Top end 911SC rebuild, reseal

[barneytirebiter]

1979 911SC 3.0 Targa, 110k miles and runs fantastic
First time posting here...had it not been for the amount of great material that is found on our hosts forum and Waynes books I dont think i would have tackled the job of removing my engine and attempting a reseal and top end rebuild...
Removing the rockers from the cam housings I found some pitting on a cam lobe, #4 intake....I've included a few pics of the ugly area...this was the only lobe where there was pitting..all others were great and showed no pitting or dis-coloration. In one of the pics i have made a black mark on the journal that approximates the position of the apex of the pitted lobe..also in that picture the cam would be rotating CCW so the pitting has occurred slightly at the tip of lobe and mostly on the lobe down ramp. I've included a pic of the foot of the rocker for number 4 intake....
What are options to correct..?
Thank you

[Flat6pac]

3.0/3.2 cams are the same and quite reasonable in price
If you get later SC or carrera, you’ll need the bolt and washer where the earlier SC had a 46mm nut and washer.
Bruce

[Trackrash]

Probably a good idea to make sure that all of the oil holes in the spray bar are clear.

There are a lot of stock SC cams laying around so no problem there, except you will want to resurface your rockers before putting them on a different cam.

[$yncro]

I’m doing the same rebuilt right now and my cam has a bit of pitting
In #4 as well.. I’m thinking of sending it to cam grinder and get it fixed.
Is that another option perhaps?

[targa72e]

You can have you original cams reground to stock (or more) grind. You would need to have rockers resurfaced as well. With the price of SC cams being pretty low if you just want to go back to stock probably less expensive to buy single cam to replace damaged unit and have those 6 rockers refaced.

john

[$yncro]

Thanks John. Will search for one I guess..

[RedCoupe]

Also, take Gordon's advice and make sure that the bad lobe is getting proper oiling. The pitting on that lobe is from excessive wear. The hardened layer is failing.

[barneytirebiter]

Hello all and thanks for the replies, considering all suggestions that are presented here..spray bars have been removed and thoroughly cleaned. Still on fence about cams because of pitting on one lobe.
Crankcase cleaned with new gaskets and seals as required, did not split the case! Also had no intention of re-ringing, Alusil cylinders looked beautiful and still showed faint signs of possibly original X-hatching. But curiosity got the best of me and and had to check condition of at least one set of rings so pulled piston out of #6 barrel to inspect, careful to not change orientation of rings in their lands. Looked good except for modest amount of carbon build up in oil ring gap and some buildup in between oil ring and bottom compression ring.
Should I pull all pistons and clean this junk off? I'm certain the carbon will be present. It would seem impossible to not change the ring positions on the pistons to clean rings and gaps with solvent and brushes. If only i had the budget for replacing P&C's, thats pricey stuff! Will the rings rotate back into their original positions and re-seat where they were when engine runs again? I would definitely make sure that gaps are clocked as should be..

[barneytirebiter]

Hello all and thanks for the replies, considering all suggestions that are presented here..spray bars have been removed and thoroughly cleaned. Still on fence about cams because of pitting on one lobe.
Crankcase cleaned with new gaskets and seals as required, did not split the case! Also had no intention of re-ringing, Alusil cylinders looked beautiful and still showed faint signs of possibly original X-hatching. But curiosity got the best of me and and had to check condition of at least one set of rings so pulled piston out of #6 barrel to inspect, careful to not change orientation of rings in their lands. Looked good except for modest amount of carbon build up in oil ring gap and some buildup in between oil ring and bottom compression ring.
Should I pull all pistons and clean this junk off? I'm certain the carbon will be present. It would seem impossible to not change the ring positions on the pistons to clean rings and gaps with solvent and brushes. If only i had the budget for replacing P&C's, thats pricey stuff! Will the rings rotate back into their original positions and re-seat where they were when engine runs again? I would definitely make sure that gaps are clocked as should be..