Running in Cam - 4.6 RV8

garrycol · Post by **garrycol** » Fri Sep 16, 2016 11:30 pm

My 4.0 RV8 that I have taken out to a 4.6 is in the truck and will soon be ready for first start. For the start and cam run in I will be using the 3.5 carbs and manifold and using the default EDIS 8 10 degrees BTDC.

I need to run the engine for 20 - 30 minutes at 2000rpm to run in the Cam and the default EDIS setting should be Ok for this. The reason I am doing this, is I don't want to be cranking a new cam when I put on the injection manifold and MS3 and do all the trouble shooting I know will be required to get MS to run.

I understand there are certain oils or additives that I should use to assist in the cam run in process to ensure the cam hardness is maintained or strengthened.

Can you recommend an oil/additive to assist in running in the cam?

Thanks

Garry

mgbv8 · Post by **mgbv8** » Sat Sep 17, 2016 10:06 pm

Just make sure that everything in the valve train is lubed with Graphogen or a proprietary lube before the first bedding in run.

I always use Comp Cams Hi Zinc lube additive in all my engines from new build and then add this on each oil change.

DEVONMAN · Post by **DEVONMAN** » Mon Sep 19, 2016 7:44 am

More a question really, Will the pistons/cylinders run hot on 10degrees at 2000 rpm.?

garrycol · Post by **garrycol** » Mon Sep 19, 2016 12:42 pm

DEVONMAN wrote:More a question really, Will the pistons/cylinders run hot on 10degrees at 2000 rpm.?

What has prompted that question?

The actual static timing for a OEM RV8 is about 3 degree BTDC and at max revs the engine runs around 45 degrees BTDC so I figure that with no mechanical/vacuum advance available the engine should be good for about 2000rpm at 10 btdc - if anything it may be retarded so heating/pinging should not be an issue - I will use 98 octane as a precaution.

On my current 3.5 carb and dizzy RV8 I run a static timing of 10 BTDC s it runs on both petrol or LPG and I have never had an issue.

Perry - thanks for the advice - I have used plenty of assembly lube and dedicated Cam lube but the engine has been turned over by hand a bit and I am concerned there may not be much cam lube left in the right spot.

sidecar · Post by **sidecar** » Mon Sep 19, 2016 12:53 pm

In order to get pinging the peak cylinder has to be high, when you run the engine at 2000 RPM the throttle will be 99% shut which means that hardly any fresh charge is being admitted into each cylinder this means that the peak cylinder pressure will be pretty low in the scheme of things, in other words it won't ping. (And by ping I presume that you mean detonation which is different from pre-ignition). I won't think that your engine will pre-ignite as I presume that it is all clean inside so there is no carbon which can form hot spots. I guess the plug is a potential source of pre-ignition but really it will be fine!

When I ran my cam in I blasted the radiator with hosepipe in order to keep the coolant temp down.

DaveEFI · Post by **DaveEFI** » Mon Sep 19, 2016 1:13 pm

Static timing on a Vitesse - which has the highest CR of the modern RV8s at 9.75:1 - is 8 BTDC. But I'd guess that is more about emissions etc.

I'd curious about the emphasis given on running in a cam. Do all new cars have the engine run in the same way to do this?

And exactly what process happens during this running in procedure?

sidecar · Post by **sidecar** » Mon Sep 19, 2016 1:44 pm

DaveEFI wrote:Static timing on a Vitesse - which has the highest CR of the modern RV8s at 9.75:1 - is 8 BTDC. But I'd guess that is more about emissions etc.

I'd curious about the emphasis given on running in a cam. Do all new cars have the engine run in the same way to do this?

And exactly what process happens during this running in procedure?

New cars place far less load on the valve train than old RV8 engines that's why they get away without running the cam in. Modern engine have a very light valve train because they are running 4 light valves and over head cams running directly on the buckets.

Old push rod engines have a very heavy valve train which means that the valve springs are heavy, this places quite a load on the cam lobes and followers, what's more the lobes are not very wide which won't help either.

What happens during the process is that the rough finish on the followers and the open pore structure on the cam is all polished smooth, I believe that a hard surface also form on the components which then gives the cam train a reasonable life.

DaveEFI · Post by **DaveEFI** » Mon Sep 19, 2016 2:01 pm

So this presumably means all RV8s (and all pushrod engines) had this running in procedure carried out at the factory?

sidecar · Post by **sidecar** » Mon Sep 19, 2016 2:13 pm

DaveEFI wrote:So this presumably means all RV8s (and all pushrod engines) had this running in procedure carried out at the factory?

I doubt it, maybe that explains why the lobes would disappear on the standard cam after about 50k miles.

Many Yank V8 engines run rollers followers, they do not need to be run in.

At the end of the day its your choice whether to run a cam in or not. The OP was not asking whether he should run it in or not, he has clearly decided to run the cam in and wanted advice on that.

DEVONMAN · Post by **DEVONMAN** » Mon Sep 19, 2016 3:09 pm

garrycol wrote:
DEVONMAN wrote:More a question really, Will the pistons/cylinders run hot on 10degrees at 2000 rpm.?
What has prompted that question?

The actual static timing for a OEM RV8 is about 3 degree BTDC and at max revs the engine runs around 45 degrees BTDC so I figure that with no mechanical/vacuum advance available the engine should be good for about 2000rpm at 10 btdc - if anything it may be retarded so heating/pinging should not be an issue - I will use 98 octane as a precaution.

On my current 3.5 carb and dizzy RV8 I run a static timing of 10 BTDC s it runs on both petrol or LPG and I have never had an issue.

Perry - thanks for the advice - I have used plenty of assembly lube and dedicated Cam lube but the engine has been turned over by hand a bit and I am concerned there may not be much cam lube left in the right spot.

I've always thought that an engine running retarded ignition runs hotter. But, that may just be under heavy load. I agree that pinging/detonation wont be a problem

garrycol · Post by **garrycol** » Tue Sep 20, 2016 4:35 am

DEVONMAN wrote:
I've always thought that an engine running retarded ignition runs hotter.

I always thought the opposite

- too far advanced timing will cause pre-ignition and associated heat. Retarded ignition means the engine runs like a dog with not enough burn time before the exhaust opens exhausting the still burning mixture.

Good point to consider though - thanks.

My investigation indicates that the RV8 is very sensitive to cam wear and that this is essentially determined during the run in process - does not like to be cranked. Other V*s dont seem to suffer as much nut is still a consideration.

This engine will be getting a MS3 to run it an I know there will be issued getting it to fire up so I do not want to be cranking away trying to sort the MS3 - hence run in the cams on carbs which will fire up straight away and hoping the default EDIS 8 works.

Thanks for all the comments - I appreciate the input.

Garry

garrycol · Post by **garrycol** » Thu Apr 20, 2017 1:36 am

Started the engine last week and it ran fine on its 3.5 carbs just EDIS 8 - could only start and run for a second or two as I did not have coolant in it.

I put coolant in today and ran for 45 mins to run in the cam. Unfortunately the EDIS 8 will not run my tacho so I put the timing light on it as it has a built in tacho.

Timing shows it is running at a fixed 14 BTDC which is near enough for my purposes at the moment.

The timing does not have a setting for the number of cylinders on the engine - not needed for the timing light function but I assume necessary for the tacho function. Must sort it out automatically somehow - there is nothing in the manual for this.

Any how, it normally does seem to read right but this is the first time I have used it on a wasted spark ignition - so No 1 cylinder is fired twice as much on a non wasted spark ignition.

So if the tacho was reading 3000rpm is the engine really at 3000rpm or because of the wasted spark - actually at 1500rpm.

Thanks

Garry

unstable load · Post by **unstable load** » Thu Apr 20, 2017 4:30 am

Most timing lights will pick up their signal from No1 plug lead via an inductor that uses the triggered spark jolt's current to induce a voltage to the light via the clipped-on pickup.
It sounds like your system is a wasted spark type, where the plug will fire along with all the other plugs on the coil pack, so your light will read that as a firing event for that cylinder and calculate RPM accordingly.

DaveEFI · Post by **DaveEFI** » Thu Apr 20, 2017 8:31 am

The EDIS 8 module has a tach output which gives the same number of pulses as you'd get from a single coil.

The problem is older tachs. If designed to trigger from a col negative, they expect a pulse of anything up to 50 volts peak or so.

You can buy adaptors when turn a low volt pulse into the higher one needed, or build your own. You'll find a circuit in the MS hardware manual. It is basically just one transistor driving a relay coil - that coil used as it is a cheap and easy to find inductor.

As regards timing lights, some modern 'smart' ones don't like wasted spark. Simple ones are usually OK.

garrycol · Post by **garrycol** » Thu Apr 20, 2017 8:59 am

Thanks for the responses - yes wasted spark - I take it then that the engine was actually doing 1500rpm rather than the displayed 3000rpm.

DaveEFI wrote:The problem is older tachs. If designed to trigger from a col negative, they expect a pulse of anything up to 50 volts peak or so.

Hi Dave you have mentioned that before but I am not sure I follow - the low tension side of the coil takes 12v (or about 10v if a ballast resistor) switched off and on by the points (electronic ignition). If anything because of the resistance of the coil in the low tension side I would have thought the voltage at the contacts would have, if anything lower than the 12 or 10v rather than the higher 50v you suggest. I appreciate the LT side induces a massive voltage in the HT side but not sure how the voltage in the LT side rises.

I put the multi meter on the tach output of the EDIS 8 (check both DC and AC) and it produces only 1.7v - way too low to run the older aftermarket tach that I have.

I will check the manual to see how to build the adaptor - not an issue when I finish the MS3 and it does have a tacho driver inbuilt.

Cheers

Garry