarantee a quick 'fire up and run at 2000rpm for 10 mins' scenario. I'll probably change the cam again later... or stuff in the 420 surrogate engine from the SEAC! It's a good job that I like messing with engines/cars.
I took the upmost care fitting the cam 2 years ago; as clean as possible, new followers, cam lube (ZDDP) galore, quick fire up and run in at 2000rpm for 10 mins. 20/50 oil changed regularly (halfords classic then valvoline later), few short runs (20 miles to work...), idles at 1000+ rpm. There's only so much you can do with suspect hardware! I'd done less than 5000 miles but the engine still felt pretty good, I think the RV8 is a pretty tolerant lump.
It's on the 'lessons learned the hard way' list.
I took the upmost care fitting the cam 2 years ago; as clean as possible, new followers, cam lube (ZDDP) galore, quick fire up and run in at 2000rpm for 10 mins. 20/50 oil changed regularly (halfords classic then valvoline later), few short runs (20 miles to work...), idles at 1000+ rpm. There's only so much you can do with suspect hardware! I'd done less than 5000 miles but the engine still felt pretty good, I think the RV8 is a pretty tolerant lump.
It's on the 'lessons learned the hard way' list.
I try to avoid idling as the followers need 1500+ rpm to rotate and keep the cam ok.
Have an OE 3.9 camshaft on the shelf as backup from a Rimmers sale a couple of years ago.
Are these any good for a standard 350i? Would not expect a change in performance, but that it at least could last a long time.
If these are ok (I hope so), perhaps worth a look as an alternative camshaft if you are not looking for a performance upgrade of the 350i.
Rob
Have an OE 3.9 camshaft on the shelf as backup from a Rimmers sale a couple of years ago.
Are these any good for a standard 350i? Would not expect a change in performance, but that it at least could last a long time.
If these are ok (I hope so), perhaps worth a look as an alternative camshaft if you are not looking for a performance upgrade of the 350i.
Rob
I generally drive off as soon as I can, and take it gently for a while.
I wondered about a 3.9 cam, I'm not sure what the differences are. I did think that the 3.9 was an off roader cam so would be tuned for low end torque rather than top end power but that may not be a bad thing anyway!
I wondered about a 3.9 cam, I'm not sure what the differences are. I did think that the 3.9 was an off roader cam so would be tuned for low end torque rather than top end power but that may not be a bad thing anyway!
3.9 cam seems to have a little less low down torque and a few more bhp higher up the rev range in a 3.5
Think it was less than 100 pounds for it, sounded like peanuts, so why not have one on the shelf I thought. Cost a fortune now when I had a look on the site, so it was peanuts. Why such a difference if aftermarket can be as good as original, especially in items that have been produced for many years in quite some numbers?
Currently all things start moving more quickly from 3500 rpm onwards (all things standard and the engine hasn't been opened up yet), which is a bit late for my liking. Was considering a Kent 218, but no need for a serious cam right now, perhaps when I need to change or do a rebuild.
Seems it could become worse with that 3.9 cam. But when it replaces the original, many horses probably have left the stable, way over 100.000 miles on the clock all ready, and it will not feel like that I assume. Will try it first before putting something more serious in.
The 3.5 is still running fine, only needs a new rising rate fuel pressure regulator to get back to have a bit more bite/poke for the time being as the fuel pressure and power is all over the place!
Rob
Think it was less than 100 pounds for it, sounded like peanuts, so why not have one on the shelf I thought. Cost a fortune now when I had a look on the site, so it was peanuts. Why such a difference if aftermarket can be as good as original, especially in items that have been produced for many years in quite some numbers?
Currently all things start moving more quickly from 3500 rpm onwards (all things standard and the engine hasn't been opened up yet), which is a bit late for my liking. Was considering a Kent 218, but no need for a serious cam right now, perhaps when I need to change or do a rebuild.
Seems it could become worse with that 3.9 cam. But when it replaces the original, many horses probably have left the stable, way over 100.000 miles on the clock all ready, and it will not feel like that I assume. Will try it first before putting something more serious in.
The 3.5 is still running fine, only needs a new rising rate fuel pressure regulator to get back to have a bit more bite/poke for the time being as the fuel pressure and power is all over the place!
Rob
Not forgetting a cheap inferior set of cam followers will chew through a top quality camshaft no problem in pretty short order once the tappet face starts to gall up 
no matter if its been run-in correctly has zinc/ZDDP in the oil whatever 
I would say there is more poor quality followers/lifters about than piss poor quality camshafts IMO
no matter if its been run-in correctly has zinc/ZDDP in the oil whatever I would say there is more poor quality followers/lifters about than piss poor quality camshafts IMO Good point Simon - anyone know if the followers are case-hardened too?
In any case I think I've spotted the source of the problem:
See the "steps " in the casting - as the followers rotate and dish, these steps (made from case-hardened steel) will catch and score the followers.
Once the followers are fouled up (as above) the cam will surely follow.
Unfortunately the destroyed lobe has taken the evidence away with it.
Just goes to show how careful we should be inspecting this stuff before fitting - I'll be taking photos and blowing them up on my computer next time!
In any case I think I've spotted the source of the problem:
See the "steps " in the casting - as the followers rotate and dish, these steps (made from case-hardened steel) will catch and score the followers.
Once the followers are fouled up (as above) the cam will surely follow.
Unfortunately the destroyed lobe has taken the evidence away with it.
Just goes to show how careful we should be inspecting this stuff before fitting - I'll be taking photos and blowing them up on my computer next time!
Hi Adam,
The casting flash/mismatch is pretty bad but I don't think it was the cause of the failure - I spotted it before I fitted the cam and ground it away so that it was below the surface that the cam followers run on. The follower surface is flat so this flash would only be a problem if/when the follower wears to a dish; by which time you'd be through the case hardening and into rapid wear anyway. However it didn't give me a good feeling about the quality of the cam!
I've been known to bin new parts when I've received them due to poor quality (suspension bushes, ball joints and brake discs spring to mind - safety critical stuff) but I thought at the price this camshaft was worth a punt.
Good call about the cam followers though, it could well be the followers rather than the cam but I suspect it's actually both. I'm not sure about how the followers are hardened, but it could also be the surface finish or the tolerances on flatness etc. on either the cam or the followers.
The casting flash/mismatch is pretty bad but I don't think it was the cause of the failure - I spotted it before I fitted the cam and ground it away so that it was below the surface that the cam followers run on. The follower surface is flat so this flash would only be a problem if/when the follower wears to a dish; by which time you'd be through the case hardening and into rapid wear anyway. However it didn't give me a good feeling about the quality of the cam!
I've been known to bin new parts when I've received them due to poor quality (suspension bushes, ball joints and brake discs spring to mind - safety critical stuff) but I thought at the price this camshaft was worth a punt.
Good call about the cam followers though, it could well be the followers rather than the cam but I suspect it's actually both. I'm not sure about how the followers are hardened, but it could also be the surface finish or the tolerances on flatness etc. on either the cam or the followers.
That Wedg1e probably has a few Brinell testers scattered around his workshop, why not send a couple of followers and a bit of camshaft up to him for testing? He's an obliging chap and I'm sure he can fit it into his busy overnight fettling schedule. Might have to ask him first though.
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