Recommendations for Rover P6 3500 cam etc

Labeline

Labeline

New Member
Hi everyone. I bought my 72 P6b 3500S in September. I had some issues with rough running which all seem to have been sorted with new leads, condensoer, points and rebalanced carbs, timing and dwell angle all reset and it is now very pleasant to drive. However the compression test revealed some issues. The highest psi was 150 and the two lowest, in cylinders 5&7 were 140 and 130. There is no evidence of any oil coming past the rings and as the lowest cylinders are adjacent, the suspicion is a head gasket failure and worn valve seats. I am therefore going to schedule some maintenance for next winter. As I intend to change the head gasket I am going to take the opportunity to have the heads upgraded/refurbished. Change the camshaft and followers and change the timing chain and cogs. I have read the numerous threads in this subject on this forum but would like some updated advice. I am not interested in increasing performance, it is a classic car, not a sportscar, but I would like to get the best out of my investment. Just to make things more interesting, I live in France so will need to get all this stuff done remotely. I am told I should be going for a 3.9 litre cam and possibly be replacing the standard heads with 3.9 ones too. Any recommendations would be welcome. I don't want to spend a fortune but I only want to do it once. I do not believe the engine is original. It is currently showing 87k on the odometer but who knows what that relates to. There is no tappet noise whatsoever. I paid a lot of money for this car and am somewhat peeved to find that I need to have this work done in addition to other things I have found since buying it.
 
Hi Paul,

I'd be looking at something like this...
http://v8tuner.co.uk/product.php?id=550

It's well worth giving him a call though - he really knows his stuff.

The 3.9 heads - i've just fitted a set to mine. Just looking for some ebay heads for you now ...

*Edit* - it seems ebay is looking a bit barren. Worth waiting a couple of days for scrappies to get back to work and list some ??
 
Thanks, They have been recommended by others too. I will certainly give them a call. I will try to find a set of 3.9 heads on EBay later on if only to reduce the £150 exchange fee. Are they all the same? No issues with valve/piston contact etc? I am not in a great hurry as the car seems to be running very nicely at the moment but it is something I will get done in the next year or so. I need to find out the full extent of what needs doing first.
 
The heads will all fit. You just need to make sure they have the correct holes in the sides for screwing in the alternator, fuel filter, autobox dipstick etc.

You need to make sure the heads are the slightly older type (early 3.9) 14 bolt heads rather than 10 bolt heads if you want to reduce the compression ratio below 10.5:1 (which is helpful if you like running on less than 5* petrol...) - i think i mentioned that on facebook?

Others on here will know more than me about the exact differences between heads though...

Rich
 
While the 3.9 heads are great, the compression ratio loss as mentioned is an issue. Look for the early ones or go
for the SD1 heads as they offer improved airflow over the original heads along with the higher compression ratio.

For a camshaft, it's a big field of possibilities out there.. I have a CRANE Mild Street cam in my car and it goes
very nicely with improved torque and a very nice burble at idle. Lots of folks go for the 3.9 Land Rover cam as it
offers better low-down torque. Always change the lifters with the cam and use a high ZDDP oil for run-in.

When ordering your parts, get the "tin" head gaskets, not the composite ones, as the composites will drop your
compression ratio.

Have a look here...http://www.v8forum.co.uk for some extra opinions and ideas as well as a good natter.
Bonne année et bon courage!
 
Labeline wrote,...
I do not believe the engine is original.
Click to expand...

What brings you to that conclusion?

Do the existing heads have single or double valve springs? If you change the heads, you can use tin gaskets with all of the 14 bolt versions.

Ron.
 
The previous owner didn't really know whether the engine was original but as the engine number was incorrect I assumed it had been changed. The car was registered in Feb 72 and the distributor was manufactured 17 73 so obviously that part is not original. I have actually seen a pair of NOS P6 heads for sale for £250 which seems quite reasonable if they can just be bolted on but I have been told to upgrade to the 3.9 heads as they breathe better. Personally I am not worried about performance improvement as it is a classic. If I had wanted a sportscar I would have bought something else. I haven't had the valve covers off yet so don't know what is under them. I need to look at the original advert to see what it says about the engine and whether it was rebuilt. Somehow I doubt it although it does look very pretty. It just goes to show that paint hides a multitude of sins. Having said that it goes well now but with one cylinder down to 130 it obviously needs some attention. There is a Range Rover specialist near to us so I will pop in and have a word.
 
That'll be NOS heads as in the raw castings which almost nobody building a Rover V8 wants. The standard SD1 head flows 16% more gas than the P5/P5 head and the very last 10 bolt heads a little more than that.

What does that mean?

The P6 engine gives 148bhp at 10.5:1 with 5 star
The SD1 gives 155bhp at 9.35:1 with 4 star

Now that isn't comparing like with like exactly because the headers and exhaust are also better flowing on the SD1.

So the obvious conclusion is that the SD1 heads keeping the CR the same (i.e. higher) on a P6 is likely to give you in the region of 160-165bhp and as the starting point with a mild cam added 180bhp ish.

That's +20% for not much money or really no money if your cam is worn anyway and needs replacing. I have no trouble on super unleaded with 10.1:1. You can easily see the valve spring type through the oil filler cap.
 
PeterZRH said:
That'll be NOS heads as in the raw castings which almost nobody building a Rover V8 wants. The standard SD1 head flows 16% more gas than the P5/P5 head and the very last 10 bolt heads a little more than that.

What does that mean?

The P6 engine gives 148bhp at 10.5:1 with 5 star
The SD1 gives 155bhp at 9.35:1 with 4 star

Now that isn't comparing like with like exactly because the headers and exhaust are also better flowing on the SD1.

So the obvious conclusion is that the SD1 heads keeping the CR the same (i.e. higher) on a P6 is likely to give you in the region of 160-165bhp and as the starting point with a mild cam added 180bhp ish.

That's +20% for not much money or really no money if your cam is worn anyway and needs replacing. I have no trouble on super unleaded with 10.1:1. You can easily see the valve spring type through the oil filler cap.
Click to expand...

Sounds tempting. I will see what I can find at the Land Rover garage. Being in France makes getting hold of the heads more awkwardly then I have to have them refurbished. I will be replacing the cam and timing chain at the same time. I am a little concerned that the gear box, being original, may not be up to the extra power.
 
I have found a pair of NOS early SD1 heads for sale. These are bare heads with no springs or any other fittings. Besides new valves and springs and other valve fitting components can I use the rocker arms etc off the old heads? What would these be worth as a rough guide.
 
No, You'll need new valves as the valves are larger on the SD1 and the single valve springs, collets etc.. Good secondhand would be much cheaper.

My Range Rover heads from 1993 were £50 and were all good (ebay). But I had them skimmed anyway to use the composite gasket (thicker and seals better). These are more of less the same as SD1 as they are the 14 bolt type. The valves differ slightly in design, that's about it
 
Thanks. I realise I would need all new valves, springs etc but wondered if the rocker arms, etc were the same as the P6 otherwise it would be extremely uneconomic. I am assuming they can use unleaded without changes.
 
The rocker assembly is identical. You may or may not need to shim the rocker posts (search for the process on this forum).
 
If it were me I'd just bide my time for a week or two. The land/range rover scrappies normally list a few a week but i guess they've all been off work for the last week or two. You could obviously use the SD1 ones as you've seen but if you can get some where the valves etc are already there it will save you a few quid...

Rich.
 
rockdemon said:
If it were me I'd just bide my time for a week or two. The land/range rover scrappies normally list a few a week but i guess they've all been off work for the last week or two. You could obviously use the SD1 ones as you've seen but if you can get some where the valves etc are already there it will save you a few quid...

Rich.
Click to expand...
Thanks. I am not in a hurry but the opportunity to have entirely new heads is tempting. I need to check for ring wear as if the rings have worn then I am looking at an engine rebuild in due course. whatever I get I will have to get the heads refurbished anyway so the cost will be about the same.
 
Have a look on the site of RPI Engineering, here the "engine" site adress : http://www.v8engines.com/engine-4.htm
Although you will meet very experienced guys on this forum, from my opinion, it´s essential to get as much background as possible. Sometimes you have the feeling, that the Rover V8 is soooo simple, but it is not, or let´s say, without reading the hard facts from the right medium, will end in a more or less desaster. I´m also on the search for SD1 heads (or better, Vitesse heads) and a LT77 gearbox and what you will be offered sometimes, is awful. The last one with SD1 heads, tried to polish the intake and exhaust sections (what I also want to do, read about...) but he grinded a little bit too much away :shock:
One good base also : The book "The Rover V8 Engine" from David Hardcastle. I´ve got one example for approx 45 EUR.
In this book there´s also a list with all available cams. If you are interested, I can scan this side.
Good luck and have some time.
 
I have spoken to V8 Tuner and he said he wouldn't overly worry as the engine sounded ok but maybe later down the line I could upgrade it. I will look for a decent set of 3.9 or SD1 heads and get them refurbished later on and fit a new cam and timing chain set at the same time.
 
Sounds like a good plan. The guy at v8 tuner knows his stuff and is really helpful in my experience.
 
I don't know if my experience is typical but the RR my heads came off did 110,000 miles. Almost no wear at all, valves and guides near perfect. But horribly dirty and covered in sticky tar.

By contrast I've heard some 4 pot valves are made of cheese. I wonder what the experience of aftermarket parts is. I see no reason on a 50 year old design that these shouldn't be as good or better with careful sourcing. It's not like machining them is some great secret and raw materials are often purer these days. Certainly I've heard some aftermarket camshafts are more durable than the original.
 
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