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HiCam Oil Pressure, Gross Stupidity and why you should always listen to Chuck


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This is a long sad saga on how one person can be so stupid and how you should always listen to Chuck. I purchased a low mileage Australia 98 from Japan a few years back, HiCam engine and running

Well bet you were all thinking this was dead and gone. So after removing my OEM V/V with Griso spring to try to lower the presssure a little I then couldn't get the valve to seal well  again.

Here is what happens when the engine was run with the Griso spring in  

Posted Images

Damm I meant to say on the video if anybody is contemplating this as a mod, what I didn't realize at the time was that there was 3 mm spacer jammed into the top of the valve as a shim. Like the dope I am I completely missed it and only found out about it later when messing with the valve again

So the valve had the 1mm crush washer installed on the outside at the top of the valve which reduces the spring tension and a 3mm shim on the inside of the top bolt which increases the spring tension. If installing without the crush washer (which IMHO isn't necessary) I'd start with a 2mm washer/spacer.

As Phil pointed out, and I found out, the only sure fire way to reliably determine the lift pressure is to use an oil tester. I've been using air and found that the valve lifted approximately 10psi earlier than when actually tested on the cranking/running engine.

Picture of the valve to make things a little clearer

ACtC-3dqJk-QAWQ_MOGrDyzETSTTc4VHR859fCYJ

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9 hours ago, Weegie said:

Damm I meant to say on the video if anybody is contemplating this as a mod, what I didn't realize at the time was that there was 3 mm spacer jammed into the top of the valve as a shim. Like the dope I am I completely missed it and only found out about it later when messing with the valve again

So the valve had the 1mm crush washer installed on the outside at the top of the valve which reduces the spring tension and a 3mm shim on the inside of the top bolt which increases the spring tension. If installing without the crush washer (which IMHO isn't necessary) I'd start with a 2mm washer/spacer.

As Phil pointed out, and I found out, the only sure fire way to reliably determine the lift pressure is to use an oil tester. I've been using air and found that the valve lifted approximately 10psi earlier than when actually tested on the cranking/running engine.

Picture of the valve to make things a little clearer

ACtC-3dqJk-QAWQ_MOGrDyzETSTTc4VHR859fCYJ

Excellent work John, but just 1 amendment for clarity so people using this as a resource in the future dont get confused. You have the plunger the wrong way around. The protruding nose on the plunger engages with the spring and the cylindrical body of the plunger slides into the outer body.

Ciao 

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10 hours ago, pete roper said:

Sorry John, I completely forgot about the oil cooler and have been tied up with a heap of other stuff. Mea Culpa. I'll try to get if off today.

Not a problem Pete at the moment I've got the small Setrab on it with Dash 8 lines and full flow fittings. On the video you can here me say I got a leak, need to run it again to see if I've managed to sort it. With the larger diameter lines and full flow fittings, the lines immediately started to warm up, something that isn't nearly as noticable with the standard set up. I think that could be due to the OEM banjo fittings introducing pressure losses and restricitng flow to the OEM cooler

Let me know postage costs wouldn't want you out of pocket

There was also a leak coming from somewhere on the engine but I'd be dammed if I could find it. It was getting onto the spine frame and running down it then dripping at the Gbx end cover. I think it was coming from the dizzie blanking plate which on the HiCam carries the two head return lines to the crankcase (or are they breathers?). When I took the airbox off to look, I was expecting oil everywhere but virtually nothing..................go figure

Going to remove the airbox and run it again to see if I can pinpoint it.

I'm as bad I need to contact my painter about these Magni decals, I've not heard a thing from him.

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11 hours ago, Lucky Phil said:

Excellent work John, but just 1 amendment for clarity so people using this as a resource in the future dont get confused. You have the plunger the wrong way around. The protruding nose on the plunger engages with the spring and the cylindrical body of the plunger slides into the outer body.

Ciao 

Yeah I did say something about that in the photograph notes Phil but probably not clearly enough, so thanks for pointing it out again to ensure anybody looking at this doesn't get confused.

John

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13 hours ago, Lucky Phil said:

Excellent work John, but just 1 amendment for clarity so people using this as a resource in the future dont get confused. You have the plunger the wrong way around. The protruding nose on the plunger engages with the spring and the cylindrical body of the plunger slides into the outer body.

Ciao 

Is this relief valve identical in the V11 motor?

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1 hour ago, docc said:

Is this relief valve identical in the V11 motor?

Yes docc, identical in construction and detail . The Daytona/Centauro is "rated" at 5 bar instead of the 3 bar of the V11 but in reality seems to provide the same pressure as the V11. I think for the 8 valve engines they just added a few shims to preload the spring a little more and called it good. As John has tested now the Griso spring ups the pressure a healthy amount which is good for the 8 valve motor but probably not necessary for the V11.

Ciao

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Phil is the rating not 4 bar?

The actual pressures I converted from the manual which aren't measured in bars but kg/cm^2 for the 2 valve sporti was 3.8-4.2 (56-60psi) and 5kg/cm^2 for the HiCam (70psi)

I'm guessing here but I'd have tought that the V11 would be the same are the Sporti 56-60psi

The problem is only related to the HiCam, with the valve set for 56-60psi the valve will choke cold oil idle and typically a 2 v/v engine will idle somewhere between 60 and 65psi

The HiCam has a large oil flow to the heads so the valve has to lift less to drop the oil pressure more, so despite the higher setpoint (which I'm unsure was ever set at the factory) the HiCam at cold idle will register 50psi.

The 2 v/v engines are much more tolerant to relief valve leakage and these valves seem to work just fine.

I don't know the effects of upping the pressure on a 2 v/v engine would be, but I don't think there would be any benefit. Given they run just peachy on the 60psi setpoint, it would seem a bit crazy to start messing with them

 

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10 hours ago, Weegie said:

Phil is the rating not 4 bar?

The actual pressures I converted from the manual which aren't measured in bars but kg/cm^2 for the 2 valve sporti was 3.8-4.2 (56-60psi) and 5kg/cm^2 for the HiCam (70psi)

I'm guessing here but I'd have tought that the V11 would be the same are the Sporti 56-60psi

The problem is only related to the HiCam, with the valve set for 56-60psi the valve will choke cold oil idle and typically a 2 v/v engine will idle somewhere between 60 and 65psi

The HiCam has a large oil flow to the heads so the valve has to lift less to drop the oil pressure more, so despite the higher setpoint (which I'm unsure was ever set at the factory) the HiCam at cold idle will register 50psi.

The 2 v/v engines are much more tolerant to relief valve leakage and these valves seem to work just fine.

I don't know the effects of upping the pressure on a 2 v/v engine would be, but I don't think there would be any benefit. Given they run just peachy on the 60psi setpoint, it would seem a bit crazy to start messing with them

 

1 kg/cm2 John is .9806 bar so close enough for me to 1/1. Mine has a "5" stamped on it but produced closer to 3-4 on the bench, for what air testing is worth. Truth is that both engines will survive happily on 50-60 ish max as road engines. If I was racing one and it was turning 6-9000 rpm most of the time I'd think it was prudent to go to the Griso spring for a little head room at the top end.

The path down this oil pressure black hole,lol which has opened up a whole lot of interesting learnings and knowledge which I genuinely enjoy originated when you had a LOP indication in traffic due in part to high oil temp. So the major issue here is to get some head room at the bottom end for hot traffic conditions so you don't get into the uncomfortable position of the oil light coming on in these situations. Not that it's a big issue idling because you can verify things are ok by a blip of the throttle and if the light goes out then all is fine. Even at the 4 psi LOP light switch threshold you'll have enough oil pressure at idle.However it is not something you want happening to distract you in heavy traffic. The easiest solution for the low end pressure is to run a XXW-60 oil at the upper end of the grade tolerance. The other pathways are the Griso spring which seems to work or in your bikes case to try and keep the oil temp down which is mainly due to I believe the full fairings it runs, something you are working on.

For V11 owners all this info could still be useful at some point if you have oil pressure issues or questions. Personally the std V11 system seems adequate to the task but a higher rated oil pump and/or a Griso spring would be a nice upgrade to provide plenty of pressure head room esp for the later models with the oil squirter holes for the pistons.

Ciao

      

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This is awesome John truth be told I thought the pump was the problem just figured sloppy cut-off point for the gears in the housing. Hey I thought the relief vale was only along for the ride. I don't want to worry you but you are dealing with systems here and changing one thing effects a whole lot of other things. Not trying to put a spin on your work I plan to follow in your footsteps. I'm can't think for the life of me why Guzzi didn't do something with this. I mean as a manufacturer they would have a vast amount of data to look at. 

What weight of oil were you using for your test? Here is a crazy idea if the spring controls pressure switching to a lighter wt oil might increase the volume of oil as a cooling media (might also take your oil cooler). You might lose a couple psi but gain a little horsepower over a 60 wt oil

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Hi Kevin

We did chat briefly on PM if remember correctly. It all seems so bloody obvious doesn't it when it's laid out and if I had listened to @Chuck I could have saved myself 2 years (or more) worth of fruitless grief & pain. He initially pointed me on the right road on WG a long time back.

Like you I thought the problem was pump or leak releated. I started down this road for the reasons Phil pointed out on the post above yours, convinced the temp and pressure problems were related (the jury is still out on that). As far as low pressure it just didn't click that the relief was the culprit, due in part to my experience with the 2v/v engines (Big Mistake!!).

It all really started to make sense when @Lucky Phil started to intervene and the majority of findings were down to his engineering ability. Starting with his engine build thread, then his experiment with the over enthusiastic relief spring and then another buddy with a HiCam installing a pressure gauge. The results obtained all pointed to 50psi being a standard cold oil pressure. Following conversations on PM with Phil he patiently pointed out what was happening one step at a time. I'm really grateful to him and so should anybody else with a HiCam who wants to sort it.

Joe Caruso also provided me with some eye opening data on the pumps and a lot of assitance (you'll not meet a nicer guy than Joe)

So to get to your questions, so far I'm testing on a 15W 50 full synth, Motul 300V.

There isn't so much changing in the systems as far as I'm aware. The bike has the Caruso pump and gears, but has had these since the problem started. The only other change is I've taken off the OEM cooler and installed a Setrab 13 row, it's actually smaller than the original but has full flow fittings and Dash 8 hose to and from the tapping points on the broad sump. Tests there showed the same cold oil pressure before and after install. I'll need to get the bike out on a shakedown run to tell if the cooler has made any difference. From looking at the OEM install though I "think" these banjo fittings must be introducing significant pressure losses across the cooler, which won't help the amount of oil going through it. The rest of the system is fixed pressure drops being controlled by the available areas and pathways the oil has to traverse.

Once the relief is removed and tested it's obvious where the problem is, testing it on air (or preferably oil) will highllight it.

The Griso spring was Phil's suggestion, all I've really did is to provide a test bed and do some donkey work. Which was Ok as the bike was partially disasembled anyway.

I'm at a bit of a loss on your suggestion to run a lighter weight oil, so forgive my ignorance. Generally these engines run on the hot side and even at 80C on a 50 weight at 4k RPM the pressure with the relief closed is 72-74 psi. I expect that during normal running the actual oil temperature would be 80 at best and perhaps 90 or in excess of 100. I'm in agreement with Phil that if I change oil grade it would be better to move to a higher weight to maintain viscosity at the higher temperatures.

John

 

 

 

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Oh @Kevin_T to also answer your question on why Guzzi didn't do it from the get go.

I can only surmise, but Guzzi were not in a good way during the 90s and could barely keep their head above water, the situation getting worse as the 90s went on and into the early turn of the century.

I think they were desperate to get a new model out and increase sales. The HiCam engine was not a well developed product, it was a race bike engine to which the minimal of changes were made to make it just about suitable as a road machine. There are many flaws in the design which were probably only really seriously addressed when the MGS-01 was designed. It probably wasn't perfect either, I don't know enough about it. The MGS heads and oil flow to the heads are different in many aspects.

Back to the HiCam, for goodness sake you need to remove the service shaft pulley to change the belts on the OEM design. You'll hear Chuck often comment that the only reason they assembled the Centauro was to make sure you got all the parts.

The relief valve is probably only one of a long list of things that should have been sorted. They either found or thought that with the increase in oil flow required they'd just make the pump bigger, leading to the "grenade with the pin pulled" pump design and shim the exsiting spring in the relief valve to increase the pressure setpoint and that would be that.

What I found when I swapped over the 1100's relief valve which is set 10-14 psi lower, there was no change still the 50psi cold oil idle. That leads me to think the spring in that valve although working well with the 2v/v engines is unsuitable for the HiCams. At 50psi the pressure is below both the 2v/v and of course 4v/v setpoint. I suspect (but don't know) that the spring is too soft and the valve is partially lifting. That's been proved through Phil's rather over enthusiatic spring holding the valve shut and seeing system pressure build to way in exceess of that required on cold oil. It can also be seen on my engine run test with the Griso spring earlier in the thread as well, where the pressure holds 82 on the relief valve setpoint.

The Griso spring though shorter is stronger and heavier, holding the valve shut, the valve still passes but not nearly as badly as with the OEM spring. From my rather limited engine run you can see how much more positive the relief valve action is. Rather than the valve floating slowly open on the OEM spring, the pressure rises until 82psi (that I had as an aribitary setpoint) then "Boom" the valve opens and you can see the gauge fluctuating in response to the valve chattering, constantly opening and closing at its designated setpoint.

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21 hours ago, Kevin_T said:

This is awesome John truth be told I thought the pump was the problem just figured sloppy cut-off point for the gears in the housing. Hey I thought the relief vale was only along for the ride. I don't want to worry you but you are dealing with systems here and changing one thing effects a whole lot of other things. Not trying to put a spin on your work I plan to follow in your footsteps. I'm can't think for the life of me why Guzzi didn't do something with this. I mean as a manufacturer they would have a vast amount of data to look at. 

What weight of oil were you using for your test? Here is a crazy idea if the spring controls pressure switching to a lighter wt oil might increase the volume of oil as a cooling media (might also take your oil cooler). You might lose a couple psi but gain a little horsepower over a 60 wt oil

The idea is to run the least pressure you realistically can to provide lubrication and cooling to save power and also give better fuel economy. This is why the latest cars in the US especially tend to run 20 weight oil like 0W-20 to meet the government regulated fuel economy targets. Less pumping losses equals better fuel economy.The same applies to a Guzzi engine except being an old air cooled design it needs a heavier oil but the same applies it's just it happens to be at a different level. No point creating more oil pressure than you can use.

High oil pressure isn't always desirable as it generally indicates a lower level of flow(pressure is just the indicated difference between the amount delivered over the rate of leakage) and you need flow to cool things like plain bearings. This is part of the reason you run wider bearing clearances in a race engine, to increase the oil flow through the bearing to aid cooling for a bearing now operating at an increased load for longer duration.

In the case of the Guzzi 2 valve and even more distinctly the old 8 valve models that have extra leak paths through more bearings and run hotter is that you are trying to balance out all the variables including the complication of air cooling. So running a 60 weight oil itself isn't particularly desirable as it reduces flow through the main and big end bearings however it has the advantage of having a higher load carrying capacity and props up the minimum oil pressure when the conditions get extreme for an old air cooled engine in high ambient conditions and heavy traffic. Its a balancing act, does the engine need the extra load carrying capacity of the 60W? I doubt it but in some cases it needs it at the other end.So basically for an old air cooled Guzzi you need an oil that will provide around 10psi/1000rpm oil pressure (although for a road and even some race engines you can get away with considerably less) and also hold up enough pressure at the idle end to keep the LOP light off. My 2 valve angine always ran on Mobil1 0W-40 oil and never had an issue with the oil light at idle and I know it had enough pressure at the other end because it never blew up,or made metal LOL.

My Daytona engine with the std spring makes 58-60 psi hot max and around 32 psi hot on 15W-40 oil. Both ends are adequate, the top end max could be better but its not going to be an issue. To get the top end better I have a choice, either a heavier oil or the John ratified Griso spring. For the moment its the heavier 10W-60 oil but further down the track when its convenient I may just update to the Griso spring and lighter weight oil.

Ciao         

     

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