Compression Test 1976 305 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

rick0312 · 01-29-2007, 11:19 PM

I finally did a compression test and was wondering if these numbers are good or bad. The test was done on a cold motor. Initial compression on all cylinders came up fast and maxed out at numbers listed.

#2 130 #1 125
#4 130 #3 130
#6 130 #5 135
#8 125 #7 140

injected some oil into #8 cylinder and compression rose to 130.

Thanks for all of your help

Rick

FarmTruk · 01-29-2007, 11:42 PM

I know very little about compression, but the #'s look OK to me. Looks like even wear on all cylinders. IIRC, ideal is 150 PSI with 10% or less variation between all cylinders, which you have. Your rings are probably showing a little wear.

I can't comment on the cold vs. warm engine testing.

wheels67 · 01-29-2007, 11:59 PM

Yep , pretty standard for a 76. If its not smoking then you can get a little more time out of her.

84_4x4 · 01-30-2007, 12:07 AM

shows your valves and head gaskets are intact not bad readings at all

rick0312 · 01-30-2007, 01:34 AM

great!! I'll clean her up and keep her going!!

rick0312 · 01-30-2007, 03:54 PM

ttt

01-29-2007, 11:19 PM	#1
rick0312 Registered User Join Date: Jan 2006 Location: Warrington, PA Posts: 403	Compression Test 1976 305 I finally did a compression test and was wondering if these numbers are good or bad. The test was done on a cold motor. Initial compression on all cylinders came up fast and maxed out at numbers listed. #2 130 #1 125 #4 130 #3 130 #6 130 #5 135 #8 125 #7 140 injected some oil into #8 cylinder and compression rose to 130. Thanks for all of your help Rick

01-29-2007, 11:42 PM	#2
FarmTruk In Memoriam... Join Date: Nov 2006 Location: Wallburg, NC Posts: 1,216	Re: Compression Test 1976 305 I know very little about compression, but the #'s look OK to me. Looks like even wear on all cylinders. IIRC, ideal is 150 PSI with 10% or less variation between all cylinders, which you have. Your rings are probably showing a little wear. I can't comment on the cold vs. warm engine testing. __________________ '68 C10 SWB 307ci 2BBL *FarmTruk Pics Here* *"You know, doing what is right is easy. The problem is knowing what is right."* Last edited by FarmTruk; 01-29-2007 at 11:45 PM.

01-29-2007, 11:59 PM	#3
wheels67 Registered User Join Date: Dec 2006 Location: southern Utah Posts: 103	Re: Compression Test 1976 305 Yep , pretty standard for a 76. If its not smoking then you can get a little more time out of her.

01-30-2007, 12:07 AM	#4
84_4x4 Registered User Join Date: Oct 2006 Location: Louisville Ky Posts: 179	Re: Compression Test 1976 305 shows your valves and head gaskets are intact not bad readings at all

01-30-2007, 01:34 AM	#5
rick0312 Registered User Join Date: Jan 2006 Location: Warrington, PA Posts: 403	Re: Compression Test 1976 305 great!! I'll clean her up and keep her going!!

01-30-2007, 03:54 PM	#6
rick0312 Registered User Join Date: Jan 2006 Location: Warrington, PA Posts: 403	Re: Compression Test 1976 305 ttt



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