4A Head Gasket change

[Little Rippa]

just wondering if anyone has done one on a 4A and would be kind enough to tell me of any unexpected suprises/ better ways to go about it or any advice in general. im about to start one on thursday and rekon id find out before hooking it. we've all got stuck into something, come across a problem, muddled it out, then found out later the easy way around. any advice would be appreciated. cheers

Jake

[JP]

Use a genuine headgasket is my advice. Steer clear of the ACL monotorque headgaskets.

[TERRA Operative]

Get new head bolts from Toyota, a can of hylomar spray from repco/autobarn for the gasket, and maybe get the injectors ultrasonically cleaned while they're out too (costs about $110 for the mobile guy here is Brisbane).

Also, replace the camshaft seals and all other seals in the head (there's only a few) and use some sealant on the cam cover gaskets in the corners where the seal loops over the cams.
When you put the cams back in, use a set of metric feeler gauges to ensure the intake clearances are about 0.25mm and exhaust are about 0.35mm or so while you're at it.

Valve stem seals are optional if you can be bothered (but probably worth doing), and if you remove the valves, you can clean the build up on them with a wire brush wheel on a bench grinder.
A 1" brass end wire brush on a battery drill is excellent for gently cleaning out the intake and exhaust ports (It comes in a cheap 4 piece set from Bunnings). Stick it in where the valves go and into the port entries/exits on the head to scour it all out (use a low speed on the drill and go gently)
Just be sure to put the valves back in the same order they were taken out. (unless you plan to lap the valve seats too).

That should ensure you have no more leaks and the ports are nice and clean.

[dangdang]

If the budget will stretch replace the cam belt, tensioner and water pump whilst you have it all apart.

[TERRA Operative]

Oh, and don't forget to change the oil after you're done.

[hosking1991]

give us a shout if you need any machine work done cheap.

luke

[beerhead]

Using a sealing agent should only be done on metal head gaskets. If its an ACL graphite coat gasket you'll ruin the dry lube properties of the gasket.

I haven't had any problems with ACL gaskets over the years. Many people go wrong thinking the "Monotorque" brand means torque it once and it'll work, that's BS. Get it hot once, re-torque, do another 1000km and re-torque again. Make sure you back off the bolts and use a small amount of oil under the washers. You want all the threads to be as clean as possible if your reusing bolts. Half the trick with torquing a head up properly is going off the feel of the torque wrench as well as its reading. Doing a really nice repetitive action that's consistent on every bolt by making sure you're in a comfortable position is really important IMO.

[TERRA Operative]

True that re. sealants. I usually only use metal head gaskets......

[beerhead]

Haha the first HG I ever changed when I was a teenager I used a sealant spray on a graphite HG. Lets just say it didn't last long

[oldeskewltoy]

Toyota "A" head should NOT need to be retorqued....

There is no mention of it in the FSM, when you use an OEM gasket...


When you remove the head... check the block deck for flaws - clean the block and head surfaces as best as you can

Don't FORGET to re-install the washers under the head bolts

[TERRA Operative]

And use lube on the bolts and both sides of the washers to ensure the correct torque reading.

[Little Rippa]

cheers boys. that was a heap more info than i thought id get!! mucho aprecio. this job is for an engine thats only gotta do till another oil change. got a 4A-E in the shed which i am planning on stripping down, giving a bit of a clean up, then dropping it in the corolla to see another sibling through the P's stage...lord knows they need a tough first car!! thanks a mint guys.