The Stovebolt Site Forums The Shop Area Engine Shop 1954 261 - questions for the wise

I have a 1946 2ton with a 1954 261 and 4spd tranny. Hadnt been run in 15+ years when i got it, previous owner said it needed a new water pump. Engine has no oil filter on it.

I put a new water pump and radiator, fuel pump and rebuilt carb. Ran all new fuel lines to a 5 gal gas can. New plugs points, wires, coil and rotor +cap.

I pre oiled the engine with an electric drill, set the distrubutor with the ball on flywheel right on TDC, i also adjusted the valves. the engine fired right up, but backfired pretty bad, i think i had the mixture screw to rich, i leaned it out and now it doesnt backfire at all....I was running some rotella T6 thru it and dumping it to clean out the engine.

Now the problem- i forgot to hook up the throttle linkage one time and when i fired it up it went pretty much full throttle...i shut it down pretty quick, anyways after that it start to smoke.about 15 sec after starting it lightly smokes, a little heavier under throttle but a bigger puff when you let off the gas..
I noticed the #3 CYL exhaust valve rod looked like it was dancing all over the place...i pulled it and straightened it with a hammer, it had scrape marks 1/2 down on the side. put it back in adjusted the lash but seemed to make no difference in the smoke.

#3 and #4 cylinders plugs are oily when i pull them. Any suggestions? I plan on pulling the motor anyways to clean it up and paint it. Although when i 1st changed the pugs #3 and #4 were much dirtier than the others
Is it expensive to have the head rebuilt? or can i just put new guides and rods and valves in it or something like that? i dont really have and experience in engine rebuilding.

Should i get compression gauges and check my compression as well? Truck is only showing 35,000 miles but mileage is unknown on the newer engine

Opinion from someone who has been in similar circumstance:

Long sitting engine - trying to revive.

(I am no expert. Everything I'm about to say I learned here.)

Compression gauge is cheap way to start. Doing a "wet" test (use forum search) after the initial will help narrow whether it's a top end or bottom end issue.

If it's a bottom end compression loss, don't immediately assume rebuild. Might be rings stuck from it's long nap. Do a forum search for "Kroil" and look for Hotrod Lincoln's procedure.

A basic head rebuild wouldn't be too bad, assuming yours isn't cracked.

I would pull the Pistons, crank, while the head is worked on, check taper on bore plus size, check rod and main bugs. It would be cheap and easy then, answer questions, save future problems.

I've never done anything like that before, kinda scared to honestly.
So if I take the head off it would be best to just take it to a machine shop and have them do everything? Do I need to buy all the parts like valve seats, etc?

I was hoping i wouldnt have to tear the whole engine apart dang it! I may need to see if I can find someone to help me if im getting in this deep

Yes, JLM. Truthfully, the machine shop would be able to tell you if the Head (Valve Guides, Valves, Springs, etc) is serviceable.

Before you do this, do a compression test first like JW51 suggests. If the numbers are around 100-110 or better and the same plus or minus 5psi or so then maybe its something different causing your problems, like too much fuel being dumped in. Too large of carb jet, or idle screw on the carb not adjusted correctly can cause wierd things. But I am like JW, I learned everything I know from here.

Then, if the easy doesnt work, the hard isn't that bad and if you are not depending on this vehicle to get you to and from work, you will learn a LOT about engines. We are here to help!

Put in some new spark plugs, make sure you have good brakes, and drive the truck. After a short time, pull the plugs and see if they tell you anything.
Its too soon to start tearing the engine apart.
You can spend a lot of time diagnosing everything, but if it idles smoothly and accelerates properly, there is no reason not to drive it. These engines like to run. Let it.
Your diagnosis of problems will be more productive after you run the engine for a while to get the "cobwebs" out
Carl

This issue sounds like it could benefit from "hotrods" kerosene crank case flush procedure. You might be real lucky and just have some stuck piston rings resultant from the trucks long nap. What do you think Jerry?

In any case given your comfort level (or un-comfort level), go slow and try cheap and easy fixes before tearing the whole engine apart.

Good luck!

Paul

I've run the engine up to temp for probably a total of 2.5 hours, it has new plugs, etc.

I ran marvel mystery oil in the fuel and oil, probably run 3 oil changes thru it just to try and clean it out.

Having the possible overspeed and the bent rod just makes me think it has to be a valve issue? The previous times i ran the engine it didnt smoke like it does now....

It smokes a little after warming up at idle, not much, then steadily more as throttle increases, then usually puffs alot on decel...i have slits in the valve cover which i can see smoke coming out of, not a ton...and a little out of the road tube ofcourse which i recently cleaned out it was pretty nasty.

Im in the process of taking the truck apart now, and planned on pulling the engine anyways to clean it up and paint it, new seals and possibly timing gears...

Still the best thing you can do now is the compression test. You should also flush the radiator and the block.

I'll have to swing by northern tool and get a compression tester, i dont have one- I assume the procedure will probably be written on the box?

I ran some coolant system flush thru a few full temp heat cycles already, also before i ever started it when i was changing the water pump i flushed the block with the water pump off with a garden hose, plugging the other holes while it did, it has a new radiator- actually my temps are only about 160-170 per my autozone gauges i bought - never seems to get very hot at all - has a 180 degree thermostat.

Ok I did a compression test cold for the heck of it and got 90psi on all
Warmed engine up and got
1- 110
2-105+
3-110
4-108
5-105
6-106

Pulled all plugs and did 3 tests per cyl about 8-10 revs of the motor, they look a little low but enough to smoke a lot? In need of rebuild? Or possibly just a valve job could fix my smoking?

Your compression test results are a good sign, but shows me that you need to put some serious miles on it before anything else.
You will likely need new rings, but you can't be sure unless you either:
1) Drive it and see if the rings free up in the piston grooves and scrape the dinosaur crap off of the cylinders.
Or,
2) Bite the bullet and pull the head and see if the cylinders are worn significantly, or see if a simple hone and ring replacement would be feasible.
Carl

I'm pulling the engine anyways..its run several hours truck isn't drive able though...
Looks like I'll pull the head and take it for a valve job and while its apart pull the Pistons and get some measurements and see what I'm working with

Since I had one slightly bent pushrod should I replace them all?can you buy them anymore for a 261? Are there different kinds?

When you take it apart, be sure to label each lifter as to the exact hole it came out of, and keep the rod with it. A lot of times you will find a number on the top of the piston. .010, .020, etc. That is the overbore size. This will help you with what size rings are installed.

I am not one of those who likes to live on the edge, so I take the engine apart labeling every little thing, but once it's all the way down to a bare block, I WILL take it to the machine shop. I let them clean, magnaflux and check the bore characteristics. The cost is nothing compared to something I could easily miss myself. Of course since its ME, I would also have the full flow modification done to the block for another $100 (it being a 261 it just makes sense to me). I would want them to inspect everything especially with a bent rod in play.

If I have a bent pushrod does that mean I should replace all of them as well as the lifters?

If you replace the lifters you should replace the cam. Each lifter is matched to its camshaft lobe. I do not think it's wrong to replace the rods. You can get them new anywhere that sells engine parts. I've been pretty happy with RockAuto in that regard.

New cam - new lifters.

New lifters - a new cam would be nice, but not necessary, unless a bad lifter scored a cam lobe.

In any case, new lifters need to be broken-in following an appropriate procedure (and use extra ZDDP during break-in).

You don't need to keep track of where the push rods came from. They will work where ever you put them. If there is wear on any of them, those individuals should be replaced.
A slightly bent push rod can be straightened and checked by rolling on a pane of window glass.
Carl

Have to take the opposite view on that Carl. If we're at that
point...that is, a bent push rod, no way would I re-use a
bent push rod unless I was out on the road and needed to make
it home. Rolling them on a "surface plate" or known flat
surface is a good time tested way to "find" a bent rod, but
once it's bent, for the cost of a new push rod ($5-$6), why
take a chance on it failing again.
If the tube is bent, the metal has been stressed beyond its
yield point stretching the materials grain structure on the
high side. When you bend it back it will pull the grain apart
on the low side and the column now has a weak point all the
way round where it's gonna fail again.

DG

I straightened 5 bent push rods on a 216 30 years ago when I did not have access to anything else. I then put 21,000 miles on it and it ran like a top until I retired it due to a cracked water jacket and a mistaken assumption of a need to do a rebuild. (All it really needed was a re-ring job. I still regret scrapping that block.)
Your results may very.
Carl

I already tried to straighten it, it's a little better but I can still see it dance around a lot.

Anyone recommend a place in dfw area to get my cyl head done?
Will they have the parts or should I buy some sort of kit with valves seals etc to drop off with the head?

Any one recommend a source for 261 pushrods? Did a quick google and didn't see much.

Egge sells them @$10.70

Hope someone posts a better (less expensive) source.

If the same as the 235 Rock Auto has this one for $5.00: https://www.rockauto.com/catalog/moreinfo.php?pk=333715&cc=1326361&jnid=468&jpid=0
Might be in a set, not clear from the site listing.

That Rockauto.com push rod measure 11.474"

This 1954 truck 235 push rod is closer in length to the Parts Manual spec of 10.58".

The 11+" push rods were used in Powerglide car engines.

It looks like manual-transmission car 235 engine and all transmission truck 235 engine and truck 261 engine push rods were the same.

http://www.napaonline.com/Catalog/R...099%204014058%205999999%2029749/Ne-25000

Wow, I didn't realize the link was that big!!
NAPA, from sealed power, $6.21 Part #sep rp3018
10.819 length.
You probably floated the valves with the high rpm blast and that bent the push rod, you also likely broke several of the valve seals, causing the oil smoke. there are a couple ways to replace the seals without removing the head.
Just one more opinion worth what you paid! Good luck
DUMB ME, SHOULD HAVE CLIKED ON LINK IN POST ABOVE FIRST!

Thanks for all the info guys, 10.819" push rods got it.

I'll call around when I pull the engine and see what a valve job would cost, if its not too bad I may go ahead and do that, I wouldnt mind pulling the head while its out anyways so I can see how the rings are and all that and see what shape everything is in. I like the idea of honing the bore and putting new rings in it etc if thats an option.

Ok I pulled the motor, lots of sludge on pickup and oil pan, found 1 lifter that appeared to be coming apart at the top, almost like it was made that way, like a cut 1/16th of an inch from the top, it would pump up and down...

All rings were free,bearings didn't look too bad to my, some had copper color showing thru.

Carbon caked in Pistons but tons more in the head and valves. #3 and #4 the worst.

.060 stamped on the tops of the Pistons, cylinder walls looked nice and shiny, was able to push Pistons out by hand.

Also found casting numbers by starter. "Con 3 A135"

Con 3 A135

Con 3 - Conveyor #3 at the engine plant
A = January
13 = 13th
5 = 1955

Most likely from a 1955 1st series truck?

What was the brand and part number of the water pump?

Is the water pump body completely below the head, or does a little of the body go above the top of the block?

JLM,

The casting numbers you found are the Casting Conveyor number "CON 3" and the Date Code "A135" = Jan 13, 1955? The casting part number will be on the passenger side all at the very front of the block down low (right above the oil pan).

Didn't mean to repeat what Tim said, I was typing when he posted...lol.

Mike B

Does it have hydraulic lifters? What you are describing seems so. That would change the push rod length wouldn't it?

If it is a 1954/55 261, normally it would not have hydraulic lifters (unless the block had been converted/adapted for hydraulic lifters).

Can you post a link to an image of the top of the lifter?

It is very possible that odd/inappropriate parts from later/plentiful 235 car engines were installed over the past 60 years - to keep the engine running. All 235 car engines from 1956 onwards had hydraulic lifters.

If you have hydraulic lifters, you might want to consider buying a set of matching push rods and mechanical lifters.

http://i1011.photobucket.com/albums/af232/mrnkc130/1946/34806E35-D536-424A-B1ED-4EDF643E7E1F.jpg

Added pictures of lifters including the one that appears to have come apart, engine and head casting numbers water pump and head.

I also bought a micrometer and took some bore measurements, 1st number is from down the bore with one of those T looking deals, 2nd is from top of bore with just micrometer, I can't feel a ridge at all in the cylinder.

1- 3.798. 3.806

2- 3.810. 3.812


3- 3.813. 3.812

4- 3.807. 3.809

5- 3.804. 3.811

6- 3.805. 3.814

Cylinders has .060 stamped on the top, I'm sure my measurements aren't exact but how does everything look?

I'd recommend rechecking a few of those measurements. A .060 over 261 should measure 3.810 at the bottom of the cylinder, and the top measurement should not be much over 3.815" to get a good re-ring job. Beyond about .005" of cylinder taper makes the rings work awfully hard to maintain contact with the cylinder walls as they have to change diameter twice for every turn of the crankshaft. At 2500 RPM the rings in a taper-worn cylinder are changing diameter 83 times a second. If you've got less than .005" of taper wear, you're in pretty good shape for a re-ring job.
Jerry

Thanks for the info! I'll measure again tomorrow and try to be more exact, I didn't know cylinders were tapered.

What do you think about the lifters?

What do you recommend to cross-hatch the cylinder with Jerry?
Osborn makes several brushes that they recommend using to take
the swarf off after cross hatching with something like a Flex-Hone.

Also ring technology and bore finish have changed by leaps and
bounds over the past few years. Kind of a challenge to choose
the correct ring set to match up with your bore pattern and
micro finish.

dg

261's didn't have hydraulic lifters, as they were truck engines only. The only exceptions were "Pontiac" 261 engines in Canada- - - -they were hydraulic.

Cylinders aren't supposed to be tapered- - - -they wear that way. Most of the taper wear happens in the first 1 1/2" or so at the top of the cylinder where the combustion pressure is the highest. That what causes a "ring ridge". You can measure the diameter about 3" down from the top and it will be almost exactly what it was when the cylinder was freshly bored and honed!
Jerry

If I'm not boring and honing for new pistons I use a button hone and motor oil as a lubricant, followed by a healthy scrubdown with a stiff bristle brush and HOT water with dishwashing liquid, followed by repeated rinses with water that's almost boiling. A round toilet brush makes a pretty good cylinder scrubber. When a white terrycloth towel comes out perfectly clean after a thorough scrubbing and the cylinder tries to flash-rust as soon as the water dries, it's clean enough for new rings.

Rebored cylinders need the last 2-3 thousandths taken out with a rigid hone to remove the machining marks and apply a good cross hatch pattern for ring seating.

The new generation of low-tension rings needs a totally different cylinder prep with a much smoother surface finish. Those rings simply don't tolerate any cylinder taper at all. I was a consultant on some problems with Cadillac Northstar engines a few years back where cylinders factory-bored 1/2 thousandth too big started using oil after only 25K miles in service!
Jerry

The close tolerances can take a lot of the credit for the high
mileage that we're getting out of the new engines. Not unusual
to find cars well up into the 100's of thousand miles and close
to 200K and still running strong with very little oil usage.
Of course advances in cylinder and ring alloys have a little to
do with it also.
Lucky you are if you could get a Stovebolt to 60K or 70K without
a major overhaul.
DG

Top of JLM's lifter
Side of JLM's lifter
Side of another of JLM's lifers
Side of the same lifter?

tcelderman

correct- the lifter with no masking tape on it is the one the came apart on the top, the one with masking tape is how all the others look- i guess i need new lifters? but if i do that it means i need a new cam?

i'm pretty sure they are all solid lifters, one is just broken.