The Stovebolt Site Forums The Shop Area Engine Shop Cam bearings swap with engine installed

I'm trying to figure out if its possible to replace the cam bearings myself with the engine installed and the cam shaft in place?
Any specialty tools required, I could rent from my local parts place?

If I go to a shop I might as well upgrade the cam to a 3/4 with solid lifters and aluminum timing gear.
I have hydraulics now and maybe even the fiber gear.

The reason for replacing the cam bearings is my low oil pressure after long freeway rides.
Maybe I need new main bearings and rod bearings as well and should have everything done at once in a shop?

Is changing the cam bearings a relatively easy weekend DIY or shall I go for the whole upgrade?

your low oil pressure might also be because of a worn oil pump as far as i know you have to pull the camshaft to take the cam bearings out i don't know how to do it i had a shop put in my new cam bearings on my 350 when i took it in to get hot tanked and check over
Nate

On the road again,

Just my two cents..if you could pull this bearing change off "in situ", you are probably the first guy in history to ever do it..although worn cam bearings could effect oil pressure, they would probably be one of the last suspects on my list.

Stuart

Try 20W-50 oil formulated for high mile engines before doing anything else. Also look at your owner's manual to verify that your hot idle oil pressure is indead too low, you could be worrying about nothing. I don't think you would be able to get the old cam bearings out in-situ even with the cam removed.

Thanks for clearing that up. Did searches about the 'low oil pressure when hot syndrom' in the past and found a few comments on going for the cam bearings first.
I like the idea of main or rod bearing replacement better - it's seems easier to do and with the engine in place, according to the shop manual and a private message.
I believe my oil pump is good, because I changed it years ago with no change in pressure.
Around town the pressure stays up, but when I go on freeways or climb hills (especially in the hot summer around here) the oil pressure drops and stays down until the engine gets a long rest.

Any specialty tools required for replaceing main and rod bearings?

Over the past ten years I tried all the oil additives and settled with pure 20W-50 for the past two years until I read about the multi-grade oils losing their 'magic' after 1500 miles.
Switched last summer to straight 30 HD.
I don't even have to go down to 20 for the winter, despite temperatures in the 30s-40s.
Maybe another give-away that my main and rod bearings are in need of replacement?

on the road again,

I'm not sure what you are trying to do on the engine, but usually you don't just replace mains and rods. The inserts would be worn AND the bearing surface of the crank as well. All this, if done properly would require grinding the crank and precise measurement of the journals.

This is a engine builders arena.. I think the most a guy could do by himself under a shadetree would be to remove main bearing shims and use a plastigauge. This would require that your truck had main bearing shims...I don't know if yours does!

I think the loss of "magic" in the multi-grades was a reference to the viscosity index. Oil chemistry is complicated, and it is easy to come to conclusions based on poor information.

I can't believe the oil companies would invite litigation by pumping out a product that went sour in 1500 miles, when the common oil change interval is about 3000 plus miles. I might be naive though.

Stuart

Figures it couldn't be that easy... I guess I just go back to waiting til something's broke - then fix it.
This is about a 1962 235 btw.
Haven't had any big issues from the low oil pressure, except for raise in water temperature during the hot summer.

I replaced the water/coolant with Evans NPG+ years ago, which was an expensive one-time investment but is a nice treat for any engine - no more corrosion, replacing and flushing for life, with a boiling point of 375*

Oil thickeners like Lucas oil additive raised the oil pressure, but didn't neccesarily keep the engine cooler.

Last summer I read about the multigrades and their polymers. I figured let pure oil do the work, instead of additives, thickeners and polymers, all subject to premature breaking down over pure oil.

Althought the 61 shop manual talks about multigrades the straight 30 seems to keep the water temp cooler longer, but also eventually goes up to 200 after a while on the hot desert freeways.
Seems to lose power when getting that hot.

Too bad for a daily driver - would love to have pressure up to spec and lower engine temps in the summer, without a complete block rebuilt.

On the road again,

You haven't said what your oil pressure is, but I sure would look at a whole bunch of other things before I blamed excessive engine temp on low oil pressure. I have a nasty old International Loadstar 1700 here at work. It has a bazillion miles on it, and the oil pressure gauge usually doesn't go over 20 lbs.

It doesn't take a gob of pressure to sustain an average engine. Do a search in this forum using "oil pressure"..you'll be surprised at what you find.

The SOP in these old rigs is poor cooling system performance equals excessive engine temp equals thinned out lube! Pick those fruit flies out of yer radiator boy!!

Stuart

Thanks for all the good advice - I always like listening and learning.
Been trying to hunt that one down since I got this truck ten years ago.
I had even higher engine temps before I replaced my radiator to a 3 core two years ago and don't use water/coolant any more.

I still have an original 30psi gauge, which is pegged at warmup and during in-town driving.
In the summer it goes down to 20 or lower at idle, in town and short trips. Longer trips and standing in traffic drops the pressure to almost 0.
On the freeway at 2500-3000 rpm the pressure drops eventually to 20 after a while and almost to 0 pressure at idle, coming off the freeway.
The hot summers make the pressure drop faster and keep it down.

The oil gauge seems to read very accurately; replaced the oil gauge line; bypass filter is correct type and installed properly with the proper sized lines.
Head gets the right amount of oil. Timing is lean and beautiful (tried all kinds of retarded and advanced settings over the years). Distributer works beautiful and is even.
Rebuilt the head completely last year.
No smoke or burning oil excessively.
Nice pressure in all cylinders - about 125.

The block just can't hold the pressure any more once everything gets hot.
Since everything else on the engine sounds and works beautifully, I always asumed the bearings must be too worn and allowing pressure to bleed off.

On the road again,


WOW..you sure have done the drill. It's pretty easy for me to sit here and say this and that, but you have actually tried everything, and pretty darn comprehensively at that.

I have always felt that cooling problems were exactly that..problems with the cooling system.

To say that the cooling system if fine, but that additional heat caused by friction from a marginal oil system is causing the truck to overheat has never seemed reasonable to me.

If lack of oil causes friction, which causes heat, then it seems like the engine would eventually seize.

If the additional friction/heat were not enough to seize the engine, then it wouldn't be enough to tax the cooling system..unless it was marginal already.

Keep at it..maybe one of the brains on the site will pop in with the answer.

Stuart

Sounds like you're fighting more than worn bearings. I'm thinking you don't have enough radiator. Don't know if it's due to an old and dirty radiator, or that these trucks were marginal on capacity to start with.

On your oil, don't be afraid to try something heavier. Around here I can buy SAE 40, sometimes SAE 50 if I want to look hard. If your air temp only drops to freezing, you shouldn't have any trouble starting with SAE 40. It's worth a shot at the next oil change.

I was looking at some of your other posts seeing you want to build a 261. I would speed that up if I could, just in case this engine doesn't make it. But you will need more radiator for that, more power needs more cooling.

You never know how long an engine will last under these conditions. I had one six in a 5 ton that had good oil flow, but little pressure. We put a few thousand miles on that engine, running wide open almost all the time in a fire truck. It could have gone at any time, but it was still running strong when we sold it.

I can't even list all the things I have done and tried with the engine. I kept a journal of the driving restoration of 10 years, which is 6 pages long in small print.
Learned a lot about which parts are OK to replace with remanufactured or NOS parts and which aren't.
Tried every multi grade oil there is and every additive.
Today, I like the idea of pure organic detergent oil and no modern additives or multigrades.
Alright - so I could even go with SAE40 and start at low temps ... I do that this weekend.

That is good thinking to keep it a cooling issue.
It's just hard to figure out if the oil pressure drops because of higher temps or the temperature goes up because the oil pressure drops.
One seems to cause the other to raise or drop respectively.
The cooling improvement I made a couple of years ago only slowed down the oil pressure drop, but couldn't prevent it.
I went through 3 old radiators, before I recored the last one with 3 core, which made a big difference after 8 years of heating up.
I even have the rare taller core, which I dropped down an inch to get closer to the water pump, which is short shaft and original lower 62 position.
The fan has always been about 3/8" close to the radiator - maybe that is just too close.


But no worries really - Before the internet and learning more about these engines and trucks (Thanks Stovebolt!), I drove this engine with the previous 4.11 rear and often pegged water temp on TX and s-CA freeways.
In the end I ran straight water with no thermostat.
No cracked head or any problems ever.
Can't kill those engines unless you do something really bad or wrong, it seems.


I just keep experimenting with higher grade oils and just wait until I can afford a second driver next year, to retire my old friend and partner to mostly in-town cruising.

The 261 short block I am trying to find will go with my NOS 848 head and all the other parts I got already.
I plan to put it into a 47/48 chevy coupe I want to find next year, which will do all the hot freeway long distance driving in the future.
I will learn more about cooling and oil pressure then, I am sure.

Are you using the Evans product now or is it water you are using as coolant. Nothing resists changes in temperature as well as water and having a higher boiling point in exchange for slower heat rise isn't a compromise I would make.

I switched to waterless coolant about two years ago and never go back.
This coolant does not have boiling water around the cylinder walls (inhibiting heat exchange) and is much more efficient than water in heat transfer. No snakeoil this stuff.
It can also be used without any pressure or thermostat, as it wants to flow to be more efficient.

That's what I will do this summer - take out the thermostat or experiment with the high flow Mr. Gasket type, when going on the freeways.

The other 'cool' aspect is that there is no corrosion and deposits to the engine, radiator and pump.
And the coolant is guaranteed to last for the life of the engine.

I am not affiliated with that company, except a happy user.
It's very expensive but a one-time investment, which pays back over just a few years in many ways.

3/8" is very close, but as long as it doesn't hit the radiator you're okay. Actually, being close improve the efficency of the fan. Means the air has to be fulled through the radiator.

At speed, the fan doesn't move any air. It actually becomes a burden when the vehicle speed is faster than what the fan will move air. That's why they started putting clutches on fans. I don't know what the speed is, but it's fairly slow.

You may want to double check the oil lines on that bypass filter. There should be a restriction in the return line from the filter. You can check to see if the oil pressure rises by blocking off the filter lines and driving it.

However, I would be willing to bet that this snake oil coolant stuff that you have in your radiator isn't as good as you think it is at heat transfer. I would go back to 50/50 antifreeze/water and change it every year, and put the thermostat back in, and I bet it will work a lot better.

No thermostat? I always thought that CAUSED the engine to run hot. Once the fluid reaches maximum hottness, the only cool factor was when it raced through the radiator. The fluid didn't have a chance to sit and rest a while. You said that super coolant had a boiling point of 375 degrees.I don't know what the "normal" operating temperature is for your motor,
but I think it is well below that. Everything everybody has said is right on target. The only thing I might suggest is a bad head gasket. They sometimes cause curious things to happen.

I was under the impression the tiny hole on the upper end of the tube inside for the outlet was restricting oil flow.
I went ahead and plugged the bypass oil filter but it didn't affect the oil pressure.

Cooling is fine, just climbs 10* when I go uphill on freeways at 2500 rpm, especially in the hot desert summer.

I guess the low oil pressure when warm and hot is because the last block rebuilt was at least ten years and 100.000 miles ago.

Takes a little longer to warm up during winter, but when the engine is at running temperature pressure is 15 psi at 475 rpm idle. It goes above 30 starting at 1000rpm. Fine for the town and shorter trips.
On the freeway, temperature stays at 180 but the longer I drive, the lower the oil pressure eventually drops to 0 at idle and 20-25 on the freeway at 2500-3000 rpm.
In the summer the temp goes up to maybe 190.
Last summer I got stuck in a freeway traffic jam and the temp went all the way up and the oil pressure was really low.

Your low oil pressure problems may be due to the fact that at freeway speeds the oil is unable to return to the pan fast enough to keep up with the oil pumps higher output. You may want to look at the oils that are used in the larger diesel engines, they are made to with stand high temps. I use a product called Premium Blue 15w40 (Cummins Blue) in all my trucks and cars(except the lawn mower my wife says it makes it hard to start). As for coolant I use the 50/50 antifreez and water mix, it work real good and if you lose coolant for some reason it is easy to find and replace, ie. auto parts stores, 7-11s even the supermarket carry anitfreez. Just one more thought, how are your radiator hoses?

If you want to stick with single grade oil,you can get a good selection at any airport flight service. I used to buy 50 wt oil for my Harley from the bulk plant that serviced our airport for about the same price as the name brand multigrades at the local parts store.
Speed

Did anyone figure out what was wrong with this 235 ?? I have the same problem, On long drives it loses oil presure. Thanks johnny

The thread is only 8 years old... give it some time.

Good compression and on the road high temps equal wear, piston to bore. And some taper. The heat is getting past the rings and heating up the piston. That makes it tight in the bore and adds lots of friction and more heat. If the bore is good then the piston grooves are worn and that will transfer more heat to the piston skirt. You will not see much blow by at freeway speeds. The draft tube is working good at that speed. How much is the oil down at the change interval? If you don't measure both the filter canister and the dip stick you won't know. Worn oil pump will do the same as it gets hotter as well. But to your credit, you have done your homework and kept good records. You might have some worn rings with very little taper or ridge. If those rings got hot they will anneal and lose the pressure to seal. And I know you have done a compression test. Now do it when it is hot and the oil pressure is down. Might be helpful. Water cooled engines are much more forgiving of this that air cooled. If this were my Harley it would be stuck by now. Just some things to think about. You have done the right stuff. Cooling system sounds good. Timing sounds good and if you don't have any stumble then air leaks are off the table. You can have a head gasket issue but that would push the coolant out so that is good to. What is left is posted above.