V8i cylinder compression results - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars
Ford Forum Ford Forum

» Auto Insurance
» Featured Product
ยป Wheel & Tire Center

Go Back   Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > Ford Cars and PAG Vehicles > PAG Vehicle Discussion > Land Rover
Register Home Forum Active Topics Photo Gallery Auto Loans Garage Mark Forums Read Auto Escrow

FordForums.com is the premier Ford Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
Old 08-20-2005, 14:01   #1 (permalink)
Dadio
Guest
 
Posts: n/a
V8i cylinder compression results

Ok, so it looks as though I will keep my existing 145,000 mile Discovery and
I am now turning into a bit more of a mechanic than expected. Needs
must....
1995 V8i 3.9
I have just replaced all the plugs and took the opportunity to compression
test each cylinder.
I did not do it quite according to the book but took one plug out at a time
(leaving the others in) and spun the engine for about 10 seconds with the
coil disconected and the accelerator depressed.
Results were reasonably consistent between 165 and 170 throughout.
Is this good, bad or average?
I am a bit confused by my Haynes manual as it suggests two different typical
compression results for the 3.9, one for the low compression version and one
for the high compression version.
How can I tell which engine I have (low comp or high comp).

Thank you

Les


  Reply With Quote
Sponsored Links
Advertisement
 
Old 08-20-2005, 15:01   #2 (permalink)
Richard Brookman
Guest
 
Posts: n/a
Re: V8i cylinder compression results

so Dadio was, like...
> Ok, so it looks as though I will keep my existing 145,000 mile
> Discovery and I am now turning into a bit more of a mechanic than
> expected. Needs must....


Good to hear this. :-)

> 1995 V8i 3.9
> I have just replaced all the plugs and took the opportunity to
> compression test each cylinder.
> I did not do it quite according to the book but took one plug out at
> a time (leaving the others in) and spun the engine for about 10
> seconds with the coil disconected and the accelerator depressed.
> Results were reasonably consistent between 165 and 170 throughout.
> Is this good, bad or average?


Sounds pretty good to me. You really should have all the plugs out, but
your results look healthy. The most important thing is that they are
consistent - ideally within 10% of each other. Yours are well within this.
FWIW, mine were all around the 130-140 mark (3.5V8) and the engine still
goes well.

> I am a bit confused by my Haynes manual


You're not alone there!

> as it suggests two different
> typical compression results for the 3.9, one for the low compression
> version and one for the high compression version.
> How can I tell which engine I have (low comp or high comp).


I think it's cast on the top of the exhaust manifold. 9.3 (i.e. 9.3:1) is
high comp, not sure what low comp is, 8 point something. It's fairly
obvious when you see it.

HTH
--
Rich
==============================
Disco 300 Tdi auto
S2a 88" SW
Tiggrr (V8 trialler)


  Reply With Quote
Old 08-21-2005, 02:01   #3 (permalink)
Tony
Guest
 
Posts: n/a
Re: V8i cylinder compression results

There are two way's to tell the compression ratio: On the nearside of the
block there is a small flat with the ratio stamped on it or by the ignition
timing Low comp No CAT 2deg BTDC, High comp No CAT 4Deg BTDC, High comp
with Cat 6Deg BTDC.

As a matter of interest my 3.5 with a 9.35 comp has pressures of 165-170
across all cylinders.

--
Tony,
110 V8i CSW
S1 Discovery V8i


  Reply With Quote
Sponsored Links
Advertisement
 
Reply

  Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > Ford Cars and PAG Vehicles > PAG Vehicle Discussion > Land Rover



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Powered by vBadvanced CMPS v3.2.2

All times are GMT -7. The time now is 12:32.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.6.0
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.