reading spark plugs

[winton 399]

hay all, what's it mean when my plugs are clean on the tip and porcelain no colour at all? black carbon build up elsewhere.

[winton 399]

lean?

[Gaz 1,085]

Rich.

[revhead 1,392]

chuck up a picci ,black n fluffy ,rich, dark grey ok, white,almost clean looking lean ,

[slydog 7,873]

Top ring above thread tells rich lean condition and detonation,earth strap tells burn condition.Plugs can only be read correctly after rpm with a all but instant shut off.Other than that if there black or clean does it for non performance shit useally

[ando76 4,354]

google plug reading.  NGK and that have some good pictures to compare yours to.  But as Sly said the best plug reads are done with an instant shut off after a loaded high rpm situation. Ideally this should be done with new, correctly gapped plugs installed for each change in timing, addition of fuel or change in heat range.   Easy to do on the race track - not so on the street unless you find somewhere safe. 

As for reading methanol plugs - well that's a whole other ball game.  same for E85. 

But I guess your talking about a street engine.  With the advent of O2 sensors and wideband gauges plug reading has become a bit of a thing of the past - but I believe that using both technology and what you see with your eyes and smell with your nose is the best way.  Yes I sniff methanol plugs.  Yes I am weird but there is a very valid reason why I do it.   

[winton 399]

cheers all. @ ReVhEaD can't do pictures, phones not compatible with site and can't workout how to cut and past on computer. its fluffy black on threads and ring. Electrode, tip and porcelain clean, like new. did take it for a squirt before I pulled them, kept it above 3k apart from when I backed it into shed. Did a comp test, lower then I expected . 9.8, going to a solid cam so need to up it to 11. thinking I'm gunna offset grind a crank and have the ring/lip on top off the pistons milled down to bump comp depending also on deck hight. Already talked to the guy I get my machining done ,said he can do it with the conrod on.

Ando, that's not weird, This is weird.

http://m.youtube.com/watch?feature=youtube_gdata_player&v=FbuluDBHpfQ&desktop_uri=%2Fwatch%3Fv%3DFbuluDBHpfQ%26feature%3Dyoutube_gdata_player

[slydog 7,873]

Read this people... http://www.wallaceracing.com/plug-reading-lm.html

[ando76 4,354]

Good informative site there rob. 

[XES 859]

Yep great info there rob. This was how I was trying to read what my motor wss doing before I put the wideband in. Old school way to do it but it works if you know how an do it properly. Wideband is the shiz tho. Once that was in I havent looked back.

[slydog 7,873]

Wideband is better for all driving for sure, never argue that fact but you can tell things with the plugs you cant with a wideband like if it detonating and such and you only need a magnifiing glass to read em.

[winton 399]

cheers. found a similar chart on a Honda forum yesterday, if anyone's interested here it is

http://honda-tech.com/showthread.php?t=3063102

bit of a topic change but can anyone tell me the minimum piston to valve clearance?

[ando76 4,354]

Well it depends on what rods you are using, what revs you intend on pulling and how good your valve train is.  more revs and stock rods requires a bit more clearance than forged rods.  Think rob is running decent clearance on his massive lift cam and we all know how he likes to rev.  Rob's clearance??/???  Rob??????

[slydog 7,873]

Piston to valve is around 86th inlet and 104th exhaust from memory? I'd have to check my thread but 80th is the suggested minimum on a street based engine.The exhaust gets hotter and stretches more than the inlet.The inlet cops a cooling charge from the fuel it lets in so it always seems to suffer less.

 

My cam is a Clive Cams roller which has 709th lift and has custom valve reliefs in the Wiseco forged pistons and sunken valve seats in the head to help.This is why cam timing HAS TO BE spot on and dialed in and never just dot to dot or what you think.It has to be checked via atleast lift @ TDC and the centreline method to be extra sure if you want.I got to within .5th on TDC and spot on in centreline measurements.Yes you HAVE to be this anal when setting up a big RPM big lift camshaft as you cannot trust anyone.It took me hrs to get the cam timing exactly spot on and 2 timing kits (which I used a cam gear off 1 set and crank gear and chain off another) and then I moved to plasticine to check piston to valve.I do this on cast piston engines too,you just have too.

 

 

Race engines which DO NOT use engine braking (drag cars) can and do run alot tighter like around 40-60th but I wouldn't suggest that on any street engine.

 

P.S on checking my notes I got 103th inlet and over 120th exhaust...

[winton 399]

rods are 250 xflow, revs cam pulls to 6500, ferrea valves single groove, still need to get some valve springs and pushrods, hopefully the yella terra adjustable rockers are upto it. I'm buying stuff as I go.

last build the pistons all had marks on them from the valves so I didn't deck it as much as I wanted but I also didn't check clearances. think I'm gunna need to put more effort into the next upgrade. thanks for the Help.

[slydog 7,873]

Do you have a cam for it already and what are the exact lift and duration @50th specs.You can PM them if you don't want to post them.The cam supplier is usually on ball with there suggestions and if using a solid it is very critical to get this bit right and use correct run in procedures.Ask me how I know this

 

Using a Clevo style retainer and lock? If using clevo gear you will need to machine the spring pad mounts on the heads...cost buggar all but and you can then use a wider variety and wider overall spring with helps with spring efficiency and harmonics.I have a few sets here with retainers that will handle ALOT of camshaft with under 100kms on each I'd suggest.

 

Pushrods should be Trend or Comp 3/8th units thru Performance Wholesale (better than using Crow or standard) I used both and found zero difference bar price.Yes the Comp ones were cheaper...Currently it has Trend 9.550 units in it but you won't know till you measure it all up.I use a stock BBC rod and a x-flow unit sleeved inside it to get my measurements or you could buy a measuring kit and then sell it off after you get your length right.

[winton 399]

yeh got a crow 647, lift is .5967, duration @50 is 254 . think the head has had the pads done, atm has crow 7333 fitted.

 

I'll have to use you rod measuring idea to.

[slydog 7,873]

I like the lift,lift gives you torque but the duration gives it HP.Should be a cranky thing.I got some clevo style 1.55 Comp springs retainers and locks that truly are as new if your interested too bloke.Or a set of  K Motion 1.46 x-flow units and super light ally retainers.

[winton 399]

what's the seat pressure on the clevo springs, think I need ones rated at 125lb, and I assume the locks are single groove, how much?