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Camshaft

R

rabet

Overdrive!
Hi all,
Seeking advice from people who have the knowledge of land rover engines.

I have a camshaft from a 1970 s' 2.25 petrol engine, on the shaft it is just stamped "petrol" with no number.
I have searched and found details ref ETC 7128 camshaft but cannot find ref to this "petrol"cam from 3 brg eng.
Q, Can I use this in a 5 brg block and will it give reasonable service.
Because it just says "petrol" does it mean that there is another version for the 3 brg diesel eng stamped "diesel"??
I have read that the ETC 7128 gives slightly better top speed but you loose a bit of bottom end torque, is this true?

I would be so greatful to hear anyone, and read your experiance.

I have spent hours searching but have found no referance to early 2.25 petrol camshafts and 3 brg engines.
You could say, go and buy a new cam, but in the jungle is costs a fortune, so we have to use what we have or try to at least.

Rabet
 
yes there were two cams, i believe this is because compression ignition engines don't need or tollerate overlap (that tiny fraction of time when both inlet and exhaust valves are open)

but i also believe the camshaft was later rationalised, i.e same cam used in both diesel and petrol engine in late series3 5 main bearing era, into early coil sprung
 
a rationalised cam from a 2.5 petrol is the same as the diesel and will fit a 3 bearing petrol. its a good upgrade for an earlier engine. couldnt say what the difference is between an early derv or petrol cam.
 
Thanks every body for answers,
To Zollaf, you say that a cam from a 2.5 will fit a 3mb petrol, but it is the other way round I want to go, ie 3mb 'petrol' cam to a 2.5 petrol.

Any ideas?

Rabet
 
should work a treat..
maybe best to give a chap called roland a call at acr, the place that makes really good landrover engines... http://www.automotivecomp.com/


he would be able to give you a definative answer. maybe you dont have phones though in borneo, or long distance woyuld cost loads, maybe an email would be better. :)
 
land rover parts manual lists a "conversion kit" for later metric cam in earlier 3mb block. digging further the kit is to do with the bolt that holds the timing sprocket on.

it woudl make sense to use all of the early 3MB hardware in that case
 
Hi all,
Well you were all right,
I mailed Roland of ACR and he said, cams marked 'petrol' were used throught the series engine, but right at the end of 2.25p and into the 2.5p the cam ETC 7128 was used and this cam was the one fitted to the "Diesel"engine, I assume of the series diesel
He stated that they had little sucess using the 2.5p cam (ETC 7128) in the 2.25 petrol, but he did not say why. He went on to say that he has never tried to fit a 2.25p cam into a 2.5p but he thinks it should work ok.

If any one can tell me what is the upgrade differance in fitting 2.5 to 2.25 it would be interesting.

So there you have it.

To the engineers out there, how easy to make a cam reprofiling machine, just to kiss the lobe and remove any flat spots.

Rabet
 
my brother had the 2.5 cam in his 2.25 3 bearing, turner head and rebuilt bottom. no figures but it did go well and was very smooth and quiet. like the smoothest 2 1/4 i have ever known, but it was built and set up well.
 
Thanks Zollaf,
I now have 3 "petrol" cams, 1 good and useable and 2 in a state that needs reprofiling and 1 ETC 7128 with 2 lobes no good.
I have this idea to make a simple cam reprofiling machine to reprofile the damaged 7128 cam and then see if it is possible to reprofile the 2 unusable 'petrol" cams in the same profile as the 7128, based on your experiance.

Advice please??
Nice little project for the jungle.

Rabet
 
It depends on how deep the case harding is on the cams. You should be able to find out and then decide if there is enough depth left. There used to be a lot of cam reprofiling for cheap overhaul engines but the cams often wore out very quickly because they had taken all the hardened layer off. If the cam is still the correct profile but has some light scoring you can try polishing it with fine emery and a wooden block held square. Its not perfect but you can get some quite good results and you are taking off the absolute minimum, if it doesn't work you can still reprofile.
 
but if the cam is actually worn, i.e its no longer a cam, then the hardening has gone and its fit only really for the bin. but then with their clever roller tappets, a 4 pot shouldnt wear a cam out, not if the oil has ever been changed :)
 
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