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Who's running VW connecting rods????
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ideola  



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PostPosted: Tue Sep 11, 2007 4:31 pm    Post subject: Who's running VW connecting rods???? Reply with quote

On the subject of connecting rods, I noted that Dave Dennet's car uses VW connecting rods...this is (not coincidentally) the basis of the Eurorace stroker conversion. Is anyone here using those rods, and if so, do they have squirters????

I did a quick search tonite for the 1.8L vw golf connecting rod, and NONE of the photos I found indicate that these rods had squirters...
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924RACR  



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PostPosted: Tue Sep 11, 2007 9:46 pm    Post subject: Reply with quote

The squirter is more or less just a hole drilled through to the bearing area, right? Maybe could be done by a good shop???

Do your new rods have squirters?
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ideola  



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PostPosted: Tue Sep 11, 2007 11:02 pm    Post subject: Reply with quote

The squirter has chamfered holes and both ends, and has almost a "nipple" type arrangement molded in on the top side of the bearing housing at the base of the shaft. Furthermore, it is at a slight angle in order to spray the pistons, and not just hit the wrist pin. I'm not sure a simple hole drilled in the rod shoulder through to the bearing surface would be sufficient.

The new rods do not have integral squirters. There has been quite a debate on my "internals" thread regarding their function and necessity (feel free to ring in, Vaughan!). To summarize, Crower claims that integral squirters are so-called 24-hr idle squirters implemented by OEMs to cool and lubricate the piston / cylinder in the event that the car was left idling for 24 hours with no slosh to assist in lubrication. They further claim that while the design is common on many hi-po OEM imports (Japanese & European), it is actually a detriment on race applications because of the tendency to bleed off oil pressure. (I have since corroborated this claim with several independent sources at the local bookstore and some research last night on the 'net). The tendency of integral squirters to bleed oil pressure at low RPMs is why none of their off-the-shelf race replacements have integral squirters, because no one wants them. Bear in mind, unlike "sprayers" (see below), squirters have no check valve, and therefore squirt all the time; in a low pressure situation, it stands to reason that they would bleed off pressure; while not critical for a street application, in a find-every-HP-available application, it makes sense that this would be a concern.

As for having a shop drill a hole, I suppose it would be doable, but Crower advised against it, citing concerns over rod strength, presumably one of the main reason for ordering an expensive set of rods to begin with. They indicated that notching the flare at the top of the bearing opening would essentially act as a squirter, and was the preferred method.

Bear in mind, a squirter doesn't act like a "sprayer" setup; with a sprayer, there is what amounts to a combination check / pressure valve: a spring a ball bearing inserted into a nozzle. With a sprayer, the oil galley is tapped and threaded, and the sprayer nozzles is bolted to the block using a banjo bolt with the aforementioned check valve inserted through the nozzle. This allows oil to be sprayed only above a certain oil pressure, presumably under high load when cooling is most needed, and to avoid bleeding off too much pressure in low load situations. It also prevents backflow, although I can hardly see where that would be a huge concern.

Despite all of this, some of our board members have argued that due to the extreme angle of our motor, the likelihood that it produces less slosh, etc., the squirters are essential on our engines. I am still in a quandary right now. It would be interesting to know if the VW rods have squirters. I may give Jorge at Eurorace a call today. While the notching approach seems like it might work in principle, it has me worried about how it would work in the real world, plus I'm not excited about taking a dremel to my new rods. So far, what I've found on the sprayer topic seems to indicate that it would be a fairly simple and inexpensive mod. For example, there are a whole variety of OEM squirters available for <$10 each. It seems at this point that it is as simple as finding the correct mounting location on our block, finding a squirter that will fit without interfering with the rod or crank, and then tapping and drilling.

Until we can conclusively determine whether the squirters are essential or superfluous, it makes me nervous slapping together ~$5K worth of custom engine parts, not knowing what could happen if the squirters don't function. At this point, I would prefer to install sprayers if it can truly be done as inexpensively and easily as I think it can, and I'm counting on the notch-in-the-rod as the fall back plan.
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ideola  



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PostPosted: Wed Sep 12, 2007 9:19 am    Post subject: Reply with quote

I just got off the phone with Jorge at European Motorworks (formerly Eurorace). The VW rods do NOT have the squirters. He furthermore stated that back in the day when they were doing lots of 924 strokers that they NEVER had a problem with rods that didn't have squirters.
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Chrenan  



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PostPosted: Thu Sep 13, 2007 2:38 am    Post subject: Reply with quote

I am a bit surprised. Jorge knows his stuff, there is no doubt about that. I'd still setup some squirters, it can't hurt...
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ideola  



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PostPosted: Thu Sep 13, 2007 3:19 am    Post subject: Reply with quote

After two independent confirmations yesterday, I have decided that I will be cutting notches in both sides of the top of the rod journal area. No easy way to install auxiliary sprayers on our cars, and the notching approach is an accepted practice here in motown, with the added benefit that unlike our stock squirters, it will not bleed off oil pressure in order to squirt the pistons...it will simply take existing oil that is squeezed thru the rod bearing and fling it up onto the cylindar walls and piston underside via the notches.
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Rasta Monsta  



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PostPosted: Thu Sep 13, 2007 3:38 am    Post subject: Reply with quote

ideola wrote:
unlike our stock squirters, it will not bleed off oil pressure in order to squirt the pistons...it will simply take existing oil that is squeezed thru the rod bearing and fling it up onto the cylindar walls and piston underside via the notches.


Identical concepts, IMO.
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ideola  



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PostPosted: Thu Sep 13, 2007 3:50 am    Post subject: Reply with quote

Quote:
Identical concepts, IMO.

Please elaborate.

In the meantime, IMO, notches and squirters are not exactly identical.

The stock squirter "steals" oil from the bearing and journal due to the hole in the bearing and the squirter passage itself. This has the effect of bleeding oil pressure out of the bearing. This is the primary reason cited in all of the research I've conducted, including several one on one conversations with local builders, for eliminating the stock squirters: they indiscriminately bleed oil pressure.

The notches are simply taking whatever oil is normally being squeezed out between the bearing and the journal, and due to the orientation of the notch, flinging it up into the cylinder cavity. There is no add'l bleed in this case because the notch is simply redirecting oil that has already been forced out thru the bearing. That is how it was described to me by three independent and well-respected sources.

I respect your right to disagree, but in this case, while the concepts achieve similar results, I don't believe they are identical.
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Rasta Monsta  



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PostPosted: Thu Sep 13, 2007 4:03 am    Post subject: Reply with quote

The squirter hole "stealing" oil pressure from an isolated area in a pressurized system seems inconsistent with fluid mechanics to me. Isn't the hole just directing oil expelled from the pressurized area around the bearing, just like your notches?

Could be wrong though, it's happened before.
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ideola  



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PostPosted: Thu Sep 13, 2007 4:09 am    Post subject: Reply with quote

Well, I'm certainly no expert in fluid mechanics just repeating what I've been told during my research by people who are more knowledgeable than me.

But it sure seems to me that a pressurized system with a hole in it is going to lose pressure faster than a pressurized system without one...
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Rasta Monsta  



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PostPosted: Thu Sep 13, 2007 4:43 am    Post subject: Reply with quote

ideola wrote:
But it sure seems to me that a pressurized system with a hole in it is going to lose pressure faster than a pressurized system without one...


True enough, but I can tell you this, above 3000RPM far more pressure and volume are being bled off by the OPRV than through those holes. . .
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ideola  



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PostPosted: Thu Sep 13, 2007 6:15 am    Post subject: Reply with quote

No argument there...but high RPMs aren't when you're typically concerned with pressure bleed...it's at low RPMs when the bleed could cause the bearings to starve for oil. That is precisely why auxiliary oil sprayers (as opposed to integral oil squirters on the rod) have check valves built in...at high RPM, the pressure is enough that the bleed is of no concern. At least that's what I've gleaned from my research and conversations.
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Min  



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PostPosted: Thu Sep 13, 2007 8:03 am    Post subject: Reply with quote

So, planning on installing auxilary oil sprayers?

Min
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ideola  



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PostPosted: Thu Sep 13, 2007 8:11 am    Post subject: Reply with quote

Min wrote:
So, planning on installing auxilary oil sprayers?

No, not feasible from a cost perspective. I'm convinced that notching the rods will be sufficient, especially if I do it on both sides (the stock squirters are only on one side).
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Min  



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PostPosted: Thu Sep 13, 2007 8:29 am    Post subject: Reply with quote

ideola wrote:
Min wrote:
So, planning on installing auxilary oil sprayers?

No, not feasible from a cost perspective. I'm convinced that notching the rods will be sufficient, especially if I do it on both sides (the stock squirters are only on one side).


Ah, I was asking in reference to ones that would be used to oil cool the backs of your pistons at high rpm. Doesn't seem to be that big of a cost thing to me.

Min
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