Seized Cam Bearings.

[converted]

I have been reading alot of posts about seized front camshaft bearings and its seems its becoming a bit of an epidemic with these engines.

I have had mine go recently on a converted SC400 engine in a boat. Im about to put my second 1UZ in the boat and I was wondering if theres anything I can do to check that all will be ok before I put everything back together. I dont want to go a chev in the boat it would be sacriledge but if i do another 1UZ in, i mightnt have a choice.

 

[spf_lexus]

Use some high quality assembly lube like Redline and coat the cams + scissor gears + cam mains and you'll be fine. Make sure the cam mains go back exactly as they came off.

Only reason these cams seize is oil starvation from sitting idle over long periods.

 

[XR8tt]

They don't have cam bearings .. I know what you mean tho...
If it's an issue ?? Why not open the oil supply gallery up a little so oil distribution is better under cam cap ??
What visc oil are you using ??
Any oil cooler ???

 

[converted]

ok better to be safe than sorry again...i'll pull the cams and have a look round first seems like its an ongoing issue for motors which have had some downtime...

 

[XR8tt]

Yea well ?? I guess pull the cam retainer cap and have a look if there's been issues before.. A few drops of oil won't go a miss either... Don't think there's any need to pull cam...Could check bucket clearance ???

 

[cribbj]

I've noticed that some rebuilders get a little too enthusiastic with the FIPG in the cam seal areas, and have partially blocked the oiling holes at the front.

About the engines that sit for long periods and start dry; I'm a big believer in external prelube systems, which will allow you to circulate oil and build oil pressure before starting. I built a system for my 2JZ Supra, and it's worked flawlessly for over 6 years, and I have them on both the 1st and 2nd UZ's that we built.

 

[Lextreme II]

I got an email few weeeks ago from an unknown person trying to sell his motor to me with the same issue. There might be some underlining problem.......

 

[Zuffen]

Keep in mind the cams aren't fed oil to each journal.

The cam itself transports oil to the journals, just like your crankshaft does to the mains, so if anything is blocking the oil supply at the end of the cam that cam, or pair of cams, will run dry.

My first engine build didn't have the oil supply fittings on the cams and it ran for 800km without any damage and this was fed by splash only so it can't be too big a problem.

I would suggest the problem lies elsewhere and the cam is the first to suffer.

 

[XR8tt]

Possibly due to engine being steam cleaned and left for some time period ....
I would imagine some WD40 or similar would be wise to spray in and around cam journals ??
Or taking tension off cam retainer bolts till engine is turned by hand ??
Then re torque cam retainer bolts...

 

[sideshow]

problem is u dont know history of motor
any lube wont help if there is gunked up oil from poor oil changes in japan very common

maybe on next motor take rocker cover off and remove oil feed tubes and give em clean and blow thru with air
most fo the time oil flow is ok at startup then after awhile something dislodges and blocks a gallery
unfortunately its luck of the draw if your motor will do it and they are getting old
best bet to buy an engine from someone who is know to bring in quality stuff compared to alot fo guys that have jumped on the importing bandwagon
this still doesnt mean the good places can have some motors which have problems

 

[gloverman]

I have seen this a bit , mainly when the motors have been sitting. Best to get a fresh one from the importer and get it in as fast as possible. Also always crank up oil pressure before starting. We also need to remember that some ofthe motors are 20 years old.

Cheers

 

[spf_lexus]

Just curious but how do you "prime" the system before startup? I need to lube my 4.7L as its been sitting for about a year and I dont want to hurt anything. Should I take the valvetrain apart and lube by hand with assembly lube or is there a special trick?

 

[cribbj]

Shawn, the UZ motor's oil pump is known for losing its prime with time, so you can start the motor up, and not have "any" oil pressure for an extended period. This could also be one of the causes of these seized cams.

To ensure the UZ motor's oil pump will function when you need it, what I would do is first manually backfill the oil pump with a basting syringe - (you'll need to take off the oil filter bracket to do this). This will ensure that it'll "catch" its prime when you fire the engine the first time.

Next, if you're up for making a temporary prelube system, and you can borrow a ShurFlo pump from someone, I would put this oil filter bracket back on, but take off the oil filter itself and make an adapter hose to fit the center threaded pipe where the oil filter spins on (which should be a 3/4 x 16 thread or same as a -8 AN), then the other end of the hose should fit a Shur-Flo pump discharge (normally 3/8" or 1/2" NPT), and the suction side of the pump should go to a gallon of whatever oil you're going to be using, then run the Shurflo until you have oil pressure in the system (normally 10-30 seconds of running). This will also fill the crankcase with oil.

 

[spf_lexus]

Great tip Cribbj, thanks a bunch. If I drain my oil pan and leave the plug out, I would see a consistent drain of fresh oil once the pump has been running long enough to have fully primed the system right?

Looked up a shur-flo and they run about $100 online and the line cant be more than $20. I'v been worried about my car sitting idle for so long but with this I guess it can stay in a coma until I have time again.

 

[converted]

bought second engine and runs fine. I used engine assy lube on the front journals and gave the engine a quick internal inspection before installing. Making good pressure and runs well.
The last engine had alot of metal in the crackcase so i reckon there were more issues at hand.
It was out of a wrecked soarer i bought the whole car for 1500, so i reckon they damaged the engine knew it and then did an insurance job on it i reckon. Car was bought from a soarer wrecker in Kirrawee. Ran in the car...but car was smashed so couldnt drive it.
If you can drive the engine first thats great if not $900 from a wrecker with 3 months warranty is the way to go. They do a bench test for comp and internally inspect them.
But yes they can be 20 yrs old now so taking a risk......

 

[Ian231]

deleted

 

[Zuffen]

I would say 90% of us do it that way.

Mine started up and ran fine.

I've had an engine given to me with seized cam bearings. It also had seized thrust washers on the crank, so which happened first?

 

[gloverman]

I always crank up oil pressure on the engine stand before putting the motor in the vehicle. Plugs out , test light for the oil light and crank it over. If I have the sump off I will prime the oil pump first with assembly lube to make it faster. Cheers

 

[XR8tt]

I wander how many of these engines giving grief are steam cleaned ???

Thrust wear on main bearings is usually an auto alignment issue...
Or too high line pressure using a G.M auto...

 

[spf_lexus]

Brutal auto shifts can actually spin/seize bearings? I did not know that. I always assumed a u-joint or pinion would give out first.