4agze heads.

[sleepyu]

i know this may seem like a stupid question but ive searched the forums and google and cant find the answer.. ive blown the headgasket in my 4agze in an aw11, and the head is a bit old so i thought i would replace it to. My mate has a spare small port head, but what im wanting to know is this just a straight swap with a bigport.. or what complications are there in this swap?

[Cuzzo]

The smallport blocks have an oil return on the back of them. The bigport head doesnt have an oil return, so you will need to block this off.

Other than that should be mostly straight forward for bolt ons.

The smallport has different inlet ports and bolt pattern to the bigport head. So you will need the matching inlet manifold with the head.

You best option would be to get the block and head surfaced smooth and flat then use a new toyota headgasket. Then enjoy the skidz.

[Hen]

As cuzzo explains, it can be done, but there are a few little things to be aware of.

Also, you will need the smallport fuel rail as the injector spacing differs between big and smallport.

You could also check the cams, if you have 7.56mm lift cams in the bigport and the smaller cams in the smallport head, you could swap them over. Not necessary, and no great improvement, but a little.

Hen

[sleepyu]

basically im doing this to tie me over until the other engine im building is finished (the resident car nut down the road is helping me out with that but hes away for the next few months) so im trying to do this, as the car is my daily, with the least amount of effort but not half ass (even if that is a bit of a contradiction). So i guess il just keep using the bigport head...

[/quote]You best option would be to get the block and head surfaced smooth and flat then use a new toyota headgasket. Then enjoy the skidz.[quote]

without going as far as sending them to a machine shop (unless its seriously damage) besides removing the gasket completely is there really anything else i should do?

[TERRA Operative]

Replace the valve stem seals and stick the bigport cams into the smallport if you are going that route.
Also, when you are replacing the seals, take the valves out and give them a clean up. A wire wheel on a bench grinder will make short work of it. Cleaning the exhaust ports would be a good idea too if there's any build up. A wire brush (smallest size with the brushes out the end, like a shaving foam brush thingo)on a battery drill fits nicely into the ports to clean them out.

[feral4mr2]

no it is not a simple swap over procedure.

basically im doing this to tie me over until the other engine im building is finished

what make you think the head off your engine is no good?
to tie you over i would clean up the old HG crap left on both surfaces, (eg. with a block of flat wood and some sandpaper, 120 wt n dry to a 400 works for me.. useing a straight edge make sure both surfaces are well.... straight, flat what ever you want to call it. put a genuine toyota 4agze HG on, torque to specs, bolt everything else back on and enjoy driving your car for another 100 odd thousand k's.


and for everyones info, the aw11 bigport 4agze does not have the early 7.56 lift cams.

[30psi 4agte]

Also, you will need the smallport fuel rail as the injector spacing differs between big and smallport.

Hen

There you go........ I never knew that !
just aswell. I have been looking for a fuel rail for my new engine..... now i know i need a bigport one

[sleepyu]

no it is not a simple swap over procedure.
what make you think the head off your engine is no good?

its not so much that i thought it was no good but more the small port head my mate had was recently reco'd so if it was a simply fit it would of been a better option..
it seems simply just changing the gasket with the existing head is the way to go. thanks for all the help.

[Talasas]

Regarding the Bigport vs Smallport injector spacing...


Bigport on the left, Smallport on the right.

Jordan, you have PM.