RV8 - Cam shaft dialling in.

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garrycol
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RV8 - Cam shaft dialling in.

Post by garrycol » Fri Feb 09, 2018 4:12 am

I have recently built a RV8 Thor 4.6 and it is at the stage of having its final configuration completed - the engine is replacing a 3.5 carby engine.

To run in the cam I put the 3.5 carb manifold on the 4.6 and ran the engine which seems to have run fine and I covered about 10km before removing the carb manifold and putting the Thor manifold on - as yet the engine has not run in this configuration. When I ran it before ignition was provided by EDIS 8 running on default mode (10 BTDC) and the engine seemed to run OK even under load.

When I rebuilt the engine I wanted a bit more torque at highway cruising speed as around 100kph, because of the low gearing of the LR FC101, the engine is starting to come off its torque curve and lacks a bit of pulling power at higher speeds. I put in a locally made cam that is supposed to improve torque a bit higher up the rev range which is what I wanted - (no need to discuss this decision in this thread).

Here are the specs of the new cam.
EM48.jpg
I was happy with all that until I read this comment on my local LR forum about the cam I had put in.
"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 . 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 also contacted the manufacturer and he said they had no issues but emphasised the need to dial in the cam. I said all well and good but with a standard engine, new single cam chain, new sprockets, new lifters etc - ad all lined up with the dots on the sprockets with nothing to adjust - what would dialling in the cam tell me other than they manufactured the cam wrong.

So as I cannot adjust anything - is there any point in pulling stuff (like the manifold and tin gasket) to dial in the cam (check its manufacturing) as the guy on the other forum did and found it all correct but not running right. I am tempted to pull this cam out and put a standard one in but then when I had the vehicle running before it did seem to run OK but I did limit revs to 2500rpm because of the fixed timing.

The reality is that going from a carb 3.5 with about 85kw to an injected 4.6 with 160kw I am not really going to know if the cam is causing issues - even if the engine is going to be down on power, it will still go better than it did.

Thoughts - comments appreciated.

Thanks

Garry



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Re: RV8 - Cam shaft dialling in.

Post by Coops » Fri Feb 09, 2018 6:06 am

Regards Tony C (COOPS)
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Re: RV8 - Cam shaft dialling in.

Post by garrycol » Fri Feb 09, 2018 8:30 am

Thanks - so I guess with standard sprokets and chain but an aftermarket cam, if it is out of specs the only thing you can do is return the cam and ask for a refund.

Would you also go through this dial in procedure for all OEM parts including LR cam?

Cheers

Garry

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Re: RV8 - Cam shaft dialling in.

Post by Coops » Fri Feb 09, 2018 11:34 am

I've Never bothered dialing a standard cam. In to be honest mate.
Only uprated ones as what's the point changing to an. Uprated cam if just putting it in without setting up.
Regards Tony C (COOPS)
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MS2 V3.57 Ecu mapable efi and wasted spark ignition.
Rotrex C38-91 supercharger and Cossie RS500 Intercooler @ 14psi of Boost. 404 RWHP, (4.6)
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Sponsored by: www.v8performanceparts.co.uk, www.interpart.biz, www.caprisport.com & www.baileyperformance.co.uk

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Re: RV8 - Cam shaft dialling in.

Post by garrycol » Fri Feb 09, 2018 12:11 pm

On the basis of what I know now, I agree - but then I bought my cam on the basis that it specifically fits a otherwise standard Rover 4.6 - off the shelf and not specifically made to my specs - really the same as an off the shelf OEM one. I did ask if it will go straight in because I didn't want to stuff around and the answer was yes.

Oh well, to check the cam now means pulling a lot off the engine so I might as well leave it in and if it doesn't provide what is expected, then pull it out then and go to a standard cam.

Thanks for the input - appreciate it.

Cheers

Garry

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Re: RV8 - Cam shaft dialling in.

Post by DaveEFI » Fri Feb 09, 2018 4:42 pm

I'm curious how 'they' can grind something as precise as a cam - but then put the keyway in the wrong place?
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Re: RV8 - Cam shaft dialling in.

Post by unstable load » Sat Feb 10, 2018 1:12 am

DaveEFI wrote:
Fri Feb 09, 2018 4:42 pm
I'm curious how 'they' can grind something as precise as a cam - but then put the keyway in the wrong place?
I think he summed it up when he said
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.
It looks like they have a bunch of blanks, a generic profile and precious little understanding of engine dynamics.
Cheers,
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Re: RV8 - Cam shaft dialling in.

Post by harvey » Sat Feb 10, 2018 7:52 pm

DaveEFI wrote:
Fri Feb 09, 2018 4:42 pm
I'm curious how 'they' can grind something as precise as a cam - but then put the keyway in the wrong place?
This reminds me of an MGB I did years back, it had a misfire, I can't remember now whether it was on 3 at idle and then went onto 4 when it was revved, or the other way around, but after checking everything else I checked the cam timing and it was spot on, on number 1, but then I checked number 2, then 3 but MGB's had two sets of timing figures, and number 3 on this one was ground to the other spec, so was different to numbers 1, 2, & 4. Changed the camshaft and it cured the problem.

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Re: RV8 - Cam shaft dialling in.

Post by stevieturbo » Sat Feb 10, 2018 11:14 pm

garrycol wrote:
Fri Feb 09, 2018 8:30 am
Thanks - so I guess with standard sprokets and chain but an aftermarket cam, if it is out of specs the only thing you can do is return the cam and ask for a refund.

Would you also go through this dial in procedure for all OEM parts including LR cam?

Cheers

Garry
Was this application using all OEM parts for that specific 4.6 application ? other than the camshaft ?

Was installation checked to be correct ? as the disclaimer always says about the end user/builder who is ultimately responsible for ensuring everything is correct for your specific application and build. Cam timing is something that always needs checked, unless all parts are actually and genuine OEM parts.
In this case that would mean crank, cam gear, chain, camshaft for that 4.6 as it left the factory.

Deviate from that on any single part or multiple parts and yes it is down to whoever is building it to ensure things are correct.

So not sure how you could ask for a refund here ? Did they state this camshaft will install blindly and be correct for your specific application and parts used ?
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Re: RV8 - Cam shaft dialling in.

Post by stevieturbo » Sat Feb 10, 2018 11:17 pm

DaveEFI wrote:
Fri Feb 09, 2018 4:42 pm
I'm curious how 'they' can grind something as precise as a cam - but then put the keyway in the wrong place?
Wrong place for who's parts though ?

Given there are so many engine variations over so many decades....and no idea what parts or combination of those parts any particular user might use...it's always down to the builder to check these things are correct for their build.

And having had many issues with almost all parts over the years, you learn never to guess anything, never assume anything as it will only cost you in the long run.
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garrycol
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Re: RV8 - Cam shaft dialling in.

Post by garrycol » Sun Feb 11, 2018 2:11 am

Yes - all OEM bits on the engine other than the cam.

Prior to purchase the seller (the maker) was asked if it just goes straight in and was told yes and used standard rocker, lifters, valves and springs - just changes timing - so took that to be that installation is exactly the same as OEM cam.

The cams the company offers for the 4.6 the one I went for is the 371771
46Cams.jpg
Second engine start on default EDIS 8 ignition and carbs - with new cam.

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Re: RV8 - Cam shaft dialling in.

Post by stevieturbo » Wed Feb 14, 2018 9:59 pm

One thing I've learnt over the years ( of many lol ) is never take for granted what is supplied is correct without checking. All too often it will be wrong and for more reasons than it should ever be possible.

Are the cams regrinds, or ground on new blanks ? With regrinds it was always essential to check.

With a new blank....it should be correct, but I've come across some that are not, keyways in wrong place etc etc It just happens. But in most cases they've been perfect.
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202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0

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