Head reco for 1HZ

[mickbeny]

Hi all...Im getting the head reconditioned on my 1HZ engine due to worn valve stem seals.The engine has a turbo.

Has anyone any tips???

Im thinking of maybee replacing the camshaft to suit the turbo,Any thoughts?

[thomo]

Check the precombustion chambers they crack.

[mickbeny]

Hi all...Thanks Thomo.

[dumbdunce]

the 1HZ cam is very mild and well suited to forced induction while maintaining buckets of low end torque, there is not much gain in changing it. valve stem seal problems are rare with this engine unless you run the wrong oil, or is is overfuelling and putting too much heat into the exhaust valves. does the motor have a lot of blowby/use a lot of oil? as already suggested, get the precombustion chambers replaced, they are bound to be cracked. make sure you get the right head gasket - in fact with a turbo it's probably best to get the 5 notch head gasket anyway to get your compression down a touch. there is no need to use new head bolts but you need to torque and rotate the bolts accurately.

if you only thought the stem seals were faulty there is no need to remove the head, they can be replaced without removing the head from the engine.

[thomo]

Make sure you loosen and retighten the cam in the correct sequence they can break.

[mickbeny]

Hi all...Thanks for the replies.

dumbdunce.the engine does have blowby.At one point the engine was overfueling and ran hot on steep long hills in hot weather,since this time ive noticed the engine progressively get worse blowing smoke from traffic lites ect,It is now letting out a huge blue cloud on take off.Yes it does use oil,maybee 1.5litres every 5000klm.I use delo 400.

The EGT are now about 550 deg.

The "5 notch gasket",is it a toyota product?if not who has it?

Because the engine ran hot,i want the mechanic to pull the head off and inspect the precombustion chambers and the tops of the pistons.

[dumbdunce]

the engine does have blowby.At one point the engine was overfueling and ran hot on steep long hills in hot weather,since this time ive noticed the engine progressively get worse blowing smoke from traffic lites ect,It is now letting out a huge blue cloud on take off.Yes it does use oil,maybee 1.5litres every 5000klm.I use delo 400.

it's more likely that you have glazed the cylinder bores than the valve stem seals being the culprit. there is no throttle butterfly -> no manifold vacuum to draw oil past the stem seals - it's more likely cylinder wall oil not being scraped down properly. If this is the problem, expensive head work will not cure the symptoms, so maybe talk to a diesel specialist and see what they recommend for bore deglazing. my personal preference is for a good hard thrash up and down the rev range in 2nd gear a couple of dozen times but maybe you love your motor more than that.

Delo400 is a good oil but DeloCXJ is better for japanese engines, it has more detergent and dispersant to control soot in the oil (the 1HZ is famous for it) and also a high calcium level which jap engines apparenty like.

The EGT are now about 550 deg.

that's not too bad, even up to 650 is pretty safe.

The "5 notch gasket",is it a toyota product?if not who has it?

yes it is the genuine gasket, you should ONLY use a genuine head gasket. they are available in 3 thicknesses - 1,3 and 5 notch. you can get them from SMS Diesel or Don Kyatt, or from toyota.

[mickbeny]

Hi all...The engine doesnt blow any blue smoke once moving along,I would have thought rings or glazed bore would blow smoke under load at revs moreso ??

Could it be possibly the turbo??The inlet is dry from oil,i made and fitted an oil catch on the breather,although it collects oil,its lucky to pick up 50ml over 5000klm.It seems to work quite well.

Thanks again for replies.