235 vs 261 engines

[Barry Churcher]

In all my experience building engines for drag cars and owning a stock car I never did figure out what a 3/4 race cam was. 3/4 of what!
Barry

[Phil Waterman]

Hi

I just posted on http://canadianmilitarypattern.com/1...e%20Manual.htm the manual pages from the 1960 Chevy Truck manual. It includes the valve timing diagram and the valve lift information. Which you might find interesting.

Just for information sake my 235 has hydraulic lifter and my 261 has solid lifters.

Cheers Phil

[Alex Blair (RIP)]

Originally Posted by Barry Churcher

In all my experience building engines for drag cars and owning a stock car I never did figure out what a 3/4 race cam was. 3/4 of what!
Barry

Barr7y/...
You probably forgot more stuff than some of these young whelps with their souped up rice rockets ever will know...
Crane still advertises them..They run a little rough on the idle but come on when you give 'er...try one...good for the street..blow away some of those young whipper snapper at the lights..
Best $129.99 US you'l ever spend..

Crane #270-100172

Energizer 3/4 Race Hydraulic Flat Tappet Camshaft & Lifter Kit
Lift: .450''/.450''
Duration: 274°/274°
RPM Range: 1800-5800

100172 - Crane Cams Energizer Cam & Lifter Kits Details

Chevy 262-400ci Small Block 1955-98

*Note: In order to use these camshafts in 1955-57 265ci blocks, it is necessary to machine a small groove in the rear main journal of the cam to allow oil flow to the top of the engine.

**Note: Beginning in 1987, most of the V-6 and V-8 engines were equipped with hydraulic roller camshafts. There are differences in the block to accommodate a cam retention thrust plate and the anti-rotation mechanism for the lifters. These blocks are identifiable by bolt holes for a cam retention plate under the upper timing sprocket, as well as bosses and tapped holes in the lifter valley for lifter retention hardware. The camshafts on these engines have a step nose and smaller bolt circle on the front of the cam. An earlier model camshaft may be used in these blocks by using the appropriate timing chain set and adding a thrust button when using a roller cam.
1988-99 Chevrolet 305 and 350 V-8 engines (and some 1987 350 V-8 engines) use a different configuration camshaft core than the 1955-87 engines and cannot be interchanged.

ROUGH IDLE, MODERATE PERFORMANCE USAGE, GOOD LOW AND MID-RANGE TORQUE AND HP, MILD BRACKET RACING, AUTO TRANS W/2500+ CONVERTER, 2600-3000 CRUISE RPM, 8.75 TO 10.0 COMPRESSION RATIO ADVISED.

Grind Number: 274 H06
Operating Range: 1800-5800 RPM
Duration Advertised: 274° Intake / 274° Exhaust
Duration @ .050'' Lift: 218° Intake / 218° Exhaust
Valve Lift w/1.5 Rockers: .450'' Intake / .450'' Exhaust
Lobe Separation Angle: 106°
Max Lift Angle: 102° ATDC Intake / 110° BTDC Exhaust
Open/Close @.050'' Cam Lift: Intake - 7° BTDC (opens) / 31° ABDC (closes)
Exhaust - 39° BBDC (opens) / (1°) BTDC (closes)

[Alex Blair (RIP)]

Originally Posted by Barry Churcher

In all my experience building engines for drag cars and owning a stock car I never did figure out what a 3/4 race cam was. 3/4 of what!

Jeez Barry..I was so excited I forgot to answer your question..Here is the history..

compiled by
HARVEY J. CRANE, JR.
October 1, 1999

Ed Winfield made his first performance camshafts in 1914. These were motorcycle cams with individual lobes pinned to a shaft.

His first automotive camshafts were ground in 1919 when he built his first homemade cam grinder. Ed was 17 years old at that time.

Ed told me his mother gave him the money to purchase a used grinding machine that he converted to a cam grinder by adding a rocker table. This homemade cam grinder was used in his mother's garage to regrind Ford Model T camshafts into racing specifications.

Ed told me he first made only two masters, a SEMI RACE GRIND and a FULL RACE GRIND! He later made a third master that was more duration and lift than the SEMI but less than the FULL. He then used the FULL RACE master as an intake and the new master as an exhaust.
He called this new reground camshaft a THREE QUARTER RACE CAM! Ed said "It was three quarters of the way to a full race cam".

According to Dema Elgin, ED began working for Harry Miller at the age of 14 1/2 in the carburation department. Within a few months he was doing other machine work on the famous Miller racing engines. Harry wanted Ed to stay on with him and offered Ed more money. Ed was being paid .60 cents per hour and was offered .70 cents, but ED wasn't fond of Harry because he was like a dictator.

Ed quit grinding camshafts in October of 1969 after he finished a batch of Drake Offenhauser camshafts. That's 55 years of grinding cams!

[Paul Singleton]

I hope Crane Cams survives the economic crisis!

http://www.autoweek.com/article/2009...NEWS/902279984

Paul

[Bob Carriere]

Bonjour Guy

I have rebuilt a 261 for my C15a cab 11.

First of all cams ( and many other parts) are exchangeable between 235 and 261.

Keep similar assemblies together to respect the engineering designs.

235 car engines and 261 car engines (usually in Pontiacs in Canada) had hydraulic lifters..... I believe you may find some early 235 (truck?) engines with solid lifters. The whole valve train assembly can be interchange but as a total unit. We were replacing a bent valve push rod on a 261 for Grant and our parts box contained two different manufacturing styles and 3 different length.

Canadian Pontiac from approx. 1957 or 58 up to early 60s can be 261....
Chev truck..... big trucks..... some large 3/4 ton pickups.... circa 1955 to 1961 would have 261 engines....... easily identified by the Captains bars above the starter motor.... more details are available from Chev Stovebolts site... engine ID.

Heads are interchangeable between engines and the best combination is a 235 head ser #####848 on a 261 block.... steam holes will have to be drilled in the 235 head..... a 261 head gasket will guide you for location.

For a CMP where bottom end torque at low RPM is more desireable than absolute top speed a 261 truck engine is far superior. A 261, from a 3 or 5 ton truck, will have solid lifters, block will be drilled for a full flow external oil filter which you can relocate anywhere along the frame, ####848 head and original carburation should give you about 145 BHP.

Forget getting the head shaved to increase compression..... just enough to set it flat is all you need. On a Chev engine, if you wish to significantly raise the compression you need to shave the deck of the block... or top of the block..... an expensive process since the crank, rods,piston and rings need to be installed to check the head space between Top Dead Centre of the piston and the space between the head/valves..... in some extreme cases butterfly cuts need to be machined in the piston top. All in all a very expensive process unless you wish to drag race your CMP

Remember a stock 261 will give you approx. 145 bhp compared to the original 216 at 82 horses..... assuming all the horse are pulling on that day!!!

Phil Waterman runs a C30 fully loaded with a large radio box and loaded with water tanks for his shower etc..... and I have followed him going up long hills in Connecticut at 50 mph steady..... in top gear.

Any of the civilian 235/261 will give you nightmare when installing the waterpump.... you will need a good rebuilt 216 pump and a "hay-dapter" plate....... and the carburator linkage for the right hand drive CMP will need some creative fiddling to make it work and look semi original..... or you can cheat and use a throttle cable. When you get to that stage Phil and I will gladly walk you through the fiddling part.

The hardest part to find in rebuilding the 235/261 is finding good rebuilt rocker arm assembly....... they seem to be in high demand.... everything else is easy enough to find.

Try to get a complete set up engine transmission unit.... or at least engine bellhousing and flywheel clutch assembly.

The 261 will bolt up to a 216 bellhousing perfectly..... but you should try to keep the 261 large truck flywheel...either the 10.5 or 11 inch... with matching clutch and matching 12 volt starter.... ring gear must match starter gear. The heavier flywheel will store more torque.... clutch for 261 are easier to find and can be ordered with heavy duty springs and plate compound.
It will allow more clutch riding if you are so inclined!!!!

Don't forget you can intall a late model 216 valve cover on your 261 to further hide its non original feature.

The 261 should get you a "bit" more top end speed with out over revving your engine....... but remember CMPs were not design for speed.... front axles can shake, brakes are 1939 design, visibility side and rear is not ideal with right hand drive........ respect the machine and it will outlast you...
after all we are playing with trucks that in most cases are older than we are.... even mine.....!

Phil..... did I forget anything or overstate myself...? We both have pictures to help you out....

Just a closing note..... finding a good reputable engine rebuilder can be a challenge...... talk to local hot rod team members or farm tractor shops for recommendations. Rebuilding a 261 was $3100. back in 2003 including all parts, balancing reciprocating parts, and assembly..... basiclly kept the block head and crank and replace everything else...... crank at 10 under cylinders at 20 over. Engine came out of a 5 ton 1959 fuel delivery truck with 85K. miles.

Good luck.... keep us posted (with pictures) if you go that route.....

...and if so inclined you can even visit the Hammond barn.....

Booob

[M38CDNBill]

Originally Posted by Bob Carriere

...Just a closing note..... finding a good reputable engine rebuilder can be a challenge...... talk to local hot rod team members or farm tractor shops for recommendations. Rebuilding a 261 was $3100. back in 2003 including all parts, balancing reciprocating parts, and assembly..... basiclly kept the block head and crank and replace everything else...... crank at 10 under cylinders at 20 over. Engine came out of a 5 ton 1959 fuel delivery truck with 85K. miles.

Good luck.... keep us posted (with pictures) if you go that route.....

...and if so inclined you can even visit the Hammond barn.....

Booob

Hello Bob,

Many thanks for these informations (for all who replied too). We have an excellent engine rebuilder in Edmundston NB and finaly, I found mechanical lifters for my 261 engine.

This engine won't go to a CMP but rather to my Chevrolet G7107. I know, I know, I'm a bad boy because I'm Canadian and that I'm going to drive an American truck . Don't worry friends, I own also two jeeps with the Canadian army markings You will find below a picture of my Chevy as well as a short video clip where I drive it near the garage of my friend.



Cheers from Trois-Rivieres

Guy