Rob, the roller wheels are the hardest , the steel cam lobes are normally surface hardened by one of 2 methods depending on the preference of the maker but regardless wiped lobes are predominantly an end result of oil failure. Multiple lobe failure almost confirms this. The tie bar damage is just resultant hammering damage, post lobe failure.
This kind of failure could normally be picked up in its very early stages,(tell tale is rocker clearances creeping wider at each adjustment).
In our race environment this means checking rocker adjustment at least each night after racing.
Shaguar
Moderator: DLRA
Re: Shaguar
Every night? That will put a significant dent in my 'teams' after 5pm activities.
That is if I had a team
GAZ
That is if I had a team
GAZ
Re: Shaguar
Gaz - you know you have a team, "in spirit". It's just that our day jobs keep us from actually doing anything. Hmm after 5 is really after 7pm once everything else is finished off on the lake and then it's time for a beer and something to eat followed by extremely loud snoring and then a 5:00am wake up and restart.
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Greg Watters
- Posts: 760
- Joined: Mon Sep 27, 2004 8:57 pm
Re: Shaguar
Stethiscope and a vu meter, once you get a reading on whats normal any change is measurable
then you go looking
When you get to know the car better a fall off in performance will get your attention
When i was doing Commodore cup, the drivers could pick one valve spring loosing tension , little slower out of a corner or didn't pull to redline as cleanly
be checked and fixed between sessions ,
then you go looking
When you get to know the car better a fall off in performance will get your attention
When i was doing Commodore cup, the drivers could pick one valve spring loosing tension , little slower out of a corner or didn't pull to redline as cleanly
be checked and fixed between sessions ,
Re: Shaguar
Greg,
I understand where you are coming from but as you know a vehicle on the salt is a different ball game. I could tell it was off song but with a throttle that is all on or all off, plus the wet conditions, getting a 'feel' was a bit difficult. I could tell more from the sound of the engine as much as how it was actually going. Maybe I am just a girl.
GAZ
I understand where you are coming from but as you know a vehicle on the salt is a different ball game. I could tell it was off song but with a throttle that is all on or all off, plus the wet conditions, getting a 'feel' was a bit difficult. I could tell more from the sound of the engine as much as how it was actually going. Maybe I am just a girl.
GAZ
Re: Shaguar
From the Americas comes the question.. if it had 0.022 clearance and we lost the lobe but the rest of the valve train is fine, why do we now have something approaching 0.500 ?
That would require a good deal of material to leave the back of the cam?
It is a good question and is currently doing my head in because the screw in studs haven't pulled, the pushrods were straight by eye and in situ, the roller rockers all appear to be sound, certainly none were broken. There were no metallic particles under the rocker covers or in the valley but lots at the base of the lifter bores.
Checking rocker clearances has to be easier than pulling the injectors daily and driving around with a potential bomb in my lap Gaz
Cheers,
Rob
That would require a good deal of material to leave the back of the cam?
It is a good question and is currently doing my head in because the screw in studs haven't pulled, the pushrods were straight by eye and in situ, the roller rockers all appear to be sound, certainly none were broken. There were no metallic particles under the rocker covers or in the valley but lots at the base of the lifter bores.
Checking rocker clearances has to be easier than pulling the injectors daily and driving around with a potential bomb in my lap Gaz
Cheers,
Rob
I owe, I owe, so off to work I go.
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Greg Watters
- Posts: 760
- Joined: Mon Sep 27, 2004 8:57 pm
Re: Shaguar
Gaz there doing a few more laps a week than we are, probably not a fair comparison
something collapsed in the follower ?
adjuster and locknut bound together but still walking up the thread ?
something collapsed in the follower ?
adjuster and locknut bound together but still walking up the thread ?
Re: Shaguar
Greg,
The followers are solids and the rollers appeared to be fine at first inspection other than the one with the bent link. I say first inspection because they were only removed and stored, not cleaned yet. The rollers did seem to spin freely and the mating surfaces looked fine other than the one noted prior with the bent link and that too did spin freely. The same goes for the rockers, none appeared broken and the roller bearings appeared fine at that point.
Zero metal particles at this time other than at the base of the lifter bore if you put your finger down and wiped the lower lip.
Cheers,
Rob
The followers are solids and the rollers appeared to be fine at first inspection other than the one with the bent link. I say first inspection because they were only removed and stored, not cleaned yet. The rollers did seem to spin freely and the mating surfaces looked fine other than the one noted prior with the bent link and that too did spin freely. The same goes for the rockers, none appeared broken and the roller bearings appeared fine at that point.
Zero metal particles at this time other than at the base of the lifter bore if you put your finger down and wiped the lower lip.
Cheers,
Rob
I owe, I owe, so off to work I go.
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ROSS BROWN
- Posts: 477
- Joined: Thu Feb 18, 2010 6:43 pm
- Location: COORPAROO BRISBANE
Re: Shaguar
Allways thought that side plate idea for holding the roller lifters straight was somewhat mickey mouse.
But as Chris pointed out it appears to be the end result of another issue..
Then Rob points out its highly unlikely that you would loose 500 thou of the back of the cam...
MY GUESS .... Valves been touching pistons. valve stems are now bent ..
Just conjecture for the time being .. the complete strip down will tell the story..
Ross..
But as Chris pointed out it appears to be the end result of another issue..
Then Rob points out its highly unlikely that you would loose 500 thou of the back of the cam...
MY GUESS .... Valves been touching pistons. valve stems are now bent ..
Just conjecture for the time being .. the complete strip down will tell the story..
Ross..
IT IS ALL A RACE AGAINST TIME.
TIME WAITS FOR NO ONE.
HOW FAST CAN YOU GO ?
S/UF 925
TIME WAITS FOR NO ONE.
HOW FAST CAN YOU GO ?
S/UF 925
Re: Shaguar
But.. the engine still runs on 8 cylinders
The two symptoms that got us this far are hard to crank with the plugs out (we still believe salt in the starter at this stage) and a 2/3 drop in oil pressure.
oh and engine not "on song" which we had previously thought to be injectors/methanol related.
The two symptoms that got us this far are hard to crank with the plugs out (we still believe salt in the starter at this stage) and a 2/3 drop in oil pressure.
oh and engine not "on song" which we had previously thought to be injectors/methanol related.
I owe, I owe, so off to work I go.
Re: Shaguar
This is fun,
Ross, I think you are probably wrong regards valves or it wouldn't run on 8
Greg, totally agreed, I use a stethoscope each night before I pull covers. I wasn't letting em off that easy.
Rob. Your gross valve lift will be around .750". Take away .500" (1/2") leaves 1/4" lift and the thing will still run on 8.
Gaz, my QUESTION is when did you check the rocker clearances last?
If your answer is prior to leaving home and more so prior to it running like crap and blaming injectors my question will be was this a wrong diagnosis.,(ie injectors )
Rob, have you looked at a lobe yet? I think you may find all the bumps are gone and this will also explain the metal filings present.
Ross, I think you are probably wrong regards valves or it wouldn't run on 8
Greg, totally agreed, I use a stethoscope each night before I pull covers. I wasn't letting em off that easy.
Rob. Your gross valve lift will be around .750". Take away .500" (1/2") leaves 1/4" lift and the thing will still run on 8.
Gaz, my QUESTION is when did you check the rocker clearances last?
If your answer is prior to leaving home and more so prior to it running like crap and blaming injectors my question will be was this a wrong diagnosis.,(ie injectors )
Rob, have you looked at a lobe yet? I think you may find all the bumps are gone and this will also explain the metal filings present.
Chris
Re: Shaguar
Chris,
The injectors were definitely an issue. Once cleaned it ran fine, without cleaning it would not start. We proved that by making a squirt bottle and giving it a splash. It would start and run fine on the prime. Once the injectors were cleaned it started on the key and ran again. First sign of trouble was a call to me at 9:45pm the night before we were to leave early, the car wouldn't start. The injectors were sonic cleaned in the am and when reinstalled the car started and ran fine. A day and a half later on the salt it was hit and miss until the injectors were soaked in petrol for a couple of days then reinstalled. With the hat removed so they could be viewed, 11 of the 12 worked at that time and that is how it was run. We also purged the complete fuel system with petrol after the run where it burped and Gaz got off it but it never really ran 100% for the week.
Gross lift at the cam was 0.700" and the clearance was 0.022" for both. I mentioned it ran on all 8 to discount bent valves. So the question still stands, how did we lose all that material of the base of the lobe(s)? The person posing that question is convinced it's an upper valve train issue but having pulled it, I don't believe so. We will look much harder at those parts when we wash them up.
Last oil change was the week before the salt. How long would it take to dilute enough to cause this sort of cam damage? My methanol experience is severely limited so I am "learning on the job."
The long block is still in the car until our next session. The cam is definitely defunct, it's just a matter of where and how badly at this point and what else has been hurt by the swarf Oh and what caused it.. It may also be a case of can we get it out of the block if it got hot enough to bend a few thou.
I am unsure when the valve clearances were last checked but it definitely was not done on the salt. I have been thinking about a bore scope and now seems like a good time to think harder, maybe when I am in the states in August.
Cheers,
Rob
The injectors were definitely an issue. Once cleaned it ran fine, without cleaning it would not start. We proved that by making a squirt bottle and giving it a splash. It would start and run fine on the prime. Once the injectors were cleaned it started on the key and ran again. First sign of trouble was a call to me at 9:45pm the night before we were to leave early, the car wouldn't start. The injectors were sonic cleaned in the am and when reinstalled the car started and ran fine. A day and a half later on the salt it was hit and miss until the injectors were soaked in petrol for a couple of days then reinstalled. With the hat removed so they could be viewed, 11 of the 12 worked at that time and that is how it was run. We also purged the complete fuel system with petrol after the run where it burped and Gaz got off it but it never really ran 100% for the week.
Gross lift at the cam was 0.700" and the clearance was 0.022" for both. I mentioned it ran on all 8 to discount bent valves. So the question still stands, how did we lose all that material of the base of the lobe(s)? The person posing that question is convinced it's an upper valve train issue but having pulled it, I don't believe so. We will look much harder at those parts when we wash them up.
Last oil change was the week before the salt. How long would it take to dilute enough to cause this sort of cam damage? My methanol experience is severely limited so I am "learning on the job."
The long block is still in the car until our next session. The cam is definitely defunct, it's just a matter of where and how badly at this point and what else has been hurt by the swarf Oh and what caused it.. It may also be a case of can we get it out of the block if it got hot enough to bend a few thou.
I am unsure when the valve clearances were last checked but it definitely was not done on the salt. I have been thinking about a bore scope and now seems like a good time to think harder, maybe when I am in the states in August.
Cheers,
Rob
I owe, I owe, so off to work I go.
Re: Shaguar
Boys,
The clearances were checked just before we left home. I have checked with a bore scope and looks ok in there as far as I can see. If there were bent valves there would be some eyebrows on the piston heads but I couldn't see any. Remember this is the same engine that I ran in a street car for a number of years (petrol- avgas) before I just put rings, bearings and gaskets in it. No big changes only overdrive 10% on the pump. The engine has done a day on the engine dyno last year and a day on the chassis dyno this year but apart from that not a lot of work.
Baffling till we pull it apart.
Gaz
The clearances were checked just before we left home. I have checked with a bore scope and looks ok in there as far as I can see. If there were bent valves there would be some eyebrows on the piston heads but I couldn't see any. Remember this is the same engine that I ran in a street car for a number of years (petrol- avgas) before I just put rings, bearings and gaskets in it. No big changes only overdrive 10% on the pump. The engine has done a day on the engine dyno last year and a day on the chassis dyno this year but apart from that not a lot of work.
Baffling till we pull it apart.
Gaz
Re: Shaguar
Cam lobes only get splash feed so oil dilution is one option, overheated oil, no oil or abrasives is another.
The only reason I suspect an oil failure as a cause is because its across the board and affected most of the lobes at once.
The only other remote possibility is it has uniformly buried all the valves deep in the head 1/2" and this is implausible.
The only reason I suspect an oil failure as a cause is because its across the board and affected most of the lobes at once.
The only other remote possibility is it has uniformly buried all the valves deep in the head 1/2" and this is implausible.
Chris
Re: Shaguar
no personal experience with methanol but hear lots of cautionary tales ,could the delayed flush from 2013 mean internal oil galleries in motor blocked with jelly?