The Stovebolt Site Forums The Shop Area Engine Shop 61' 235 camshaft removal

Need a little advice on removing a suspected damaged camshaft. I have gotten a lot of helpful hints and have the camshaft gear exposed but, I dont see how to "pry" it out of the block. The other gears I've pulled had a center point and adjoining threades to gain leverage to pull the gears. This one has two holes to expose some bolts on the front of the block. I've read the manual's recommended procedures but they just say once exposed remove the camshaft.

Also, in case this gets too expensive to rebuild any suggestions on what other used engines would be readily available for replacing this 235 in a 61' 235? Most folks say get a short block 350, but what about matching us a tranny and rearend.
I'm not ready to abandon the 235 but what started out as a probably ring job is now looking like a complete rebuild of the head, serious re-conditioning of the block and maybe even the tranny.

I think that you can remove the camshaft without pulling the gear. Those two bolts behind the gear hold the retainer in and you just unbolt it and slide it out after removing the lifters.

First, set your engine so that #1 cylinder is in the firing position, rotor should be pointing toward the #1 plug hole. Then align the dots on the cam and crank gears. I can't recall if the cam gear allows you to remove the screws behind it in this position or not, if it doesn't you will have to remove the screws then re-align the dots. Remove the lifters and distributor. Now your cam should pull out, turning with the curve in the gear. Be careful not to mar the cam bearings as you remove the cam, don't let the rear of the cam drop.

One problem you will encounter if the cam & crank gear aren't aligned is with either the #3 or 4 counterbalance on the crank not clearing a cam journal.

Exactly as Fred t. says

Fred T: A few questions more if you would be so kind:

"set your engine so that #1 cylinder is in the firing position, rotor should be pointing toward the #1 plug hole"

I know where tdc is and the end of the stroke, but how do you detemine firing position and pointing toward the #1 cylinder bore or spark plug hole?

"Then align the dots on the cam and crank gears."
Are these "dots" painted or are they supposed to be machined or cast on the gear surface?

" Now your cam should pull out, turning with the curve in the gear."
In the direction of the spin?

"One problem you will encounter if the cam & crank gear aren't aligned is with either the #3 or 4 counterbalance on the crank not clearing a cam journal."
Is this on the re-install?

ukonjac,
*The rotor should be pointing to the #1 plug wire at the dist.cap(some people just drop the dist.in and start the plug wires wherever the rotor is pointing).I try to drop the dist. in and reference the rotor to the #1 plug hole/cylinder itself for future reference.
* The dots on the crank and cam should be machined or stamped in the gear faces.
* The cam gear will turn a little as the gear teeth are helical(angled).
*The cam has two flat spots cast into the shaft itself.These must be properly lined up to clear the crank-shaft counterbalances on the removal OR install.

Well, I may have screwed this one up. Here's what I've got.
1. I lined up the holes in with the screws and 1 bolt? to loosen the retainer plate
2. then lined up the spots on the cam and crank gears
3. removed the distributer
4. pulled the cam out about 1/4 inch and got resistance, could not turn the cam as I pulled because the cam gear had not cleared the crank gear when I felt resistance. I dont want to force it or try to pry it. I had already removed the crank idler pulley so had to turn the engine over by moving the truck in gear. Also did not have the distributer lined up, but, does it matter?
I tried re-installing the distributer to see where the rotor pointed but now it will not go back down all the way. The end of the shaft is slotted and looked as tho the slot on the cam and the distributer were in the same position. I have pulled camshafts before but a long time ago, and only on diesels. I guess it's not quite the same but it seems as though it should be.

Did you remove the push-rod cover and rocker cover,loosen the rockers,take out the pushrods and lifters?

Yep, this whole thing started after compression checking #5 cylinder. It was at 90lbs on a compression check, all others at about 140 and suspected maybe needed a ring job. I removed the valve cover, racks and as i pulled the push rod for #5 it was stuck, came out slightly bent. So, I removed the head just to get a good look at the cylinder condition and decided it had not been firing at all. Suspect the cam lobe is probably damaged, maybe even the block.

Did you get the cam out yet? If you have not removed the lifters, they will be hanging up the removal

Yes the head is completely off, pushrods are out, I assume you mean rocker assembly are the lifters?

No, that is the rocker assembly.
The lifters are located behind the side-cover(pushrod-cover).The lifters ride directly on the camshaft.they fit in small holes along the length of the block directly above the camshaft.
If you do not remove them, you will not be able to remove the cam

You will need to take the fuel pump off too .

Keep the lifters in order as they came out , in case the cam is ok and you want to reinstal them .

Have you had the valves out of the head yet ?
Was # 5 exhaust burnt ?

Ukonjac, why do you suspect the cam is to blame for the misfirng?Did you pull the lifter to have a look at the cam lobe?Does the valve fail to open and close when the engine is rotated?

Update on the suspected cam problem. As the kids say, my bad. Looks as tho the lifters ARE working properly. The #5 exhaust valve was not burnt but did have heavy accumulation of unburnt oil residue. Should I go ahead and take out the lifters? They all apeared to be moving and no sign of damage which puzzles me because there was a bent valve in #5. All the other cylinders and corresponding valves looked normal, a slight layer of burnt carbon up but no more than expected from an engine with 200,000+ miles. One other thing worth noting, #2 and #3 piston heads had been "kissed" by a valve. My guess is I ought to take out the #5 piston and see what the rings and bore look like. If I can get that cylinder cleared up, I think it ought to run ok. All other cylinders tested at 140 to 135 on the compression test.

Well , why not Ukonjac ,, you've got it this far down ,, be interesting to hear if there is a broken ring on #5.
I assume you checked the plug and plug lead to #5 and got a good fat spark thru them ?
The bent push rod may be from a sticky valve , but if the engine is really long in the tooth , then they are probably all loose as h*** , and due for new guides .
Maybe it was from when you had your foot right up it chasing that chic in the 57 T Bird .

Now Dusty is speaking from experience

LOL , Luke , ,
Yeah , a friends truck ,, reved pretty good there for a while ,,

zoooooooooooom . . . . . . . . . clatery , clack clack ,, .

Hmmm,,,,, leaving out the details on whether or not you guys caught the T-Bird

Naa ,, but the truck went HEAPS better with the worked over 302 Jimmy in it ,,

Busted rear ends real good ,, LOL .

Yeah, lol, chasin a '57 T-bird would take both feet and then some with a dead cylinder. Besides, my chasin' days are all over, married 29 years my friend.

Doh!I forgot to finish answering your questions.
Yes, the #5 spark plug was as gunked up as the cylinder, but eye-balling it as it was cranking, plenty of spark,even put in new plugs just in case and no improvement in the compression. But that leads me to another question bout removing the piston. Given it has been in there since before I even knew there were chics to be chased in T-birds(9 yrs old in 61"), what's the best way to get it out without doing any damage to the piston skirt or cylinder walls.

Crowbar ,, ,, oops ,
You will want to check the cyl walls just down from the top of the block and feel the ridge that is worn there from where the top ring has stopped a couple of billon times , proper technique says use a ridge remover tool (machine shop) , I'm guessing there are broken or gummed up rings in this bore , sounds like a full strip down is in order , hmm more $$ . You will find plenty worn when you start doing that . .
Check in the workshop manual for your year engine , it is full of good information and instructions .

Well, when you have the ridge at the top of the cylinder removed, you will need to have the oil-pan off to get to the connecting rod bolts.WHen you loosen the rod-cap bolts, gently tap the nuts(still on the studs) with a soft face hammer to help loosen the cap.Remove the nuts and the cap.Put some sort of protector over the threads on the studs so as to NOT sratch the crankshaft journals when you shove the rod and piston up out of the cylinder.
.
(If that is not working properly, borrow a large come-along(puller) from a friend,heli-arc a hook to the top of the piston to help remove it from the cylinder )

Okay, two more questionw for now guys.
1. What would you recommend to use for removal of the ridges?
2. Is the removal so that it feels completely smooth to the touch?
Thanks for all your help, I'm going to need it to get this engine up and running again. It's my first attempt at an inframe repair.

If the ridge is really bad, you will want to borrow or rent a tool called a ridge reamer.It fits down inside the cylinder and cleans the ridge from the bottom up to the top and allows easy removal of the pistons.(Be sure to use some pieces of snug fitting hose on the connecting rod bolts so you do not scratch the crank journal when you shove the piston out of the cylinder

This sounds much more involved that just a cam replacement. Are you going to replace the piston rings, rod bearings, camshaft, etc? If you want this motor to live a long time, I would suggest removing the engine from the car for a complete rebuild.

A in-frame rebuild will not last nearly as long as a complete overhaul. Why, you ask? Because you can't replace the cam bearings, main bearings, freeze plugs, or bore the cylinders with the engine in the car.

You say that the cylinders have a significant ridge to them. This indicates that the cylinders have severe taper (wear). You need to know exactly how much taper your cylinders have. If the cylinder taper is about .010" or more, new piston rings can break due to flexing.

I did a ring job on a 235 back in '91. It had 68K original miles, moderate cyl taper and worn pistons. The engine ran another 30K miles before it failed in '96. The new rings cut the original #6 piston in half at the oil ring, due to wear in cyl and piston ring lands. Years later I heard that piston separation was a known problem when using new rings in a worn straight 6. So you must also check your ring side-clearance in the pistons, to prevent piston failure.

You also said you might have some piston to valve contact in two cylinders. That may be due to carbon buildup on valves & pistons, or a bad valvetrain part. You'll need to have the valves checked for damage, and the pistons & rods checked too.

How was your oil pressure when the motor was idling hot? 25 PSI or less at idle is an idication of worn cam or main bearings. Even if you replace the rod bearings and oil pump, your pressure could still be low due to the worn cam and mains.

You'll also need to check your rod journals for out-of-round and wear if you're replacing the rod bearings.

I don't want to scare you. I just don't want you to spend money and time, and the engine fail early. An in-frame rebuild requires almost as much money, time and effort as a full rebuild. If you go through that much trouble anyway, do the job completely.

Whatever you decide to do, we're here to help!

Chip

Very well stated chip

Chip I could not agree more. My original intention was to remove the engine and send it to a reliable rebuilder (oxymoron?). However, something called a budget, layoff and college tuition forced me to re-think my plans. Now all I want to do is see if I can get away with a cheap inframe, piston rings hopefully. As for the oil pressure it was fine, never below 40 psi, of course I am assuming the oil gauge was right. Someone else mentioned to beware the ridge wear, but it does not appear to be signicant. I really think the only immediate problem when it was running was the one dead cylinder. Of course if it starts to look as though other parts need replacing or repair I'll be looking for a later geneation replacement engine.

I don't know what vehicle the 235 is in, but usually it cost just as much or more to swap in a later engine than it does to rebuild a 235.

The bellhousing, tranny, motor mounts, tranny x-member, driveshaft, wiring, cooling system and linkages are different between a 235 and any later model engine, 6 or 8 cyl.

You may be able to get away with an in-frame rebuild, assuming there is no serious damage/wear to a part you can't fix in-car.

Look for excessive cylinder taper, cylinder scoring or gouges from old piston rings, cylinder-to-piston skirt clearance, or out of round cylinders. Check the crank throws for out-of-round journals, scars or gouges, 'bluing' from overheating, or flat spots from loose bearing inserts. Check the crank end-play for worn main thrust bearing. More than .010" indicates a main bearing problem. (trust me on this one)

You can see the cam bearings from under the car with the pan, rods, and camshaft removed. Look for scoring, marrs, or copper showing through the bearing material. Check the #1 cam bearing for strange wear patterns from timing gear runout.

If re-using the pistons, check for impact damage from valves. Any moderate or serious impact damage on any piston requires replacement of all 6 pistons. Clean the pistons of all carbon, especially in all ring grooves. Check new rings for proper side fitment and depth in ring grooves. Check ring end-gap, to prevent broken rings. Hone cylinders with a bottle-brush style hone of about 250 grit.

Have all 6 rods checked for out-of round big ends, straightness and proper pinch-clamp bolt torque.

Cost for in-frame rebuild:
rod bearings 40
gasket set 100
oil pump 45
rings 30
pushrods 35
head work 300
machine shop work (rod inspection etc) 50-100

So the lowball cost comes in at about $650 if there is nothing else wrong. This assumes that the manifolds, carb, water pump, fuel pump,cam, gears, lifters, pistons, distributor, rocker arm assembly, rods, main bearings, cam bearings, cylinders, crank, etc are still usable. Also check your freeze plugs for seepage and your cooling and oiling passages in block for sludge or blockages.

Be prepared to buy tools, hoses, lines, filters, gizmos and whatzits that you didn't know you needed.

Sheesh, yet another novel...

Chip

Have you tried finding a running 235 or 261 to drop in? It might be your cheapest way to go.

I had bought a running 235 that I decided to tear down. Something just didn't feel right. What I found was a driveway overhaul. Very little ridge, less that .010. but the rods were stretched, it showed on the crank. Popped the pistons, fairly new rings. Then I got out the snap gauges to check the bores. I had one cylinder that was so far out of round that it was within .005 of having to go to .080 over instead of .060.

If you do go for the later 250 block there will be a lot of work to make it fit. Chip is right about that, too.