289 Compression Test

289 - 351 cid Small Block Performance
comethead
Posts: 5692
Joined: Sun Nov 09, 2003 7:44 pm
Location: Palmdale, CA

Re: 289 Compression Test

Post by comethead »

Lou's Comet wrote:
Fri May 20, 2022 8:29 am
comethead wrote:
Thu May 19, 2022 7:36 pm
Lou's Comet wrote:
Thu May 19, 2022 6:09 pm
When you did the compression test did you have the carb/throttle wired wide open?

Seen engines with worse run good long time.
8)
I did have the throttle open for the driver side bank not the passenger side :roll:
I guess I’ll have to run the test again but the right way. operating temp, throttle open.
That’s good news though that you’ve seen this before and it wasn’t a death sentence! That’s the reason I’m on the fence about this is its running good but the numbers seem low.
Ill report back after a retest.
Thanks Lou!
Put the parts on it and have fun!

Lou
Lou I like your style! My buddy said the same thing! 8)
1965 Caliente HT- 289/4 speed
1964 Falcon HT- track car- 302/4 speed
Image

User avatar
poboyjo65
Moderator
Posts: 7058
Joined: Thu Oct 20, 2011 9:40 pm
Location: Camden, Tenn.

Re: 289 Compression Test

Post by poboyjo65 »

comethead wrote:
Fri May 20, 2022 11:53 am
poboyjo65 wrote:
Fri May 20, 2022 1:11 am
Joe have you ever run anything like seafoam thru it ?
I did once a long time ago. Not sure if it did anything. Do you recommend it Johnnie?
I was just thinking if it had carbon build up around the valves might affect the numbers a little. & I hear the gas is crappier out there. Be cool to see if it helped the numbers any. I'm not necessarily recommending it though,I tried it too , but cant remember if it helped or not :roll: . maybe there is something better for cleaning out carbon, seams like someone posted fairly recently about cleaning their pistons with something. Maybe Joe T.?
Image
Johno

User avatar
Joe Travers
Posts: 2437
Joined: Mon Sep 21, 2020 6:23 pm
Location: Louisiana

Re: 289 Compression Test

Post by Joe Travers »

poboyjo65 wrote:
Fri May 20, 2022 12:07 pm
seams like someone posted fairly recently about cleaning their pistons with something. Maybe Joe T.?
Yeah, Lucas Fuel System Cleaner. It contains a lot of nitrogen like the drip used in shops to 'de-carbon' fouled engines. Couldn't get the drip juice w/o a license so tried Lucas & it works well after a few tanks of fuel.

I was chasing a rattle, not a miss. Tried carbon cleaner, colder plugs & richer jetting to try and cover it up. Ended up being distributor curve problem.

Joe
Image

1963 1/2 Custom Hardtop
342 stroker, solid roller, T-10, 3.55 posi

comethead
Posts: 5692
Joined: Sun Nov 09, 2003 7:44 pm
Location: Palmdale, CA

Re: 289 Compression Test

Post by comethead »

Thanks Joe thanks Johnnie!
I’ll do a little research and see what’s out there.
Cleaned the plugs and put it back together and it fired right up! Kinda hard to tear things apart when it runs so well :?
1965 Caliente HT- 289/4 speed
1964 Falcon HT- track car- 302/4 speed
Image

User avatar
Joe Travers
Posts: 2437
Joined: Mon Sep 21, 2020 6:23 pm
Location: Louisiana

Re: 289 Compression Test

Post by Joe Travers »

Hey Joe, I bought a dirt cheap scope online that I plug into the laptop to power. It runs off USB or Android power terminals.
Display runs off Microsoft camera app. You can take snapshots w/ it if you need to.
Pull a sparkplug and take a peek inside. Comes in handy for diagnosing w/o tearing down.

Joe II
Image

1963 1/2 Custom Hardtop
342 stroker, solid roller, T-10, 3.55 posi

User avatar
Jims65cyclone
Posts: 2764
Joined: Sun Nov 23, 2014 10:29 pm
Location: Lexington, SC

Re: 289 Compression Test

Post by Jims65cyclone »

I've got one of those cameras that connects to my cell phone. Records video or photos in color. Head is about 3/16" diameter on end of 10 ft cable. Got it off Amazon for about $10. Great for looking under the dash without standing on your head. :wink:

Jim
Image

Rocket989
Posts: 1678
Joined: Sat Jan 11, 2014 2:53 pm
Location: Kansas City Metro

Re: 289 Compression Test

Post by Rocket989 »

Yah, rerun it hot. For those engines, cold, the numbers are about right, 150 to 120 is a decent spread though. I’d say she’s a bit on the decline. You could do the squirt a wee bit of oil into cylinder thing to see if it jumps up on the lower cylinders. You have a leak down tester for the oil rings?

Do tell more about the 302 that’s been hanging out…! :)
'cause Johno says you gotta have a sig pic! :)
Image

comethead
Posts: 5692
Joined: Sun Nov 09, 2003 7:44 pm
Location: Palmdale, CA

Re: 289 Compression Test

Post by comethead »

Joe Travers wrote:
Fri May 20, 2022 8:20 pm
Hey Joe, I bought a dirt cheap scope online that I plug into the laptop to power. It runs off USB or Android power terminals.
Display runs off Microsoft camera app. You can take snapshots w/ it if you need to.
Pull a sparkplug and take a peek inside. Comes in handy for diagnosing w/o tearing down.

Joe II
Thanks Joe!!
I happen to have one as well…kinda forgot I have it :lol: Ill do some poking around in the engine to see what I see.

Joe
1965 Caliente HT- 289/4 speed
1964 Falcon HT- track car- 302/4 speed
Image

comethead
Posts: 5692
Joined: Sun Nov 09, 2003 7:44 pm
Location: Palmdale, CA

Re: 289 Compression Test

Post by comethead »

Rocket989 wrote:
Sat May 21, 2022 10:00 am
Yah, rerun it hot. For those engines, cold, the numbers are about right, 150 to 120 is a decent spread though. I’d say she’s a bit on the decline. You could do the squirt a wee bit of oil into cylinder thing to see if it jumps up on the lower cylinders. You have a leak down tester for the oil rings?

Do tell more about the 302 that’s been hanging out…! :)
I have a leak down tester. Gotta whip it out and run that test too.
The rebuilt 302 I have is nothing special. It’s out of a 68 mustang that a friend didnt have the will to finish. It’s a stock build with a mild cam. I bought it off him for $500 about 150 years ago. It’s been wrapped in the corner of the garage awaiting its day in the Comet!

Joe
1965 Caliente HT- 289/4 speed
1964 Falcon HT- track car- 302/4 speed
Image

User avatar
Joe Travers
Posts: 2437
Joined: Mon Sep 21, 2020 6:23 pm
Location: Louisiana

Re: 289 Compression Test

Post by Joe Travers »

comethead wrote:
Mon May 23, 2022 12:22 pm
The rebuilt 302 I have is nothing special. It’s out of a 68 mustang that a friend didnt have the will to finish. It’s a stock build with a mild cam. I bought it off him for $500 about 150 years ago. It’s been wrapped in the corner of the garage awaiting its day in the Comet!
'68 was a crazy year for small blocks. I've owned a couple over the years. Check the displacement stamp in the lifter valley and the casting number on the crankshaft. There was some mix and match going down when the 289 parts were being depleted and 302 coming online. One I had was a 302 block w/ 289 crank.

Joe
Image

1963 1/2 Custom Hardtop
342 stroker, solid roller, T-10, 3.55 posi

comethead
Posts: 5692
Joined: Sun Nov 09, 2003 7:44 pm
Location: Palmdale, CA

Re: 289 Compression Test

Post by comethead »

Joe Travers wrote:
Mon May 23, 2022 12:49 pm
comethead wrote:
Mon May 23, 2022 12:22 pm
The rebuilt 302 I have is nothing special. It’s out of a 68 mustang that a friend didnt have the will to finish. It’s a stock build with a mild cam. I bought it off him for $500 about 150 years ago. It’s been wrapped in the corner of the garage awaiting its day in the Comet!
'68 was a crazy year for small blocks. I've owned a couple over the years. Check the displacement stamp in the lifter valley and the casting number on the crankshaft. There was some mix and match going down when the 289 parts were being depleted and 302 coming online. One I had was a 302 block w/ 289 crank.

Joe
Very true Joe! Ill verify that once I move it to the front burner some day
1965 Caliente HT- 289/4 speed
1964 Falcon HT- track car- 302/4 speed
Image

Post Reply