After recently having a slightly low dyno result, i thought id have a little investigation into why.

First thing was the timing which i found out was out by 1 tooth, i thought this could be a possible answer to the low power but carried on with the investigation anyway for peace of mind!!

Next on the list was a leak down test which has thrown up some MAJOR issues!!!!

Results,

CYL 1. 5%
CYL.2. 8%
CYL.3. 85%
CYL.4. 10%

The cyl 3 test was leaking air from the exhaust valve, is this just a case of knackered valve etc??
I couldnt hear air leaking from anywhere else other than the exhaust valve.

Has anybody else had the same experience or seen something similar or can offer advice about what to do next? I suppose its engine out and a strip down to find the damage??

Any suggestions/help/advice would be really appreciated!!

A gutted subaru owner!!

Tim.

 

As you say mate, engine out and investigation, could be a valve seat problem, how was it running?

 

That's quite a big loss on exhaust valves unless something is badly amiss.

I'm going throuh similar at the moment but car had a shakey idle. I did a leak down and heard loss past the exhaust valves on no.2 cyl. After taking the heads off mine has 2 bent exhaust valves and resultant valve burning from poor seating.

Like you, I also found my timing belt to have been fitted incorrectly. When the rest of the marks were alligned the n/s inlet cam was 1 tooth advanced. This also showed up on romraider with the AVCS not going below circa 4deg advance at idle when it should be 0.

My theory is the 'specialist' that fitted my cambelt clashed the valves (as there's no piston contact evidence) when fitting the cambelt (as both n/s cams are 'on cam' when alligning) and bent them slightly. If they can manage to fit the belt wrong I'm sure the ham fisted ***** could damage the valves easy enough.

 

Cheers for the reply guys,

jdc1,

car was running o.k, made 303bhp last week on the dyno 96type ra, 440s, td05 etc, but was expecting slightly more hence the investigation. Had a slight hunting at tickover but put that down to the gems ecu!!

james wrx,

like u say its a huge loss and im surprised she made 303bhp on the dyno with such a problem. Guess im gonna have to get stuck in and pull it to bits.
I would hope that with the timing issue (urs/mine) that someone couldnt make such a mess of it to clash the valves with pistons, as when the crank pulley is lined up with its timing mark all pistons are mid stroke in the bore so no matter what you do with ur cam pulleys you shouldnt be able to clash valves/pistons.

 

I was meaning the valves, ie exh and inlet clashing. The n/s is on cam and if they've let it go and then reset them without following correct procedure it's possible to clash valves. This can cause a bend to the valves obviously.

 

james wrx,

I see what you mean valves clashing, I suppose ive just gotta get in there and have a look!! Joy!!!

Anybody else out there thats had similar symptoms or problems??
If so, what did you find on strip down??

Cheers tim.

 

Engine will obviously have to come apart, but with that amount of leakage it sounds like the valve isn't seating properly as has been said already.

Probably a case of a new valve or two and perhaps some guides and re-lap the valves, time it in correctly and off you go. But you'll have to see what you find on strip down.

Graham

 

Was your specialist in Essex?

 

If it's been a tooth out, you may have had exhaust gases leaking and burned the valve?

 

Hi graham,

Thanks for the comments/advice, looks like im gonna have to get stuck in and strip her down and take it from there.

Will post up the results and pictures when i get 5.

Thanks very much for help guys!!