4agte

[Sam_Q]

it wont flick a shim no but it will rip the living shit out of the driveline unless theres some carefull radiusing of the buckets and a certain type of cam profile. Dont know why you would want big lift with a turbo anyway, even with the standard lift they flow a crazy amount.

T28 BB is a very good choice

as for the losing the valve clearence if I am not mistaken its not too common for engines to be non interference from standard so if it works for them then why cant it work in this case? Belts are cheap, new engines arnt.

[Talasas]

I think it should also be pointed out that if you use the lower compression GZE pistons (8.0:1) the cutouts for the valves are very minute, and since there's some allowable gap for stretch during higher rpm, should a timing belt snap it wouldn't mean that the valves WILL hit the pistons.

I also would really like to know why so many people say the 20V flows so well. Let's sidetrack for a second and go with the popular belief that the 16V bigport is better for a turbo setup than a smallport. If this is true then by that same logic, the 20V should flow worse than 16V since the ports are even smaller than a smallport 16V.

Now a blacktop does have slightly larger (and much different shaped) ports so that I could perhaps see. Being a 5-valve design it makes you wonder where people get these ideas from...

[Gavatron]

Finally some people who know what they are talking about.

In regards to flicking shims, you can get shimless buckets for the 4AGE is I'm not mistaken. I'd go 16v too if I was doing a turbo setup. Can run the beefier cams if that's what you want. And quads aren't as important using FI really.

In regard to the GZE pistons, don't they have a reduced deck height to reduce compression? Wouldn't this be some sort of benefit to making it less interference? (great Engrish there )

(Wait's for some idiot to come and tell me I'm wrong and neg rep me again)

[Sam_Q]

Talasas you have a good point, its like some people who assumed that the 1J engine flowed better than a 2J head. With the intake though the rough flow is worked out by finding the circumfrance of one of the intakes and adding it twice for the other valves. The 20v intake does have a serious flow potential. Also the ports are massive. I normally wouldnt assume much but Bill Sherwood says they respond the best to forced induction, and from what I have seen he gets his knowledge from real world experience, I like that.

Gavatron, the problem lies in the diameter of the bucket not the shim. But if your talking about the 16v then thats different

Heres another one for you guys, what about ACL pistons, they are 8.5:1 and seem to be a reasonable weight. They arnt made by them, but by Marle (spelling?)

[Sam_Q]

gavaton, I have been thinking you have an interesting point with the deck height of the ZE piston, the cut is tiny and ontop of that the cam angle is narrower on the 20V, I wonder if it would really hit at all? if you were pedantic it would probably only need a tiny flycut out of the piston to suit the middle intake valve, thats on a steeper angle than the other two

[Gavatron]

And even then, there are plenty of interference engines out the from factory. I don't see it as being a problem at all, as long as you follow proper maintenance.

[DX20VT]

I run a 100% standard 4AGE 20v where the only non standard parts are AE101 GZE pistons and Rings.
I also run a T28 turbo on it, although it is a modified version.

I know for a fact that if you have a cam timing issue it will bend the valves,
but that's not so bad as it only bent 12 out of the 20.
All the exhaust valves and all the 3rd inlets.
That was a failure at about 6000rpm in race conditions.

Was actually a keyway failure between the crankshaft and the cambelt drive,
but same end result as a broken belt.

Sure they become an Interferance engine, but in reality how often do belts break?
My problem was also self inflicted as it's not common either unless the crankshaft pulley nut if left loose.

I fitted another s/h head, surfaced it, fitted new genuine toyota headstuds and rod bolts,
and I run 18psi. Makes just over 200kw atw and had done for many events now with great power and reliability.

The rods are identical to the later model 4AGZE, so are the cranks and block,
'and they do run oil squirters.

[30psi 4agte]

I know for a fact that if you have a cam timing issue it will bend the valves,
but that's not so bad as it only bent 12 out of the 20.
All the exhaust valves and all the 3rd inlets.
.

I love when people only look at the bright side