datsun-roadsters
[Top] [All Lists]

Re: Compression & Vacuum

To: SlowBoy <SlowBoy@cox.net>
Subject: Re: Compression & Vacuum
From: Steve Ehlers <stevenehlers@charter.net>
Date: Thu, 02 Jan 2003 22:18:08 -0600
Hi Jim ,
If you did this test when the engine was warm ( suggested time ) then in my
opinion ,
You have a Really Used engine ( another words , it's pretty worn out :-) .It 
will
run ,
but it is never going to be as strong on bottom end torque .Any more than 15-20
psi
increase on wet test confirms worn out rings .You can cause accelerated ring 
wear
by running too rich also .So you may have even caused it by not having the 
engine
running clean .On the positive note , if you can lean it down correctly ,get the
plugs
to clean up ,over time the compression can come up some ,especially if you 
didn't
do the
test on a hot engine in the first place .On another note ,I have seen low 
reading
results
given to me by customers that did it them self ,with their own gage ,only to 
have
me
verify it ,and find that their gage was inaccurate ( Many times they had lower
readings than actual )
Also ,I find cranking speed can be a factor caused by a battery that's not that
hot and
old starters that are not up to speed .Don't forget to have your throttle 
"opened
up"
( good reason for that mechanical cruise control :-) .Combined , all these 
things
can factor in .
Good luck ,
Steve Ehlers
2- 68 1600
2- 69  2-Liters ( 1 with Solex )
73 510  2 dr "Brock Buster"
77 280 Z Fairlady  ( 610 hp ATRW's )
and 8 other Datsun / Nissan products
www.risingsunperformance.com


SlowBoy wrote:

> Evening,
> Just checking what would be normal for a 1600.
> Cylinders from front to rear of car I'm looking at
> Rear 4, 3, 2, 1 Front
> Dry compression was 140 on all cyclinders and wet was 185
> Vacuum is 18 inches running and jitters on the 18
> Spark plugs were carbon fouled
> 1 Medium carbon
> 2 Light carbon
> 3 & 4 were Heavy carbon
> So, what do you think?  Everything look okay except a carb adjustment?  Is 140
> okay for the compression?
> Thank you!
>
> Jim

///  datsun-roadsters@autox.team.net mailing list
///  Archives at http://www.team.net/archive


<Prev in Thread] Current Thread [Next in Thread>