I have a 87 VandemPlas 4.2 efi with NO COMPRESSION. The Car was
running, shut it off, went to restart 30min later and nothing. It
turns over, spark to plugs, timming mark at zero, piston TDC, Valve
train rotates, but no-compression, no start. Please, what else
should I look for that would cause this? I might add that I also
tried a wet cyl. test with a little oil added to each cyl. ans
still nothing. Cam and rockers all appear to-be working also. The
veh. has 134,895 miles on her. Thought my comp.gauge was bad at
first, but placed my thumb over spark hole and cranked engine over
to no avail. NOT even a whisp of air could be felt.
ANY HELP TO WHAT TO LOOK FOR WOULD BE APRECIATED - THANK YOU LARRY–
Thanks~~ Contact== AmericasMW@Cox.Net
Las Vegas, Nevada, United States
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In reply to a message from CoyoteOn2 sent Thu 13 Mar 2008:
Are you quite sure both cams are rotating?–
The original message included these comments:
I have a 87 VandemPlas 4.2 efi with NO COMPRESSION. The Car was
running, shut it off, went to restart 30min later and nothing. It
turns over, spark to plugs, timming mark at zero, piston TDC, Valve
In reply to a message from almcl sent Thu 13 Mar 2008:
Al, I have timming mark at pointer at ‘‘0’’ deg. and piston is TDC at
this time. Thatt is of course if I’m not backwards, I have the
piston closest to the firewall at TDC, that is # 1 is it not? or am
I wrong and #1 is the front most piston?–
Thanks~~ Contact== AmericasMW@Cox.Net
Las Vegas, Nevada, United States
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In reply to a message from CoyoteOn2 sent Thu 13 Mar 2008:
I would have another person do a compression check for you - just
as a cross reference. Removing the head is a big job and if you
have mis diagnosed the initial problem… You simply do not lose
compression on all cylinders at once unless the oil pan and the
crank are laying in the street behind you. Just does not happen–
Alyn
Seattle WA, United States
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In reply to a message from CoyoteOn2 sent Fri 14 Mar 2008:
OK AL, I went and looked at the cams, BUT - I DO NOT see any
notches, are they on the face of the cam gears, or on one of the
teeth of the gears? Exactly where would they be located on the
cams? Will I have to rotate the Engine to be able to see them as
the chains could be covering them? AGAIN THANKS for the assist.–
The original message included these comments:
OK, and the notches in the cams are aligned correctly?
In reply to a message from Alyn sent Fri 14 Mar 2008:
Alyn, You have a VERY good point, maybe I’m just tired and need to
take a break from it, and get a fresh start in the morning along
with getting a second oppinon (comp. test) with a differant gauge.
I’d really HATE MYSELF if I removed the Head and discovered it DID
NOT have to be removed. AGAIN!!! Thanks to all, in your responses
and assistance. I will update any findings or conclussions on this
matter as they accure.–
The original message included these comments:
I would have another person do a compression check for you - just
as a cross reference. Removing the head is a big job and if you
have mis diagnosed the initial problem… You simply do not lose
compression on all cylinders at once unless the oil pan and the
crank are laying in the street behind you. Just does not happen
In reply to a message from CoyoteOn2 sent Fri 14 Mar 2008:
If the cam chain or sprocket were not turning in sync with the
crank the engine is toast. If the timing chain broke there is going
to be interference between the valves and the pistons - big time
Big bang. You would know without looking that the timing chain
broke (if it did) by the sounds of silence after the big bang. Ah
poetry… No this is something else and you must have compression–
Alyn
Seattle WA, United States
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In reply to a message from CoyoteOn2 sent Thu 13 Mar 2008:
My wife overheated one of these engines to the point where
oil burned off the outside of the block. When cool the
engine cranked over and fired up just fine. It’s unlikely
the head would cause all cyls to be 0 compression.
Ignition/cam timing is based off the front cyl nearest the
radiator. When the crank is at 0 degrees the correct timing
is the two cam lobes inlet and exhaust should be vertical on
the front cyl. At this point the two notches which are
located immediately behind the cam sprockets and are cut
into the cam flanges should be vertical. The ignition rotor
should be at about 5 O clock. Make sure when you check
compression someone has the throttle fully down. The engine
has to pump air. The most likely fault on these engines is
fuel injection related. Remove the air filter and get
someone to crank it while you spray a little ether into the
inlet. See if it fires
Alex–
alex paterson
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In reply to a message from CoyoteOn2 sent Thu 13 Mar 2008:
Alex, thanks so much! That will give me a place to start fresh in
the morning. I thought I may have had the cylinder in reverse, you
know, like ford and dodge. Will post what I find tomorrow, and
again a BIG thanks to you all and this site!!!–
Thanks~~ Contact== AmericasMW@Cox.Net
Las Vegas, Nevada, United States
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In reply to a message from CoyoteOn2 sent Fri 14 Mar 2008:
Al, disreguard my question on the notch location on the Cams. I
found the answer in one of your previous posts,(located right
behind the first saddle on the shaft its self). The post even had
photos that showed them. I will check their alignment tomorrow in
the daylight.–
The original message included these comments:
OK AL, I went and looked at the cams, BUT - I DO NOT see any
notches, are they on the face of the cam gears, or on one of the
teeth of the gears? Exactly where would they be located on the
cams? Will I have to rotate the Engine to be able to see them as
the chains could be covering them? AGAIN THANKS for the assist.
In reply to a message from CoyoteOn2 sent Fri 14 Mar 2008:
Don’t panic. If your car ran OK then simply wouldn’t restart you
have not simultaneously trashed all six pistons and/or at least one
valve in each cylinder. These are the only way you get zero
compression so that you can’t even feel it with your finger over
the plug hole. And if that was the case, your engine would spin
much faster than normal on the starter. Is that happening?
A small amount of lift on a stuck valve - say a millimetre or so -
WILL result in zero compression but that would not happen on all
cylinders at the same time. Plus you do not need to have the cams
in any position in particular to do a compression check of course,
(as opposed to a blow-by test) you just crank the motor. Assuming
you don’t have a faulty hose or fitting or mechanism on your gauge,
and your cams actually rotate, you’re doing something wrong I
think. Be interested to hear how it turns out.
In reply to a message from CoyoteOn2 sent Fri 14 Mar 2008:
Al, disreguard my question on the notch location on the Cams. I
found the answer in one of your previous posts,(located right
behind the first saddle on the shaft its self). The post even had
photos that showed them. I will check their alignment tomorrow in
the daylight.
That’s about it, mister - to emphatically reiterate other postings: The
engine MUST be set to the TDC mark and the rotor MUST point to #6
(frontmost) spark plug lead. If it doesn’t; turn the engine one full
revolution to the ‘next’ TDC mark. At trhis stage the notches should be
90 degrees, right angles, to the head surface. A worst case scenario is
a slipped cam chain - which will show up as a notch misallignment…
And Alyn’s point about a rest and a retest with a differen person or
indeed a different test gauge is very pertinent. As he says - losing
compression on all cylinders simultaneously is either incredible - or
very disasterous…
But the ‘finger-over-the-plug-hole-while-cranking-with-nothing-felt’ is
not good - or hopefully misleading…
In reply to a message from Frank Andersen sent Fri 14 Mar 2008:
PROBLEM LOCATED!!! I must have been so tired yesterday while
looking for the answer that I just could not see it. Turns out it
is a Timming Chain issue. The Exhaust cam is advanced aprox. 19 /20
degrees over the Intake Cam. So guess my next step is to aquire the
famous so called ‘‘BIBLE’’ the all important SHOP MANUAL and get down
and get my hands dirty. But first and foremost, I want to express
my gratitude to everyone that provided input. Now it’s time to
spend $$$$$$$.–
The original message included these comments:
90 degrees, right angles, to the head surface. A worst case scenario is
a slipped cam chain - which will show up as a notch misallignment…