99 cobra compression problem

[mr99svtcobra]

I recently had my 99 Cobras motor built with comp stage 2 blower cams stock heads put 2k miles on it and went for a dyno tune ... We could not tune the car because of a bad 02 reading long story short my tuner told me to perform a compression test driver side compression is 135 all across passenger side is 150 all across my tuner tells me cams were not degreed properly ...person who degreed them tells me I have washed rings

If the rings were washed wouldn't the compression test be all over the place on the passenger side for example 130 125 119 130 ?

Why would every cylinder read 135 on the passenger side ? Poorly degreed cams? Please help so I can set my mind at ease

Engine 9.5 to 1 bored .20 over Manley rods and Pistons comp stage 2 blower cams with Crower valve springs (no adjustable cam gears were used to degree the cams)

 

[01yellercobra]

I would suspect the cams as well. Since it's all four cylinders. Did the person actually degree the cams or just line up the dots?

 

[mr99svtcobra]

I wish I knew my tunner tells me he couldn't have degreed the cams without adjustable gears

 

[shurur]

That's the test: if one head's compression, across all cylinders, is not the same as the other head, the cams are not degreed.

I think of it as both heads need to each be degreed to TDC and evenly matched....or personifying..."both heads need to know what TDC is."

PM NA SVT and get him to chime it.
This is his test...or where I saw it first mentioned and explained.

 

[Outonyou]

I wish I knew my tunner tells me he couldn't have degreed the cams without adjustable gears

It can be done without buying adjustable sprockets. You have to grind the original camshaft sprocket keyways down just a bit.

 

[soccerman002]

Who built your engine, and have you contacted them yet?

 

[shurur]

You can get $100+ worth of parts from summit racing to get this done....and the procedure from na svt.

 

[mr99svtcobra]

Thanks for all the help guys I just wanted to feel better knowing that it's not the rings ... I contacted the person that "degreed the cams" and he said I washed the rings ....mean while my tunner is telling me to pull the motor and bring it up to him to have a person that actually knows what they are doing ....now let's say it was the rings wouldn't the compression on that one side be all over the place ? Not just 135 even?

 

[na svt]

cam timing is what I suspect. What makes the builder assume that the rings are washed out?

Is the driver side cranking compression low?

 

[TBCobra]

cam timing is what I suspect. What makes the builder assume that the rings are washed out?

Is the driver side cranking compression low?

Sounds like he is just trying to pass his crap work onto someone else. He probably didnt degree them right.

Tell the engine builder you'll pull the motor apart and if you find out that they cams are not degreed properly you will send him the bill for the labor to have someone else do it right. If they are fine then he owes you nothing.

 

[mr99svtcobra]

Na svt what do u mean by cranking compression ? The driver side compression is all 135 passenger side is all 150 sorry if that does not answer your question

 

[shurur]

What comp cams are you running? Specifically... part number....

Na svt can give you:
a list if parts you need...
the setting you need to degree those cams to...
and a procedure that you or your builder can follow using those parts.

 

[mr99svtcobra]

Comp 106360 is the part number stage two blower cams

 

[na svt]

The driver side cranking compression (PSI) being lower tells me the cams were not degreed. The reason for this is that when using the stock gears (unmodified) the intake LC driver side is at a lobe center 3-5 degrees higher than that of the passenger side. The higher lobe center and resulting later intake valve closing point reduces the cranking compression by allowing the air to escape through intake port as the piston begins the compression stroke.

https://www.facebook.com/groups/481330828691064/

 

[mr99svtcobra]

He said he modified the stock cam sprockets to degree the cams ....I'm going to do a leak down test before I pull the motor just to be sure nasvt

 

[na svt]

I guarantee it's not washed out rings on one bank; it just doesn't happen like that.

 

[mr99svtcobra]

Yea I hope so man

 

[cobrabit]

im with Todd on this. Classic example of incorrect cam timing or plain lack of degreeing. a leakdown test will most likely show fairly consistant readings indicating the rings are fine and cams are not where they should be based on the cranking compression test.

 

[mr99svtcobra]

Leak down test 9% loss on every cylinder on the drivers side we can hear air coming out the exhaust 4 % loss on passenger side every cylinder no air leaks anywhere ..so something is wrong on the passenger side side exhaust valves I'm at a loss I'm guessing it's not timing it not degree ?

 

[mr99svtcobra]

Pull the motor took the cam off the head in question and did another leak down test the exhaust valves are still leaking along with the intake valves on the head in question ...the person that timed and degreed the cams pulled off the head and says the valves look burnt to him ....waiting for the machinist to take a look at it

Here is a pic of the head with issues