Reply With QuoteLet me start by asking what oil were you using?
DAVE
Hey Guys I pulled off my tunnel ram last week looking for a vac. leak (running very lean).Anyway I found wear on my cam shaft were the roller rides.Grooves on one side of the lobe.You can actually feel the lip with your finger nail.Its a comp. cams hyd. Roller (gen 6)It happened on 4 diff. lobes.CP is replacing it but now one has a answer to what happened.would appreciate any help thanks.
Let me start by asking what oil were you using?
DAVE
First I used Kendall 10-30 gt1 / lost three pistons to a lean mixture.After rebiuld I ran vavoline cyn.for and Hour then back to kendall gt1
I have been running a crane roller cam with crane roller hydraulic lifters in my 350 chevy. I had a roller lifter fall apart and drop into the cam and seize the motor. When I tore the motor down, I found several other lifters that were about to fail (had cracks) and my cam had a groove in it like jstwkd described. I wrote it off as a bad batch of lifters after I sent them to Crane and they replaced them for free, including my cam.
I was describing my engine failure to the guys at Pick's Racing Engines in Santa Ana, and they had an interesting take on roller lifters - for highperformance boat applications (not race), they did not like to use roller lifters because of how much idling boats do. They said idling is the hardest thing on roller lifters and cause grooving and other failers in lifters. They told me to get better life from my roller setup, that I should avoid being under 2000 RPM as much as possible.
They said that there were motors that never had a problem, but with the extreme growth of roller cams and roller lifters making their way into recreational applications, the failure rate is atleast 10 times higher than in race applications, they think it is more like a 100 times higher. They also said that racers seldom put more than one season on roller lifters, where recreational users tend to only replace things that are broke.
Also, there is only one company that makes roller lifters for all the cam companies - there used to be 3, but 2 stopped making them due to high failure rates in non-race applications, and people wanting their money back.
In my opinion, 10w 30 is not a good oil to use unless you boat in cold wheather.
Use a straight weight 30 or, a 40 for higher temps if you want to stay with petroleum.
If you want to use synthetic I suggest either Mobil 1 15/50 or Royal Purple 15/40.
It's hard to sit here and say what went wrong with your engine without looking at it. But, I think your oil is a good place to start.
A multitude of things could be the culprit. From broken or inaccurate valve spring settings to defective/bad bearings inside the roller.
DAVE
I was under the impression I couldnt or shouldnt use anything higher than staight 30 weight in a 86 or newer motor.I did use staight 30 gt1 and lost three pistons.than went to the snythetic vavoline. and on the last oil change I went gt1 10/30.I ve only got maybe 12 hours and 1 rebiuld (for the three pistons) bewteen oil changes.
jstwkd:
I was under the impression I couldnt or shouldnt use anything higher than staight 30 weight in a 86 or newer motor.I did use staight 30 gt1 and lost three pistons.than went to the snythetic vavoline. and on the last oil change I went gt1 10/30.I ve only got maybe 12 hours and 1 rebiuld (for the three pistons) bewteen oil changes.I was under the impression you lost 3 pistons from a vacume leak...runing a few cylinders lean.
So are you, or could you blame the 30wt on that?
Dont know how I would feel about the comment "They said idling is the hardest thing on roller lifters and cause grooving and other failers in lifters."
There sure are alot of motor's (diesels) that spend all night, night after night idleing and there getting over + 500,000 miles on those roller tappets.
Just wondering if the cam may have been a little soft? And for the oil weight...I've been under the impression 40 wt. is the way to go...however this season I've been using Kendalls GT 20/50. The 10/30 seems a little on the thin side for something as stressed as a marine engine.
It would seem that a roller cam has many advantages over a flat tappet cam for (preformance) reasons...but one small speck of debre could stop a roller from spinning and...well you know the rest.
Personally I'd be surprised if the 30 wt caused the issue...now add in a vacume leak, leaning out a few cylinders,pistons are getting real hot, and then a piston skirts start to gaul, and presto...there's your debre that could cause a roller to fail.
There are many possibilties...I'm thinking a soft cam...debre stopping a roller from spining, showing grouves on the lobes...and the 10w30 is a no no.
I personally feel that I lost pistons due to a lean mixture.I havnet been able to find a vaccume leak or anything saying I had one except that Im running a 950 hp With huge jetts and plugs read white.Headers still have almost no idication of fuel inside of them.I actually pretty lost I talked to a guy up here who wants to see my set up.
jstwkd:
I personally feel that I lost pistons due to a lean mixture.I havnet been able to find a vaccume leak or anything saying I had one except that Im running a 950 hp With huge jetts and plugs read white.Headers still have almost no idication of fuel inside of them.I actually pretty lost I talked to a guy up here who wants to see my set up.send me pics of this piston heads and combustion chambers.....also the HP carbs should be stamped on the sides of their bodies on this little square mount on the side
[ September 04, 2002, 01:14 PM: Message edited by: Hotcrusader76 ]
The loss of pistons most likely had nothing to do with oil. That is most likely a fuel problem or a mechanical failure of piston, ring or valve material.
Oil is the "life blood" of your engine.
The important thing is Temp. First and foremost.
Temp should be between 220 - 250.
I personally recommend (for petroleum based) a straight 30 for most climates. I wouldn't be against straight 40 in places like So. Cal., S. Fla and places that boat all year round. The plane truth is that straight 30 can and will give you as much protection as you need.
In cold climates for early and late season running I suggest a 10/30.
I personally use synthetic. I, just yesterday infact, had a discussion with the head engineer at Royal Purple. I have personally seen the effects of RP over petroleum.
One of the questions I asked him yesterday was about roller lifters "dragging" over the cam instead of rolling over. He told me in all the research that they have conducted, he's not seen any indication of that problem.
Anyway, getting back to your real problem.
Do you think it is possible that you got debris throughout the engine when loosing the 3 pistons.
It sounds very possible to me.
Just throwing out some possibilities
DAVE
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