possible issue found

[br4inl3ss]

hi.
yes its me again.
my luck...................

anyway. i just found out that my exhaust valve is leaking.
was a brand new fully assembled head.

i know good ole american v8 engine not smaller engine of any type.
i know that in chevy and dodge v8 engine, such a small leak is terrible.
but ive been told in such small engine tis not a problem. i have doubts right there.

anyway while changing the camshaft and rocker, decided to check valve in case they were bent, or any other visible damage ( because of issue and weird noise )
no sign of hit or damage at all. not even under a usb microscope.
BUT there is a slight leak on the exhaust valve.
here is the video




i cant seem to be able to lap them properly ( with proper tool!!!, even tried old trick with a drill ) after 20 minutes, so i ordered a Glixal valve kit on amazon ( 18$ CAD shipped, hey no time to waste ! ). look like they were not sealing from factory. exactly like all the heads i bought for v8 ( my 360 magnum head was the best but still not 100% sealing ).
i should have done valve lapping from the box, but ive been told its not necessary like car.... stupid me for believing Ford truck owner advice saying they're reliable but constantly at the garage. should of know..... anyway.

thats not my weird noise issue, but can be my fueling issue ( old head was also leaking, it seems ).

not sure it is my issue tho. had fueling issue since a very long time. ( if you remember, even the Naraku carburetor didnt fix the issue back then )


EDIT:
this is alot of picture of the old camshaft and rocker. the bearing ( opposite to the gear ) is shot ( it spin but we feel its shot ).
cam lobes look over-used. 





























































everything look shot.

[repherence2]

made from Chinesium?

[aeroxbud]

That sucks. But it's nothing money won't fix. 🙊

[GrumpyUnk]

Cam followers have some wear, question is what did the tip that rides on the lobes feel like? Can't tell from the pics if it was a rough surface or not. Should be kinda smooth.

Soapy water... did it leak out the exhaust port? Air blasted in apparently can lift the valve a bit. If the exhaust port was dry, then it should be fine.
OTOH, if wet, that is a problem. Most times a more volatile liquid, such as gasoline, is used to test valve leakage with liquids. It seems gas will penetrate better than water. At least I think it does.
Did you happen to take a pic of the valve seat, and one of the valve face after lapping? My personal test, not proven by anybody, but me, is to look at the separation when you pull the valve after lapping. If the compound forms a ridge all the way around the face that forms when it separates, I figure I have good seating.
I do not remember checking valves using gas or soapy water for that matter.
Honestly, I am not sure if that amount of leakage would make it run poorly, but likely would be most notable at idle. Did you check compression using a gauge? It may be slow enough that you got decent compression cranking. Only way to know is to measure.
tom

 Do post a couple pics of the valve seat and face.  It should be interesting to see if the visual shows the problem.
tom

[snaker]

It has all the markings of a lack of lubrication.
If the oil level is run low, that area is the first hit.
You will need to check your cam bearings closely.
Also the cam follower pivots.

One of the main cylinder/head studs and stud holes is also part of the oil system.
You can see the oil passage groove from the stud hole in several of the photos.
A plugged passage will cause oil starvation as well.
I don't recall if that required a special stud to go in that corner or not.

[br4inl3ss]

Apr 12, 2023 7:51:46 GMT -5 GrumpyUnk said:

Cam followers have some wear, question is what did the tip that rides on the lobes feel like? Can't tell from the pics if it was a rough surface or not. Should be kinda smooth.

Soapy water... did it leak out the exhaust port? Air blasted in apparently can lift the valve a bit. If the exhaust port was dry, then it should be fine.
OTOH, if wet, that is a problem. Most times a more volatile liquid, such as gasoline, is used to test valve leakage with liquids. It seems gas will penetrate better than water. At least I think it does.
Did you happen to take a pic of the valve seat, and one of the valve face after lapping? My personal test, not proven by anybody, but me, is to look at the separation when you pull the valve after lapping. If the compound forms a ridge all the way around the face that forms when it separates, I figure I have good seating.
I do not remember checking valves using gas or soapy water for that matter.
Honestly, I am not sure if that amount of leakage would make it run poorly, but likely would be most notable at idle. Did you check compression using a gauge? It may be slow enough that you got decent compression cranking. Only way to know is to measure.
tom

 Do post a couple pics of the valve seat and face.  It should be interesting to see if the visual shows the problem.
tom

nope, no pics right now. that can be fixed if that stupid arm pain go away.

it does sems to run ok ( doesnt go past 55 km/h on flat with minimal wind pushing me in the back while it used to hit 60-61 in its good day on flat with no wind before rebuild ) but not at idle. most of my problems is at idle.

unstable idle, carb tuning, one time its over rich, the next time its poor, next time its almost ok, constant bogging on 1 to 50% throttle... those problems runs since YEARS way before i open the engine the first time.



i never seen any valve lift using air. all the v8 i built was done using this method, all ride on mower too, and my friend which is a mower/snowblower mechanic use this method since at last 28 years.

also take note that the intake valve is fine, doesnt leak at all even with compressor at 90 psi ( did the test this morning before arm pain show up )

i think the same, gas is better to check elak than water. thing is i didnt had gas, but i had water 
if it leaks liek that with water, imagine with gas... 

i turned the valve like 1/4 of a turn, redid the test, only ONE bubble after 6-7 seconds of blastign air and thats it. turned it 1/2 of a turn, bigger leak than on the video appeared.

[br4inl3ss]

Apr 12, 2023 9:18:24 GMT -5 snaker said:

It has all the markings of a lack of lubrication.
If the oil level is run low, that area is the first hit.
You will need to check your cam bearings closely.
Also the cam follower pivots.

One of the main cylinder/head studs and stud holes is also part of the oil system.
You can see the oil passage groove from the stud hole in several of the photos.
A plugged passage will cause oil starvation as well.
I don't recall if that required a special stud to go in that corner or not.

oiling is perfect ( almost got oil spitted in my eyes from the stud hole when turning the engine with a drill to be extra sure nothing hit anywhere ). since i own it i never let it go lower than halfway inbetween the min and max lever, always keeping it at max level as much as i can.

i had a weird pan flute ( like in the song famous Sadeness by Enigma, the low notes ) noise when i tried the 50mm NCY bbk with stock head, but i heard it once or twice in the first month i owned it and went away for no reason. camshaft had some heat coloration, but everything seemed fine, including oiling.

and no its the same stud as the 3 other. all 4 studs are smaller than the holes tho.
the original base gasket ( the one that was in there at least ) was blocking 20 to 30% of the oil passage, but like i said, i got oil spitted in my face turning the engine with a drill ( about 800 rpm at best ? ) so probably wasnt the issue. usual chinese gasket fitment.

[br4inl3ss]

the pics @grumpyunk asked.
after extensive valve lapping of over 20 minute with a drill
this is only the exhaust valve. cant find any leak on the intake valve so i didnt even remove it ( new valves on the way, anyway ).
PS its only dirt. nothing to clean it right now but yesterday seat was shiny











cant wait to get my valve compressor tool to retest the sealing after the abusive lapping. cant do it manually anymore with my arm pain so i ordered the tool. should be here today but everything is late so....

[br4inl3ss]

and this was the old stock 39mm head with exhaust valve, leaking like crazy using no air just gas. 40+ minutes valve job on this one from last summer. ONE of the reason for a rebuild, hoping my issue would go away.

[GrumpyUnk]

The old vavle suse did not look as if it seated anywhere...
The new valve looks good, actually. I would never have suspected it to leak.
The new seat in the head also looks fine. Very even and nicely finished.
Is the new exhaust valve out of round? It must be to allow bubbles and differing amounts(more/less)depending on where it is rotated to.
Did you check the valve guide for wear/loose fit? It could allow the valve to move radially and seat willy-nilly depending on the wear. Could have oval shaped guides. I would think about putting the valve stem on the flattest surface you can find, and rolling the stem with the 'tulip' of the valve hanging off the edge. You might be able to see an irregularity in the motion as it rolls. A bent valve would show as a wobble, bet it is so slight you can't see it.
tom

[br4inl3ss]

thanks for the reply.
no, nothing look out of round. not somethign we can see at least.
valve guide, both on old and new head, seems very good.
i did try your last step, but couldnt notice anything. that may be just me. even tho i have strong eyes, sometime im blind as fuck. yesterday i spent 15 minute trying to find my valve spring, it was right in my damn morron face. blind as fuck.



received brand new valve kit eysterday, did valve lapping to be sure.
using the same method using air, minor leak. i was done wasting time with those valve so installed it anyway.
the leak was VERY minor ( still on the exhaust side ).
showed the video to 2 mechanics at the nearby stealership ( the owner is a jerk but workers are extremly friendly and help people out a smuch as they can ). they looked at each other and said this could possible be an issue later on but right now its nothing i should care about since my symptoms doesnt fit such a minor leak, especially on the exhaust valve.

anyway... weird noise from the camshaft area seems gone( this noise is hard to hear sometime, and i have to fix the bent exhaust flange so no more exhaust leak ).
but still impossible to get a proper idle. it either idle way too slow ( 600-900 rpm ) to get an acceptable AFR ( 13:1 to 15:1 ) so it constantly stall and discharge the battery, or can make it idle properly at 1800-2200 rpm but WAY too rich, with adjustment screw completly seated and cannot get it leaner than 10:1 ( probably more... my gauge do 10 to 20 afr ).
increasing idle with IDLE screw also increase AFR. so stepping on the throttle emplify the other problem i have ( way too rich from 1 to 50% throttle, at any rpm/speed.

this fueling/idling issue drive me crazy its been like that since a very long time.
someone told me to check float height again. i will try to find someone do it for me to adjsut it. i cant stand those ALIEN slanted bowl that have no info as how to actually get it right. once with the old stock carb i tried the transparent hose trick, but it didnt change anything. so i guess it shouldnt be measured in the middle. thats what was making sense but if it dont work, then it dont work. manual is of no use once again.

actually everything is NEW on this engine but the chain tentioner that work A1.
crank, crank seal, cylinder, piston, rings, head, valve, valve spring, cam, rocker, chain, chain guide, intake spacer, intake, airbox, air filter element, 4 to 7 BRAND NEW carb ( forgot exactly, its been too much, including a returned pointless legit keihin )... the pair ( egr ? ) system is removed ( that useless crap was in the way, and i tought it was part of the problem 2 years ago.. but it wasnt ). its all Glixal parts. i know the bullshit bla bla bla its dropshipping junk like all other bla bla bla. its what i could have without waiting for months and decent price. alot of people around here runs them with high apreciation rate.

EDIT: slow/pilot jet is 33, the smallest that seems to exist in the whole internet for any cvk carb.



i wanted to try my old stock carb again even tho i had this issue back then, but its leaking from every possible place. the 5 rebuild kits i ordered wasnt the right one so only the bowl gasket was correct and cannot find a proper rebuild kit. do i need to say i'm done wasting money on carb ? and on everything ?... people went full retarded so buying another scooter is a no go. cheapest in 250 km radius is a ACP Motor Compagny no paper no wheels engine unknown condition and broken plastics for 1300$ CAD.

[br4inl3ss]

ok so i put it seems better adjusting the flat ( he said he adjusted it aproximatly without trying it ).
not the adjustment screw has some use......... but is it normal that even 1/8 of a turn on idle screw completly change the AFR ? like from 14.7:1 to 13.0:1 jsut with 1/8 of a turn ?

anyway. i can set the mixture properly now, but it MUST be at least at 2000 rpm. its better near 2200 tho. but its a bit fast for no reason...

also, it still become extremly rich on 1 to 50% throttle. it SEEMS a bit better with 33 pilot jet compared to 35, but its still too much fuel.