Chugs between shifting gears new break-in. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

realsteelGM · 01-02-2011, 04:36 AM

What causes chugging between gear shifting? Sticking valve? Vacuum leak?
The engine lopes at idle and erratic. Could I have worn cam shaft down at break in running at idle too long to find timing issues. The engine is a 283 with vortec heads eddy carb 500 cfm and intake, mild cam.

JimKshortstep4x4 · 01-02-2011, 06:38 AM

Have you tried readjusting the valves?

Jim

Wrenchbender Ret · 01-02-2011, 11:26 AM

.What are the cam specs? Sounds like you have a bad vacuum leak or too much cam for the engine. A 283 can't handle as much cam as a 350.

realsteelGM · 01-02-2011, 02:20 PM

With vacuum gauge hooked up needle flutters and I cannot get more than 15 inches of vacuum. Cam specs are for 283, nothing too radical. I believe the #1 cylinder has a sticking valve would this be the problem. Everything else checks out great, all components including heads are brand new. What causes the valve to stick? Valve guides?

01-02-2011, 06:38 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Re: Chugs between shifting gears new break-in. Have you tried readjusting the valves? Jim __________________ 1971 Shortbox step side 4x4, 350 sbc, 3:07 rear end 1965 Impala SS 400 sbc, Muncie rock crusher 1966 Impala SS 396 bbc, TH 400 1969 El Camino, 350 sbc, TH 350 1971 Snowplow built on a Blazer frame 1972 GMC Short bed, stepside, TH 400, 427 BBC

01-02-2011, 11:26 AM	#3
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,229	Re: Chugs between shifting gears new break-in. .What are the cam specs? Sounds like you have a bad vacuum leak or too much cam for the engine. A 283 can't handle as much cam as a 350.

01-02-2011, 02:20 PM	#4
realsteelGM Registered User Join Date: Jan 2007 Location: Whitehorse, Yukon, Canada Posts: 169	Re: Chugs between shifting gears new break-in. With vacuum gauge hooked up needle flutters and I cannot get more than 15 inches of vacuum. Cam specs are for 283, nothing too radical. I believe the #1 cylinder has a sticking valve would this be the problem. Everything else checks out great, all components including heads are brand new. What causes the valve to stick? Valve guides? __________________ "gotta love something that works without a computer"

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01-02-2011, 04:36 AM	#1
realsteelGM Registered User Join Date: Jan 2007 Location: Whitehorse, Yukon, Canada Posts: 169	Chugs between shifting gears new break-in. What causes chugging between gear shifting? Sticking valve? Vacuum leak? The engine lopes at idle and erratic. Could I have worn cam shaft down at break in running at idle too long to find timing issues. The engine is a 283 with vortec heads eddy carb 500 cfm and intake, mild cam. __________________ "gotta love something that works without a computer"



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