I've just bought a XR6 cam from the for sale area of the forums and will be attempting to put it in my 3.9L EA and was wondering if there would be any issues with things like valve clearances and if i'll need to get a larger harmonic balancer to run it. Also are the valves in the XR6 larger, and if so will this affect the performance of the cam in any way? Thanks
Yep the XR6 valves are bigger by about 2-3 mm.I have a Crow 825 cam in my EA which is bigga then a XR6 but not by a very large margin.It ran with the standard valve springs for nearly 8 months but I got the mod bug again and fitted a EL manifold.Dynoed it and found I lost power.The cause was not the manifold but my springs where floating.Installed a set of ED XR6 springs,dynoed gained 10kw throughout the rev range and now it revs to 5500rpm without power drop off.So in all it might be something to consider if you are chasing power.
I would check valve clearances as well.EA's have 2 types of shims to vary the adjustment,last thing you want is your valves to ride.
Harmonic balancer is ok as long as it is not spun??
So do you think it will be okay to test the cam without changing anything first, just to see how it goes?
I don't want one of my valves smashing into the pistons or anything like that, but then again I don't particularly want to take the head off again to get a engine rebuilder to check it, as I only took the head off a few weeks ago!(before i got the cam)
You have to take the head off to change the springs etc don't you?
How safe will it be running it with the cam in it, thats what I really need to know.
When I first fitted the cam on my EF, the mechanic screwed up by not shimming the thing properly.
(Not really his fault, as he ordered a Billet Cam, and got a severly regrinded one)
Anyway, the thing sounded like a diesel truck, with the valves not closing properly, and the Lifters not touching the Cam, and the whole thing clattering away.
The mechanic believed that the Lifters needed time to bleed up, so he sent me away, and told me that if the car is still making the same noise after a day or so, to bring it back in to get the lifters replaced.
Anyways, called him up, said it was no good, and went back there to get the lifters replaced.
When he went to fit the new lifters he realised what the problem was, and went about shimming the lifters for the cam.
Anyways, the thing required something like 3mm of EXTRA shims, and thought WTF ?)
Anyway, called the cam suppllier, got the new cam, fitted the new lifters, kept the same shims, and all was sweet.
After all this, I was worried that not having the valves closing would have done some damage to the engine.
To cut a looooong story shorter, although it isnt good for the motor, I was told that I could have run the thing like that for a couple of months, without doing any major damage to the Head/Cam/Lifters.
All that was happening was that I was losing power, from the valves not sealing properly.
Mind you, the motor sounded Terrible, and I think I would have died from embaressment long before the Engine would have died.
As for the Valve springs, Crow Cam, and Dynotec (Mine) recommend for utmost performance, that the valve springs be upgraded. The reason is similar to above, basically, so as the Valves are forced shut, and do not oscilate, bounce or anything.
Finally though, Im not a mechanic, and I confess that although to me this sounds correct, people could be feeding me B.S.
Well a XR6 cam will not cause your valves to smash the piston.Its re-ferred to as a baby so don't worry about that but like Xphoid pointed out its manly for complete sealing for better performance.Makes it rev out alot better to.
Xphoid I thought you couldn't shim a lifter from EF onwards.EA to ED are ok as you can buy shim 1 or 2 dots for them.I could be wrong unless they used washer around 10mm in diameter to compensate.
is it a eb-ed xr cam?? use p/n ED 6513 A xr valve springs they do make a difference and will cost less than $80.00 a set from ford.
you can change them with the head on all you need is too fit a airline to the spark plug hole it will hold the valve in place while you compress spring.
donuts2001 are you sure they are XR6 springs??Just that I priced a set and they were $20 each and thats trade.They should be red in colour other wise I could have been ripped off.The part number is right though.
You can up grade the valves but only by a couple of mil.In most cases you are better off with quality then quanity if you get my drift.What else to you plane to do to the motor??You will not notice much in the perfomance side of things unless you plan on exhaust 2 1/2 inch and extractors other wise you are wasting your time.
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