Compression release

[andybcumming112]

How do you check compression release in intek 407777 engine twin cylinder.

[RoyM]

Are you having a problem with it kicking back against the starter? Set the valves according to specs. With the spark plugs removed roll the flywheel by hand, you should see the exhaust valve move momentarily on the compression stroke. If nothing happens the acr has failed.

[andybcumming112]

Having a problem with one side of cylinder. Like it gets too much compression. Won't start with spark plug in. Take out will start. Have adjusted valves to .006. The intake valve on cylinder one was .012. Also manual don't say nothing about going 1/4 past top dead center to adjust valves. Says tdc compression stroke. I seen before the release working on single cylinder. The intake valve would open little. But haven't seen before on twin cylinder. Don't see on parts list either.

[KE4AVB]

As Roy said adjust the valves to specs and then check valve movement during the end of the compression stroke to see either an intake or exhaust moves a little. Also check the amount of valve rocker arm movement. It should be the about the same for all four valves. If no little movement then ACR has failed or if one valve has very little lift then you have a cam failure. I have seen where cam lobes wear completely round.

From the Service manual for valve adjustment.
1. Set No. 1 cylinder at 1/4” (6.4mm) past TDC, compression
stroke.
a. Adjust valves.
Valve Clearance (cold) IN and EX .005” (0.13 mm)
b. Torque jam nut and adjusting screw to 60 in. lbs.
(7.0 Nm).
2. Set No. 2 cylinder at 1/4” (6.4mm) past TDC, compression
stroke.
a. Repeat for No. 2 cylinder.

3. Install valve covers with new gaskets.
a. Torque screws to 100 in. lbs. (11.0 Nm)

[bobodu]

Go 1/4" past TDC...

[andybcumming112]

Ok I will go past top dead center. Will the little movement on compression stroke for release be on both cylinders or just one. And thanks for the help guys.

[andybcumming112]

Well after adjusted the valves engine cranks up both spark plugs. Glad it did because they don't sell camshaft with date code 02. Have to buy shortblock. I still didn't see intake valve bump any on compression stroke after intake closed. But valve was tight till top almost. Thanks for the help guys. Now the guy and his buddy will put back on And call me again. Because I know they don't know how to adjust choke. Thanks again for the help.

[StarTech]

Compression Release is accomplished on the INTAKE valve on all B&S engines except Vanguard V Twins. That engine utilizes an,"Easy Spin" cam grind for compression release, no moving parts. The Intake valve finishes closing very late into the compression stroke, IF not, then the Intake Cam lobe is worn off.

Walt Conner

Hmmm. I must seeing things then as I have seen Briggs where it is on the exhaust.

[Walt 2002]

Compression Release is accomplished on the INTAKE valve on all B&S engines except Vanguard V Twins. That engine utilizes an,"Easy Spin" cam grind for compression release, no moving parts. The Intake valve finishes closing very late into the compression stroke, IF not, then the Intake Cam lobe is worn off.

Walt Conner

[Walt 2002]

Compression Release is accomplished on the INTAKE valve on all B&S engines except Vanguard V Twins. That engine utilizes an,"Easy Spin" cam grind for compression release, no moving parts. The Intake valve finishes closing very late into the compression stroke, IF not, then the Intake Cam lobe is worn off.

Walt Conner

Hmmm. I must seeing things then as I have seen Briggs where it is on the exhaust.

Would like to know the model number of that engine unless Vanguard V Twin, even the Vanguard single uses the Intake Valve for compression release.

Well the old Cast iron engine did use the Exhaust for compression release.

By the way, the original Service Manual did say to adjust at TDC but this was quickly amended by a Service Bulletin which I have on file.

Walt Conner