Cam Gear Problem

[Vive le Sport]

Hallo,

My German is not very well, so i will ask in English. Sorry for that.

With my R5 turbo2 engine i have a problem with the small gear between camshaft and the oil pump.
It get damaged very quickly. After less then 100km all teeth on the small gear are gone.

I have looked on the internet to find anwsers what is causing this problem. And it seems to be a known problem with these engines. But i can't realy find a clear anwser.

Some say:
- Lubrication problem. (I have drilled holes between the teeth of the gear)
- Cilinder Head allignment (on Sun International website USA)
- Materials of both gear and camshaft do not corespond. (Camshaft and camgear are both Renault parts)
- Shape of teeth on camshaft and cam gear.  (I had a regrinded R5 Alpine cam)
- Camshaft line was not drilled good in center. (I have a C1J engineblock from 5 Gt turbo)
- To high engine rev's ? I do 7200RPM

And why does this problem not occure on other Renault "Cléon" -type engines.

Some of My engine's specs:
- C1j engineblock
- R5 Alpine turbo cilinder head
- Steel liners (1400cc)
- Woessner R5 Turbo pistons
- R5 Turbo conrods
- R5 Alpine camshaft, regrinded by Catcams
- Spesso 1.9mm head gasket
- EFI with KMS Engine management
- 660cc RC injectors
- TR30R Turbo

It's a very fast and powerful engine, but i can't get rid of this problem.

Since a couple moths i have a Kent Cams camshaft in combination with a standard Renault cam gear.
And after a short drive, you could already see some slight damage on the small gear.
(I can take it out now without removing the cilinder head)

Looking forward for your opinions about this..

[Vive le Sport]

Here are some pictures:

[joe]

Hi Vive Le Sport and welcome to our forum.

The cam gear situation had previously been discussed here, the following thread is in German: http://www.backenturbo.de/forum/index.php/topic,1285.0.html
Mecaparts seem to have had a quality problem with their cam gears, one of our colleagues could return a damaged gear and got a credit note "for the supply of faulty material". After these issues Mecaparts have introduced a new cam gear with a new part number (see last page of the thread).

On another note, there is a theory that if the oil pressure is set to high there will be substantial wear on the cam gear, it is recommended not to raise the oil pressure (by shimming of the spring or installation of a harder spring) by more than 10%. Could this be the source of your problem?

Last but not least everyone here would like to see some pictures of your car and maybe some more information about the specification. Did you put your car on a dyno, if yes what is the output with your modifications?

Cheers, joe

[daniel ch]

Hello

What oilpump do you have and wich oilpressure do you have at 4000 rpm?

If the oilpressure is too high the oilpump has more drag or resistance to movement, this can cause the damage. This happens often when the oilpump is modified.

What ignition distributor do you have? If the distributor is not fitted correct or the lenght of the distributor is not correct, this also can cause the problem.

Regards
Daniel

[lecar5]

Welcome Vive le Sport !

Maybe my comment is not the answer to your specific problem, but I remember back in the 1990s a friend of mine built up an engine for a Renault 5 Alpine Turbo (108 PS), put the cams of the Alpine Turbo in with a drive pinion for the distributor taken out ouf a Renault 5 Alpine (93 PS). This combination works very well at first, but after about 600 km the engine failed. The reason was 'lost teeth' of the drive pinion. He could take out the drive pinion without disassambly the cylinder head, put in one of a Renault 5 Alpine Turbo and the problem was solved.
You wrote, that you drive your engine with a Renault 5 Alpine Camshaft. Probably you have the same problem of not combinable camshaft an drive pinion.

By the way: all guys here in this forum are always pleased to see photos of new members - mee too !
Best wishes, Hubert

[Vive le Sport]

Thanks all for your replys. 
The oil pump that i'm using is standard. We did not raised the pressure.
I'm not using the ignition distributor anymore. But i have made an aluminium piece with a trust bearing at the end to keep the cam gear at its place. With the subscripted play. Or maybe the aluminium piece extends to mutch from the hot oil?
But i suspect that the problem will be that the camshaft and drive pinion are not combinable.

I will get some more pictures and info of my fat 5 in the correct section of the forum later today.

[daniel ch]

I'm not using the ignition distributor anymore. But i have made an aluminium piece with a trust bearing at the end to keep the cam gear at its place. With the subscripted play. Or maybe the aluminium piece extends to mutch from the hot oil?

Hello Vive le Sport

Can you please put a picture of the piece with the trust bearing and another picture with this piece fitted on the cam gear?

This cam gear is a very "delicated" part and maybe this construction to replace the distributor is your problem.

Regards
Daniel

[Vive le Sport]

Hi Daniel,

Here is a picture of this part.
I also use it for engine ventilation.
Would you suggest to use the standard ignition distibutor? I have to find one then.

[R5MaxiTurbo]

Hi guys,

just a quick note about the failed gears. Is there any possible relation between failed gears and the thickness from the cylinder head gasket? If a thick gasket is used the play between gear and distributor is increased and the gear can rattle up and down. Is this increasd play causing the failures?

Cheers

Dirk
 

[daniel ch]

Hello Dirk

Usually the thicker gasket is used when the surface of the head has been reworked and is lower than the standard height. In this case there is no problem, but if yous use a normal height T1 Cylinder head that is the heighest and you put a 2,4 gasket maybe you can get this problem with to much play. Also if you use a reworked (waterpump flange) Alpine Turbo or Alpine Atmo Cylinder head (low height) with a 1,4 gasket you can have the oposite problem that the gear is seized...

Regards
Daniel