Camshaft change

desertrover · Post by **desertrover** » Thu Jul 16, 2009 10:14 am

Hi there,
as I´m not very pleased with my Piper 270 cam in my RV8 4.6, I want to go back to the standard 3.9 Rover camshaft.
I ran the 3.9 for 6 years and the engine ran great with it.
My q now is, can I run the 3.9 cam with the valve springs of the Piper ( lifters will be changed ), or does that have to much effect to the engine characteristix?

With the 3.9 my heavy-loaded LR 90 ran like wild in the dunes of Tunisia and had the torque right on spot, with Piper I always have to change gear down and floor the pedal to the metal to get good acceleration and power delivery.

So the fuel consumption is worse although.
Many thanx
Stephan

ChrisJC · Post by **ChrisJC** » Thu Jul 16, 2009 11:27 am

I'm running a Piper 270 in my 4.6, and I reckon it's pretty good. Certainly goes like a rocket.

It's in a SWB Land Rover with auto transmision BTW.

Are you sure your cam is dialled in correctly?

Chris.

desertrover · Post by **desertrover** » Thu Jul 16, 2009 11:52 am

Hi Chris,
can´t check it right now, because the car is in Nairobi and I´m in Germany.
But if the procedure for the Piper is the same as with a standard cam, yes I´m sure.

CastleMGBV8 · Post by **CastleMGBV8** » Thu Jul 16, 2009 12:45 pm

Stephan,

I believe there are two versions of the piper 270 cam, one being the original spec and the other 270Iintended for injection vehicles which suggests that it has a wider lobe centre angle than the original, and would have less overlap and therefore more torque.

The duration and lift is probably the same.

Do you know which version you have and are you running Hotwire EFI?

Cam specs.

http://www.pipercams.co.uk/NewPiperWeb/ ... rames.html

Kevin.

desertrover · Post by **desertrover** » Thu Jul 16, 2009 2:37 pm

Hi Kevin,
I´ve got an old camshaft ( was stored for years ), that I bought new.
The psex differ a bit from the figures Piper now give:
Power Band: 1500-6000 ( now: same )
Valve Timing: 28-64-64-28 ( -"- )
Duration: 272° ( -"- )
Valve Lift: .445" ( now: .420" )
Full Lift Inlet ATDC: 108° ( now 108° )
Now is stated that the 270/110 ( 26-66-66-26 ) can be used for massive high torque on carbed engines.
I´m running an EDELBROCK 500.
But btw, I think it expected more delivered power than what it actually does.

CastleMGBV8 · Post by **CastleMGBV8** » Thu Jul 16, 2009 4:20 pm

Stephan,

The problem is the Lobe centre angle of 108 deg. for your usage you really need a cam with more like 112 deg. LCA and unless the heads have had some serious work, any cam hotter than that will be waisted as it will want to breathe heavily only at high RPM.

Swapping the cam and lifters(essential) will be fine with the valve springs you have assuming they are the single one coil less upgrades that are usually fitted for all but the more serious camshafts.

If you intend to sell the Piper cam make sure you number the lifters as you remove them, otherwise the cam an lifters are technically worthless.

Kevin.

desertrover · Post by **desertrover** » Wed Aug 19, 2009 4:30 pm

Hi there and thanx,
does anybody know what figures the standard 3.9 efi cam has, especially
the lobe centre angle LCA.
Again thanx!

CastleMGBV8 · Post by **CastleMGBV8** » Wed Aug 19, 2009 7:55 pm

Stephan,

Sorry cant answer you question re cam specs dor the 3.9 cam but I'm sure somebody will.

I have a question, you say the car is in Nairobi which I believe is at fairly high altitude so whilst the car is there you are going to suffer a significant drop in power, Tunisia is much closer to sea level so normal power will be restored.

Is it in fact in Tunisia that you feel the Piper 270 lacks power?

Kevin.

topcatcustom · Post by **topcatcustom** » Wed Aug 19, 2009 8:23 pm

I know Kevin has already said it, but if you do change the cam- number all the lifters properly- it will save you having to buy a new set if you put the cam in again and if you sell it you can sell the lifters with it which will see you more return!

TC

desertrover · Post by **desertrover** » Thu Aug 20, 2009 8:41 am

CastleMGBV8 wrote:Stephan,

Sorry cant answer you question re cam specs dor the 3.9 cam but I'm sure somebody will.

I have a question, you say the car is in Nairobi which I believe is at fairly high altitude so whilst the car is there you are going to suffer a significant drop in power, Tunisia is much closer to sea level so normal power will be restored.

Is it in fact in Tunisia that you feel the Piper 270 lacks power?

Kevin.

I can´t remember clearly, because I was irritated by a getting worse gearbox problem. But the car felt not very healthy.
On a plain road alongside the mediterr. sea, with wind from the front, I had to change from 5 - 4 or to 3 to keep up with an standard LR110 Td5 ( 122 bhp ) and an Unimog.

desertrover · Post by **desertrover** » Thu Aug 20, 2009 8:43 am

Speed was 110 km/h = 68 mph and the fuel consumption was enormous.
average 5l more than before the cam change.

CastleMGBV8 · Post by **CastleMGBV8** » Thu Aug 20, 2009 9:01 am

Stephan,

That doesn't sound right, and assuming everthing else is in good state of tune dare I ask whether the cam was run in correctly, as per the recommended procedure of coating the cam with the specific cam lube and run for 20 minutes at 2000 - 2500 RPM and not allowed to idle during this time.

It is also important to use oil with a high ZDDP cintent in a rover V8.

If this wasn't done the cam lobes may have worn severely which could explain the loss of performance.

For some indication you could run the engine at idle with the rocker covers off and see if any of the valves are not getting much lift.

Kevin.

topcatcustom · Post by **topcatcustom** » Thu Aug 20, 2009 9:19 am

I'd agree with Kevin (again) that you either have a cam which has not been dialed in properly or has not been run in properly (or was dodgy?) and has major lobe wear. You will have to take the engine out to swap cams unless you can get the cam out with it in place so you may as well remove the front cover and check the timing, if ok you can remove the cam and measure the lobes with a vernier and go from there.

When I bought my cam from Real Steel they said unless I put the additive they supply in with the oil (for running in only) they void the cam warranty.

TC

kiwicar · Post by **kiwicar** » Thu Aug 20, 2009 9:32 am

Hi
with a cam as mild as 272 degree on a 3.9 litre engine I find it difficult to think you would have any drop in low end torque against a "standard" cam from memory you have a total of about 8 degrees more timing (4 on each lobe ) over standard (though I confess this is from memory as I can't find the spec of the oridinal 3.9 cam).
I think you have another issue here, timing of the cam, collapsed lifter, warn lobe too little ignition timing, blocked transition CCT on the 4 barrel, or just wrong float levels.
Best regards
Mike

Wotland · Post by **Wotland** » Thu Aug 20, 2009 1:57 pm

Here value of 3.9 genuine camshaft ETC 8686:
Timing : 32/73/70/35
Period : 285°
Lift : .390"