View Full Version : FAQ's on MKIV.com

13-12-02, 12:45
Did you know that the FAQ's on mkiv.com is now working ?


NEW - http://www.mkiv.com/faq/acronyms.htm - NEW

Just found this posted from Gavin which, is very nice :)



Supra Nz site

Oz Supra site

And do not forget

13-12-02, 13:00
They have been working for some time now ;)

13-12-02, 13:07
I had stopped trying this link since April as it had stopped.

It's helpful to the new guy's & me!

13-12-02, 13:10
It def. is. Never seases to amaze me how much info on the MKIV is readily available.

13-12-02, 19:52
That is a shed load of info. Cheers m8 never knew it was there.


14-12-02, 09:42
Thanks Peter

This will keep me occupied for a few hours:)

Steve W
14-12-02, 16:23
Just out of interest WHERE/WHO did all this info come from ? ?

The bit that interests me is where it says the mkIV has a NON-
Interference engine ! !

There are VERY few modern engines that are non-interference.

THAT MEANING: if the timing belt breaks NONE of the valves will
touch ANY of the pistons regardless of position or how many
times the engine turns over after it's broken.

ie. YES, you should get the belt(*) changed when recommended
to avoid breaking-down in the middle-of-nowhere....
but, NO, it won't cause any major engine damage, and, providing
an EXPERT replaces the belt (ie. times it up right - cams/pulley etc)
it will just start/run/and carry on as normal ? ! ?
(* AND tensioner ! !)

The problem is, that to make an engine NON-interference, by default
the valves cannot open so far that they could touch the piston
This means LOW-LIFT cams = LOW power ! !
(OR, very low compression pistons that can't 'reach' the valves)

LOVELY if we have a really powerful engine which won't self-destruct
when the belt goes:thumbs:

[ we've discussed this before in other threads, but NO-ONE was
willing to say YES or NO ? ? ]

ANYONE know wether it IS or NOT and WHERE's the facts ? ?

MORE to the point - anyone had a belt actually BREAK ?
We'd know once and for all then....
(it either DID, or it DIDN'T....THAT person would know ! as long as
the repair garage didn't lie:sly: )


14-12-02, 18:08
As far as I know, ALL recent toyota blocks are non-interference, which is part of what makes those blocks so damn good (especially the 3S-G(T)E and the 1/2 JZG(T)E).

A somewhat shady list can be found here (http://www.angelfire.com/ar/dw42/freewhee.htm), a better list is this pdf (http://members.aol.com/rtclapp/tbelt.pdf).

Non-interference engines simply have more clearance between valves and pistons than interference engines. This still allows high lift.

Steve W
14-12-02, 18:26
Non-interference engines simply have more clearance between valves and pistons than interference engines. This still allows high lift.

You either need Low-Lift valves, OR, Low compression (ie. large
combustion chamber).

You can't have a small combustion chamber + High-Lift Valves and
still have a NON-interference engine ?

EVERY modern car we deal with that's had a belt 'gone' has got bent
valves ! !:-

ALL diesels (Pug/Ford/Vauxhall/Renault....)
[the last diesel that sometimes didn't do valves was the
Ford 2.5Di - that bent pushrods and sometimes the rockers]

The last petrol that didn't was the Ford Pinto 2.0 (even the 1.6
tended to clip the valves)

All new engines: Rover K-series, Ford ZETEC/DURATECH, Vauxhall
Ecotech (ESPECIALLY the 2.5/3.0 v6's ! ! = ALL 24valves !)


I'm not saying it's NOT a N/I engine.....just want to know FOR SURE !


15-12-02, 11:48
Diesel engines have very high compression ratios and it's therefor pretty much impossible to have a non-interference diesel... too little space between the head and the pistons.

However, I think you should never rely on NI to save your ass...
just replace your belts (instead of letting 'em snap) and you'll be safe.

The stock supra block is NI, but obviously you can turn it into an interference engine by adding very high lift cams.

Steve W
15-12-02, 12:31
.......to save your ass...just replace your belts .....
Of course.....

and, mine's rather a large ASS to save ! !:p

08-01-03, 16:16
There was a lengthy thread about this a while back. I was as gobsmacked as you, Steve.

I don't know about other Toyota engines, but apparently some guy in the states took one apart and deduced that it was non-interference.

Gaz Walker
09-01-03, 00:42
Well, thats the second thing I've learned today. Knock me down with a feather. :)


Supra Pilot
09-01-03, 13:18
I agree for the TT it is Ni, but for N/A's with higher compression ratio it may not be the case..... (IMHO)


09-01-03, 13:53
Having had the head of several MKIV's, in breakers yards, one engine with no belt, but can't be sure if the bottom end was still turning when the belt came off. I have not seen any signs of contact in the piston indentations. With pistons at DTC there was no contact when the cams were turned on stock valves on a Jap spec 94 engine. Still not worth not changing the belt, to put this theory to the test on the road.

07-06-03, 12:10
I dont know if its the same on a supra because I have not had a close inspection but there is a really easy way to change your timing belt without the need for re-timing.

All you do is remove all the plugs and cam cover, get a sharp stanley knife and push it into the belt in the middle, NOT acrossways, along its length, then either turn the engine over by hand on the crank pulley bolt (best to get a mate to do this) or if you have a steady hand, crank the engine in short bursts (mate here would be useful)
Until you have cut the belt completely into two seperate "belts" that are still on the pulleys, pull the front half off, and put the new belt on, cut off the other half and push the new belt all the way on, job done!

It definately works cos i've done it on several cars, and it saves a shedload of time and hassle.


Steve W
07-06-03, 16:15
Unfortunately, you have to get the Crank' pulley off to get the old
belt off (and new belt on!)

the Ancillary belt pulley completely masks the crank 'cog' so....

....OFF IT COMES, I'm afraid ! !:(

23-06-04, 15:07
Links updated and a new one added.