The Stovebolt Site Forums The Shop Area Engine Shop 261 first start

Got the 1962 261 running today after a complete rebuild. Had some issues like the temp guage on the run stand did not work, i have another guage. Fuel line leaked, bad flare and the valve cover had a slight bend evedentily bad enough to cause a leak. But it did fire right up. Might as well get an aluminum valve cover and be done with it. All in all it ran just fine, no funny noises. Once i get these things fixed i'll start it again and get it timed a little closer. What fun.

Congratulations, Tim

Ain't it fun when they start the first time? Congratulations.

Exciting. Congratulations.

Regards,

Cosmo

Tried it again today. Fixed the fuel leak on the line, switched the temp and oil gauges. fired right up ran a few minutes and the temp was up to 210 with a 180 thermo. Shut it down and let it cool then removed the thermo and tried it that way. Temp was up to 195 after about 5 min. Just can't seem to keep it cool. The radiator is mounted to the stand and it's a big one. The last engine was a 383 stroker and it keep it cool with just a box fan on the front of the radiator. Then the rebuilt by me zenith started to leak out the side of the trottle body where the butterfly goes through. Any ideas on what the problem might be with the cooling. everything is new.

Tim,

What do you know about the block? Was it cleaned out? Those blocks are prone to getting plugged up in the rear.

Before I finished the installation of the water pump relocation plate on my 1960 261, I found an almost completely clogged rear of the block. I was able to gain access from the water pump hole in the block and from the drain-cock hole on the lower rear mainifold side of the block.

Make sure the timing is set correctly.
I find these engines run best and coolest with the timing advanced at least 5 degrees more than stock with today's fuels.

Dave,

What is the standard timing specification for a 1962 261?

The Motor's truck manual specifys "ball on the flywheel".
195 degrees F is great for no load run in and the vehicle fan will be a lot more capable than many of the box fans I run across.
You probably have access to a infrared temperature gun that will tell how well your radiator is working.

Is the radiator and water level elevated enough that coolant will flow to top of engine?

The Motors Manual tells you how to set the timing, not the timing specification in degrees TDC, BTDC, BUDC, ATDC, AUDC.

Flywheels get changed, especially if a 12v 261 flywheel was swapped for a 6v flywheel, or if a 216/235/261 flywheel get interchanged on a different size/year engine.

A swapped flywheel might be from a 216 or 235 or 261. In the same year, a 235 and a 261 might have different timing specifications but the same timing method/instruction (set so the pointer lines up with the ball on the flywheel).

Tim, what year/engine flywheel is on your 261? And, how did you set your initial timing?

Checking out your cooling system seems to be a good place to start.

Tim,

Not sure what some of those degree letters are, but...
the ball is about 5 degrees before TDC.

You can get an idea here thru 1960, cars & trucks.
http://chevy.oldcarmanualproject.com/engine/5560cgt/5560cgt60.html

Oilrag,

I cannot get that link to work. I'll try on another computer.

These letters were taken from various Chevrolet Truck Shop Manuals:

Same meanings:
TDC - Top Dead Center
UDC - Upper Dead Center

The B prefix means Before
The A prefix means After

My point is that the ball is not necessarily the same timing specification for different engines, even in the same year.

For example: in 1960 and 1961 (at least), the 235 truck engine's timing specification is 5 degrees BTDC and the 261 truck engine's specification is TDC.

If you had a 1960 261 flywheel, the ball is set at TDC. In that year, there was/is another mark at 5 degrees BTDC (used for the 235).


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edited - added later: this tune-up link works (the final "l" in html was missing):
http://chevy.oldcarmanualproject.com/engine/5560cgt/5560cgt60.html

here is the full-size image of the tune-up specs
http://chevy.oldcarmanualproject.com/engine/5560cgt/images/5560cgt61.jpg

Oilrag,

The Chevrolet 1955-1960 Chevrolet Guardian-Tune for All Models that you linked-to shows 1960 261 and 235 engines both having a timing specification of 5 degrees BTDC.

However, the 1960 Chevrolet Truck Shop Manual shows different specifications for 1960:

ENGINE TUNE-UP 7-16 (Chapter 7, page 16)
Ignition Timing for Thriftmaster 235 = 5 degrees BTDC - Note 1A: first short radial mark clockwise from TDC timing ball
Ignition Timing for Jobmaster 261 = TDC

ENGINE TUNE-UP 7-16, step 22. TEST IGNITION TIMING AND ADVANCE (Chapter 7, page 16)
. . . for correct timing, steel ball in flywheel (261 only) or 5 degree mark (235 only) should line up with the pointer on the flywheel housing . . .

My guess is that the poorly worded last line, above, caused confusion when writing/producing the 1955-1960 Chevrolet Guardian tune?

I'll raise the radiator because i think that's the problem. As far as the flywheel goes. The truck is a 1953. It had a 1960 235 in it when i got it. I have no Idea what the flywheel or bell housing are. My guess is it's the original truck bell housing and flywheel. I had the flywheel resurfaced, teeth where good. It's a 6v starter with the generator converted to 12v. The odometer read about 99000 so i'll have to assume that everything worked before. Since the flywheel is probaby a 216 and the engine is a 261 from what i've read i can't use the timing mark and the hole to time it. I installed the hei from Langdons and followed the instructions. I plan to use a vacuum gauge to time it. I push on the foot starter and it fires right up and seems to run well. I kill the power and it shuts right off so the timing should be close. I think the radiator is the problem. I'll know soon enough. I did check the t-stat and it works fine. I will check for a infrared gun. I do appreciate the info. I'll take it one step at a time.

Sounds good, Tim

Good luck.

Ok, an update on the 261. I raised the radiator on the run stand, reset the float fired it. Played with the dist. using a vacuum gauge and now it seems to run very well. I ran it a couple times today about 1/2 hr each best guess on the rpms ranging from 1800 to 2500. so far so good.

Congratulations