4.0 compression

copter14 · 05-23-2010, 05:18 PM

are theese good numbers, this is 4.0 litre out of 1991 i wanna use for my swap into 88bII.
cyl 1@165
cyl 2@175
cyl 3@190
cyl 4@175
cyl 5@185
cyl 6@175

top end has tick so i will prob have it redone.

bluestream1 · 05-23-2010, 08:34 PM

There should be no more than 10% variance between cylinder readings.

**Maniak** · 05-23-2010, 10:15 PM

Your just outside the range of what is considered "good"...

Lowest of 165 meaning the highest should be 181.5. How exact were those numbers? I found many people just round the # to the closest 5.

Also, did you try a wet test after the compression test? If the #'s go up with a little oil in the cylinders then you know its rings.

~Mark

copter14 · 05-24-2010, 08:37 AM

thoose were exact numbers i didn't round them off.
i'll try another dry test to confirm #1 cyl is that low.
then i will do a wet test and post.

05-23-2010, 08:34 PM	#2
bluestream1 Wannabe Elite Explorer Waterloo Ontario 2000 XLT 4.0 SOHC 4X4 Join Date: Nov 2005 Posts: 625 Vehicle Specs	There should be no more than 10% variance between cylinder readings. __________________ 2000 Ford Explorer SOHC 4X4 249,000KM 2003 Ford Escape 101,000KM

05-23-2010, 10:15 PM	#3
Maniak Moderator-Stock 91-94 Vail, Arizona 1992 XLT 4x4 Join Date: Feb 1999 Posts: 10,736 Vehicle Specs	Your just outside the range of what is considered "good"... Lowest of 165 meaning the highest should be 181.5. How exact were those numbers? I found many people just round the # to the closest 5. Also, did you try a wet test after the compression test? If the #'s go up with a little oil in the cylinders then you know its rings. ~Mark __________________ Click HERE to see our Explorer Specs

05-23-2010, 05:18 PM	#1
copter14 Wannabe Elite Explorer Join Date: May 2008 Posts: 5 Vehicle Specs (Original Poster)	4.0 compression are theese good numbers, this is 4.0 litre out of 1991 i wanna use for my swap into 88bII. cyl 1@165 cyl 2@175 cyl 3@190 cyl 4@175 cyl 5@185 cyl 6@175 top end has tick so i will prob have it redone.

05-24-2010, 08:37 AM	#4
copter14 Wannabe Elite Explorer Join Date: May 2008 Posts: 5 Vehicle Specs (Original Poster)	thoose were exact numbers i didn't round them off. i'll try another dry test to confirm #1 cyl is that low. then i will do a wet test and post.