Why you shouldn't machine a Fuego head.

[mistareno]

A few months ago I posted a query regarding why Renault state in the manual that head resurfacing is not permitted on a OHC Fuego motor.
At the time certain peole said all was apples with resurfacing but no-one gave me a satisfactory answer as to why Renault stated that in their manual.

Well after a bit of research, and consultation with a few Renault specialists, I have found out the real reason why.

If the head is distorted and you get it machined, the cam bearings must be line-bored or else they will chew out the bearing surface very quickly.
You should under no circumstances JUST get the head machined....

It is up to you as to weather you take the risk.

 

[Damien Gardner]

That sounds reasonable, i once had Repco resurface a VW Passat head & was told to bring it in with Cam still bolted in, probably for similar reason.

 

[Europa]

When I had an OHC head surfaced recently, the guys were fully aware of the cam issue - in fact, they asked me to bring the cams in to be certain that everything was OK and no finishing was required

 

[Ray Bell]

It's not the resurfacing that puts the cam bearings out of line, it's the warping that makes the resurfacing necessary. Presuming, of course, that the remachining isn't due to corrosion.

Once a head is warped you have these problems... which is why it's much smarter to build the head with separate cam bearing carriers - like the Datsun 1600/180B/Bluebird engines.

Though not everyone wakes up to this... I know of one Datsun 260Z that had a cam break because they machined the head surface and didn't correspondingly machine the top of the head as well... which is what's necessary in these cases.