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..... Planning on doing the exhaust guides but if the rest of the intake guides check out similarly tight does it make sense to do them anyway as a preventative?
Do the whole lot. It's not twice the work to do twice as many, considering the processes of setup/machining/chilling/heating involved. They're a relatively short guide, which go from OK to way out of tolerance fairly quickly, and it's worth having them them all perfect.
^^^^ In that case pull the other head off too and refresh it.
Also, there is too much carbon on that exhaust valve, since it burnt because of carbon (I've seen this in other engines, non Porsche) and if you only do some of the effected valves, the others (on the other cylinders) will more than likely end up the same way soon too.
Definitely doing both heads which includes lapping seats and replacing seals, guides and any valves that are out of spec. Of course as Greg warned sourcing the exhaust valves is going to be a challenge but we'll cross that bridge when we come to it.
If you're going to keep the car, do both intake and exhaust, and get the valve job. It's a little more expensive, but you will be able to enjoy it much longer and it shoudl purr like a kitten (or roar like a lion... all depends on how you like to drive).
I've never seen carbon build up like that on a 928 motor, maybe Greg has, but something isn't right, IMO.
Hi Kevin: Let me know when you are ready to start reassembly. I'll come down and help, especially with dropping the engine back in where a few extra eyes and hands can really help. I'm mobile again with a used tranny from 928 Intl doing very well.
If you're going to keep the car, do both intake and exhaust, and get the valve job. It's a little more expensive, but you will be able to enjoy it much longer and it shoudl purr like a kitten (or roar like a lion... all depends on how you like to drive).
I've never seen carbon build up like that on a 928 motor, maybe Greg has, but something isn't right, IMO.
Could be from very work valve guides and seals...lots of oil.
It's been a while so here's an update. So far I've done the following:
Pulled the engine.
Sent out most of the engine bay bits for Cad plating. Results on this were ok, I probably needed to do more of the prep work myself, but still a huge improvement over the old stuff.
With Bill Ball's help installed rebuilt heads supplied by 928intl. Thanks Bill!
Cleaned, cleaned and cleaned some more, especially in the engine bay.
Got sad when I opened the Minerva thread to know what clean really is.
Replaced coolant reservoir, heater hoses, power steering and oil cooler lines
Fixed the Oil Cooler fitting using Greg's technique.
Incessently nagged Greg Brown, Speedtoys, Bill Ball and countless others whenever I hit the slightest speedbump.
Reassembled the rest of the engine. Bill's coming down on Wednesday to help me drop it in. Wish us luck!
Exhaust manifolds going back on after dressing with Slip-Plate (similar to Calyx, but spray based instead of paste), pretty sure it won't last but it's cheap enough and doesn't require nearly as much prep as Calyx. Before I torque them down, are the manifolds directional? The only difference I can see is the location of the test ports being up or down.
01-18-2016, 07:31 PM
