rolling road session spoilt, boost tails off at 5000 rpm, CAMS FAILED !

[OLDSKOOLRYAN]

hi everyone. my car is at mikeanics in cheshire for a set up on the dyno. Got the call today to say that my engine is healthy and running well but the boost is tailing off at 5000 rpm. The car made 170 bhp but would do more if it wasnt for the boost issue. Has anyone got any ideas on what the problem could be ?????? my engine spec.... new hybrid turbo new -31 actuator msd chip grs front mount ported & polished head samco hoses piper cam with new ford valve springs 071c plugs exhaust & air filter bailey dump valve any ideas ??? please help thanks

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[Karlos G]

What do you mean by hybrid turbo, what is it's exact spec?
If it only makes 170bhp then either it's a standard turbo, boost leak, weak actuator, heavily worn cam, etc..etc..
But your tuner should be able to test for most of those things, unless of course he doesnt know what he is doing?! lol

[OLDSKOOLRYAN]

well im no mechanic but the invoice for the turbo states t3 hybrid 360, cut back blades.
the cam is new
actuator is new (msd)
my tuner is going to investigate further in the morning, im just trying to get a head start and maybe save myself some money.

[Karlos G]

Hmm.. sounds like a "Stage 1" with 360deg thrust bearing and cut back blades which improves exhaust housing flow but limits maximum spool, if it is then 170bhp is a little low but not that far off normal mate!
Some will disagree with me but I and many others have never seen more than around 185bhp out of a stock turbo, and the cut back blades may limit it further.

Thats what I'd be looking at if everything else is found to be good.

From TT website..

S106 Ford Escort RS Turbo Stage 1
Power output 130-180 BHP
Boost 8-18 PSI
7° cutback turbine assembly
270° screwed thrust bearing
£415 + VAT - Buy now

Although you have a 360deg bearing this doesnt improve flow/power!

[OLDSKOOLRYAN]

fair enough, any ideas on why the boost is tailing off early ??

[xr2wishy]

i would have to agree with the above with my knowledge of turbos.
doesn't sound like the compressor is bigger or that the exhaust housing is bigger either.
i reckon with a bigger exhaust housing it'll let you pull more power, but a bigger compressor side would let you have more boost without it getting quite as hot.

either way, the tuner should know why it is hitting a brick wall.

[xr2wishy]

in regards to why boost is tailing off, then the compressor can't draw in enough air and as the engine revs more, the demand for volume increases and the turbo simply can't flow enough highly compressed air. so in effect the pressure of boosted air will drop.

[OLDSKOOLRYAN]

ok cheers,
im a bit fed up with tuners so far, if he cant sort it ,then thats two tuners who have let me down regarding my boost problem. 1st was msd they diagnosed weak valve springs, which i have since replaced.
mikeanics also mentioned valve springs untill he realised they head been replaced. they now think its a turbo related problem ? i thought they meant it may be faulty but they may have meant what you have mentioned.
if it is the issue you have suggested then i would be happy to have less psi for better boost throughout the rev range.
could this cure it ??
many thanks

[Karlos G]

What Sean (xr2wishy) says is spot on!
On my old engine that was a very similair spec to yours my stock T3 would peek at 17psi and then gradually drop to 11psi as the revs increased, you could force it to hold a bit more with an electronic boost controller, but really a higher flowing turbo is what is needed.
If this is your problem of course!?

IMO very rarely do we see weak valve springs on these engines, as they are really heavy to start with!

[xr2wishy]

best thing to do is get a cosworth 2wd or 4wd turbo.

pop up to me when i have some time off and get the cores and compressor side swapped over, then it'll boost more more easily.

[boothy]

mike should be able to find out whats up with it,He is very good

[OLDSKOOLRYAN]

thanks guys, see what tommorow brings

[OLDSKOOLRYAN]

still no joy. tuner has checked the turbo & actuator, swapped actuators etc.
he now thinks its cam / valve related.
i have a receipt for a complete head rebuild inc piper bp 285t cam. the car has done less than 2000 miles since.
any ideas???????????????????
thanks

[white2lsr]

Give tony at turbo systems a ring. Have a chat with him and maybe get him to have a look at it. Id say he is possibly the best in the country at tuning these engines.

[xr2wishy]

get cam out of head and measure lobes, piper cams can die in much less time than 2000miles saldy and some can last years.

[juffer]

I have noticed that you are using ford cam springs with a piper cam. would this effect it as piper springs are not being used?

[Chopshop85]

I agree with the flow comments. Mine was having the same problem where the std turbo was struggling especially with the FMIC. The tuner ended up replumbing the actuator vacuum hose into the cross over pipe. I have no idea why he would do this ( maybe someone could shed some light), but the boost peaked at 17 and held at around 14/15.

[Karlos G]

If he didnt swap the turbo for a bigger one, then there is no way of knowing if it's that or not!
Cam could have shit itself, so yes whip it out and meassure the lobes, and lifters to check they are in tolerance.

Chopshop85, that was so the actuator responded to actual boost pressure making it to the inlet rather than just boost pressure from the compressor housing (it allows for boost drop through IC , etc..).

My gut still says your turbo is the problem, well not even really a problem, just under spec'd for what you want.

[Chopshop85]

Originally Posted by Karlos G

Chopshop85, that was so the actuator responded to actual boost pressure making it to the inlet rather than just boost pressure from the compressor housing (it allows for boost drop through IC , etc..).

ahh, knew someone would know why he did. He started explaining it to me... i Just stopped him mid sentance and said drill away! lol

[xr2wishy]

back to Karlos on this again if not the cam.
think about having a small pipe, you can only get so much flow through it, so you upgrade to a bigger one to get more flow out of it.
a turbo is the same thig really, if your exhaust housing doesn't get bigger than the limit will still be the same.

[H7 CYA]

I would have a look at cam lobe wear...not uncommon on those and kent cams unfortunately

[Karlos G]

or any cam... lol

[OLDSKOOLRYAN]

thanks everyone for your advice.well my cars coming home tommorow, im going to check the cam then take it from there.
thanks again

[Karlos G]

Email Piper (or whoever it was) and get the lobe tolerances mate, they were quite helpful when I asked for them.

[OLDSKOOLRYAN]

just sent an email to piper, thanks karlos

[OLDSKOOLRYAN]

just been reading some old posts, some people have complained of valve float problems.
could this be an issue ???
cheers

[juffer]

i was runing standard cam springs and followers and the guy who was RR my car had problems with boost and getting power. It turned out to be a dodgy follower that was causing valve lift

[Karlos G]

Originally Posted by OLDSKOOLRYAN

just been reading some old posts, some people have complained of valve float problems.
could this be an issue ???
cheers

Valve float is not common really on CVH's, as I mentioned earlier the sprins rate is really high to start with so even if they were a little weak it should still be enough! lol
I'm using 20 year old springs as far as I know and have no probs with a rev limit of 7000rpm and thats with a Newmans cam and solid lifters.

[OLDSKOOLRYAN]

hi everyone, just a quick update.
i have been through my history again and inspected the head rebuild invoice again.
Its an engineers invoice, just for the head rebuild and parts fitted to the head.
so im guessing the previous owner of my car fitted the head him self.
and im also guessing the cam wasnt "run in" properly. (2500rpm for twenty mins ??????)
An engineer friend of mine has offered to check my cam tolerances at the weekend, i have emailed piper for the tolerances and not had a reply, but i found this info on there web site
http://www.pipercams.co.uk/pipercams...n=8&engine=122
will this be enough inormation or do i need more ???

thanks again for all your help

[rsmark86]

guys i brought a piper cam kit before for my old rst turbo with ...
ahmed stage2 chip
-31 standard turbo bleed valve
piper 285t kit
radtech front mount
exhaust and good filter ect

and anything above 14psi and i would get valve bounce with brand new piper springs fitted so i put double valve springs in and afterwards it was peaking 19psi and holding around 16psi and made 192bhp ...

and another one i had that had a problem like this was a sticking wastegate and ive brought faulty actuators so could be anything

[OLDSKOOLRYAN]

cheers mate, if the cam looks ok then i will try some double springs.

[OLDSKOOLRYAN]

WOW !
£142 plus vat for piper double springs. best make sure it is the springs before i buy some !
Its got ford springs in at the mo

matt lewis is sellin newman double valve springs for £65, will these be ok with my piper cam ??

cheers

[rsmark86]

Originally Posted by OLDSKOOLRYAN

WOW !
£142 plus vat for piper double springs. best make sure it is the springs before i buy some !
Its got ford springs in at the mo

matt lewis is sellin newman double valve springs for £65, will these be ok with my piper cam ??

cheers

i would have thought it would be fine with them mate

the other thing to do is take off the actuator and test it..... ian ball at power engineering would sort this car in no time at all i know some people will say dont take it there but the only time i had problems there was when chris todd was there ..... it was ian who sorted my old cars mate.

might be worth just giving him a bell....

and how much does the boost drop because if it completely drops off then it could be what karlos said and be the turbo

[OLDSKOOLRYAN]

i have taken the cam out this evening, how do i post pics on here ??
the cam looks ok, cant see any marks, just some dis-colouring

[rsmark86]

Originally Posted by OLDSKOOLRYAN

i have taken the cam out this evening, how do i post pics on here ??
the cam looks ok, cant see any marks, just some dis-colouring

use photobucket mate..

[Karlos G]

Pics will do us no good mate you need to meassure it!

[OLDSKOOLRYAN]

just had a mate round. my cam is shagged !
the exhaust lobe on cylinder four is 2mm out

[OLDSKOOLRYAN]

can anyone tell me the exact procedure for fitting a new cam please.
i know i have to fit new tappets at the same time.
i think i have read somewhere that it needs to run in at2500rpm for twenty mins ??? is this correct
thanks for all your help guys

[Autoflock Motorsport]

not 2500, different cam different proceedures, when i fitted my kent cvh34 i held it at 4k for about 8 mins. I was told this on the forum so it may be the wrong proceedure but it seemed to work

[tasos77]

Originally Posted by OLDSKOOLRYAN

WOW !
£142 plus vat for piper double springs. best make sure it is the springs before i buy some !
Its got ford springs in at the mo

matt lewis is sellin newman double valve springs for £65, will these be ok with my piper cam ??

cheers

Take a look here.......
http://cgi.ebay.co.uk/RS-Turbo-cvh-u...item2a07663e91