THOR high comp 4.6 camshaft

[mpwdhc]

hi guys,

are there any comments regarding choice of cam for a 9.37:1 4.6 thor engine with vapour injection LPG? mine could do with replacement and it may as well be as worthwhile as it can be.

i'm more interested in low/mid torque and economy. without a change to injection (which i'm not interested in undertaking), is anything but the stock cam even worthwhile?

lots of info about early cars and gems but not so much thor

thanks!

[Pedro_The_Swift]

Kent H180 Camshaft Sports Torque – Turner Engineering (https://www.turnerengineering.co.uk/h180-kent-camshaft-sports-torque-nn-c2x20634399)

change your valve springs.

[TheTree]

Another option with similar specs

Buick Hydraulic Flat Tappet Camshaft (https://www.crower.com/buick-215-340-compu-pro-hydraulic-cam-258-hdp.html)

and

Hydraulic CamSaver Buick & Land Rover V8 - Lifters (https://www.crower.com/lifters/hydraulic-lifters-hi-lube-buick-215-300-340-350-v8-345.html)

Steve

[101RRS]

I have a Crow Cam - they make two versions for the 4.0/4.6 - Crow Cams - the most advanced cam development and CNC grinding facilities in Australia (http://www.crowcams.com.au/) .

135391

[TheTree]

I have a Crow Cam - they make two versions for the 4.0/4.6 - Crow Cams - the most advanced cam development and CNC grinding facilities in Australia (http://www.crowcams.com.au/) .

135391

Hi

Did you fit the HT969-16 lifters as well?

I am thinking of replacing my cam when I do my lifters and pushrods

Stev

[mpwdhc]

thanks for the responses

Pedro, is this what you've used? is other machining required (guide height etc) in addition to new valve springs?

Steve, are they suitable for use in a serpentine belt engine?

Garry, which one have you got? the car will mostly be normal driving, occasionally some sand or towing work, but mostly road stuff.

has anyone any experience with the Dynotec 216 which is what i think TRS supply?

such a confusing and difficult to quantify topic given that there are so many variables - stock cam gears, degreed crank gear. compression ratios, etc.

[101RRS]

Hi

Did you fit the HT969-16 lifters as well?

I am thinking of replacing my cam when I do my lifters and pushrods

Stev

No - my engine is standard so stayed with standard pushrods and (new) lifters.

[101RRS]

Garry, which one have you got? the car will mostly be normal driving, occasionally some sand or towing work, but mostly road stuff.

I went for the 371771 but my engine is not in a D2 or P38. It is going in my 101 which is low geared - so at low speed etc the gearing provides plenty of power but I cruise on the highway at around 3000 rpm where torque on a standard RV8 starts to drop off so I wanted more torque higher up the rev range.

That is probably not needed in a P38 but I am not sure - the chart I put up has the rev range for each cam where you can expect best performance so you need to select what suits best - at my 100kph the same revs probably are giving you 160kph so different requirements.

Garry

[Pedro_The_Swift]

Yes,, on Turners reccomendation. Very happy so far, but the Tornado ECM makes a bigger difference....

[prelude]

I should think that as far as cams are concerned the gems and thor are the same? In any case in my gems I have a piper285 and a tornado chip. afaik it should fit the thor as well. More mid torque and more high end power. The only real downside is a slightly rougher idle, but since the P38 is an auto box, you won't notice it unless the engine runs in park or neutral (unloaded)

I have a chart at home with everything that was changed on my engine but afaik you can run this without modifying anything else though port and polish of the heads is recommended.

-P

[Pedro_The_Swift]

Garry is lucky in a way,, its a lot easier to get these things to make more KW/NM at higher revs,, its really hard to get more at 2600rpm,, and yes, on the highway 400 revs in top is a lot to overcome.
I have this fantasy about running defender TC gears,, that would bring 100kph at 2600rpm,, still with the ability to tow faster (not very often) but it would make the 80 - 100 range much less work.
hmmm.[bigwhistle]

[TheTree]

Hi

Apparently LR used a few differtent factory cams, so it's hard to find an "original" spec.

I have compiled a list of mild cams below ad the crow 371771 looks like a good choice, especially given the feedback from here [thumbsupbig]

Steve



Cam
Exhaust Duration
Intake Duration
Exhaust Lift
Intake Lift


crower 50229
260
258
0.446
0.43


Piper 285
278
278
0.445
0.445


Crow 371613
264
254
0.408
0.382


Crow 371771
262
258
0.405
0.395


Kent H180
262
262
0.44
0.44


CamTech CT37
262
260
0.399
0.399

[mpwdhc]

hi guys,

thanks for the responses.

that chart is interesting - such a confusing topic, though.

i emailed camtech for their recommendation and the information provided seems to conflict with their website.

a cam of the same spec 274/274 (aside from lift, but one is quoted at 1.6 .472 and the other 1.5 .442 ratio - not sure how to calculate this) is described by email as "Smooth idle, enhances throttle response and low end torque. RPM RANGE 1400-4600" but on the website "Fair idle, strong mid range and top end. Recommended for modified engines. Min 9.5:1 comp ratio, 3.08 + diff ratio. RPM RANGE 2000-5500". very different!!

the crow website gives slightly different figures to those in the chart but perhaps the cam design has been updated.

i am wondering if perhaps the best thing might be to just get a stock cam from tr spares in sydney.

[mpwdhc]

after all that, i found some factory specs here -

RR camshaft specs - The V8 Owners Forum - (https://www.v8forum.co.uk/forum/viewtopic.php't=10773)

and plugged the info from the scan into here -

Camshaft Technology and Calculations (https://www.rbracing-rsr.com/camshaft.html)

which tells me the stock 4.6 cam is 264/264

10.57mm lift is 0.416"

seems very close to the stage one cams often suggested, and pretty much directly between camtech CT37509 and CT37524 any difference would be lost without a degreed crank sprocket?

perhaps therefore ER5250 may be the one.

according to the LR spec sheet and that calculator, the 4.0 cam works out to 285/285 but with 0.391" lift.

the email from camtech includes a chart specifically for 4.6 which suggests 274/274 with .472 lift is their mildest recommended cam. i had read the kent's lift at 0.44 was already at the limit for stock springs, etc?

confusing !

[mpwdhc]

however, i have just noticed that despite having similar durations, the timing varies considerably across the cams... but i don't know what the implications of that are. even more confusion.

[Pedro_The_Swift]

i had read the kent's lift at 0.44 was already at the limit for stock springs, etc?




Thats my info as well,, the reason I replaced them at build time.

[FisherX]

G'day Guys,

When I did my 4.6 conversion of my D2 I fitted the Crow 371771 but was really unhappy with it. It made the car very sluggish and a 0-100 time of 19 sec [bigsad]. I rang Crow about it to ask if the cam had any advance or retard ground into it, and no. I mapped the cam out on a degree wheel to check proper timing and it was fine. One thing Crow said to me was "they work well in a 4.2 Commodore" so I'm thinking that the Crow cam is more a generic grind than Rover specific.

I was so unhappy with it I pulled it out and fitted a new stock 4.6 cam. Wow what a difference, back to what it should be 0-100 in 11 sec.

I still have the slightly used (about 1000km) Crow 371771 around but I didn't want to sell it on and make someone else unhappy.

I have heard that the Kent is the one to go for.

Anyway just my 2 cents worth, others may have had better results with the Crow than I did.

[mpwdhc]

very interesting FisherX!

i suppose the next question relates to the quality of the cams sold by TR Spares (Syd)

[101RRS]

When I did my 4.6 conversion of my D2 I fitted the Crow 371771 but was really unhappy with it. It made the car very sluggish and a 0-100 time of 19 sec [bigsad]. I rang Crow about it to ask if the cam had any advance or retard ground into it, and no. I mapped the cam out on a degree wheel to check proper timing and it was fine. One thing Crow said to me was "they work well in a 4.2 Commodore" so I'm thinking that the Crow cam is more a generic grind than Rover specific.

Having just put one of these in my engine - this is something I didn't want to hear [bigsad].

Hmm I also spoke to Crow and confirm the 771 cam grind profile is common across a range of engines - he also said that the new cam has to be dialled in correctly (well I just followed the LR Cam installation instructions but apparently that is not good enough) and that the ECU will need reprogramming to take into account the new cam - well we know that the is not really an easy option for the Bosch Motronics ECU. I am going to use Megasquirt not the OEM ECU in my engine so I may not have this issue a I can tune the ECU accordingly - well supposedly if I can work it out.

Anyway the guy I spoke to is going to check with one of their client engine builders/tuners to see if they have issues and get back to me - but as usual the initial response is that we have never heard of this issue before.

Garry

[DiscoClax]

Thats my info as well,, the reason I replaced them at build time.General consensus is anything much above 0.43" at the valve may result in the retainer clouting the guide. It was around that in mine so I machined down the guide and seal area slightly for my higher lift cam. Springs are actually OK, you just run out of clearance there well before the springs would bind. Plus a"bigger" cam can overpower the stock springs...= floaty.

[101RRS]

Anyway the guy I spoke to is going to check with one of their client engine builders/tuners to see if they have issues and get back to me - but as usual the initial response is that we have never heard of this issue before.

Garry

As expected the client engine builder has had no issues with the cam going into the RV8s. He reiterated that thye cam has to be dialled in - I indicated that I understand that but if the engine is other wise standard - standard crank/cam cogs, chain etc then what is there to dial in - it is either correct or not - anyway to do that I will have to pull the manifold and tin gasket off and that isn't going to happen anytime soon.

As I am going from a 3.5 to a 4.6 I am not really going to know if there is any issues.

Here is the cam information

136065

Garry

[Pedro_The_Swift]

I've seen a honda B16A dialed in,, took quite some time and if you are chasing the very last bit of HP is definately worth doing.
not sure any of us here is in that boat, maybe discoclax? [bigwhistle]

stuff explained here..
One of the least understood topics and regarding engine tuning and building continues to be the concept of cam timing and (http://www.starracing.com/Cam%20Lobe%20Center%20Explained.htm)

[PLR]

G`day ,

non adjustable can be adjustable with help .

The card will give std set but can be altered

Advancing and retarding alters the revs of occurrence .

A cam not set other than dot to dot can give the same differences but without degrees it`s not known .

When you consider a cam the working revs for torque and HP are topics of note but the cam has to be set for them to have relevance

If it`s not a personal concern it doesn`t matter i don`t see the point without .


ADD
Most reasons for replacing a camshaft poor power poor torque poor economy etc can be achieved by not having a camshaft timed correctly .




Cam timing - Adjustable sprockets and keys (http://mgaguru.com/mgtech/power/cm201c.htm)

[TheTree]

Hi

Given all the voodo here and the fact I have a Tornado chip installed, I think if I need to replace my cam when I replace my lifters, then I will fgo for a standard cam

Very interesting thread though [bigsmile1]

Steve

[mpwdhc]

so i went for a standard 4.6 cam from tr spares in sydney. the result is impressive when comparing it to my LC gems car! i hadn't driven the thor car before the work - it was purchased with the heads off.

i think it might need an AFM though. and the coil springs someone has fitted are horrible and just about make the car unusable from a comfort perspective on the country roads around here. not sure how much of a factor the bigger rims are, again compared to the early car which is also on springs.

[Pedro_The_Swift]

Hi

Given all the voodo here and the fact I have a Tornado chip installed, I think if I need to replace my cam when I replace my lifters, then I will fgo for a standard cam

Very interesting thread though [bigsmile1]

Steve

You could reverse engineer the cam[bighmmm],, why not email Mark and see what he reccomends for your ECM?

[Pedro_The_Swift]

General consensus is anything much above 0.43" at the valve may result in the retainer clouting the guide. It was around that in mine so I machined down the guide and seal area slightly for my higher lift cam. Springs are actually OK, you just run out of clearance there well before the springs would bind. Plus a"bigger" cam can overpower the stock springs...= floaty.

So at 0.44 will I hear tapping or a single loud bang? [bighmmm]

I understand Floaty is a technical term,, but up high in the rev range? and it misses or revs funny?

[DiscoClax]

I believe that the first contact will be between the top of the seal and the bottom of the spring retainer. That would be a soft hit and pretty quiet but would chew up the seal. A few thou (?) more would be metal to metal and not so good... bent pushrods, etc possible. Not sure what that would sound like but probably 'clattery' like pumped down lifters.
Valve float normally exhibits initially as a drop in power (valves staying a bit open bleeding off compression) but if pushed much further may end up eventually with valves clouting pistons. Yes, higher revs is where that'd happen. Dependent on springs and camshaft profile for when or if.

[Pedro_The_Swift]

Well I've obviously had none of those so far,, and apart from the valve springs softening up over time I dont expect to change driving style much,,
I think there would be a lot of these cams out in the wild,,,

[Battler]

I've just been recommended the Crow 371771 for my modified 4.6L in a D2. After looking at the specs, the cam looks like it's milder than the stock 4.6 cam and a lot milder than the current Piper 270 that I've got in it now.

It's so confusing!!

[101RRS]

It is a towing cam not a straight power cam.