post rebuild analysis 4 years later

[theiceman]

so i redid the top and myself on my car ( 78sc 3.0 litre 250K km ) due to 3 broken head studs and found it a very rewarding experience.

I replaced all the lowers with steel and left the uppers alone. i did not replace the rocker shafts on the rebuild but used RSR seals and still had leaks. so then replaced all the rocker shafts with more RSR seals and still had leaks, even tried a bit more torque and still had leaks ( over 2 years ) so said screw it and just drove it.

so this i think is year 4 and had the car at my buddies place and its starting to look like the exon valdez under there...


what im wondering is could i actually be leaking from the base gaskets here ? i used the copper base gaskets in my rebuild kit and torqued to spec. But never actually went in and retorqued after my build .

Should i have gone in after some type of initial break in and retorqued all the head bolts ??

Thanks

[theiceman]

Well i did some searching ( maybe should have done this before posting ) and its a mixed bag, some do some dont. But bottom line is it cant hurt to recheck them. Maybe during next oil change ill whip the covers off and redo the head studs at 25lbs.

[boyt911sc]

Originally Posted by theiceman

Well i did some searching ( maybe should have done this before posting ) and its a mixed bag, some do some dont. But bottom line is it cant hurt to recheck them. Maybe during next oil change ill whip the covers off and redo the head studs at 25lbs.

Clive,

If I were you, I would degrease and clean the engine well. Then start monitoring for any new sign of oil leak/s. Do not wait for the oil to drip on the garage floor. That’s too late. You want to see a dry spot gets moist with oil and finally forms a 💧 (droplet). Once you locate a moist spot or area with oil under your motor, time to trace its origin. They are not easy to identify at first because the oil leak tend to travel down and find its way to the lowest spot due to gravity.

If you want to fix your oil leak/s, you need to identify and locate the source/s. Then plan a course of action to remedy the problem. Knock on wood, my first engine rebuild is about 30 years old now and miraculously does not leave any oil mark on the floor. And this motor does not have RSR seals because they were not available or never heard about it 3 decades ago. Now it is a trend to have them on the rocker shafts.

Tony

[dannobee]

The way we check for leaks at the stealerships is to add oil dye, then have the customer drive it for a few hundred miles, then put it up in the air and check for the trail with a black light and yellow glasses. The dye will stick out like a sore thumb with the black light.

That leak looks like something from above. Maybe check the highest spot first, at the triangle of death area, with a mirror and flashlight.

[Gianni at Pelican Parts]

Originally Posted by dannobee

The way we check for leaks at the stealerships is to add oil dye, then have the customer drive it for a few hundred miles, then put it up in the air and check for the trail with a black light and yellow glasses. The dye will stick out like a sore thumb with the black light.

That leak looks like something from above. Maybe check the highest spot first, at the triangle of death area, with a mirror and flashlight.

I believe the Liqui Moly Molygen line comes with fluorescent dye in it as well that helps spot leaks under blacklight

[Eagledriver]

I would suspect your oil cooler.

[al lkosmal]

Do not forget the triangle of death.......I check here 1st....leaks from this area can cause a mess.....on top and under the fiberglass shroud and can run between the cylinders to the underside of the engine.........





regards,
al

[theiceman]

thanks guys

triangle of death is near impossible to check... unless i pull off all the fiberglass and intake... im going to clean it up as Tony suggests and start a the top. intake rocker shafts i think would be a relatively easy place to start..

im wondering if i scored the bores taking them out as it was my first ever rebuild.

[Walt Fricke]

Start at the top, which means the triangle. For access, do a partial drop, removing the big intake boot if need be. Clean the heck out of that area. You don't need to remove any fiberglass, etc. Just clean the surfaces you can reach.

While one hears of the thermostat O ring leaking, that seems to me not all that likely - it is captured nicely. The idiot light sender, on the other hand, is very apt to start leaking at some point. When I replaced one of mine I carefully epoxied over the seam between steel and plastic. Some years later, it was leaking. Baah - just put a plug in the hole for that switch, and used a two function VDO pressure/idiot sensor back by the fan.

But replace the idiot sender while you are in there, just on spec.

Dye is probably the quickest way to find the source. Maybe even without cleaning things up? But cleaning up is useful every which way - you will do it eventually, so why not now?

The biggest rocker shaft leaks come when the shaft walks some in its bore, especially if it walks very far. Easy enough to check with the covers off - are the shafts still where you put them? It just takes one shaft to produce quite a lot of oil.

[Josh D]

Easy to see if rocker shafts are leaking by just pulling the valve covers.

[theiceman]

well gents looks like i will start with the triangle of death .. couple of other small projects to wrap up first. Yes Walt i did the same during my build so ide be pissed if it was all leaking there since i put a new switch in AND epoxied over it. to me it seems it s coming from to far to the rear of the engine for triangle, but you have to start somewhere.. i find that breather hose gets very hard very quickly. if its hard and leaking again im getting an OE Porsche one next time.

[rockreid]

I rebuilt my

[Walt Fricke]

I took another look at the pictures. Assuming the oil sump plate is oriented the way mine is, the leaking is in the area of the #1 cylinder, isn't it?

That's not the triangle of death - though if the #3 or #6 look like that, that's different.

A leak by #1 or 4 could be from a bad cam seal. It could be from one of the chain housing pins for the bits and pieces of the chain and tensioner system getting loose in its hole in the chain housing. It could be from a leak between the chain housing and the mane case. Or from one of the rocker shafts for those cylinders.

I don't think (based mainly on that one picture) that the leaking is from the cylinder base copper gasket. Has anyone found that to be a common issue at that level of leaking? What has been the experience of guys who found they had driven for who knows how long with several broken head studs? And in particular the lowers? Big leaks from the cylinder/spigot seal as combustion tried to lift the head away from the cylinder and thus the cylinder not compressing the seal enough?

[theiceman]

Originally Posted by Walt Fricke

I took another look at the pictures. Assuming the oil sump plate is oriented the way mine is, the leaking is in the area of the #1 cylinder, isn't it?

That's not the triangle of death - though if the #3 or #6 look like that, that's different.

A leak by #1 or 4 could be from a bad cam seal. It could be from one of the chain housing pins for the bits and pieces of the chain and tensioner system getting loose in its hole in the chain housing. It could be from a leak between the chain housing and the mane case. Or from one of the rocker shafts for those cylinders.

I don't think (based mainly on that one picture) that the leaking is from the cylinder base copper gasket. Has anyone found that to be a common issue at that level of leaking? What has been the experience of guys who found they had driven for who knows how long with several broken head studs? And in particular the lowers? Big leaks from the cylinder/spigot seal as combustion tried to lift the head away from the cylinder and thus the cylinder not compressing the seal enough?

absolutely correct Walt, i thought the same thing but didn't want to argue with advice so though better to check. I hope its not the cam seal as that was all new and followed the advice of waynes book, but we will see soon enough , that's really why i asked originally about head studs as i could not think of anything else in that area.

The reason i had it apart ( about 20K km ago now ) was to replace all the lower studs due to a stud breakage. I think i need to check for a walked out rocker shaft ASAP.

[Walt Fricke]

I once forgot to tighten the three small bolts which hold the cam seal to the cam carrier. However, the ensuing leak was very soon apparent (resolved by getting in there with engine in car and tightening, which is another story with a happy ending). It wasn't something which could be ignored for more than the time it took to drive the car into the trailer to head off for a race.

So I'd say the cam seal is just theoretical. Inspecting, and cleaning, maybe dye, will get you closer to a cause.

And, aesthetics aside, are you getting drops on the garage floor after every time you drive back in?

[theiceman]

Originally Posted by Walt Fricke

I once forgot to tighten the three small bolts which hold the cam seal to the cam carrier. However, the ensuing leak was very soon apparent (resolved by getting in there with engine in car and tightening, which is another story with a happy ending). It wasn't something which could be ignored for more than the time it took to drive the car into the trailer to head off for a race.

So I'd say the cam seal is just theoretical. Inspecting, and cleaning, maybe dye, will get you closer to a cause.

And, aesthetics aside, are you getting drops on the garage floor after every time you drive back in?

no not every time Walt, but im moving to a Condo in a year or so and i cant have any leaks that drip onto the floor, and of course it drops onto my exchangers so quite a stinky smokey mess.
.. '

I have decided to park the car until i can get a closer look at it in case i have a walking rocker. Its only a couple hours to check the uppers so think its time well worth investing.

Ill update here when i do that

[Classic 911]

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[theiceman]

okay Gents here is an update. Some interesting discoveries.

Firstly i would like to thank everyone who has contributed so far. Some great advice and suggestions here.
I decided to check for obvious known issues first before getting into dyes and what not. The first thing i decided to check was the rocker shafts. I redid all my leakers about 3 years ago before i put my SSIs on as access was so great and found that a couple had walked after my rebuild.
This time i checked and im pleased to report out of the 6 on the left side i would classify just one as a " leaker," ( oil pooled in thick wall of the cam housing) the others were a situation where the bolt ends of the rockers were bone dry, or just slightly damp with no dirt or oil buildup on the horizontal surfaces of the cam housing between rockers . So good news in that i've resolved just about all of my leaking rockers, but bad news that i still have some pretty good leaks somewhere.

My other working theory was the head nuts were loose causing leaking at the base gasket. ( and this is where it gets very interesting ) . Also very likely issues caused by me on my engine build, as i missed an important step.

i decided while i had the upper cover off on drivers side i would do a quick check of the head nuts.
I shockingly found that all 6 were loose. When i say loose i mean not to torque . all 6 took easily a half turn , maybe even 3/4 turn to tighten. in fact the first one i thought i had pulled the stud. as it took so much , but nope she tightened up nice. Same process for the other 5 , a small crack sound as it broke free then tightened right up.
Then i went to the lowers , did the rockers there ( found one just bleeding but redid that one ) . on the lowers however when i checked the head studs just started to move then click. all 6 held torque perfectly.
i then realized my mistake i made during my build.

Firstly i should state that i only replaced the 6 lower Dilivar studs on each side during my build as i was nervous about pulling the suds and didn't want to invite trouble so left the uppers alone.
When i went to check the torque for this retighten i noticed it said coat studs with anti seize. I don't remember doing that so checked with my borescope the head studs and sure enough no sign of ant seize. This means i would have hit the tightening torque without the required clamping force. big mistake.

The new studs would have had no corrosion or buildup and even had a light coating of oil on them as many car parts do, just enough to allow for proper torqueing in my case. this is why i'm thinking lower ones were perfect.

i then went to the passenger side , no leakers there at all . cam housings bone dry. ( I think the issue on this side may be the oil cooler but that's an issue for another day. )

Anyway i checked the head studs on that side and sure enough uppers all loose again about the same 1/2 -3/4 of a turn. so snugged them up. Should have done the bottom too but my back was barking pretty good by that point.

So i know that I have not torqued in the correct sequence doing it how i did. Im thinking maybe next valve adjustment i will pull all covers. and back off the nuts put anti seize in them and do the
2 stage retorque from scratch , unless someone things that's a bad idea.

So some interesting findings and route cause may be a process error by me. I decided at this point to just stop and see if it has an impact on my oil leaks.

Next step is to put her up on the ramps and clean the heck out of what i can and take it for a good run and see what happens. Im sure there are other things going on , but now i know my rocker shafts are good. ( well 9 out of the 12, still 3 to check. ) and i know i had issues with head nuts.

So next steps are using my borescope to see if i can see if triangle of death is leaking. From what i could see with my mirror it looked okay but it is really hard to tell. Also investigate if i can remove and test oil cooler with the engine still in the car.

As always comments are welcomed and encouraged.

[theiceman]

okay have not run it too much but looks a LOT more improved in all areas after tightening head studs..
i went in with a borescope this weekend and its still really difficult to get in there but i got a good luck at the triangle of death .. all looks clean dry and good to go.
I think i do in fact have an oil cooler leak and shame on mye for not testing it when i had it out.
because i have a 3.0 litre CIS car that aluminum pipe is going to stop me from getting the cooler out with engine in.

could be the porous case too in that spot.

Next steps are drop the engine and get that cooler out.

stay tuned.

[RockMacho911SC]

Im interested in buying a 911, where is the best place to search?