Job # 1838 (TS)
Dodge Viper Turbo - Cylinder head rebuild, Stage Two polish and port

Report date - March 25, 2008

I am pleased to report that we have now completed this rebuild and your heads (and intake manifold) are ready for collection.


We have now completed the machine work and all that remains is to assemble the heads. We should have this job wrapped up and ready for delivery on Monday (3/24).
Matching the ports on the
intake manifold
Custom 2.040" intake valves
Cutting the 5 angled valve job for
the new intakes
Reshaping the bowls
Heads were pressure tested again after
port work was finished
No problems!
Re-surfacing the heads
After a thorough cleaning all that will be
left is reassembly

We have been notified that the custom 2.040" intake valves will be delivered tomorrow, so we should be able to wrap this rebuild up in the next couple of days.
Exhaust valve job now completed
Exhaust valves being re-used
Chris has started porting your
intake manifold

Lots of progress...
Intake manifold will also be massaged
Ports will be matched to
intake runners
Silicon bronze guides
Honing the new guides
Intake set up at .001", exhaust
set up at .0012"
Cutting out old factory intake seats
 New intake seats installed in
the first cylinder head


Chris has been busy in the porting room and has done a beautiful job with your intake runners.


We now have your port work underway. The custom 2.040" intake valves have been ordered and we have been promised delivery by 3/21/08.


Report date - March 12, 2008

We have now torn down and inspected your cylinder heads and identified a number of issues. It looks as if the engine has been running rich, and also burning a little oil. Stem to guide clearance, which was originally set up at .0008", now measures between .0012" and .0015". While this is still within acceptable parameters, it is enough wear to have allowed some carbon build up on the neck of the valve. We believe this is what ultimately caused the valve to stick.

Having initially thought we would simply replace all the guides, the one damaged valve, and do a straight forward valve job, we then ran into a problem with the factory intake seats. While heating the head prior to removing the guides, one of the intake seats literally fell out. A little further investigation revealed the seat had been installed with only a .0015" interference fit. This should have been between .003" and .005". In view of this, we decided to replace all the intake seats with custom CM seats, manufactured for us .040" oversized. The larger seats mean we can now go with a larger intake valve (2.040"), which of course was too much to resist!

It will be interesting to see what the flow numbers are after we have ported the heads and done the big valve conversion. Watch this space!

 Checking stem to guide clearance
 Measuring installed spring height
Beehive springs are best option 
for Vipers
Springs all tested fine - between 125 and
135 lbs
 Ports will be opened up
to match gasket pattern
This type of mismatch makes fine
tuning very difficult
 We flow tested the head to 
get a baseline
 Harold thinks this may be evidence
of fuel wash
Factory seat dropped out with the head heated 
to not much more than operating temperature
Custom oversized intake seats 
With larger valves, port work will now include 
reshaping the chamber slightly


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Go to other CJ engine rebuilds