Stealth Cam Long Term Review
Discussion
Nine years ago almost to the day Rob Robertson replaced the original KC TVR435 cam in my 4.0HC, the car and it's 435 cam had covered just 30,000 miles from new but all the followers had started to dish, a review of the cam itself showed that two lobes were worn, one quite badly, and the other 14 lobes while serviceable looked like they could easily be ready to follow suit soon.
The 435 cam TVR used in the 5.0 litre cars and the 4.0HC was know to wear prematurely, some say this was due to poor quality followers and others suggest the more aggressive profile grind breached the case hardening. Perhaps it was mixture of both plus low levels of zinc in the engine oils uses, either way at just 30,000 mile my 435 was shot but I was pleased I caught it in time and before it put a ton of cam material through my engine.
Fast forward 9 years and as Alex Wheatly had removed the body to complete a renovation of my chassis, and as my valley gasket was leaking badly it made sense to replace it as access was greatly improved, this is what we found.....
Basically the cam is in perfect shape, I was especially pleased to see a consistent polished surface across all lobes as it's quite common to see darker areas on the shoulders of the lobes, clearly each lobe mated nicely with its new corresponding follower, very even and overall wear is more or less nonexistent.
Nine years ago Rob & Ray charged me £850 all in to supply and fit the Stealth cam, new quality follower set, the excellent JP vernier timing set with true roller chain and induction hardened sprockets all gaskets, antifreeze, engine oil ect ect. I drove up to V8 developments early one morning in March 2011 and was back home with my new Stealth cam fitted by 4.00pm, these guys really know their way around a Rover V8 so I just let them get on with it, and what attention to detail they showed too.
In addition to all the work you would expect, in the five hours they worked together on my engine they managed to do all this too.....
Highly recommended
The 435 cam TVR used in the 5.0 litre cars and the 4.0HC was know to wear prematurely, some say this was due to poor quality followers and others suggest the more aggressive profile grind breached the case hardening. Perhaps it was mixture of both plus low levels of zinc in the engine oils uses, either way at just 30,000 mile my 435 was shot but I was pleased I caught it in time and before it put a ton of cam material through my engine.
Fast forward 9 years and as Alex Wheatly had removed the body to complete a renovation of my chassis, and as my valley gasket was leaking badly it made sense to replace it as access was greatly improved, this is what we found.....
Basically the cam is in perfect shape, I was especially pleased to see a consistent polished surface across all lobes as it's quite common to see darker areas on the shoulders of the lobes, clearly each lobe mated nicely with its new corresponding follower, very even and overall wear is more or less nonexistent.
Nine years ago Rob & Ray charged me £850 all in to supply and fit the Stealth cam, new quality follower set, the excellent JP vernier timing set with true roller chain and induction hardened sprockets all gaskets, antifreeze, engine oil ect ect. I drove up to V8 developments early one morning in March 2011 and was back home with my new Stealth cam fitted by 4.00pm, these guys really know their way around a Rover V8 so I just let them get on with it, and what attention to detail they showed too.
In addition to all the work you would expect, in the five hours they worked together on my engine they managed to do all this too.....
- Steam clean inlet manifold
- Remove & refit all eight injectors that were badly seated (engine running on 7 cylinders when I arrived in the morning, that's another story)
- Steam clean timing cover
- Remove seized bolt from timing cover (required a lot of heat to free it)
- Replace various corroded bolts, free of charge
- Check oil pump for wear (all good)
- Uprate oil pressure, double relief spring fitted
- Clean, polish & deburr oil pressure relief valve plunger & seat
- Oil pressure increased from 35 psi to 40psi on the TVR gauge (probably more like a true 50 - 60lbs with a decent gauge)
- Rockers stripped from rocker shafts, rocker end faces deburred, flatted & polished on a surface plate
- Rocker shafts deburred & polished
- Steam clean rocker covers & secure loose oil trap late screws
- Drill out old snapped off stainless screw in rocker cover (hard as hell) & fit new dip stick retaining bracket
Highly recommended
BIG DUNC said:
It’s good to know it has lasted. How many miles has it done in those nine years?
The answer is many more thousands of miles than the the original 435 cam gave, that had definitely begun to wear prematurely as shown in my images above. When my Chimaera reaches 130,000 miles the V8D Stealth will have done 100,000 miles and I'll be checking it again then, but from what we've seen from the latest mid term inspection I can see no reason why my V8 Developments Stealth cam won't last at least 100,000 miles or more.The secret to long cam life in a Rover V8 is actually no secret at all, V8 Developments used quality hardened followers, a properly case hardened cam, and really good quality timing gear from JP in Australia with a full roller chain and induction hardened vernier sprockets. Equally important however, if not more important if you're going to get good cam life, is the oil you use! I swear by Penrite HPR15 which is a fully synthetic 15W/60 that contains over 1,000 PPM of zinc which is the essential anti-wear additive for flat tappet engines.
https://www.classic-oils.net/Penrite-HPR15
BIG DUNC said:
Is it very different to the original in terms of performance and drivability?
The cam was installed when I was still running on the Lucas 14CUX and distributor, drivability is a subjective thing of course and can be influenced by many more things than the cam profile like ignition system condition, vacuum leaks, earthing, sensor condition especially the air flow meter, ect ect ect. I would however consider myself very fussy about drivability, and as the car was driven on the original 435 in the morning and the Stealth in the afternoon I feel confident in my review of this cam being accurate.First of all the engine remained very tractable below 2,000rpm and as you might imagine idled smoother given the 435 was down on two lobes, the smoother idle was accompanied by a noticeable change in power and willingness to rev above 3,000rpm, the engine really came alive and I was grinning all the way home after the Stealth had been fitted. It felt like the engine had picked up at least 20hp a figure born out in a later rolling road session, actually the engine went from a rather disappointing 190HP to a far more respectable 220hp so the cam swap actually added a surprising 30hp. Later on and after the Canems system was installed I recorded 250hp and 263ft/lbs on LPG ... not bad for a 4.0 litre Chimaera running on £0.55p a litre taxi fuel
Also when I replaced the 14CUX and distributor with the Canems system it made the engine even smoother, as well as more powerful, but I can definitely still recommend the Stealth cam to anyone running the Lucas system. Saying that I have a 4.0HC with valve reliefs machined into the piston crowns, TVR thought this work necessary when fitting the higher lift 435 profile cam upgrade which was a £1,000 option back in 1996. With this in mind I recommend talking with V8 Developments if you have standard pistons without these valve reliefs, because if anything the Stealth feels like it has more lift then the TVR 435 as fitted from new to my 4.0HC.
spitfire4v8 said:
The other secret to long cam life is to use the car a lot.
My V8S 4litre had the std tvr cam, and had 117k miles on it when I removed it to fit the 5 litre. Still on the original cam and original clutch. Over 100 track days easily, and hundreds of runs on the dyno. use it or lose it
Absolutely, RV8 TVRs often sit for months on end, sometimes years, in that time the cam lobes will be dry.My V8S 4litre had the std tvr cam, and had 117k miles on it when I removed it to fit the 5 litre. Still on the original cam and original clutch. Over 100 track days easily, and hundreds of runs on the dyno. use it or lose it
And it's that first start up that'll wipe your cam lobes out.
After winter hibernation I throw 1 litre of warm/hot engine oil down the filler to drench the valley/lifter area but not before using my sump heater pad , now the engine is over filled but I change that straight after lay-up anyways , just now my sump pan temp after a couple of hrs 
I need to move the car to replace the diff , agreed the Stealth is a great cam especially real word use 
I need to move the car to replace the diff , agreed the Stealth is a great cam especially real word use Edited by Zener on Saturday 4th April 13:57
ChimpOnGas said:
Basically the cam is in perfect shape, I was especially pleased to see a consistent polished surface across all lobes as it's quite common to see darker areas on the shoulders of the lobes, clearly each lobe mated nicely with its new corresponding follower, very even and overall wear is more or less nonexistent.
I think you may be misinterpreting the wear pattern that occurs on a hydraulic camshaft. Since the lobes are ground at an angle in order to rotate the followers, there should indeed be a darker unworn area on the front shoulder of all the lobes. There is little value in looking at the tips of the lobes as they will always have a 'consistent polished surface' no matter how worn. The place to look is at the base of the lobe and indeed the shoulders. On an unworn lobe, the base will be polished over less than half distance and this darker unworn area will taper to just below the nose. Conversely, on a worn lobe, both sides of the base will be polished and, depending on the degree of wear, this unworn patch in the center will only extend as far as the lobe lift begins.
This picture shows a worn and only slightly worn lobe next to each other.
And this photo shows the wear pattern on the shoulder, worn lobe to the left.
It is hard to pick out these details from your photograph accurately so I won't comment on the appearance.
And perhaps, without taking offence, a more critical look would be worthwhile.
Dougal.
+1 on Dougal's cam contact comment.
I bought the stealth cam around 5 years ago as a kit from V8 and installed it myself. When it come to timing and a couple of questions I had they were great over the phone. Nice piece of kit to boot, high quality.
The stealth cam is recommended with pocketed pistons which I know the 450 & 500 have, don't believe the 400 has them.
The power from 2k is a noticeable improvement over the OE cam that had worn severely,
Jools did a RR after I installed the stealth cam and mine pooted out 280 bhp, not bad for an old 450.
I bought the stealth cam around 5 years ago as a kit from V8 and installed it myself. When it come to timing and a couple of questions I had they were great over the phone. Nice piece of kit to boot, high quality.
The stealth cam is recommended with pocketed pistons which I know the 450 & 500 have, don't believe the 400 has them.
The power from 2k is a noticeable improvement over the OE cam that had worn severely,
Jools did a RR after I installed the stealth cam and mine pooted out 280 bhp, not bad for an old 450.
Chimp871 said:
The stealth cam is recommended with pocketed pistons which I know the 450 & 500 have, don't believe the 400 has them.
The 4.0HC had valve reliefs machined into its piston crowns.I have a 4.0HC, this was how I was able to go with the Stealth.
And very happy with it I've been too.
ChimpOnGas said:
The inspection was very thorough, trust me my cam is in rude health.
The point of my post stands, I would not have shared the information had it not been completely accurate.
Just to add my 100k + miles on the KC 435 had one egging cam lobe and v minor signs of wear along the rest and non cratered/dished lifters barring the parent shagged lobe The point of my post stands, I would not have shared the information had it not been completely accurate.
if it wasn't for that I would have give it another 20/30k miles vernier cam gear set chain was well worn however 
motor previously un-opened IMO seems backed up with the paperwork folder that came with , agreed type of use and oil choice have a major influence Zener said:
Agreed type of use and oil choice have a major influence
Prior to the purchase of my 30,000 mile 4.0HC Chimaera the car had been serviced by Offord TVR, as I'm not especially trusting of the servicing standards of others I went right through the car after getting it home, and sure enough it was quite clear the attention to detail from this so called TVR specialist left a lot to be desired.Given the standard of their work I decided to call them to see what oil they used, the guy on the other end phone proudly told me they only use Shell Helix 10/40W, first of all that's a bit light for the old RV8, but more importantly this is a modern oil designed for OHC engines running catalytic converters so contains little or no zinc, for these two reasons it is highly unsuitable for the flat tappet Rover V8 engine.
In addition to the oil point, the fact the engine had only covered 30,000 miles in 13 years lead me to believe it had very likely seen long periods of inactivity. All this was just about the worst recipe for the the cam, so I measured lift at the rockers which strictly speaking is not an especially accurate method with hydraulic followers, however it did allow me to identify two suspect lobes later confirmed as worn when we removed the cam.
If the correct oil is used and the car is driven regularly there's no reason why a quality cam running on quality followers shouldn't last 100,000 miles or more in Rover V8, however run the wrong oil and fail to use the engine regularly and the onset of this kind of early wear at 30,000 miles is to be completely expected.
Fortunately I consider we caught it just in time, and 10 years later the Stealth cam that replaced it is now confirmed as being in much better shape than the original 435, this is a completely fair comparison as both cams have covered a similar mileage. My final point would be there's no way of telling how the original 435 was broken in, it's anyone's guess if TVR ran my engine up at 2,000 rpm and held it there for 15 minutes to break the 435 cam in properly.... but I very much doubt it!
On this point however one thing is for sure, my Stealth cam was properly broken in, because I was there when this important break in procedure took place
Even though my AJP8 was badly neglected when I bought the car, with tappets that were starting to dish, the cam lobes were and still are in perfect condition
I doubt the engine was actively protected with an appropriate high zddp oil, and even if it had been I expect the oil change intervals meant the level of zddp was often too low
I have just filled my AJP8 with Penrite HPR10, so I completely agree that using the right type of oil is essential, but my conclusion is that the cams used as standard in the TVR RV8 were rubbish
Until my Chimaera owning mate told me that he had just had his engine rebuilt because the cam lobes were nearly round, I hadn't even realised that cams lobes could wear away
He was one of those owners who could truthfully say that the car was maintained regardless of cost, so the damage was definitely not due to deferred maintenance
My only previous knowledge of cam lobe damage was that the closing flank would start to pit, and that this affected high lift flat tappets
It seems counter-intuitive that the surface following the nose would suffer damage
I doubt the engine was actively protected with an appropriate high zddp oil, and even if it had been I expect the oil change intervals meant the level of zddp was often too low
I have just filled my AJP8 with Penrite HPR10, so I completely agree that using the right type of oil is essential, but my conclusion is that the cams used as standard in the TVR RV8 were rubbish
Until my Chimaera owning mate told me that he had just had his engine rebuilt because the cam lobes were nearly round, I hadn't even realised that cams lobes could wear away
He was one of those owners who could truthfully say that the car was maintained regardless of cost, so the damage was definitely not due to deferred maintenance
My only previous knowledge of cam lobe damage was that the closing flank would start to pit, and that this affected high lift flat tappets
It seems counter-intuitive that the surface following the nose would suffer damage
You do have to question the cam quality. When I first researched buying a 350i, almost 30 years ago, I was told by a well known specialist "check whether the cam has been done. They only last 60,000 miles".
& yet in a range rover with essentially the same engine, the cams seem to last for ever.
I do agree that frequency of oil changes and quality and grade of oil are critical.
& yet in a range rover with essentially the same engine, the cams seem to last for ever.
I do agree that frequency of oil changes and quality and grade of oil are critical.
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