RB26 head -Cam journal damage

[fleshfeast]

Winter is here and its about time to rebuild the spare RB26 into something mean


Personally I don't like this one bit, would you use it or throw it overboard?



The damage is only on the one journal the rest are perfect.




strangely this barely has any scratches

[caliber676]

If your making big power I personally wouldn't work with a bummed head. But in reality, a machine shop could fix that pretty quick with no problem. Best to ask the machine shop how much it would be to correct that, may end up being more expensive than a used head from the parts section

[Skym]

They could weld aluminium on the head, regrind it to correct shape. They do that with failed exhaust stud holes, I think cracks, etc. Or probably could machine and fit slightly bigger diameter custom camshaft.

[fleshfeast]

I was looking to P+P the head, Cams, valves. probably not worth all the work for this one.


I dont know if I would trust welding right there for any duration. Id be nervous about the alignment of the cam after its torqued up. I think Id have to have the head and block surfaced before Id be completely comfortable.

thanks for the second opinions before I go searching for a new one.

[newalliance123]

You could buy my ported head I have for sale. Comes fully hot tanked, with new Tomei valve guides. $700. PM for info, not avail till December as im at work...

[dark_sky]

This is you car and your choice what you do. But in my opinion with a little polishing (not sanding) it will be fine. Cams turn 4 times slower then the crank, and don't have the pressure on them that the crank does. It's not damaged just a little worn. I did a car earlier this year and the cam journals had little pits in them looked like an arrow bar with little holes, it was air pockets from casting process and were showing through after the cam had worn on them for so many KM's. Took the hole ordeal to the machine shop, he said that it's fine and if any thing it will help hold oil for lubrication. Notice how cams don't have bearing like the crank because they don't need them. Not the same pressure. It's good to be concerned but take it to a shop and get an expert to give you their professional opinion.

[Dragon Humper]

Depends on what the cap looks like (is that the cap in the last pic?), if its good, your fine. A quick polish to take the high spots off is all that's needed. The cap takes all the pressure, the head virtually none, more of a locator than anything else. Aluminum is so soft it doesn't take much to damage it. You could line bore the journals to clean it up fully if you want, easy to do. The only thing is that all your cam clearances will be a touch tighter. I don't think you need it though if the cap is good.



Jon.

[Akula]

true...I had that on my first 2.2 20V RS2 Audi...was so hard to find head for that,so i polished it and thats it.after that did 20K kms (580whp) with no problem.

[rolyaT]

I have a head with kinda similar damage. Looks like something got in between the camshaft lobe and the head on mine. Grooved the camshaft, the cap and head. I would rock it still though. As said take down the high spots and basically it's now a oil gallery hehe. If I was doing a insane build obviously I wouldn't but stock to mild build I would

[fleshfeast]

That was the matching cap in the last pic. Cap is in good condition as well as the cam itself, It didn't even cross my mind that the cap would see most of the force from valve springs. I highly doubt this happened immediately before I tore it apart and it held oil pressure so it should be the same after the rebuild. This is just a spare engine so I think I will work with the original and keep this one as a spare.

No real power goal for this one Im trying to pull most of the power from mods to the block like I was building an NA, retain factory internals and run more or less stock boost. what I had in mind was:

-moderately ported head more of a cleanup and polish
-lumpy cam, want a bit of lopey idle sound not sure which Il choose yet
-3"exhaust
-holset HX40
-600cc injectors
-Megasquirt
-walbro 255
-stock IC

Any idea at possible potential I have no idea what to expect just build it and see, Im hoping for a reliable torquey beast.

[Skym]

RB30 = more than RB26 throughout power, torque bands.

[Blackcossie]

-lumpy cam, want a bit of lopey idle sound not sure which Il choose yet

Im hoping for a reliable torquey beast.

Lol, dont buy cams for sound, buy them for purpose. If you're looking for a motor that is going to make lots of torque you may be driving the wrong car. The RB 26 is not the best platform for torque, probably has alot to do with the 3" long intake runners and cam design. Stick with the stock cams and get some adjustable pulleys, or RB30 is always and option.

[fleshfeast]

lol yeah that was a pretty bad cam description.

I will definitely be camming this engine. I never did find the stock cams fit my driving style, I tend to rev the hell out of engines and a fairly aggressive high lift cam and a bit more duration and overlap than most would prefer fits me best.

You don't find these engines have some torque? Ive been driving over square subaru EJ20's for a while. Comparatively the GTR feels like a tractor.

[cortexx]

Take the head toa machine shop and get them to align hone the cam journals - it doesnt cost much.

They will grind down the cam posts very slightly then recut the journals . This will bring your cam very slightly closer to your head but the adjustment for this is to reshim the buckets, and if you go over 9.15 mm lift you will be machining the head either side of the buckets to make sure the lobes dont hit the head on rotation.

When you get it back assemble the cams into the head with no valve gear , torque the cam caps to spec and make sure the cams spin freely . If they dont - take it back to the machine shop. No matter who does your maching - always check it to make sure they didnt make mistakes