zero clearance motors?

[el_wagon]

Just after a list or way of easily identifying 'zero clearance motors'. What I mean by zero clearance is a motor that will destroy valves if the cam-belt snaps. From what I know most old family cars with belts are safe (not a zero clearance). Most sports cars are zero tolerance. But what about modern family cars? I was told a daewoo nubira is zero tolerance. I have also been told zero tolerance is only common in high compression motors (how does a daewoo nubira fit in this category?) I'm a bit confused as you can see. At the moment I can tell a car has a belt if it has a plastic timing cover as a general rule, and chains don't just snap without warning. Just after this info so I don't buy a zero clearance motor in my next car.

[MNM96]

Interference is the descriptor.

[MNM96]

Have replaced engines in Hilux and Camry, so I would guess that most Toyota petrols are.

And broke a chain on my 3.9 falcon without warning.

[jpd80]

Ford 2.0 OHC was a bugger, I remember my father telling me Metro Ford had early TC Cortinas back under warranty
because owners parked them uphill in first, engine rolls over backward, skipps timing, hit the starter and bend valves.

[Lightning Strike GT]

Originally Posted by MNM96

Have replaced engines in Hilux and Camry, so I would guess that most Toyota petrols are.

Broke the belt on our old ST204 Celica and it minced the valves but did not damage the pistons
Same motor as the Camry the 2.2I

[Yellow_Festiva]

I just searched in google. I remember the Festiva has an engine that gets wrecked if the timing belt snaps.

[el_wagon]

Thanks for the feedback so far.
I remember owning a 1986 telstar, belt snapped, engine was fine. I might have to go buy an old telstar :(
Had the belt go on a diesel triton and caused major damage, but I believe all diesels will do this due to their high compression?

[el_wagon]

I was also wondering if new cars are going back to using chains? I believe the mazda 3/sp23 have been using chains to drive their DOHC for the last 5 years?

[Paxton]

Originally Posted by el_wagon

I was also wondering if new cars are going back to using chains? I believe the mazda 3/sp23 have been using chains to drive their DOHC for the last 5 years?

Falcon's OHC engine has always been chain driven. The Barra Twin Cam is also chain driven.

Hyundai are embracing it slowly for their I4 as well.

[Cheech]

alfa twin sparks & V6's use timing belts & must be replaced every 3 years or 60k at great expense to my wallet.
Snapped belt = engine re-build.

[GasoLane]

I had an old Skyline Prince GT that broke a timing chain.

The Hicomp pistons bumped into the valves which in turn bumped into the overhead cam........... very messy

[RASER]

Originally Posted by Cheech

alfa twin sparks & V6's use timing belts & must be replaced every 3 years or 60k at great expense to my wallet.
Snapped belt = engine re-build.

And other older FIAT products, and also Ferrari and its $9k [engine out] cam belt removal and replacement.

I HATE CAMBELTS!!

[CAT600]

Modulars built to 0 deck height are an issue, that means all 4.6/5.0 based including coyote, and 290 Boss 5.4 as well... With US models of 5.4 including the 260 engine there is a chance you will get lucky as the piston sits 0.120" or so down the bore at TDC

[EDManual]

These days who cares if your motor breaks into a million pieces, which isnt likely!. You can get second hand engines with very low km for cheap/reasonable prices, even BMW engines are worth near nothing!
(Diesel dual cab utes are the only ones that seem to be expensive)

[mik]

1uzfe toyota 4.0l v8 qaud cam = non interference later vvt = interference

[desGT]

Porsche 928 (V8)! Rebuild cost scares the hell out of me.

[music189]

Daewoo nubria same engine as later Holden astra,engines were Made in Melbourne Astra Belt breaks goodbye engine $1800 plus
GM ghanged belt change limit to 60000 kms and they dont go very far past that
Similar engine in Saabs and Alfas, so guess they would break too

V6 vectras as well, lunch the engine

Old BMW 320's destroy engines

[Mr Hardware]

From the top of my head

Clearance (non-interference) w/timing belt
2.2L Toyota Camry (1993-2002)

Non-clearance (interference) w/timing belt
All Hyundai Sonata's built before 2006 (4 and 6 cyl)
Most Mitsubishi motors
Holden Astras
Renault Laguna

Cars that you think would have a belt but actually have a chain
2006-on Toyota Camry
2007-on Toyota Corolla
2006-on Hyundai Sonata

[2011G6E]

I can assure you that the 4G63 Mitsubishi engine (used in Lancers and Hyundai Sonatas) is an interference motor...snap the timing belt and you destroy the valves. The Toyota 4AGE engine is likewise.
There would be plenty of others out there.

Don't think chains won't break either...

[graham7773]

I have a Ford Telstar with the FS 2 liter 16 valve Twin cam motor in it and it is a free(non-interference) motor in it. the reason it is free is that the manufacturer was smart enough to machine grooves into the top of the pistons. Why can't all manufacturers do the same thing? It is a simple matter of a little more machining in the piston manufacture process. With automated machining used these days it would not cost more than a few cents per piston. I owned a 400 cubic inch small block Chev V8 a few years ago and it was made in 1970. It had clearance grooves in the tops of the pistons so the method has been around for a long time and works...and 2011G6E, I agree, timing chains do break without warning and nothing much is said about that. I have owned a couple of 6 cylinder E series Falcons which broke their timing chains. Easier and cheaper to buy a good second hand 6 and go from there.

[EL97]

For subaru engines, the SOHC engines are non-interference (ej22 for example), while the DOHC engines are interference. Manufacturers who don't use timing chains are chasing $$$, Subaru's timing belt kits are ~$500, and then there is the labour. Good money earner right there.

[el_wagon]

I might have to get an old 2 stroke suzuki carry van lol

[2011G6E]

The grooves in the top of pistons are, usually, in older engines where efficiencies aren't as important, and were't there to "save the valves", but to allow for higher compression by letting the pistons and head get closer together. Higher tech engines have the swirl worked out very finely, and will have flat tops usually as it doesn't introduce variables like the patterns caused by the two or four grooves.

Still notice a lot of thought that chains won't break...even timing gears can fail.

[mik]

i could count the timing chain breaks reported for the falcon in the past seven years i`ve been on this forum on one hand(probably), the 3 years i was also in a ford workshop as well, and it`s not known if there where extenuating circumstances in those breaks, for the amount of falcons on the road i`d say it`s very uncommon.
as for the valve reliefs i`d say most manufacturer steer away from them if possible, the less sharp contours in the combustion chamber the less chance of pre ignition.

[Olbucko]

All 4.1 or 250 IL 6 Falcon engines could be classed as interference engines. If the timing chain broke or the woodruff key that held the timing chain sprocket in the correct position on the end of the crankshaft sheared off the counter weight on the crankshaft would hit a camshaft lobe, smash the camshaft and crack the block. The only good news was that the pistons and valves were not damaged. I have seen it happen. This could only happen to the 4.1/250 Motors, The 144, 170, 200, and 221 motors had a shorter stroke and the crankshaft could not hit the cam.

[Rusty62]

I would have thought there weren't many (if any) motors that could be spun with valves open and the will piston clear them?

[music189]

some Civics lunch the motors as well cant remember which ones though! must be getting old

[stevepet]

Yeah vectras daughter did hers parts alone $1500 got a secondhand motor for $260 put new timing belt on it.