Compression on motor question.....

ols0051 · 07-08-2005, 04:47 PM

I started up my 302 I rebuilt this spring and after 10 min of running it, I did a compression test on all cylinders.#1=105,#2=155,#3=155,#4=155,#5=170,#6=15 0,#7=160,#8=130. Are these numbers ok, or how long does it take for the rings to seat. I have trickflow track heats,stock pistons, tfs stage 2 cam,with a carb. Also have a rocker making some noise. thanks for your input.

smokedchevy · 07-08-2005, 05:19 PM

What kind of piston rings? Moly or iron? Iron seat easier than Moly rings. Give it 500 miles at least. A leak down test would be appropriate at this point. See if it's leaking at the valve guide or into the crankcase. Moly rings need a certain cross hatch pattern to seal good. Also are they file to fit rings?

ols0051 · 07-08-2005, 06:42 PM

The rings are irons. The bores were in very good shape, so said the dial bore gauge. So I just ran a rabbit turd hone through it and cleaned the walls really good with carb cleaner. Than oiled them. So I shouldn't be worried about it until I get some running time on it? When I went to start it the first time it wouldn't start because the rockers we too tight. than went over it again now she fires right up. But I was worried if maybe I bent a valve. But all seems OK. I hope.

Gearhead999 · 07-08-2005, 08:30 PM

What's going on with #1??

ols0051 · 07-08-2005, 10:46 PM

Your guess is better than mine. I can't see why it's so low. Maybe in time it will work itself in. I could work on the rocker arm adjustment a little. Being I was not able to get it right the first time. See what happens when you read the directions......

mustangII460 · 07-09-2005, 12:09 AM

Squirt a tablespoon of oil in #1. If the compression does not come up, its a valve.

smokedchevy · 07-10-2005, 07:58 PM

There's old skool experience for ya!! I forgot about that one.

USMC302 · 07-14-2005, 07:00 AM

Yeah, the valve adjustment has my vote, all the others sound fine.

ols0051 · 07-15-2005, 10:38 PM

I went over them again and all seems well now. but I was not able to check the compression again. now the motor has about 5 more minutes of run time on it. I hate to start it and shut it down, but I have some old neighbors that don't care for my noise.(longtubes open) I would like to get it to the track and make some slow passes on it then check the compression again. But the car is in the paint shop for about 10 days...

07-15-2005, 10:38 PM	#9
ols0051 Registered Member Join Date: Sep 2002 Location: cent.wis Posts: 203	Re: Compression on motor question..... I went over them again and all seems well now. but I was not able to check the compression again. now the motor has about 5 more minutes of run time on it. I hate to start it and shut it down, but I have some old neighbors that don't care for my noise.(longtubes open) I would like to get it to the track and make some slow passes on it then check the compression again. But the car is in the paint shop for about 10 days...

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
#1 @ TDC on compression stroke?	302 LX Eric	Windsor Power	1	09-23-2003 04:19 PM
Speed Secret # 3	jim_howard_pdx	Windsor Power	13	11-09-2002 10:35 AM
Compression....	cyberstang5.0	Windsor Power	1	03-22-2002 09:37 AM
Compression problem?	96Saleen	Modular Madness	1	10-22-2001 01:14 PM
high or low compression engines	Mustangboy89	Windsor Power	6	01-26-2001 03:04 PM

07-08-2005, 04:47 PM	#1
ols0051 Registered Member Join Date: Sep 2002 Location: cent.wis Posts: 203	Compression on motor question..... I started up my 302 I rebuilt this spring and after 10 min of running it, I did a compression test on all cylinders.#1=105,#2=155,#3=155,#4=155,#5=170,#6=15 0,#7=160,#8=130. Are these numbers ok, or how long does it take for the rings to seat. I have trickflow track heats,stock pistons, tfs stage 2 cam,with a carb. Also have a rocker making some noise. thanks for your input.

07-08-2005, 05:19 PM	#2
smokedchevy Registered Member Join Date: Jun 2000 Location: ventura,CA Posts: 438	Re: Compression on motor question..... What kind of piston rings? Moly or iron? Iron seat easier than Moly rings. Give it 500 miles at least. A leak down test would be appropriate at this point. See if it's leaking at the valve guide or into the crankcase. Moly rings need a certain cross hatch pattern to seal good. Also are they file to fit rings? __________________ 92 GT, 4:10 gears, centerforce clutch, 6# powerdyne blower, bbk h-pipe, flowmasters 65 Mustang 13.50 107mph 3000' ALt. 65 Falcon Straight Axle Drag Car

07-08-2005, 06:42 PM	#3
ols0051 Registered Member Join Date: Sep 2002 Location: cent.wis Posts: 203	Re: Compression on motor question..... The rings are irons. The bores were in very good shape, so said the dial bore gauge. So I just ran a rabbit turd hone through it and cleaned the walls really good with carb cleaner. Than oiled them. So I shouldn't be worried about it until I get some running time on it? When I went to start it the first time it wouldn't start because the rockers we too tight. than went over it again now she fires right up. But I was worried if maybe I bent a valve. But all seems OK. I hope.

07-08-2005, 08:30 PM	#4
Gearhead999 Registered Member Join Date: Sep 1998 Location: Oviedo, FL Posts: 992	Re: Compression on motor question..... What's going on with #1?? __________________ "Support our Troops" Dave 1968 Cougar 2004 Thunderbird 2007 F150 Harley-Davidson, SuperCrew 1986 LTD 1997 Ranger 1992 Honda Civic

07-08-2005, 10:46 PM	#5
ols0051 Registered Member Join Date: Sep 2002 Location: cent.wis Posts: 203	Re: Compression on motor question..... Your guess is better than mine. I can't see why it's so low. Maybe in time it will work itself in. I could work on the rocker arm adjustment a little. Being I was not able to get it right the first time. See what happens when you read the directions......

07-09-2005, 12:09 AM	#6
mustangII460 Factoy Five Roadster Join Date: May 2000 Location: Sevier Co,Tennessee Posts: 1,681	Re: Compression on motor question..... Squirt a tablespoon of oil in #1. If the compression does not come up, its a valve. __________________ Frank

07-10-2005, 07:58 PM	#7
smokedchevy Registered Member Join Date: Jun 2000 Location: ventura,CA Posts: 438	Re: Compression on motor question..... There's old skool experience for ya!! I forgot about that one. __________________ 92 GT, 4:10 gears, centerforce clutch, 6# powerdyne blower, bbk h-pipe, flowmasters 65 Mustang 13.50 107mph 3000' ALt. 65 Falcon Straight Axle Drag Car

07-14-2005, 07:00 AM	#8
USMC302 Registered Member Join Date: Apr 2001 Location: Gallatin, Tn Posts: 1,326	Re: Compression on motor question..... Yeah, the valve adjustment has my vote, all the others sound fine. __________________