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Hi, it's been a while since I posted here. I recently decided to give some love to the 951. Long story short, last year I tried to take care of a unknown engine oil leak, ended up replacing the following parts:
-Both balance shaft front seal
-front engine seal
-oil filter housing gasket.
-oil pressure sender
-timing belt and waterpump while I was there
The engine was still leaking oil at the oil filter housing again!... (lower right bolt)
This week I started to take the head appart as well as the oil filter housing...
The car has 100 000 miles, no oil/coolant mixing, could not really diagnosed oil consumption because I barely did 2000miles since I have the car.
Sent the head for inspection and resurfacing, the guy told me that it looks like I was burning oil by looking at the combustion chambers... I this that bad ?
Anyway, I located some small oil leak at the end of both balance shaft covers, is it possible to remove the lower bs cover without removing its front cover ? I dont want to mess with the front seals. And it looks like upper bs cover cant be removed without removing its front cover right ?
you can remove the balance shaft covers without disturbing the front seals. the only seal that would be affected is the big black housing o-ring, but not the shaft seal itself.
definitely looks like burning oil - at the very least you need valve stem seals, at 100k it might be time to do the valve guides as well (while youre in there...)
Great, and can you replace the rear orange o-ring without removing the balance shafts ?
Valve stem seals will be replace for sure, they'll remove the valves to clean them and I'll reassemble everything. I might replace the valve guides as well thank you, I didnt know they could get worn out.
I didnt find any information about replacing valve guides, is it doable at home our you need some special press ?
Assuming they are the factory ones, can I keep the head studs and only replace nuts and washers ? The engine won't see more than 15psi of boost and it's a street car. I don't mind spending the extra $100 but I dont wan't to struggle with broken studs or damaging the block while removing them...
best let a machine shop do the guides.
shops near me charge $5 per guide to remove/replace, and the guides cost about $6 each by themselves.
i think your extra $100 estimate is about right.
get the head surface cut smooth while having the guides/seals replaced.
while the head is at the shop you can clean up the block gasket mating surface with a sharp razor blade (taking care not to scratch the surface, but to scrape up the chunks of old gasket), and then finishing with green scotchbrite and WD-40/motor oil until it is clean aluminum all the way around. finish with brake cleaner and paper towel wipedown. dont bother trying to clean the piston tops.
take your time torquing the head down evenly, follow this pattern...
and to these values...(i prefer using the torque figures rather than the angle figures but YMMV)
I'm removing the turbo in order to replace the AOS o-rings while I'm in there. When the head will be back on with the lifting bracket, I'll replace the oil pan gasket and rod bearings. I hope not to see any oil leak after that...
I just ordered valve guides on pelican parts. I'm wondering if I chose the right ones. I took the canyon 1st replacement (9mm x 13.08mm) are they the right ones or I should have take the others with the normal OD ?
Those are the ones I've always used without issue...
The machine shop needs to re-size the hole after removing the original guide so the replacements are a hair larger for a proper interference fit.
Seems like this comes up every week...lol
It's just a blind hole, doesn't go anywhere or do anything.
My guess is that it was for mounting the block for machining during initial production.
03-30-2017, 09:21 PM
Questions while doing the headgasket job.
