The Stovebolt Site Forums The Shop Area General Truck Talk 235 or 261?

Engine still in an old bread type truck with up draft carb set up. Does have Captins Bars. Can't read casting number at the moment. The number right behind the distributer is A L 0542045. Does have a 848 head. Could it be a 1954 235 with Captins Bars

The serial number you give is the wrong format for a '54+ engine. It suggests an earlier model. The AL prefix would be for a 235 from a '41 COE, which would have had the updraft carb. However, an 848 head wouldn't work on a '41 engine. Double check the serial number and try to find the block casting number.

Sorry the the number should read: LA 0542045

That makes a difference, but it still doesn't fit the format for a '54+ engine. A prefix beginning with L would signify a '53 engine, but it should be a 3-letter prefix. Any LA* prefix would be for a '53 passenger car 235. An 848 head does fit a '53 235. That still doesn't explain the captains bars, though.

There is a chance somebody restamped the number on a '54+ engine, perhaps to match a '53 title.

sorry for my %?+*!~|"
what are captains bars?

They are explained/shown here:

http://www.oldchevytrucks.com/cgi/htmlos.exe/003220.5.2987645496900025883?

From Carter's site:
"Watch for the "Captain's Bars!" The 261 has two pairs of parallel raised 3/4 inch long bars cast in the block. This is not seen on a 235 except 1954. One pair is above the starter and the second pair is at the top middle of the left side of the block very close to the head. See photos below. The one exception is the early 261 produced in 1954 to mid 1955. It has only one "Captain Bar" above the starter but keeps the pair on the left side."

ya just have to love this site

thanks for the expanded knowledge, gents

I have a 1953 235 with captains bars, it's out of a passenger car with powerglide trans. This motor was first to have full pressure oiling, if you chose the stick shift that year you got the last splash oiler.

JiMerit, Do you have any pictures of your motor? I have what I believe to be a 53 Powerglide block. It has a stamping that reads:
LAQ4269I9. I have been told that the LAQ means it is a 53 PG car motor made in the Tonowanda plant. I just haven't been able to spot the casting number which should be in front and below the distributor.

http://www.picturetrail.com/gallery/view?p=999&gid=9706179&uid=1946755&members=1

LAQ is indeed the prefix for the '53 235 PG car engine.

I was wondering if, in Mule 1951's serial number, the first digit of the sequence number is really a Q instead of a zero, which would make the prefix LAQ. That would make sense, as the sequence numbers in '53 didn't have leading zeroes.

One list of stamped #s by prefix I have for 53 shows:
LAA orM 235 reg prod passenger.
LAC or P-235 w/10 3/4 clutch.
LAE or R- 235 w/powerglide and pwr steering.
LAF- 235 w/alum timing gear, pass.
LAQ- 235w/powerglide pass.

There are others, these are the only beginning with LA.

I rechecked the letters in the number and it is LAQ not LAO. Being fifty years old it has a little oil and grease build up. Thanks every one!!

TODD M- I don't have any pics of this motor, I could shoot some, but don't know if that would help you. Just let me know what part of the motor you need to see as it's out of the car would be easy to do.

One little correction to JiMerit's '53 prefix list. LAE/LAR are for the regular car 235 with PS. The 235 w/PG and PS had the prefix LAS. It seems all '53 PG engines came from the Tonawanda plant.

There were other LA* prefixes:
LAG/LAT = 216 used in sedan deliveries;
LAJ/LAV = 216 w/HD clutch used in sedan deliveries.

The above info is from a '53 resto pack.

JiMerit,

I was trying to find out where my casting number is. My head has a casting mark that I have been told Identifies it as Feb 56.
http://pic9.picturetrail.com/VOL284/1946755/9706179/138155661.jpg

The head also has a casting number of 383 5913 GM20 on the driver's side top.

The motor has the stamping LAQ 4269 I9

In this picture you can see the captain bars above the starter.

http://pic9.picturetrail.com/VOL284/1946755/9706179/138155656.jpg

I have cleaned a little bit and there are markings below the Captains bars but they seem similar to:

http://www.oldchevytrucks.com/cgi/htmlos.exe/002583.7.134165166100032122

This is a 261 though and is different. It has different motor mount holes for example. What I am looking for is my casting number which should be a 7 digit number. In the above example it is 3769925. I have done my best to look in the area below the distributor both forward and aft of it. I am wondering if it is hidden by the starter? I have not cleaned the driver's side much, but from what I understand it should be on the passenger side somewhere. I have only found a number 3 with a large GM below it on the lower forward passenger side of the block.


mule 1951,

You had asked me if mine was a full pressure oiler. I am not sure how to determine that without taking it apart. Maybe someone here can tell us. I think that I read somewhere that full pressure oiling was new in 1953, but if that is so, did it include all the 53 motors? I thought I read that it was 53 Powerglide motors. I am new to this so any help out there would be appreciated.

Todd:

Try looking for your casting number in front of the fuel pump, just above the oil pan rail (see here ).

3835913 is a 235 head from '54-'56 or so. I have the same head on the '54 1/2-ton engine that's in my '53. My head also has the B36 date code. I've seen the B36 code on a few 3835913 heads. That's either quite a coincidence, or B36 isn't really a date code.

The '53 PG engines were the first full-pressure oilers, and they were the only full-pressure engines in '53. They also had hydraulic lifters and aluminum pistons. They were essentially a preview of the '54 engines. The '53 PG block casting number was 3701481. I think this same casting was used for the early '54 235 also (both PG and non-PG).

Curt, Thanks, unfortunately, I will not be home to do more research for another 3 weeks. I am really curious as to my block casting number. I might tend to agree that the B36 is not a date code and was looking for some confirmation. I don't know what it is. Although anything is possible after 55 years, I would think that most motors and heads would remain paired up. Although the date stamping I have says it should be a 53 motor, I wondered if it could be a 54 because of the head. But things do get swapped around. The LAQ seems to be a 53. If it is a 53 PG motor with the full pressure oil, would there be any outside indication? I take it that the upgrades you listed were made without holes for an external filter.

I don't know of any way to distinguish between low or full pressure by outward appearance. As far as I know, all of the blocks of this era had the holes for the bypass-type oil filter, which was an option for many years.

I'd say the LAQ code clinches the engine's identity as a '53 PG (assuming the serial wasn't restamped at some point). I'm sure heads were changed all the time, due to cracks or rebuilding, so the head would not be a reliable indication of the year of the original assembly. Also, the engine serial numbers had a different format starting in '54, with the use of suffix codes instead of prefixes.

Todd,

I am not certain if the information below is correct for the 1953 Powerglide auto engine but I think it is.

The picture that you posted of the distributor side of the block has a side cover (push-rod cover) for a high pressure 235 (and 261). The earlier 235/216 had a side cover that extended over the spark plugs. The head on that engine is also from a later 235 (or 261) - it has a later valve cover.

Regarding "full-pressure oil". The commonly used (and confused) terms for the oiling systems in 216/235/261 engines are:

low-pressure oil system: a feature of all 216s and all pre-54 235s, except for the 1953 Powerglide 235. These low-pressure oil system engines had a different head from the later engines and they had a valve cover that is held down by two bolts. I think these low pressure engines had some sort of small triangular plate/cove on the exhaust side of the block (this is another characteristic that distinguishes this block from the later block).

high-pressure oil system: refers to the 1953 Powerglide 235 and all 1954 and later 235/261 engines, which had a high-pressure oil system (and insert rod bearings, rather than the earlier babbetted bearings). All of these heads (except the '53 Powerglide?) had valve covers that were held down with four machine screws (they look like stovebolts).

by-pass oil filtration system: an option/accessory available for almost all low-pressure and high-pressure 216/235/261 engines. I believe that about 10% of the oil was diverted through the by-pass oil filter. This might seem odd but it does work fine.

full-flow oil filtration system: only used on 1958-1962 Chevrolet truck 261 engines (Canadian Pontiac 261 engines did not have a full-flow filtration system). GMC engines, which are in many ways superior to the Chevrolet engines, did not have a full-flow oil filtration system. The easiest way to identify these engines (besides using block casting or block/engine ID codes) is to look at the size of the oil filter hose-fittings on the exhaust side of the block - the full-flow 261s holes for the filter hoses are 1/2" NPT (looks like a 3/4" hole).

The term "full-pressure" oil system might be used to describe the high-pressure 236/261 engines but the term can be confused with "full flow" ("full pressure"?) oil filtration system on some 261 engines.

So, regarding your question ". . full pressure oil, would there be any outside indication?", the short answer is "yes". The push-rod side cover is one giveaway of a high-pressure engine and the triangular plate/cover on the exhaust side of the block is another giveaway. There are also external giveaways/characteristics to identify full-pressure(high-pressure)/full-flow oil-filtration systems (on 261s or 235s that have been adapted - see Tech Tip ).

If I have stated or described anything incorrectly or unclearly, we can be certain that people will post corrections.

Good luck,

Tim

Curt and Tim, thanks to both of you for your help.

Curt,
You mentioned the transition from the serial number prefix in 53 (LAQ) to a suffix in 54. My serial number also seems to have a suffix of I9. I have not been able to figure out what it means. Do you have any idea?

Tim,
Sounds like I have a 53 PG hi-pressure oiling system. I have seen filters on some pictures of engines including 216s. In the tech article you linked, I understand that all the oil goes through the filter not just 10%? Also, in the by-pass filter system, where are the connections made? I think that I would like to have an oil filter on my engine, but don't really want to install the holes for the full-flow filtration system.

One minor correction to one of Tim's points. The short side cover actually began with the 235 redesign in 1950. The '50-'53 235's had the short side cover, but were still low pressure (excl. '53 PG).

Todd: The I9 in your serial number is just part of the sequence number. Many times the letter I was used instead of the number 1. That means your full sequence number is 426919, which means it was the 425919th engine built at Tonawanda for the '53 model year (the numbering started at 1001).

Todd,

Here is a photo of the exhaust side of a 1954 235 truck block. I do not know if the '53 Powerglide block looks the same. The holes might be labelled incorrectly (in vs out) but look at the next picture and you will see how/where the lines connect to the block and tro the filter.

Here is a copy of the 1953 Chevrolet auto oil filter installation instructions. My guess it that this is a low pressure engine.

Xram53, Thanks for the correction. It would be nice to have pictures of these distinguishing features on the various 216/235/261 engines. Another good reason to go to truck shows and taking pictures.

Tim

The 47-54 Factory Assembly Manual also has some pictures of the RPO 237 oil filter installation, though they're not much better than what Tim posted the link to. That picture of the block is excellent though. The holes are labeled correctly. The hole for the outlet to the filter is also where the oil pressure gauge sender goes.

I had forgotten about the oil distributor on the left side of the block. On the early low-pressure engines, this oil distributor fed oil to the top of the engine through external tubing. On later low-pressure engines, this distributor was eliminated, but the block still had provision for it. The hole was covered with the plate that Tim mentioned above. All evidence of the oil distributor was completely erased from the full-pressure blocks (though I too am not positive about this on the '53 PG block).

That tech tip for full-pressure oiling is really for full flow oiling.

Curt & Tim,

Thanks again!