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 Post subject: Re: Our little cultus racer
PostPosted: Sat Jun 01, 2019 6:54 pm 
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It'll be interesting to see what your engine builder reckons for cams and lifters. As far as I can see there aren't a lot of options left for cams. CatCams still list billet cams but I can't see many other options. Lots more options for solid lifters depending on how the clearance is set and the clearance required. I guess there's also the option of running larger and longer valves from something like a Honda D series and using shorter Toyota solids. The valve springs are a problem beyond 10mm lift so longer Honda valves might help with that. I'm guessing it may be possible to run Honda springs as well.


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 Post subject: Re: Our little cultus racer
PostPosted: Sat Jun 01, 2019 7:15 pm 
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well we won't race tomorrow. :evil:
F$%^ing oil pressure heading south again.....rrrrgh!!!!!! over it.
something is up with that motor....I reckon its in the head.....thse bloody hydraulic lifters etc.
down to 51 PSI on my gauge which is less and more accurate on the link of around 45 psi at WOT....so stopped. Took the accumulator and oil cooler out of the system...fitted oil filter direct to the engine...tested at home....ran it till oil temp up.....30 psi hot idle....ok but down from before....rev to 4000 and straight up to 50 psi....rev to 7000 rpm...virtually no oil pressure change....what the F### is going on with this thing!
Motul 10w40.


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 Post subject: Re: Our little cultus racer
PostPosted: Sat Jun 01, 2019 8:10 pm 
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Well I guess the positive is that you've still got reasonable pressure so hopefully it won't be too bad to sort out. It's hard to know whether the lifter noise is the cause or a symptom. There's quite a few potential causes from oil pump, pressure relief, crank bearings, cam bearing clearance etc so you need to work out where the pressure is going. I guess it needs to go back to the engine builder.

At least it hasn't failed completely so it should make it easier to identify the cause and work out why.


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 Post subject: Re: Our little cultus racer
PostPosted: Sat Jun 01, 2019 8:25 pm 
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Not telling you how to suck eggs - had a look in my manual, says to run 5W-30 with oil pressure 51.2-62.5psi @ 3,000rpm. Over pressure valve should open at 65psi.

Race engine builder would know best I suspect.

Did you shake the bottle well before using? :p

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 Post subject: Re: Our little cultus racer
PostPosted: Sat Jun 01, 2019 8:48 pm 
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thanks guys...

yes...i have the book figures but as the engine builder points out...

mother going to pick up bread at local supermarket....3000 rpm....50 to 62.5 psi....normal. 5w30...all good.

Glenn or Nick trashing little motor at 8000 rpm at 45 psi.....going to cost a lot. plus 5w 30 too thin.

bearings are new...mains and big ends...line honed mains...bmw studs....excellent oil pressure after build...brand new Japanese aisin g13B pump....no issues on track....now tappy lifter....pressure reducing....dont think its the bottom end somehow....I read a forum somewhere where a guy was pulling his hair out over low pressure...ended up changing the head...problem fixed....had done EVERYTHING else before that...G13B. maybe my cam clearances are crap...perhaps the lifters are shot....perhaps the clearance on the lifter buckets to the head are sloppy.

Im at the point of giving up....three engine builds is going to beat me. no money left in the kitty for this. wifey not happy. I cant catch a break with this motor.

plus we hit the kitty litter today....minus one nice front carbon splitter.....so im pretty pissed off at the mo with all this.


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 Post subject: Re: Our little cultus racer
PostPosted: Sun Jun 02, 2019 2:11 am 
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Hey, before my rebuild, my oil pressures after multiple laps would drop down to 5-10psi on idle. I never bothered with it because I was going to rebuild. However the engine still made good power.
After the rebuild, surprise surprise, oil pressure is still very low when my oil is about 220f, I use 5w40 oil. If I were you I would do a compression test tk see if you've lost any. I am due to do one myself


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 Post subject: Re: Our little cultus racer
PostPosted: Sun Jun 02, 2019 7:07 am 
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Hey I haven’t lost power.....compression check won’t help with oil pressure loss.
I’m not worried about idle oil pressure.....even 25 to 30 is positively excellent. The pressure rises quickly to 50 with a small blip.....the problem is it stays there....which it did not do at the start....we got 60 down the back straight hot in the summer.....now cold in the winter same straight 50. We have lost 10 psi and it levelled.....chis said the link ecu actually reported 43 psi. Which used to be 55. A worrying trend. Last time I ignored tell tale signs......kaboom. You get it. It’s telling me something.....I must listen. Two bob to a rotten gooseberry it’s in my head....literally.


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 Post subject: Re: Our little cultus racer
PostPosted: Sun Jun 02, 2019 7:23 am 
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I suspect you can be pretty certain the problem won't be worn cam journals or tappet bores. They're problems with worn engines at accumulate over time. If it's gone from 55 to 43psi in the matter of a couple of hours. You'd also expect the engine builder to have measured the cam clearances.

I guess it might be worth trying an oil change and getting rid of the additive before you start pulling things apart.


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 Post subject: Re: Our little cultus racer
PostPosted: Sun Jun 02, 2019 7:32 am 
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Done that Sam....it’s got 10w40 in it same as before....additive drained out.
Taken everything off front of motor put filter directly on front of motor....that’s what I did last night....


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 Post subject: Re: Our little cultus racer
PostPosted: Sun Jun 02, 2019 9:52 am 
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I guess you must be logging both temp and oil pressure? What does it show? Did it come up to temp and the oil pressure slowly decline over the session or was it ok and then suddenly drop 10psi?


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 Post subject: Re: Our little cultus racer
PostPosted: Sun Jun 02, 2019 3:53 pm 
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Oh no, the splitter!! The drawbacks to racing :(

She is a tough nut, but I think you have beat things harder than this before. All the willpower, knowledge and expertise is at your fingertips, you will find the cause of the issue.

How does one go about chasing oil pressure issues? Is it silly to tap into the oil lines and install gauges in various places to get the differential readings? (Big job I can understand!)

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 Post subject: Re: Our little cultus racer
PostPosted: Sun Jun 02, 2019 3:54 pm 
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Just throwing it out there, is it worth taking out the oil pump to check the bypass valve is set correctly and does not have schmoo stuck in it?

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 Post subject: Re: Our little cultus racer
PostPosted: Sun Jun 02, 2019 4:53 pm 
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sam it declines over the race....then stabilises...5w40 at race temp on 8000 rpm got down to 43 psi on the Link ECU. Dangerous.
On 10w40 51 psi. still too low.

I believe in all honesty that this crap lifters situation with cam clearances near the max is causing the issues. Coupled with larger clearances for racing on the mains and big ends....means hot oil flows too easily. Im sure others have been here before. So....plan....solid lifters, solid lifter cam profile, 15w 50 oil to suit the mains and big end clearances but not have to pump up lifters....shooting for 60 to 65 psi race temp hot at 8000 rpm.
book figures dont work here...its not a street car so cannot be treated as anything like it. I believe 5w40 or 10w40 will produce those figures without internal oil leakage.

Hi Michael...no point looking for grunge....this is a newly built super clean motor.....the symptoms do not match a stuck oil pressure relief valve.....usually this is low pressure though out the range...stuck closed is high oil pressure. The relief valve is more than likely fully closed allow full flow....but the hot oil temp is not viscious enough for the internal leakage to maintain pressure.

Chris wants...55 psi absolutely min at any time and pref 60 psi.

two instances of solid lifters I personally know of increased oil pressure to the point where relief valves needed to be modified to reduce oil pressure!!!

Thats where i'm heading....let you know.... :?


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 Post subject: Re: Our little cultus racer
PostPosted: Sun Jun 02, 2019 6:48 pm 
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There are a number of places on the head that measurement can be taken so adding sensors and reading the results could ID the culprit area. This might or might not mean head replacement or rebuild. Did he measure cam journal clearances?

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 Post subject: Re: Our little cultus racer
PostPosted: Sun Jun 02, 2019 7:12 pm 
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I reckon solid lifters would be a good idea but it won't be a cheap solution. Your engine builder won't be keen on getting a profile ground from stock cams. Blanks are pretty hard to obtain, at least Kelfords reckon they can't get any. You'll get cams from UK/Europe but it'll be expensive. If you're going to that much bother then if it was me I'd build up a new head with different valves and springs. If the problem is just the lifters then I guess you can replace the culprits and keep going while you build another head. Stock springs are likely to bind at lifts greater than 10mm and high velocity profiles go from about 10-12mm.

I guess your engine builder will check the bearings. One thing to be aware of is that the oem crank mains are cross drilled. In other words if you put a piece welding rod in the main bearing oil hole then if comes out the opposite side. The big end feed intersects the center of that hole and runs to the center of the big end journal. The small issue with this design is that to get oil to the center of the main it needs to overcome the centrifugal force of the spinning crank. The faster it goes the greater the oil pressure required. Some say it's around 50psi at 8k rpm. It's a common problem with 4AGE's as well. There are various mods that can be done to over come this and your engine builder should be well aware of it. Hopefully it's not a big end problem but it's another reason not to push the revs too far unless you've dealt with the threat.


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 Post subject: Re: Our little cultus racer
PostPosted: Sun Jun 02, 2019 7:59 pm 
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Yes cam journals std size but head on the max size so was not ideal. They shaved the caps but that only reduced clearance on the top and bottom....a trick they can use but not ideal.

Kelfords cannot do blanks anymore. Cat cams still do cams....$1600 inc gst del. that’s billet. But need $800 worth of cco11 solid lifters, plus springs etc.....so by the time that’s all done another 3 k.

Sam...I have seen a lot less pressure at Taupo and it was a big end that died....the mains looked fine.

Franklins? Build up lobes? Grind to solid lifter profile? Mod buckets to be solids? Cheapest way out.
Then need to machine cam caps to fit journals
What new lifters....can’t get them.....except aftermarket mizuno....I already have some in the cupboard but don’t trust them.


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 Post subject: Re: Our little cultus racer
PostPosted: Mon Jun 03, 2019 6:11 am 
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You probably don't need to use CatCams followers but if you do then you'll also need the lash caps as they set the clearance. There's plenty of other options that you can look at; Toyota 31mm solids, Supertech shim under, Arrow Precision etc.

Not sure welding will be any cheaper. Kelfords reckoned about $60+ per lobe to repair a worn billet cam I have here. Not sure spending a $1k building up oem cams would be money well spent. CatCams probably provide the easiest solution in terms of doing all the bits that you need but there might be ways of achieving a better result. Looking at the CamCams springs they're inch od which is pretty common. Honda D series are the same and the valves are the same except longer. A G13B bucket is around 17-19mm thick but the Toyota 31mm solids start from just over 5mm. Using those should allow longer valves to be used. Options to consider.

Building a new 4AGE Atlantic spec head costs north of 6k using quality parts ( Supertech or Ferrea ) so that gives you an idea of what race heads cost done properly.


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 Post subject: Re: Our little cultus racer
PostPosted: Mon Jun 03, 2019 10:19 am 
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getting close to putting a honda in it or just buying a honda race car for 10k...yuk.

spending 6k on the head...wont happen...ill go play with my boat.

why cant i use solid lifters on this hyd cam? whats the main issue?

can i not get the same profile with minor adjustments made to suit solid lifters....get the hyd lifters modded to go solid....then use 15w50 oil?

using 5w40 oil yielded 43 psi wot hot.
using 10w 40 oil yielded 51 psi wot hot.

so even though the first figure is the cold rating and the second the hot rating there is obviously a crossover and the thicker oil maintains better pressure...cost me $450 worth of motul to find that out...i know the lifters wont like 15w50 but if i had solid lifters it would not be a problem....having said that....doing the head clearances and ditching lifters might bring the pressure up even on 5w40.

today the car sits in the corner in disgrace....im playing with my boat motor... 8-[


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 Post subject: Re: Our little cultus racer
PostPosted: Mon Jun 03, 2019 3:17 pm 
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I've changed my lifters out to the mizmo lifters, using it for about 3 years and it's fine. I suggest trying this as it's relatively affordable and you can do it yourself. Of course that's if you can adapt to solid lifters.


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 Post subject: Re: Our little cultus racer
PostPosted: Mon Jun 03, 2019 3:19 pm 
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New lifters should be fine with 10w40, just keep with the regular oil changes, a little initial lifter tick may happen but will go away after it's warm


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