DIY valve clearance check/adjustment MY98 WRX
 

How hard a job is this to do?

I have a leaking rocker cover gasket on the NS head and will be replacing this soon. So while I am doing this and due to running LPG I thought it may be a good idea to check the valve clearances.

I'm thinkinmg 6 - 8 thou for inlets and 8 - 10 thou for exhausts?

Any help or links to threads would be great. I have had a search but nothing much comes up for a DIY job.

Cheers,

Wayne.

IIRC v3/4 with shims want 8 thou on the inlet, 10 on the exhaust or thereabouts. Easy enough to get the measurements I guess, you'd need to turn the cams to get them off-cam for good readings.

Is it easy enough to do WITH the engine still in the car?

NO! - in the car it is a bitch of a job. That year model has external shims and you can lever carefully on the edge of the bucket to get the shim to pop out. But that is not easy due to limited access for the lever.

There is a special tool from IM that mounts on the cam caps that presses down on the bucket edges and makes life much easier. Bearing in mind that doing it in the car is not at all easy.

Doing it cos you feel like it, is not the smartest idea that you have had.

AND what are you going to use for replacement shims? As each one measured out of limits will need a ' new ' shim. Some will be able to be put here having come from there, if you follow, but you're going to need to buy a few after you have done your groundwork. That means the car sitting around for a couple of days waiting for shims to arrive.

If it ain't broke don't fix it. Is my best advice.

David APi

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David,

Thanks for the advice. I should have mentioned that I am aware of the need for shims and can well have the car stationary for weeks if required. I would probably be coming to you for these mate.

I suppose I could just take the engine out and pop it back in to do it. It's not really the biggest job to be honest.

The car has done 80,000 miles so should have had them checked at 60,000 iirc.

How would I know if I have valve seat recession without checking them? The gaps would close and I would have a non sealing valve, but with what symptoms?

Wayne.

Wayne, Sure, the valve seat sinks - but that is allowed for with wear of the cam lobe, shim and bucket. They generally all wear together and relatively evenly. especially so if they are original factory settings and have not been 'adjusted ' ever.

I really wouldn't go looking for trouble, l expect it'll be fine.

David

Cheers David!!

If you're regularly running LPG then the clearances are definately worth checking IMO.

I've seen several LPG equipped Imprezas and Legacys with zero clearances after prolonged gas usage, due to valve seat recession.

Id rather be replacing shims than valves/seats

Ive only done 15k so far on LPG. At what mileages did the other cars require attention?

Wayne.

Hi wayne, I'm in the process of adjusting valve clearances on my forester turbo due to continued running problems and eventually a persistent misfire, when I checked the offending cylinders clearances I found zero clearance. I too am running lpg and have been chasing this problem for months. At the moment I only have the n/s rocker cover off and although it is tight it is possible. Although I don't know if the other side will be as easy when I come to check them. I see you're in sheff, I'm in barnsley just off 36 you're welcome to come for a nosy,

Bri

97UK Turbo Impreza was having hot starting issues after about 20000 miles - It had (cold) clearances of between 0 and 2thou on exhaust valves and 1 to 4 thou on inlets. I had a local cylinder head specialist replace all the valve seats for hardened variants. -All the clearances were set a bit wide when the heads were put back together (10 to 11 thou) - As far as i know it's done about 10K since, and running fine.

I'm not sure how many miles either of the N/A Legacys had covered on gas before having problems. Both cars had secondhand replacement engines fitted to cure the problem, so i'm sure it's only a matter of time... ;)