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Is a 285 degree cam a 'wild cam' ? [B30]

B

B-lennium

Member
Joined
Aug 3, 2005
Location
Holland
I installed my kg-17 cam + go fast goodie's and tried to start today.
The car started and after breaking the cam in (scary moment!) The idle is sh*t! This is lumpy!

The megasquirt show's a 100kpa map signal @ 850 rpm. When I rev to 1100 the 'idle' gets back stable @85kpa.

Problem number 2 is that I don't know the right valve lash settings. The OEM setting is 0.50mm cold. But with the new dubble spring, isky pushrods and followers nothing in the valve train is 'stock' any more! The valve's are realy loud now... And the guy I bought the stuff is on vacation. Could the wrong valve clearance be the cause of the low vacuum @idle ?

Any one have experiance with the Isky valve train and kgtrimmning camshaft's on the B20 or B30 engine?
 
yes that would be considered a wild cam.

the valve lash depends on the valves, the length and type of metal and temperature .050mm would be a good starting point. are you sure you are hearing valves and not the injectors. at 100kpa they will be opening pretty long.

use a stethoscope to determine where the noise is coming from for sure. even a long screwdriver works well put the handle up to your head and touch the tip to the injectors, valve cover, engine block etc.

I installed a megasquirt on a sirocco that had big cams and the idle ended up being at 80kpa after tuning but it did idle smooth. I used 6* idle timing with it ramping up to 20 with increasing loads. the 9A engine has smaller bores so you will probably use more timing in the b30.
 
I had some 272 advertised cams in my 16v. A 900rpm idle was lumpy and would shaje the car a little! My idle vacuum was 8 to 9 inches.

I smoothed the idle out by richening it up to about 13.0
 
The KG-17 is similar to an R cam, ( little less lift, lsa and duration)

I ran an R cam in an R-sport head on a B20 and it idled with joyous thunder w/twin SU's and very rich needles, timing at 23.5 deg adv, idled very well at 1100 rpm. 11.8:1 compression
If the head is not seriously ported and your intake flow increased over stock the cam will lumber.
Valve lash for a big cam like this should be 0.022 to 0.025", but 0.020 where you are should be OK, too.
 
285 measuring the ways the Swedes do is barely a fast road cam..of course that's not enough info---like what is the LCA..But for rad cams look at the typical rally cams in Sweden and you'll see numbers around 308 to 312 degrees duration, 106 to 108 lobe center angle.
Did you chop off a mm or so on the head to correct compression for the ---we imagine, but don't know-----later intake valve closing?

Having supplied hundred of cams for hot road cars with 308-312 duration in the last 25 years, and those cars had carbies, sure there was some 'lope' at idle, but turn up the idle to about 950-1000 and they were fine....And Nathan is right, a bit richer at idle made sure it didn't lean surge.

But as always, not enough info to say anything definitive.
 
John V said:
285 measuring the ways the Swedes do is barely a fast road cam..of course that's not enough info---like what is the LCA..But for rad cams look at the typical rally cams in Sweden and you'll see numbers around 308 to 312 degrees duration, 106 to 108 lobe center angle.
Did you chop off a mm or so on the head to correct compression for the ---we imagine, but don't know-----later intake valve closing?


But as always, not enough info to say anything definitive.
Click to expand...

John, from the forum resources:
cam lift dur LSA
KG17 11.1 285 107 KG-trimning Low RPM torque, dual carbs, stage 2 head

And I agree about the compression, somewhere above 11:1
 
MODELL V-LYFT 0-SPEL NOCKVINKEL DURATION
KG10 n?got starkare ?n D och K. G?r mycket bra tillsammans med insprutning. ?ven l?mplig f?r turboanv?ndning.
L?mplig topp steg 2.
L?mpliga f?rgasare 36/36DCD eller 2X40 - 45:eek:r. 11.1 110? 280?

KG17 drar bra fr?n l?ga varv passar utm?rkt till veterancupen med exempelvis dubbla SU-f?rgasare. G?r givetvis ?nnu b?ttre med dubbla 45:eek:r. L?mplig topp steg 2. 11.1 107? 285?

KG19 sn?ll s? kallad gatkam, drar mycket bra fr?n l?ga varv. <---""nice" so called street cam"
L?mplig topp steg 2 - 3. in 12.40
ut 11.25 105? in 312?
ut 292?

KG6 Kanske den b?sta kamaxeln som tillverkats till Volvo. Mycket bra vridmoment, drar fr?n l?ga varv ej att j?mf?ras med S eller U-profil eller liknande.
L?mplig fr?n steg 3 topp och upp?t.
L?mpliga f?rgasare 2X45 - 48DCOE eller 48DHLA. 12.54 105? 312?

KG5 N?got vassare ?n KG6, ger ca 10HK mer. Mycket bra vridmoment, drar fr?n ca 1500-2000 varv.<---- very good torque, pulls from cirka 1500-2000 rpm
L?mplig topp fr?n steg 3 och upp?t.
L?mpliga f?rgasare 2X45 - 48DCOE eller 48DHLA. 12.9 104? 320?
Click to expand...

Look at those figures, all pull from the bottom.
Your can is the next mildest thing they make.
Their "sn?ll'' kam is way badder or as they say v?rst (worst, sarcasm like we say It's bad, man) than yours..


Tell us what valves, what compression, what intake manifold(s) you have.
 
I have a stock B30e head, shaved to a 11.5 compression, bigger exhoust valves (37mm) stock intake valves ,3 angle valve job and a porting job on the exhoust, a bit of cleanup on the intake. The intake is a stock injection one. I use the stock injection exhoust manifolds and a 3inch (240 jt superflow) exhoust after a 80cm header (the original 2x 2inch pipe joined together after 80cm to end in the 3inch).

If the current valvelash is ok, then I think I am doing something wrong setting it up. What would be the right procedure to follow, again I think the stock one would not be the right one. The noise it make's now is not ok!

@JohnV you think the cam is not that wild so it should idle better than this?
 
It has been a long time since I worked on a pushrod engine, but why wouldn't the valve lash be the same, even with your modified setup? Valve lash is valve lash. I'm sure someone here will show why I'm ignorant.

Here's a link to a procedure from Comp Cams in case it helps.

BTW - I'm very interested to see how this all works out for you. I've got a 75 164E that I'm contemplating doing some mods to.
 
B-lennium said:
@JohnV you think the cam is not that wild so it should idle better than this?
Click to expand...

As said, at 1000 rpm it will be fine as you yourself found. There's nothing wrong with a 1000-1100 rpm idle on a motor like yours with that cam, don't expect it to behave like a C cam.

Even if it is not as wild as a race cam which John points out, it is a relatively big cam (bigger than 90% of cam's people on this board are using in redblocks), I would call it a Street Performance cam. It is a carb cam, but D-Jet injection would work well with it as it simply flood the intake runners, but if the MS is set with sequential fire and limits fuel injection duration then this cam may run lean, and the chatter is the valves. You may also want to increase ignition dwell for this cam, and run the advance up.

Also when adjusting valves on a big overlap cam you can't use the Volvo Greenbook procedure, you should go one at a time in crank rotation, and get precisely opposite the lobe peak to avoid adjusting with some lobe duration present at that point of rotation.

Giving the bigger cam a bit more valve lash can do a few things to the way the motor runs. More lash will reduce the effective overlap, but if only .005", not enough to affect performance but helps the engine rev more freely as the lobe hits the tappet later at a different angle and can smooth out the valve train. Too tight and the lobe is in contact with the tappet longer, has more friction and a greater torque angle, making the rev's feel more rough. With double valve springs a big cam can wear out faster with the lash too tight.
Call it adjustable duration, if you want it to idle better, open it up.
 
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vvpete said:
Also when adjusting valves on a big overlap cam you can't use the Volvo Greenbook procedure, you should go one at a time in crank rotation, and get precisely opposite the lobe peak to avoid adjusting with some lobe duration present at that point of rotation.
Click to expand...

As said just do one valve tappet adjust at a time. There's no fancy stuff involved here. That procedure is a little verbose. Just make sure the lobe is 180 deg from the adjustment point.
Start at cyl 1 TDC, intake valve, then rotate cam until intake 3, etc in sequence of timing firing order, then repeat for the exhaust valves. Rotate the crank a few times and start again but just measure, and adjust only if it is different.
Since you've already got everything installed the parts are already broken in and seated, this final adjust should be good enough. I would stay above 0.020" lash, not stock with that cam.
 
I set the valvelash to 0,50mm (0.020") now, the noise is almost gone now.

The engine is cold now, but the 1000 rpm idle is not that bad, maybe it even gets better when it's all warmed up!

Some where across the internetz some one advised the following:

"turn the crankshaft until the mark is at 0, then adjust all the 'free' valves, then turn it 360 degree's and adjust the other one's"

It sounded a bit TO gangster for me, so I clicked it away :p

Now I have to tune again!
 
B-lennium said:
Some where across the internetz some one advised the following:

"turn the crankshaft until the mark is at 0, then adjust all the 'free' valves, then turn it 360 degree's and adjust the other one's"

It sounded a bit TO gangster for me, so I clicked it away :p
Click to expand...

That is pretty much the Volvo procedure in the Greenbook. It will give a sloppy adjustment.

It works fine for a mild stock cam, but as the lobe duration gets larger the back side of the cam opposite the lobe gets smaller as far as the % of the circumference that doesn't have any amount of the lobe duration.
In your case, about 70 deg or +/- 35deg of the back side of the lobe Does Not have lobe duration that enlarges the camshaft
360-285= 75 deg, and as cam's are spec'd the back side non-overlap patch is even smaller, like 1/2 of that, so +/- 15 deg from 180.
A stock cam may have 120 deg or +/- 60 deg from 180 deg opposite the lobe peak that you can safely adjust the valve.

I just have to add that when I was doing valve adjust on a B20 w/R cam, I'd put magnetic dial indicator on the head and meaure the end of the rocker arm to find TDC of the valve to be adjusted, just to make sure I was opposite the lobe
 
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I got the car running today. It still runs very rough, I have to get familiar with the Alpha-N code of the megasquirt I think.
 
What fuel management was the car using? The idle I can live with, but now even cruse isn't what I expected. I learned that ITB-mode is the way to go on the megasquirt, I am reading now :)
 
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