Cambelt on my cossie snapped a couple of months ago (long arse story so wont bore you with it). Bent 6 valves. Mark kindly let me do all the work myself at his new premises So lapped 6 new vales back in and put the car back together. Fired it up all is ok. Mark took it for a test run and it wouldnt boost over 2 bar. Before the cambelt snapped we saw 2.4 bar. Absolutely nothing has changed, so am confused as to why the boost would not be there. Mark had to give the acutator a good old wind to get the boost to 2.2 bar. I want my original boost figure back

Anyone had this problem before? The actuator is -34 and hasnt even covered 500 miles. Could a weak spring be casuing this, or can anyone else shed some light. I defianltely have no boost leaks, thats all been checked.

Any ideas?

 

anyone

 

Awww

 

Did any shrapnel from the valve / piston "coming together party" damage the exhaust blades of the turbo?

 

or cause the wastegate to not seat correctly.........

 

No Mike. All valves were intact and together just 6 of them were bent Pistons had no markings whatsoever on them so it looks like the pistons just kissed the valves.

 

Pretty sure the wastegate penny is properly seated as there seems to be no problem with building the boost up (which wouldn't be the case if the wastagte wasnt seated properly i asume), it just doesnt boost as much as before

 

wonder if the valve piston contact damaged the hydaulic lifters, not opening fully now?

funny one this......

 

It is a funny one isnt it. I thought maybe the actuator had gone weak due non use for 3 months

 

i suppose it is possible, if everything is set up the same it must be that.... verniers dialed in the same as before?

 

Yes mate, all exactly the same, just 6 new valves. Same thickness of cometic headgasket (new of course), same cams, etc

 

must be the actuator then.....



unless the valves hit so hard it bent the con rods and you now have a 5.6:1 cr

 

rofl I think there would be damage to the pistons if that had happened, but there were no marks. thank chrsit for valve pcokets

 

anyone else got an input before i go spending on a new actuator?

 

Skimmed head?

 

nope, didnt do that. Nothing has been skimmed. it all went back the same as it come off

 

have you got the pipes on the right way from amal valve to turbo to actuator etc

 

I have mate. The pipe with the restrictor in in goes to the turbo and the other one to the actuator. I really am begging to lose the will to own a cossie recently.

 

How do you know 100% there isn´t a boost leak? How did you check it?

Do a sylinder leaktest too just to be certain.

 

Here you are jumping to conclutions. You don´t know if it´s seating proberly if you haven´t checked.
Asuming is the mother of all f*ck up´s when it comes to troubleshooting.

I think there will be no problem building boost with a small leak. But getting very high boostpressures as you are running aren´t very easy with internal wg.

 

Hi Rich,

I think the actuator on my T38 is a -34.

I can post it to you if you want to try it (its brand new unused)

Speak to me on MSN mate

Steve.

 

...put a bleed valve on if that dont give you 3bar i dont know what will

 

Thanks for the replies all. Right,

Before the cam belt snapped, the peak boost was 2.4 bar. So there can be no way that the wastegate is leaking, seeing as the car stopped instantly and didnt get started until the engine was back together.

The boost pipes cant be leaking just from taking them off and putting them back on again, but i will do a leak test to make sure.

there is only 2 things left. Either the turbo is fucked, or the actuator has gone weak, but i just cant see it. 30 secs before the belt snapped, i had full boost, of that there is no doubt.

Steve. MSN in about an hour my friend.

Phil, we took the pipe off the actuator, therefore giving basically full boost with no control, and it made no difference.

 

Plenumgasket blowout when the engine went pop?

Tried with startgas to search for leaks?

 

.....oh ok...i ruled out actuator because i thought Mark may have already told you that if it was.....to me though personaly deffo actuator!

 

Plenum gasket re-newed when put back together mate.

 

We basically run out of time, and Mark didnt charge me for having my car there and has been very decednt when coming to a figure of how much i owe him for timing up my cam and trying to source this problem, so i didnt want to take the piss and outstay my welcome, even though Mark said it was not a drama

He said either my turbo or actuator is at fault. Cheapest thing to try 1st is the actuator, although thats only covered 500ish miles

 

Try putting a spring from the actuator mounting point on the turbo to the wastegate, to try and encourage it to stay shut, that should rule out the actuator going weak.

If it still wont make boost then, it seems likely the turbo is damaged

 

Cheers Chippa,

every idea helps

 

I did Dave yes.