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

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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.

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