valve springs
Turbo Mini Forums

after having problems with my car reving in 3rd and 4th under load ive changed many things to with fueling and have checked timing numerous times on the laptop.

today i got it to rev up to 6k nearly in 3rd but it held back and gave what felt like a slight misfire. didnt get it into fourth.

if youve read my other topic a few weeks back youll know all the symptoms ive had. ive been racking my brains, could it possible be the valve springs have shagged out, causin it not to rev in 3rd and 4th where the engine is producing peak power. im sur it doesnt feel like a fueling issue now. Have any of you guys experienced this and had to change valve springs.

im unaware of what valve springs they are but they are double valve springs.

thanks

i doubt that this is the problem but.......... the spring will be tired though

if its ok in other gears my moneys on fueling issues

thanks for the reply mate. really am stuck on what it could be the valve springs were an educated guess.
ive changed everything on fueling, ie new reg new pump, proper return, new needle valve, etc.

could it be something simple like putting another dashpot spring in maybe?

Run the symptoms by us again...


Are you saying that its fine in first and second, no matter how fast or slow you try to accellerate? starts getting worse in third and then wont pull at all in top?

Laptop? so Megajolt I presume, maybe post your map? and did you check the timing was on i.e 10 degrees with no Megajolt attached. Did you check with a timing light that it advances as expected??

what oil is in the dashpot? is the dashpot seal OK?



Terry

Edited by Turbo Tel on 8th Sep, 2007.

website:- http://www.terryhunt.co.uk

If the valve springs were knackered it would only rev to a certain point no matter what gear it was in.

Have you done a compression test? Sounds like the same symptoms I had when my cam lobe had worn.

Edited by matty on 8th Sep, 2007.

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1/4mile in 13.2sec @ 111 terminal on 15psi

ok this is what is happening. the car runs well in 1st and 2nd gear right up to 6.5k not that i would wish to push it this far all the time but it does pull that fair, 3rd gear will go to about 5.5k and just stop accelerating and will just sit their and hold back. 4th gear will get to about 4 to 4.5 k and do the same as in 3rd gear.

ive check everything could it the the edis components how do i check all of these the lap top reads well and advances with the table as it should do. it was map at the rolling road and i have retarded timing a few degrees to see if that made any difference and it does pull better but stil stops pulling at 5k ish in 3rd.

Ive changed and check everything to do with fueling what could it be. it does either point to fueling or timing but its accurate i could take you out in car and put foot down and tell you when it will do it just by looking at the rev gauge. i not sure if this is linked but the rev gauge flickers alot does this mean its getting interfence could this be a sign of something not being right with the megajolt. the rev gauge sits on zero idle sometimes then blip throttle and it moves to the correct revs. sometimes when you decelarate the gauge flaps about and goes to zero till you touch throttle would this have something to do with it or not. saying that when the car gets to 5k in 3rd it is steady and doesnt play up when i am experiencing the trouble i am having.

thanks i hope we can sort this out been playin up for ages .


cheers matt i will try a compression test what should i be getting or what should i not be wanting to see.

website:- http://www.terryhunt.co.uk

When you do a compression test all the cylinders should be equal.

It does make a difference what gear your in with this problem as in first and second gear it doesn't take as much power/torque to get to the higher revs in the higher gears it does. Its worth checking as it sounds like you've tried everything else.

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1/4mile in 13.2sec @ 111 terminal on 15psi

thanks turbo tel ill check the megajolt tomorrow i would post it up but ive always had trouble with it like before could i email you it instead is that ok? as for 1st and 2nd im sure it pulls just fine it doesnt feel like im getting any porblems with it however it doesnt sit in the gears long enough does it but it does pull very well in 1st and 2nd.

the engine was rebuilt yes however we used a standard cam but it weasnt new but it was checked out and it all seemed fine.

its a bugger really i cant get my head around it surely it is something simple.

i havent got an afr gauge i do want one but cannot afford one at mo last time i went to rolluing road they guy said it wasnt leaning out or he would have said wouldnt he. he just said its missing when it got high in revs in 4th. he suggested cam timing but we have checked that with the engine in well my dad did and he said its correct. could it well be the mega jolt playing up or something like that. ill send you the map if you would be so kind and take a look at it for me.

Edited by Turbo Tel on 8th Sep, 2007.

website:- http://www.terryhunt.co.uk

i do not have a turbo dizzy any more so i cant try that unless i can use a standard 998 one which i dont think i can. is it possible for the edis componets to be dead or the whole mj unit as i bought this from a guy tried and tested. so i hoping that its the edis components. can i test these.


ill do a compression test on monday my bro has one at work. what did you say if compression is down what does this indicate?

really appreciate the feedback mate.

I'm pretty sure low compression on all cylinders can indicate bad cam timing. If the valves open up at the wrong time it never gets a chance to develop the pressure fully, hopefully someone can confirm that. Odd cylinders with low compression can indicate rings or valves.

180 psi is for a standard 9.4 CR I get 175 or so with my 9.0 CR and if you search the site others have posted numbers for lower CR's

Terry

website:- http://www.terryhunt.co.uk

ok i have disconnected the mj and put the timing light on it it reads 10 degrees as it should do.

plugged mj back it gaive it another go. now you mention it it sometimes does feel like a slight missfire in 2nd in higher revs but it seems to rev through this and keep pulling. its still the same in 3rd gear can get to about 5.5 k in 3rd and 4.5k in 4th.

it definatly doesnt feel like its leaning out im sure of it. its def a missfire.

what are my options. will do compression test tomorrow. could the mega jolt unit be dead itself or could it well be the cam. any other suggests please guys.

You didn't mention...
After you plugged the Mj back in did you check the advance??

Terry

website:- http://www.terryhunt.co.uk

website:- http://www.terryhunt.co.uk

sorry i could not try the advance again with the mj back in because i cannot get access to my lap top till tomorrow so will try the advance on lap top with the time gun tomorow.

and ill put the 998 dizzy in and that if can get coil etc and try that and just take the actuator arm off right? ? thanks for the reply mate i do appreciate it cant wait to get to the bottom of this, just hoping its not my megajolt as i only bought it iin march time and barely use car it seem to have the problem ever since then so who knows.

You can at least check with a timing light that it advances at all... If theres something up with the Mj you will be running in limp mode and it will stay at 10 degrees, and that could cause the symptoms...

Just look for it advancing to 20 or 30 degrees when you rev the engine

website:- http://www.terryhunt.co.uk

Has it always done this since you fitted the megajolt? Are you sure your coilpackis a good one and not a dud?
Had a friend with a Mondeo road car, misfiring at md/high revs, it was the coilpack u/s.

update. i have disonected mj and it works fine in limp mode. plug it back in and it appears to be fine on the drive blipping the throttle the engine advances with it.

im not sure on the coniditon of the coil pack can this be tested, i would guess at this being dud now as ive gone through everything else even checking vr bracket etc for play and clearance.

but guess what my head gasket has gone agaion now so ill have fix that first but will keep you updated. do you think i shiuld try the coil pack next. also my rev gauge flupuates alot when you lay off throttle or blip the throttle what does this mean

cheers guys

just letting you no i fitted new valve springs and believe it or not that seemed to fixed the problem. the old ones some of them you when fitted you could still push them down with fingers and some were shorter than others to due to wear i would guess

thanks for all help

matty which springs did you fit ?

200 lb double valve springs

Interesting....

Sounds very like a problem I had many years ago with 2 cylinder heads from the same company that plagued me for months.

Only finally reverting to my old cracked head cured the problem. I had little notion about springs etc way back then though. Just took for granted the head supplier was doing their job.....

Im still learning I should never take things for granted, especially when it comes to "experts" supplying stuff..

Although the Swiftune head I got after that worked perfectly too.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will