Wiping cam lobes help.

[750H.P.V6]

Turbowrenchhead,

The way I like to break in the cam is as follows. I always make sure there is plenty of cam lube on the lifter faces and on the lobes themselves to start with.

I always pre oil the motor to insure everything is well lubricated. Amazingly enough I know a guy localy that thought he could do this by turning the oil pump with a screwdriver. Needless to say he started the motor, the pump didn't prime, the idiot light didn't work, he didn't have a gauge and he smoked everything.

Next I make sure the cam sensor is set correctly. If you don't know how to do this there is info on the GN TType website. If you're still unsure have some double check it. If it's set wrong the motor won't start and you'll be wearing on the cam as you turn it over.

Lastly you need to prime the fuel system. Checking for leaks is only the half of it, insuring the car starts ASAP is critical. I like to run the car at a high RPM (2500 or so) to ensure good lifter rotation and splash lubrication for approx 20-25 minutes.

Have a hose handy incase the car gets hot during the break in so you can spray some water thru the radiator to cool it down .

That's about it.

Neal

P.S. In regard to the question about re-machining the lifters, I'd tell you to call Reed cams and maybe they'll do it for you for a nominal fee.

 

[turbowrenchhead]

Got a link or contact for Reed cams?

 

[JDSfastGN]

Thanks for the tips 750hpv6 I don't know the link for reed cams, but I think that those are the cams that ATR sells, I had one and it went south but it was due to 3 valve spring dampers breaking, and I lost 3 lobes right at the top of 1st gear at WOT. At least thats what I am guessing happened, I also spun two cam bearings so I don't know what happened first.

 

[750H.P.V6]

Guy's,

Here's a link for Reed Cams: http://www.reedcams.com

JDSfastGN,

I think you're right about ATR selling Reed cams. Not sure about the problem you had. Sounds like a valve spring issue to me. Did you do the install or did a local shop do it for you?

Chevy II,

I do know of I guy who went to the trouble of having the lifter bores bushed in both his stock block and his Stage I motor. Not sure of the actual cost but I know it wasn't cheap.

Neal

 

[NASSTY]

Originally posted by 750H.P.V6

Next I make sure the cam sensor is set correctly. If you don't know how to do this there is info on the GN TType website. If you're still unsure have some double check it. If it's set wrong the motor won't start and you'll be wearing on the cam as you turn it over.

Lastly you need to prime the fuel system. Checking for leaks is only the half of it, insuring the car starts ASAP is critical. I like to run the car at a high RPM (2500 or so) to ensure good lifter rotation and splash lubrication for approx 20-25 minutes.

This may have something to do with my dilema.I had a MAF crap out on me while breaking in my cam.I was worried when it happened but the car ran like a raped ape for about 5k miles so I thought I got away with it.But then the performance dropped off.I haven't torn it down for inspection yet.On the bright side,due to the bad break in there is still hope that my lifter bores have good alignment.

 

[GNandTTA]

Do all blocks have the #3 lifter bore problem? Are some worse than others? I just went outside and measured the distance between each bank of bores and all were the same except for the #3 cylinder. There was an extra 1/8 inch distance between them. Sounds simple but I never thought of measuring between the bores. It is clearly visible that the #3 exhaust lobe on my shiny new CC 206/206 is more "in the middle" of the bore than the others.

Mike from MM said a good solution is to enlarge the lifter oil galleys. I'm trying a more ghetto way of doing it by piping a dedicated oil line and have it splash right on the #3 lobe. Getting the supply from the brass block where the oil supply is for the turbo and OP sending unit. In order to not deny the turbo any oil I regulated the supply by crimping the new metal line a little. Seems to work. I cranked the engine over (with no lifters or heads on it) and there is a steady stream of oil that blankets the lifter. Maybe it will help, maybe not. We shall see.....

I'm very scared of starting this engine back up. Never did this kind of job before. Just to be on the safe side I made a homemade pre-luber system. Going to make sure there is plenty of oil pressure when she's fired up.

 

[Silver 6]

I was able to buy some blocks from a late production run, about 1991. These were a service parts SG1 casting and the change in the #3 exhaust lifter location was easily visible. On a visit with Lonnie Diers, he stuffed a cam in one and we checked lifter rotation. It was much better than earlier castings. So it looked to us like Buick saw the same things we do and made a change. It just may be those limp noodle factory valve springs helps the stock cams last longer.

 

[ijames]

ATR also recommends putting in an extra quart of oil for lots of extra splash lubrication during breakin. Makes sense to me.

So is just the #3 exhaust out of position or is the #3 intake also not where it's supposed to be relative to the cam lobes? Maybe just that one bore could be bushed, much cheaper than doing all of them.

 

[BJM]

Wouldn't this be easily fixed by using a cam blank that places the one bad lobe in the correct position for the lifter bore? Where do the cam blanks come from, I thought their were only a couple of suppliers of blanks. Wouldn't they have figured out a fix by now?

 

[CPAKCP]

Re: lifter bore alignment

Originally posted by chevyII
just read a reply from 750hpv6,he talked about lifter bore alignment. has anyone machined the bores bigger and put in bushings.in pro stock racing 1 hp is alot and in the last few years lifter alignment/bushing the bores has brought BIG gains. I would imagine the cost would be high?

I had my lifter bores trued, cost was $650 - not cheap. I was fighting an oil pressure loss issue on lifter #6. After reading Neal's post, makes me feel better that it was done.

Good Luck

 

[chevyII]

bushings

650 up front is cheaper than making round cams,who did the machine work are they offset different for each bore?

 

[Two Lane]

Anyone had their cam cryo'd prior to install?

Just thinking it might help...????

 

[turbo]

Originally posted by Two Lane . Anyone had their cam cryo'd prior to install? Just thinking it might help...????

Yeah, I was thinking the same thing.

I was also wondering why they could start our engines and just drive them off the lassembly line. NO CAM BREAK IN and no problems!

 

[CPAKCP]

Re: bushings

Originally posted by chevyII
650 up front is cheaper than making round cams,who did the machine work are they offset different for each bore?

You have to find a shop that has the tooling to do the job. As not a lot of folks use our blocks, the demand is not high. What's the old saying low demand = high cost.

I would think that if one was willing to spend the money to true the lifter bores, maybe the idea of a hyd. roller cam makes more sense? What do you experts out there think?

 

[49-blues]

By trueing the lifter bores- do you mean brass bushings were installed cause i wondered if rebushing the bores would not correct the problem but at $650. i think i would rather go to a ductile roller cam.

 

[yullose]

Not to take anything away from the lifter bore misalignment suggestion, but I think poor oil priming may also be a big contributing factor.
When I first dropped the motor in my car, I was shocked at how much trouble it was to get a prime and see oil pressure. It appeared as if the pickup tube siphons all the oil from itself when the pump is cracked open. What I eventually did was fill the oil cooler and lines with oil, then connected one of the lines to the oil pump. I then put a little air pressure to the other cooler line to force oil into the pump and oil galleys. I then refilled the lines and cooler, disconnected the fuel injector harness and spun the motor over with the key, but without the sparkplugs in it. I let it crank and crank and crank until I saw good steady oil pressure. Even when I change oil, I still try to fill the filter as much as possible, and crank the motor until I see oil pressure while the injectors are unplugged. With the oil filter mounted on it's side and so high up, it's not surprising there are so many oiling related issues with these cars...

 

[Ormand]

There's another thread on this subject, complete with pictures of the #3 lifter bores. You can see the lobe is more centered under the exhaust lifter. The discussion that goes with that says that the stock buick cam had seven lobes tapered one way, and five tapered the other way. The lobe for the #3 exhaust is tapered "backwards" from the other lobes in that bank,specifically to deal with the odd lifter bore location. After market cams typically have them all tapered one way, like a chevy, or they have 6 tapered one way, and 6 tapered the other way- they don't catch the "odd" taper for the number 3 exhaust.
Heres a link to the other thread:Thread on flat tappet cams

 

[yullose]

You know what I say ?

FUKKIT....

You guys all have me convinced to drop a roller in mine now... :biggrin:

 

[Chris McDade]

I cryo'd my cam last time I rebuilt my motor and it seemed to work fine.

 

[Jerryl]

I cryo'd my cam last time I rebuilt my motor and it seemed to work fine.

Chris,
Who was the MFG?
Where did you send it, what was the cost and leadtime?
Did you cryo the lifters as well?