piston squirter question
 

I have skirted around this q on another post but not really asked it so heres another thread. (sorry) i have pulled all of my 930 piston oil squirters and am looking to replace them but I have heard that there is a larger squirter that will give better cooling. can anyone advise me? is the larger squirter a straight swap or do you have to machine the case? and what model did the larger one come from?

Thanks,

Andy

It is either cyl 1 or 4 or both in a late model 3.6 or TT that have a larger orfice probably to equalize pressure to all squirters. I think the increase is in the order of .25 or .5 mm
Best regards

Hey Andy do you have a pic of the pistons you bought from me? I would like to show someone the coating on a porsche piston. Mine are coated but in the box at my mechanics shop:)

Thanks!

Eric Hood

hi Eric, yes I have, they were 'as is' and so a little dirty nut you can see the difference in colour Ill dig it out and send you it.

Andy

eric, i sent you an email. Can anyone else help with my squirter q?

Andy

anyone? please? go on........you know you want to........................just a little bit of info for a skinny english man...........


Andy

Andy, 993tt squirters are what you want...did you email Stephen?

gonna give him a ring in a while, thanks eric.

Can you change the piston squirter or bore them out doing a top end rebuild?

Andy, I'm interested in what you learn about the piston squirters too. Any word yet?

Yerman, I would be real carefull if you are going to attempt this and aren't going to split the case. Drilling them out causes lots of metal bits to fly around (not good for the bottom end). simply pulling them with a slide hammer is a better option if you aint going to split the case but I didn't manage to get a single one out with the slide hammer alone and on top of that problem there is still the chance of getting some bits of metal from around the squirter in the bottom end.

Andy

Hi Rob, I spoke to Stephen at Imagineauto (very very helpful) who advised me to use the 993t squirters which have a larger flow rate. the oilway needs drilling out to accept the new larger squirters. dont know by how much but im sure it will become obvious when I get my hands on some. one issue i have with them is that there is two sizes-22mm and 33mm. thats the only bit i don't get! ill let you know if I find out any more.

Andy

Thanks, Andy. I may do some research too. I'm at the stage where if I'm going to make the switch, now's the time. I'm not sure about the 22 mm or 33 mm numbers. Somewhere in my mind I believe I heard that the early 911 squirters were 1.0 mm in dia (the orifice); 930s were 1.5 mm and 993TT were 2.0 mm. But that could be complete bunk. No dimension could be 22 or 33 mm, unless the decimal point is missing. Have you checked the PET CD? That may be where I'll start. Do you get the impression that all 6 squirters are (supposed to be) the same, or is there some difference cylinder to cylinder, as stated by racing 97?

Rob, I think the 22 and 33mm dimention is for length. As for same/different size orifices-don't know. I didn't ask Stephen when I spoke (always forget to ask something!) but Im sure that if there was a need for a mixed set of squirters to equalise pressure then he would know about it. I spoke to a porsche GB tech yesterday and they are sending me a fax with some details on squirters so Ill keep you posted. let me know about what you find on the PET


Andy

Anyone familiar with the oil passage modification?

And are the 1.0-1.5-2.0 mm sizes correct as Rob stated?

Souk, Im thinking that the oil passage mod is simply a bore out to accept the new larger squirter but I may be wrong. When I spoke to Stephen (imagineauto) he was just talking about reaming out the hole and fitting the new squirter. he said that if I had managed to get the old ones out then I should be able to deal with putting the new ones in. Christ! no pressure then!

Andy

I'll have to give Stephen a call. Thanks.

Let me know how you get on Souk

Andy

Souk, did you speak to Stephen?

Andy

Andy, I was planning on a Monday call. I'll post my findings.

Cheers Souk! By the way, you might want to ask him if he knows the difference between the 22mm squirters and the 33mm ones. the guys at porsche GB didn't know, maybe he will!

Andy

Will do Andy.

Souk, any news from Stephen?

Andy

Andy,

Here's what I got from the PET parts CD. It shows that for a 78 930, the "splash valve" has part number 930 101 015 00. There's a different part number for the 911 SC from that year; it is 911 101 011 00. There's no reference to orifice diameter or length. Then, for the 89 930, it shows the same part number as for the 78 930, but there's also an "oversize" splash valve with the part number, except the last two digits are 50. I'm going to guess that it is of a larger diameter, in case the case hole becomes enlarged (but it's only a guess). Again, no reference to length or diameter. Then, for the 94 964, the splash valve is part number 964 101 020 00 with an oversize version ending in 50. Finally, for a 97 993, there are four parts shown: the two with 964 part numbers as above, each saying "22,5 mm" and two with 993 numbers: 993 101 018 51 and an oversize version that ends in 60. Both of the splash valves with 993 numbers show "33,5 mm" which, as you suspected, may refer to the length. I haven't had time to dig any deeper (say, by calling a dealer), but that's what I've learned so far. I'll be interested in what you and Souk can add to this.

Rob

Rob, my local porsche dealer parts guy sent me this copy of a manual. its for a 993 carrera but it gives some good advice on pulling them/re fitting them. I havn't got any more info on big/little squirters though. maybe souk can shed some light once he's spoken to Stephen at imagine auto

Andyhttp://forums.pelicanparts.com/uploa...1110323829.jpg

Gang,

I did speak to Stephen…first…what a great guy! Very honest.

Here is the deal, the 993T squirters are longer and have the 2mm orifice, and the oil passage modification is simply to bore the squirter holes deeper to accept the 33 mm long squirter nozzles of the 993T. The modification is actually fairly simple, get the 1mm squirter out and bore deep enough so that once you tap the 33mm squirters into the case they are just about flush (below flush). You then tap/stamp/chisel (peen, as in the instructions above) the metal surrounding the squirters so that they don’t come out of the case when the engine has pressure. It is important to have an interference fit for the squirters.

Someone asked me about running without the squirters at all. NOPE! Not possible unless you modify things to maintain pressure at the bearings. When I heard about the no-squirter option and coupled with my reading of this thread, I assumed the oil passage leading to the squirters were 1-2mm. Given that assumption, the squirters were then assumed to only provide spray pattern or direction…nope!

So, looks like running the 2.0 squirters is the way to go on a very hot engine. I wouldn’t want to do this mode unless I split the case. I wouldn’t want to do anything to the squirters w/o splitting the case.

Hope that helped.


Nice picture Andy...it's going in my file!

Souk and Andy,

Great info. Thanks also to Stephen.

Several questions remain in my mind, if anyone can help, including some pretty basic ones. Standing back from the details for a moment: Is the function of the squirter to cool the piston crown, or is there a (greater) need for lubrication in the cylinder? Where does that oil go? Wouldn't it be burned in the combustion chamber? (Do you really want a big stream of oil spraying on the piston and being burned?)

Then the more specific questions: Is this worth it for a big power turbo motor? Under what circumstances would be beneficial? Does the larger orifice of the 993TT squirter cause any issues with oil pressure being diminished? What about the original discussion suggesting different sized orifices in different locations in the engine? Is the best plan to use all 6 993TT squirters (all with the largest orifice size of 2 mm)?

Cooling is the primary reason for the squirters but they do provide lubrication as a side effect. If the piston only needed lubrication the oil flung off the crank would be enough.

There is not a big oil buring issue since the squirter is aimed at the bottom of the piston so much of the oil does not end up on the cylinder walls. If it did it might be too much oil for the rings to deal with.

I believe the original 930 squirter was the same used on the 935 so I am not that concerned about the bottom of the pistons needing more cooling oil.

I am concerned about head temps so I have opened up the oil holes in my cam tower spray bars just a smidgen.

I, too, have heard varying opinions on whether the original 930 squirters provide enough cooling for a modified 930 motor. Some people think so, others not. I'm thinking at this point I'm going to leave mine alone, but I'm glad to know how it should be done, if I change my mind. I agree that with larger oil squirters, there shouldn't be much more oil that ends up in the combustion chamber, but it seems that to spray at the piston, even from below, is asking for some increase in oil consumption. Any concerns about diminished oil pressure from the larger orifices?

I'd be cautious about enlarging the cam spray bar oil holes. I wouldn't think that more oil through the cam spray bars would have a very noticeable effect on head temps. Oil temp and head temp are not very closely related from my experience, plus, what little oil gets near the head doesn't look like it it's in a location that would carry away very much of the heat. It appears that oil in the cam carriers was intended to lubricate the cams, not to cool the heads. Interestingly Porsche changed to cam oil line restrictors in the later cars that limited the amount of oil to the cams, reportedly to reduce oil foaming in that area and to increase oil pressure at the bottom end. What you're doing is moving in the opposite direction from the factory research on this.

Porsche engines aren't just air cooled, they are air AND oil cooled. If memory serves me correctly something like 40% of the heat generated in the engine is carried away by the oil and the remaining 60% is handled via the cooling fins. The spray bars in the heads supply much more oil than what is required to lubricate the valve train for this very reason.

The restrictors might be fine for a low output 911 motor but if you are boosting your power output it only makes sense to do what you can to eliminate heat from the heads. On the exhaust side of the head the oil is critical for carrying away heat. Foaming is a non issue with a quality oil and I never had oil pressure problems without the restrictor.

This has been hashed out over and over. See this:
Cam line restrictors

My point is only that by drilling out your cam spray bar holes, you are going opposite some of the sentiment and research on this issue. You can see that the restrictors are controversial, but they were used by the factory on the 965 and no one has suggested that the cams and cam boxes need *more* oil than the stock setup.

But we're getting off the track here...

A 965 is not a 930 and I only increased the size by about 8%.

If you think that no additional oil could help a high performance motor why are you curious about the need for larger piston squirters?

For all practical matters related to this issue, such as internal oiling, a 965 (or more accurately a 964 turbo) has the same engine as a 930. And if you go to buy cam line restrictors now for your 930, 964 turbo, or any 911, you will get the new, smaller-orificed versions that debuted with the 964 turbo. So, for all the reasons stated in the thread I referenced, there is a move to reduce oil to the cam tower area, ostensibly because of significant studies conducted or endorsed by Porsche. But as I implied, I'm a bit skeptical of the concept. I'm not suggesting that less is better in all situations, and neither you nor I know all that is necessary to make such a decision. My only point here, as I have said several times, is that I would be very hesitant to assume that drilling the spray bars to a larger orifice is a good idea. Based on the available data, it seems not only that it might worsen the potential oil foaming that's apparently been documented, but worse, it may compromise the oil pressure to the lower end of the engine, where you'd least want to have a problem.

Now back to piston squirters:

I'm curious about larger piston squirters because I'm building a high horsepower 930 engine that will run on the track, and I've heard that some people recommend them for that application. I've also heard some people say that it's not worth it. I haven't heard anyone say that they may be detrimental, and I'm looking for counterpoints just for that reason. Obviously, they work well for a 993TT, but I don't know what other oiling differences there are between my engine and a 993TT, so I can't assume that they will work well for me. I said above that I'm leaning away from using piston squirters, but I'm interested in exactly how to do it, should I decide to do so (thanks to several people above, that's now handled) and I'm interested in healthy debate over whether they do any good (or cause any potential harm) for this application. I'm concerned, as I said in an above note, that the larger orificed piston squirters may compromise oil pressure in the engine to some degree (though maybe not significantly), and they may have other detrimental effects. But I have no idea, and I thought it would be good to throw it out to the Pelican world and see what comes back.

Nice one Souk, Stephens a great bloke. very aproachable and very knowledgeable (did i spell that right?!) Rob, I read somewhere that the oil squirters acheived a reduction in head temp by 50deg. thats excellent. So what Im thinking is by using the cam line restrictor I would effectively be pushing a little bit more pressure to the bottom that I could put to good use by using the larger squirters for a slightly better cooling effect. after all everyone go's on about how the backbone of the whole turbo thing is removing heat from the combustion chamber/piston crown to avoid detonation. Im hoping that by moving a slightly larger volume of oil over the underside of the piston I will reduce that head temp a little more. for what its worth, my squirters came out real easy with about half a dozen pulls with a slide hammer and a no10 wood screw (after drilling them out first)

im off to get some 993tt bits!

Andy

Good luck Andy...post some pix when install the new nozzles.

will do

Andy

Don't forget that a 965 has larger pistons than a 930, so it would make sense that they might have larger piston squirters to deal with the additional piston area that would need to be cooled.

With the larger case squirters and a same sized oil pump as the 930 (I assume) it would make sense that they might use a head oil restrictor due to the additional volume being passed by the bottom end.

The main point I am trying to make is that just because it was a changed part on the later model motors is not the same thing as an 'upgrade'.

The restrictors may be directly related to the later model piston squirters which may be the direct result of the larger bore size of the 3.6 and 3.8 liter motors.

The bottom line is that as long as you can maintain adequate oil pressure you should send the oil where you need it. Its a fact that head temps need to be kept in line on high performance 911/930 motors and there is not much you can do on the air cooling side but there is something you can do on the oil cooling side.

IMHO restricting the flow of cooling fluid to the head is not the right path to take on a 930 motor.

No, they're the same -- 97 mm 3.3 liter pistons. The main difference was that the cylinders were fully finned, and there was a gasket difference at the base, I believe.

I'm not sure the 964 T had larger case squirters. Do you know if that's true? I don't think so. But the cam line restrictor was imposed by Porsche for all 911 engines back to 1965, starting recently. You can't even buy the original cam line fitting anymore. (So I've been told; I haven't tried.) I have no idea if more oil is being passed by the bottom end of a 964T, but I doubt it.


No, it's not an upgrade at all -- it's much more than that. It's a retrofit. It's a superseded part. You can't even get the old cam fitting with the big hole in it anymore. Porsche has made the decision that the new cam line restrictor is the proper part for all air cooled 911s back to the beginning of time. I know, it's strange, but that's what's happened. Check it out. I bought a set, just to see them, but I'm not going to use them. They only cost about $7.00 each. They can be distinguished from the original cam line fittings by a circumferential groove around the hex head.

The main point I'm trying to make is that I'd be cautious about drilling out those spray bar passages. I don't know anyone who's ever done it, and as an engineer, I know how much work it would be to understand all the effects before I felt comfortable making a change like that. Empirical data is the only way to verify it. Unless you have some, I wouldn't assume "more is better" in that location. There will be tradeoffs, as with any change. I just don't want you to hurt all that beautiful work you've already done. And I wish I had your machining abilities...

Nope. It's been universally adopted by Porsche for all 2 liter to 3.6 liter engines. (Again, I'm not saying I like the restrictors or will use them, but this is what has happened. Frankly, I find it amazing that after 40 years of production, Porsche is making a fundamental change to an engine oiling system part from 40 years ago.)

I sort of agree. The problem is being sure that you've maintained oil pressure properly. The gauge is a good start, of course. I'd just hate to build the engine a certain way, with deep internal changes, and find that the oil pressure is lacking. Plus, according to Porsche, there was an issue with oil foaming when too much oil ended up in the cam boxes. This is harder to assess than oil pressure. I just don't trust myself to be redirecting oil within the engine without some verification that it will do what I want it to do without doing something that I don't want it to do.

Well, thank you for the info Rob. And all this time I assumed that the 3.6 motor had a larger bore. My bad.

I Know I am taking a small chance with the spray bars but I am confident that it will not be an issue. If I am wrong it won't be that hard to pull the towers and put in a new set of bars.

The main reason I drilled them in the first place was due to the fact that one hole was boogered half way closed from the factory, mostly likely from when they were inserted into the head since the bars are pretty soft aluminum. The hole in question was for one of the rockers and I could see how there were lubrication issues in the form of mild galling. There were other holes that were far from a consistant size too.

The closest drill I had was just a tad larger (~0.001") so I decided to take my chances for the sake of head cooling. To avoid another boogering incident and slightly fan the oil spray I have also added just a bit of chamfer to all the holes.

I am sure that the increase in hole size is not going to deprive the rest of my engine of oil and as I have said before, a good oil should not foam just by spraying onto a valvetrain.

I don't even know why people want to blame oil foaming on the valvetrain when the scavenge pump is more likely to foam the oil than a spinning cam followed by over a foot of drainage could.