The V8 Owners Forum -

Hi folks

I'm hoping you can help with a little contradictory advice I've read. I have a Rover P6 3500S engine (suffix A) that I've completely stripped down for rebuild. You can read about it over on the Classic Rover Forum . I'll be fitting a new camshaft and lifters and replacing the front and rear oil seals. They are both rope type seals so I'll be replacing the front with a lip seal and the rear will get another rope seal. All the advice I have read states that when running in a new camshaft and lifters the engine should be run at 2000 rpm for 20 mins on initial start. However, and here's the contradiction, the Rover workshop manual states that the engine should not be run at more than 1000rpm on initial start up as this will damage the rear crank oil seal. I know things have moved on a bit since the Rover workshop manual was printed so any advice would be gratefully received.

Cheers Dave

IMHO, 'running in' a cam is hyped out of all proportion. Why is it only recently in IC engine terms it has become so important? I'd guess it may be more necessary with some aftermarket type with a savage lift profile. Or just give the vendor some excuse to blame you when it wears out quickly.

I'd love the chemistry explained. Does it heat up enough to temper the steel?

Of course it should have an adequate oil supply of the correct oil from the off. But that applies to the rest of the engine too.

Hi
to me this is a no brainer, a cam and lifters will set you back about £300 to replace, a rear oil seal, about £15 for all of them, furthermore you can replace the oil seals in an afternoon without taking the engine out, but if they are oiled properly when you install then they will handle 2000 revs with ease.
The problem with running in a cam is real, it is proven and is a big problem with a flat tappet pushrod cam engine.

"Why is it only recently in IC engine terms it has become so important?
This is a simple one, the Zinc addative in engine oil was reduced to about 20% of it's original levels because Zinc destroys catalitic converters nearly as quickly as lead, it was removed over a period of about 18 months about 12 years ago.
It was fealt to be OK to do this because most engines were running multi valve or roller rocker engines bt this point and both types can servive muck lower levels of Zinc.

I'd guess it may be more necessary with some aftermarket type with a savage lift profile.
The more steeper ramp profile requires stronger springs this in turn increases the pressures involved. The removal of the Zinc coincided in the use of thinner layers of parkerising (that is intended to provide a lubricated surface layer) by aftermarket cam makers and tuftriding replaced it all together in some instances. This was done because the parkerising process uses a lot of arsnic and it costs money to get rid of the residue and get premises inspected so that you can carry out the process, combined with the need for decent polution standards the cost of the process went up, thiner layer less cost.


Or just give the vendor some excuse to blame you when it wears out quickly.

I'd love the chemistry explained. Realy is is Physics and Materials science, not chemestry, there are no chemical bonds involved. There are 2 things happening when you first start the engine with a new cam, you have 2 surfaces of freshly machined steel that hopefully have been given some sort of surface treatment to provide a good surface texture and wear resistance. When the engine starts running the fresh surfaces slide against each other under very high pressure, if you have enough lubricant you will get an easy sliding action that will tend to "push" any high spots into the surface of the cam or tappet, depending which you are looking at, this process generates a lot of local heat, when I say local I am talking local to the high spot on the surface. Spinning the engine up to 2000 to 2500 revs allows good oil over the surface, it also tends to reduce the loading on the sides of the cam lobe and the nose giving these surfaces time to flatten more easily and for the oil to get in, this is key to why you spin it this fast. At the same time Zinc in the oil is providing lubrication to the surfaces and getting combined into the surface in solution in the steel (iron) over time (about 20 nim or so) and as things get hotter there is enough Zinc built up in the surface for it to still provide lubrication when the oil is not there (the oil is not capable of lubricating at these pressures it is the Zinc that does it the oil cools things and carries fresh Zinc in suspension. The running in period and over the next few thousand miles you get a decent layer of higher density steel that has a nice smoothe surface and has lots of lubrication Zinc in it.
Does it heat up enough to temper the steel? temper is not the right term here but there is a lot of surface "conditioning" going on.
Best regards
Mike

Er... !!

Right. So the answer is to use the correct oil. If you're using oil without suitable additives for a push-rod engine, the cam will have a shortened life - regardless of how it's run in.

Hi Dave
you either need the right oil or a tube of addative, good parkerizing helps, it is an attempt to get a metal lubricant (arsenic and iron phosphate) into the surface of the lobe it also explaines why you have to keep tappets and cam lobes together and why you shouldn't swap cams without changine tappets on flat tappet cams.
Best regards
Mike

kiwicar wrote:to me this is a no brainer, a cam and lifters will set you back about £300 to replace, a rear oil seal, about £15 for all of them, furthermore you can replace the oil seals in an afternoon without taking the engine out, but if they are oiled properly when you install then they will handle 2000 revs with ease.

That makes complete sense Mike, thanks. I had thought of treating the rear oil seal as a sacrificial component on first start-up because to my mind getting the cam and lifters right is the priority. I just don't like having to do a job twice. I'll just make sure I give the oil seal a good soak before fitting and not wait too long between fitting and first start up as I wouldn't want it to dry out again.

kiwicar wrote:good parkerizing helps

Had to look that one up. You learn something new every day

Cheers

Dave

On the Cobra forum a lot of guys use Valoline VR1 20-50 for RV8, SBC, SBF etc. It has a high Zinc content. The only problem is that with it being a 20-50 its quite thick when cold so you need to warm up your engine carefully to avoid overloading the oil pump drive. (Well you should warm up your engine carefully anyway but you know what I mean).

The biggest issue that I can see when running a cam in is when the piston rings are new, the last thing you when them to be doing is going up and down the bores with no real gas pressure behind them. Without the gas pressure the ring are in light contact with the bores and they can start to glaze them, once that's happened then the rings won't bed in properly. If it was my lump and the rings were new I reckon I'd still bed the cam in and then I would not run the engine again until I could put it under load 10 times by accelerating quite hard in 3rd or 4th gear.

sidecar wrote:On the Cobra forum a lot of guys use Valoline VR1 20-50 for RV8, SBC, SBF etc. It has a high Zinc content. The only problem is that with it being a 20-50 its quite thick when cold so you need to warm up your engine carefully to avoid overloading the oil pump drive. (Well you should warm up your engine carefully anyway but you know what I mean).

The biggest issue that I can see when running a cam in is when the piston rings are new, the last thing you when them to be doing is going up and down the bores with no real gas pressure behind them. Without the gas pressure the ring are in light contact with the bores and they can start to glaze them, once that's happened then the rings won't bed in properly. If it was my lump and the rings were new I reckon I'd still bed the cam in and then I would not run the engine again until I could put it under load 10 times by accelerating quite hard in 3rd or 4th gear.

This was a problem I came up against many times with tuned ford 4 cyl engines I was into years ago (mainly the X Flow pushrod eng) run the cam in for 20 mins or whatever shut down check for leaks oil level coolant level then take out for a hard run for at least 50 miles never had problems with these builds inc oil consumption etc even when one of them was built with the notoriously oil thirsty Lotus piston & ring design I also changed the oil and filter after the 1st 100 miles and my 1st fill was with 15/40 mineral Diesel/Petrol oil back then that would of been full fat/zinc oil cos this was early nineties have always run my built engines hard from the off without any problems whatsoever, way I see it if you get any problems with this approach the build was no good anyways

kiwicar wrote:Hi
If you are worried about the oil being a bit thick you can always install a sump heater
http://www.amazon.co.uk/Andrew-James-El ... by+belling
These are being used a few drag teams now, cheap simple and they are small enough to run off a normal generator in the pits.
Best regards
Mike

There was actually a nice sump warmer than just attached to the sump some years back, well more like a mat really I am sure some of the TVR SP6 engined owners used there wrapped around the oil tank most were impressed and I think the item was made in New Zealand and intended for this purpose may be a bit blurry with this info though here you go http://www.ebay.co.uk/itm/ENGINE-PRE-HE ... 1177847499

Hi
If you are worried about the oil being a bit thick you can always install a sump heater
http://www.amazon.co.uk/Andrew-James-Electric-Double-1500-watt/dp/B004BM6HXM/ref=sr_1_10?ie=UTF8&qid=1379580750&sr=8-10&keywords=baby+belling
These are being used a few drag teams now, cheap simple and they are small enough to run off a normal generator in the pits.
Best regards
Mike

Hi
yes I have seen those, I will probbly get one or two for my dry sump tank over winter or install one into the tank. The trouble is that they are no where as cheep as the solution posted, an if under engine access is not a problem thay are instantly removable!
Best regards
Mike

Hi all .
Been following this with interest as i'm about to fit a 3.9 cam and lifters , Along with rebuilt heads SD1 It's all documented on the classic rover forum here http://www.classicroverforum.net/viewto ... 65&start=0
( Hi P6 people on here )
Any hoo . I have it all worked out how to go about it , but reading this i'm now a bit worried about putting too much pressure on the oil pump drive during the running in process from cold . I have a real steel oil pump kit i fitted 18 months or so ago and run it on Millers 20/50 mineral oil because of the higher zink content .
Do you guys think it'll be o.k ?
Stina

I'm pretty certain 20/50 was the factory spec oil for the UK up until '83 when it changed to 10/40.

DaveEFI wrote:I'm pretty certain 20/50 was the factory spec oil for the UK up until '83 when it changed to 10/40.

I know it's the right oil , just wondering about running it that hard from cold being thicker . I know other p6 people have , but they didn't read this first . Wishing i hadn't now ! ignorance being bliss and all that