couple BHG q's

[twd420]

im a total newb to the BHG and just need to ask these to get my supra back on the road.

how necessary is it to machine the block and head when doing the HG repair?

when disconnecting the turbo piping to the air box i noticed the port was stained in what i think is oil. any insight to what that might be?

how do i check if there is any shaft play in the turbo, since thats one thing ive seen on here alot.

and is there any true benefits for 7mge cams into a 7mgte engine? i can get n/a cams for 75$, i only thought about using them since a couple lobes have rust spots on em.

any insight and help would be great, thnks

[cre]

Originally Posted by twd420

how necessary is it to machine the block and head when doing the HG repair?

Depends on your goals. If you're keeping it all stock then follow the TSRM to the T and make sure there is NO significant pitting in the block... at this age you should get the head shaved regardless. Get the valve stem seals replaces and get the head vacuum tested and UV inspected while it's at the shop. Then use a regular Toyota HG.

If you're looking for more power and upgrades in the future or the block deck can't be cleaned up readily or the honing in the cylinders is no longer present or you find that one of the cylinders is out of round... you'd do well to listen to all of those before you who have been through this... these are old blocks and need some care; We're not making that up.

Originally Posted by twd420

when disconnecting the turbo piping to the air box i noticed the port was stained in what i think is oil. any insight to what that might be?

I don't entirely understand where you're seeing the oil. Some oil escaping from the turbo and some oil escaping from the PCV system is normal... how much you see over any given period of time and which place it is coming from are the deciding factors on how much attention it needs. I expect you're seeing oil from the PCV system if it's in the plumbing before the turbo (although a leak in the turbo can end up getting oil here too). Clean it out very well and check it frequently to see how quickly it's getting in there.The PCV system has two ports into the intake, the other is after the throttle body, so a teaspoon in a couple days is probably more like 4 teaspoons. If it is coming from the PCV system it's most likely due to worn piston rings. Do a compression test or a leak down test to see.

Originally Posted by twd420

how do i check if there is any shaft play in the turbo, since thats one thing ive seen on here alot.

Any axial play at all, rebuild it... some is ok, but not enough that you'll actually feel.

More than a millimeter of radial play is generally fine and pretty common. Much more than that though and I wouldn't plan on upping the boost beyond stock and I wouldn't beat the hell out of it without accepting that I'd be replacing it in a year or two.

Originally Posted by twd420

and is there any true benefits for 7mge cams into a 7mgte engine? i can get n/a cams for 75$, i only thought about using them since a couple lobes have rust spots on em.

NO. This is rubbish and once every three years it's dredged back up and people start swearing by it. The GTE and GE use the SAME exhaust cam. The GE's cam is profiled to get the power while the getting's good... it closes up the valves while the GTE is still capable of providing more air still... the GTE chokes. There are plenty of people who've done dyno tests, had the cams profiled and compared and it's always the same... a TINY bump in torque (so small I'm not sure I should even mention it) around 3K RPM (IIRC) and then it CHOKES up after 4K RPM and the GTE's power curve takes a dive. There's NO benefit.... you want more power with the GTE get a boost controller (a cheap manual one will do) and bump the psi by a pound.