Ive been told that impreza heads will sort my legacy out.
So thats what I'm getting done.
Now if only i had a wrx turbo

 

It seems you are having a lot of problems. Which one do you think the heads will actually fix??
If you change the heads, you will have to change the pistons too to match the heads to obtain the correct CR.

 

CR on early imp`s and legacy`s is the same.The heads are to stop the very noisy lifter problem that many Legacy`s suffer from.In this case it is so bad that the Knock sensor is detecting it and backing the boost/ignition off.This was a choice of either replacing the lifter`s which as you will be aware does not cure the problem indefinately,or fitting impreza heads.I think by the way the owner of the car has been passed round from pillar to post ,he just wants to have the car running correctly and be able to enjoy the car and use it to its full potential.If you are conversent with both heads,i needn`t bother explaining the differences.

 

I am conversant with both heads, and you will need to change the pistons to suit the heads. Legacy's and Imprezas may run the same CR, but they use different sized combustion chambers, and piston dishes to obtain it.
If you use Impreza heads with Legacy pistons, there will be an increase in CR. I have not measuerd how much, but it is enough to cause pinking when using above 13psi boost at high revs. A std CR UK Impreza or Legacy will happily run 13psi+ with no ill effects.
I know this for a fact, as I did for a while run my engine like this.
I ask what he was hoping to achieve by swapping heads, as he did not actually specifiy a problem. There are various threads scattered round scoobynet, where he seems to have a lot of problems with the car.

 

I also suggested checking this problem before paying to have the heads fitted (which I dont believe will fix the problem) by simply unbolting the knock sensor...

I have heard worse legacys running our remaps at 15psi..

with the timing advanced more than a std legacy and these dont run knock correction

David

 

I have done this conversion that many times i cant remember .Never yet have i had one fail.At present it sounds horrendous,how bad was it when you heard it David.Would you not say it was dangerous to run without a knock sensor with a standard ECU,i was always told that the standard ECU advanced its own ign till it detected det via the knock sensor then backed the ign off to what is regarded as a safe level.Personally i dont fancy disconecting the knock sensor because of this.If the owner does thats up to him. I have never implied that this car cant run one of your re-maps,what i was asked to do was find out why the car was holding back.I have in my opinion done this unless i`m overlooking something??.

 

On std boost, I doubt that the knock sensor would ever be coming into play, unless some seriously bad fuel was used. If however the boost has been increased, then retaining the knock sensor is probably a good idea. If it is just purely to test that it is the problem, then I would really worry about disconnecting it for a bit. Could also be worthwhile attaching a knocklink to it, to see if the knock sensor is actually being triggered by whatever noises the engine is making.
Did you actually buy the car making these noises, or has it got like that over time??
Sounds like they are pretty bad.
What is the problem with the way it goes??

 

Hi. Having read your problems i was told that there was some different heads available for legacy to cure the problem. Cross Country Cars at whitney in Oxfordshire have sum in stores growing cob webs i was told. No harm in giving them a call mt8 they could do you a deal to get rid of them

 

Howard... I wasnt saying that it couldnt, what I was saying is that there was no audible knock when I went out in it.. and it wasnt running correctly then... I suspected the temperature sensor or iscv... I was just saying that, the level of tapping that I heard was less than other 'modified' legacys, therefore I doubted that that was causing the CEL.

If the knock has got worse since I went out in it then fine, but that wasnt causing the boost issue when i saw it.

Interested in the outcome of this.

David

 

IMO, I would want to do some checks before swapping the heads.

I agree about disconnecting the knock sensor, but would also make sure the car was set up to run standard boost first.

If you are concerned about knock/det', then use a set of "det' cans". If you don't have any, I'll lend you mine !!!

The knock sensors are also notorious for giving spurious readings, and causing all manor of problems. I would want to eliminate this too.

Mark.

 

Swapping the heads would be a last resort, as there are few problems I can think of that would actually require a head swap to fix. Not sure what HCD is saying when he has carried out numerous conversions??? If he is referring to head swaps without the pistons, then I hope those people never try and turn the boost up, as they will encounter problems, as I did.
What is the history of this car?? Has anyone been working at it and caused this problem, and failed to tell mention it??
What exactly is the problem??? Low boost? poor running?? missifre?? Low power?? Is it there all the time??
Can the car actually create boost?? have u tried a bleed valve or similar, to see if it is possible?
Are all pipes etc sound? no leaks
Is the chargecooler pump working??? If not, the car may only ever get low/safe boost. You should be able to hear it running with the ignition on AFAIK. The pump is below the battery in the inner guard. I have mine wired direct to the ignition as when I got my car, it never worked. Pump was fine, but a wiring problem somehwere.
Are all the inlet manifold gaskets ok??
Has the noise ever been worse than it has?? I had a problem once when I put the legacy engine back into my car, where a lifter fu*ked up. After a while, the noise went away, happy days I thought. Then the car developed a missfire, or deadness above 5000rpm. Other than that it drove perfectly. After a lot of fu*king about it actually turned out the reason the lifter noise went away, was that a cam follower had fell out, and one of the inlet valves was no longer opening.
This took a long time to find, and the car drove as normal below 5000rpm.
It may be worth chacking cam timing too I suppose.
Obviously it is very hard to diagnose when I cant see the car, but the above is some suggestions, and problems I have encountered.
As Mark says, it would be worth removing the knock sensor from the equation. Even if you just remove it from the block, and earth it, so the ecu still thinks its there, but will hear no noise, and not bring up a CEL
Changing the heads would be a last resort, although I suppose a worthwhile upgrade not forgetting the pistons. It does seem likely that unless there is a mechanical problem with the current heads such as I mentioned, then I doubt swapping them will fix whatever problems there is with the engine..It will just relocate some money from one persons pocket, to another


[Edited by ustolemyname??stevieturbo - 11/17/2002 2:51:31 PM]

 

Could i explain as to why i suggested impreza heads.
This car came over to our garage last monday,the owner complaining that the check light was on (code 24)and the car wouldn`t "pull".I noticed that the wrong Lamda was fitted(it looks like a 2.0l n/a)and that the position of the ISC vale was full to one end of its adjustment.I presumed at this stage that it possibly had struggled an emmision test with the previous keeper and somebody had tried to remedy this in some weird and wonderfull way.The owner took the car and came back on the thursday, then i fitted a turbo lamda and replaced the Isc valve. For the first time then i drove the car.I saw immediately what was meant by it wont "pull".Nearly all the time i was driving this car (About 2m)you could hear the lifters rattling very loudly.Apparently the owner had over filled this car with oil at some point, i think David is aware of this as i was told he cleaned the boost solonoids.Anyway i got the car back to the workshop and did change the boost pack, i find it easier to swap the full pack .No better!!.I changed the ecu,no better!!.All the time the lifters rattling like hell.Upon speaking to the owner again i was informed that the problem`s only seem to have appeared since his oil escapade,could it be he used the wrong oil he asks,but was unable to say what he had used.So i thought to remedy this uncertainty well give it another one.Still no better,So next some wynn`s lifter treatment,this is a product i have had varied levels of success with, particulary on the older L series models which suffer the same problems as the legacy turbo`s.I dont think there was any improvement.For those of you who dont know the legacy runs a very small tappet on top of which is a post and then a finger follower like old Pinto engines run,the very early legacy turbo`s did have a design fault with the heads.After i think it was 93 they were fitted with a re-designed or modified head.Most pre 93 cars had these later heads fitted under warranty at some point.The cost of these lifters is around £24 each.Although a new set might stop it rattling for now there is no guarantee it wont come back.I have known them to be just as bad after less than 10k.The only way to cure this permanantly is in my opinion to fit impreza heads.Yes there is a slight difference in combustion chamber sizes,but i was informed that this wasn`t a problem on a standard ecu.If the boost is to be increased i was not aware.Perhaps it would be easier to drop in a full imp engine if this is the intention.It isnt a case of releive the owner of any cash as i said i would fit heads for the same as lifters.I have known in the past that when the lifters have rattled as bad as this one for the knock sensor to confuse it as det and cause this problem,our own old estate that we use for a chase car was similar if not worse.This has covered 70k since fitting heads albeit with standard boost.As to the intercooler pump working, yes it is.I have worked my way through this, what else is left??We are not intending to start this for quite a while due to our other work commitments so any constructive suggestions are welcome.

 

So after fitting the ISCV and lambda, are the faults all cleared from the ecu now??

Agree, it could sometimes be handier just to swap a whole engine, as timing belt backing plate covers are also required, and most breakers I know charge plenty for these. Generally for time involved, it is quicker to swap complete, as less gaskets etc are required which are expensive.

It does sound like this fault has not just occured. It almost sounds like someone has caused it. I may be wrong, but it all sounds strange. it would just be a nightmare to change the engine/heads to find that the fault lies elsewhere. The owner may claim he is competent, and able to work with engines etc, but he has made a few mistakes with things he has done, which would make me think he is less than competent. Sometiems its best to leave well alone if you dont know what you are doing. It makes peoples jobs who actually have to fix it a lot easier. Also tell them what has been done, even if it was something stupid.
I think if playin with the knock sensor doesnt do anything, the inlet manifold gaskets could be worth a look. If they are leaking, it can sometimes cause strange things to happen. Is the dump valve leaking??
I am just offering suggestions above, assuming the noise is just noise, and that all 16 valves are opening and closing as they are supposed to even if it isnt as much as they should be due to dodgy lifters. Does the engine have good compression??

 

Been down this road , and had new set of lifters fitted in the end. Would like to know how much an imp engine would cost ? The lifter job cost £900

 

Im sure you could pick up a complete engine for close to £1000. + fitting.
But if the lifters are all replaced, and the heads thoroughly cleaned out, then there is no reason why they shouldnt be good for another 100,000 miles or more.