1979 SC Chewed a Valve - Total Rebuild

[Henry Schmidt]

Originally Posted by OsoMoore

The path towards finishing next weekend has some new snags - sump plate fitment and missing exhaust stud.

I talked to PP parts specialist on the phone back when ordering my sump plate cover, and now am finding it does not fit over my newer oil pump.

I also found one of my exhaust studs is missing, presumably from the replacement head I bought used and sent right to the rebuild shop without passing through my hands.

Can I use a normal stud on the exhaust, or does it need something special for the heat? Also, I'm now slightly that even the expensive aluminum sump plate won't fit. Hopefully I can get all these issues sorted by midweek to make the big push Thur-Sun.

I'm a little surprise that your heads came back with exhaust studs installed. We generally remove the intake and exhaust studs when we do a valve job. It is probably a habit we got into when we started to see customers trying to remove exhaust studs at home because they didn't fit the exhaust system they were installing.
We always use the best quality studs available but DIN 938 or 939 are pretty standard.

As for your sump screen issue: What pump are you using? We are finding that some of the aftermarket pumps and sump screens have some fitment issues. You can probably manipulate the screen to accommodate the sump cover. I would suggest that compressing the screen (slightly) with the sump cover is generally required.
When you retrofit a permanent screen pump (late 83 and later) in an sump plate case you will need a retrofit cover. Once again, not all the covers are made equally.
We used to offer a sump cast aluminum sump cover but the tooling was stolen so the new product is still in production.



How the screen should fit.

[Henry Schmidt]

Originally Posted by OsoMoore

The oil pump extends almost the length of the studs below the case - nearly 1/2" in the center. Looking at the other sump plates on PP I'm not sure any of them will clear it.

This screen is entirely too tall. Your next concern will be: If I reshape the screen will there be enough clearance for the oil to enter the pickup venturi?
My guess is yes, but I'm not in your garage holding your hand.

[OsoMoore]

Originally Posted by Henry Schmidt

This screen is entirely too tall. Your next concern will be: If I reshape the screen will there be enough clearance for the oil to enter the pickup venturi?
My guess is yes, but I'm not in your garage holding your hand.

Ok, I messaged my local shop who helped order the main parts set. It seems this project has no shortage of surprises.

Maybe the screen screws deeper in or something? Will investigate.

Micrometer shows 0.4 inches extended past the case.

The generic curved plate I currently have has a 0.35 in gap when it's contacting the screen.

The curved plate with oil drain that I got from our host has a 0.485 in gap.

I had seen suggestions about shimming it out using the old second piece screens rim but it's far too big of a gap for that.

[mikedsilva]

https://www.pelicanparts.com/More_Info/MCD99310700100.htm?pn=MCD-993-107-001-00&gad_source=1&gad_campaignid=22774292773&gbraid=0AAAAAD_tz50sLrQwVmyYeXpUKOEg-6qhl&gclid=Cj0KCQjwgpzIBhCOARIsABZm7vF9ve7Y7v0BuumOajNS L6QFJE3hA4BvSRjQqEMm9IZ3WmF6uuEZJscaAjMCEALw_wcB

[stownsen914]

That's really odd. I wonder if the venturi (the hole where the oil goes into the pump) is located correctly. Can you take a bottom view pic of the screen?

[Henry Schmidt]

Do not shim the sump plate. Whoever suggested that must have memories of the deep sump on the type four engine.
Your best bet is to measure the distance from the screen to the venturi. Then compare that to the gap you are seeing when the sump cover touches the screen. If the gap to the venturi leaves you adequate space for oil the scavenge freely, you should be alright. If the gap to the venturi is less than say 6 mm, you will have to find another pump.
There are some here who tend to be rather neanderthal so you might consider bending the pickup in place. If you go that route, leave me out....lol

[OsoMoore]

Originally Posted by mikedsilva

https://www.pelicanparts.com/More_Info/MCD99310700100.htm?pn=MCD-993-107-001-00&gad_source=1&gad_campaignid=22774292773&gbraid=0AAAAAD_tz50sLrQwVmyYeXpUKOEg-6qhl&gclid=Cj0KCQjwgpzIBhCOARIsABZm7vF9ve7Y7v0BuumOajNS L6QFJE3hA4BvSRjQqEMm9IZ3WmF6uuEZJscaAjMCEALw_wcB

I was originally going to get that one, but I called PP tech line and the Porsche expert (waited a while in line to talk to him) said the one I bought should fit. I think I may ask them to have someone measure the darn thing before shipping it to me.

Originally Posted by stownsen914

That's really odd. I wonder if the venturi (the hole where the oil goes into the pump) is located correctly. Can you take a bottom view pic of the screen?

Took a pic, see below. Looks to be about 1/3 the total protrusion of the screen. Screen is sticking 0.4 inches, or 10 mm. So screen extends approximately 7 mm past the venturi.

Originally Posted by Henry Schmidt

Do not shim the sump plate. Whoever suggested that must have memories of the deep sump on the type four engine.
Your best bet is to measure the distance from the screen to the venturi. Then compare that to the gap you are seeing when the sump cover touches the screen. If the gap to the venturi leaves you adequate space for oil the scavenge freely, you should be alright. If the gap to the venturi is less than say 6 mm, you will have to find another pump.
There are some here who tend to be rather neanderthal so you might consider bending the pickup in place. If you go that route, leave me out....lol

Per my rough calc above, we have 7 mm from venturi to screen. See pic below. For more precision, I can take a pin out there and measure manually.

I swear I've taken that engine's sleeping bag on and off a hundred times so far.

[Henry Schmidt]

Any chance your oil pickup got bent in shipping? I can't imagine how else you got here.
All 911 oil pumps have a similar pickup location so it not a case of "wrong" part.

[OsoMoore]

Originally Posted by Henry Schmidt

Any chance your oil pickup got bent in shipping? I can't imagine how else you got here.
All 911 oil pumps have a similar pickup location so it not a case of "wrong" part.

I'll talk to my shop guy, but it seems unlikely. I'd think it would be difficult to bend without some serious force.

Tomorrow I can check carefully to see if it is at all "tilted" with respect to the case.

EDIT: This photo seems to show it is quite straight. A bend would leave it tilted.

[Flat6pac]

For thin flange heat boxes, it looks like the new studs are too long, made for thick flange heat boxes.
Bruce

[Henry Schmidt]

Actually the pickup tube is fairly fragile. It could easily be bent in shipping.
The alternative is that the pickup tube was manufactured improperly. Given that the tube is furnace brazed to a flat flange, it is probable made in a jig. The thing about a jig is they are fairly consistent. It is possible that the venturi was brazed incorrect to the tube but same situation applies. Probably a jig.

If you get to the point where you take the engine apart, I can supply a factory pickup to replace yours.

Do you know about the largest river in North Africa?

[stownsen914]

The challenge you'll have even if you manage to re-shape the screen enough, is that you've only got ~7 mm of screen to venturi gap to play with, which is less than the ~.4" sump plate gap you need to make up to get it to seat on the case. The venturi will be essentially touching the sump plate and there won't be enough space for the pump to properly scavenge the oil. Damn.

[OsoMoore]

Originally Posted by stownsen914

The challenge you'll have even if you manage to re-shape the screen enough, is that you've only got ~7 mm of screen to venturi gap to play with, which is less than the ~.4" sump plate gap you need to make up to get it to seat on the case. The venturi will be essentially touching the sump plate and there won't be enough space for the pump to properly scavenge the oil. Damn.

Later this morning I'm going to call a couple of places that have what look like deeper plates, and ask them to measure theirs. Patrick Motorsports has a custom one. I'm also going to call our host and see if someone can measure their aluminum one.

[OsoMoore]

Originally Posted by stownsen914

The challenge you'll have even if you manage to re-shape the screen enough, is that you've only got ~7 mm of screen to venturi gap to play with, which is less than the ~.4" sump plate gap you need to make up to get it to seat on the case. The venturi will be essentially touching the sump plate and there won't be enough space for the pump to properly scavenge the oil. Damn.

The 10 mm (0.4") is from the screen to the case.
The 3 mm is from the venturi to case.

With the plates on: The curved plate w/out oil plug I've got now gives me about 3 mm gap, and the curved plate w/ oil plug looks like around 7 mm.

So we really can't give up much screen deformation (even if we could do that safely) before we hit the 6 mm gap minimum.

[OsoMoore]

PM emailed back:

Our sump plate is roughly 13.5mm deep, a little over 1/2". These were designed and made for the exact type of application you are referring to, as we often use the newer style or GT3 style oil pump in many of our engine builds.

[stownsen914]

Looks promising. How much deeper is that than the plates you already have? Sorry if I missed that measurement in your previous posts. I think the stamped steel plates might be like 1/4" deep? From your measurements, you need an additional .4" depth compared to you already have.

[OsoMoore]

Originally Posted by stownsen914

Looks promising. How much deeper is that than the plates you already have? Sorry if I missed that measurement in your previous posts. I think the stamped steel plates might be like 1/4" deep? From your measurements, you need an additional .4" depth compared to you already have.

Measuring from my case to the peak of the screen-cover was 0.4 inches.
The current plates I've got are curved and shallower, and have more curve than the oil pump screen.