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From: dave.williams@chaos.lrk.ar.us (Dave Williams)
Newsgroups: rec.autos.tech
Subject: Freewheeling Engine FAQ
Date: 2 Nov 94 07:12:00 GMT
Freewheeling Engine FAQ version 94.11.01
maintained by dave.williams@chaos.lrk.ar.us
The original basis of this list was a transcript from Motor magazine,
August 1991, p. 22, posted to rec.autos.tech by Tom Leone,
<tgl@slee01.srl.ford.com> and used with his permission. The original
list was extensively amended and expanded by by Tommy Wilson,
<tommy.wilson@chaos.lrk.ar.us>. Other corrections as noted.
(Thanks guys!)
Manufacturer Engine Recommended Engine
Applications (1) Change Damage
Interval Likely?
(Miles) (1a)
------------ ---------------- ----------- ---------
Acura All 1986-89 None Yes
All 1990 90,000(2) Yes
Alfa-Romeo 1987-89 Milano 50,000(16) Yes
164 50,000 Yes
Audi V8 90,000(3) Yes
Diesel None Yes
All others None No
BMW 2.5, 2.7L 60,000 Yes
Chevrolet Vega 2300 (22)
3.1 DOHC V6 No (25)
Spectrum 60,000 ___
Chrysler Corp. All Chrysler-built None No (4)
All Mitsubishi-built 60,000(5) Yes
Medallion 2.2L None Yes
3.5L 24 valve V6 100,000 (24)
Daihatsu 1.0L 3-cyl. 60,000 Yes
1.3L 4-cyl. 60,000 Yes
1.6L 4-cyl. 120,000(6) Yes
Fiat '61-77 124 Coupe/Sypder 24,000 Yes (17)
1988- 124 Spyder 24,000 No (17)
2000 Spyder, 131 24,000 No (17)
Ford Escort 1.6L to '83 60,000 Yes
Escort 1.6L '83-1/2 up 60,000 No
Escort 1.9L None No
Mazda-built 2.0L diesel 100,000(7) Yes
Mazda-built 2.2L 60,000 Yes
All 2.3L Pinto/Must/etc 60,000 No
Ranger 2.0L 60,000 No
'70-'74 Pinto 2000 None(20)(21) No
1.3L (Festiva) 60,000 --- (26)
1.6L (Capri) 60,000 --- (26)
1.8L (Escort/Tracer) 60,000 --- (26)
1.9L (Escort/Tracer) lifetime --- (26)
2.0L (Probe) 60,000 --- (26)
2.3L TPH (Mustang LX) lifetime --- (26)
2.5L (Probe) 60,000 --- (26)
3.0L (Taurus SHO) 60,000 --- (26)
3.0L (Villager) 60,000 --- (26)
3.2L (Taurus SHO-Auto Trans.)60,000 --- (26)
Geo Prizm 60,000 ___
Honda All Prelude 60,000 Yes
Civic, 1.5, 1.6, & HF 60,000 Yes
1985-89 exc. Civic None Yes
All 1990 90,000(2) Yes
'82-'88 Accord 50,000 Yes
'89-'93 Accord 80,000(13) 50/50 chance
Hyundai All 60,000 Yes
Infiniti All 60,000 Yes
Isuzu All 60,000 Yes
Lexus All 60,000 No
Maserati V6 (Biturbo) 30,000 Yes
Mazda All exc. diesel 60,000 Yes (23)
Diesel (1984-85) 100,000(7) Yes
Mitsubishi All exc. diesel 60,000(5) Yes
Diesel 60,000(7) Yes
Nissan '85 Sentra 1.6L No (15)
most pre-1986 None Yes
all 1.6L 60,000 ___
1986 and later 60,000(8) Yes
Peugeot 1.9L None No
2.2L None Yes
Porsche All 4-cyl. 45,000(9) Yes
V8 60,000(9) Yes
Sterling All None Yes
Subaru All 60,000 No
Suzuki All None No
Toyota All 60,000(10) No
Volkswagen 8 valve 60,000(14) No (11)
16 valve 60,000(14) Yes (14)
Volvo All 4-cyl B2[13]F gas 60,000(18) No
1992? 6-cyl gas 30,000(19)(5) Yes
5 and 6 cyl gas 60,000(5) Yes
All Diesels 75,000(7) Yes
Yugo 1.1L None(12) Yes
1.3L None(12) No
(1) "All" refers to all engines equipped with timing belts for each
maker; does not apply to engines with timing chains or gears.
(1a) The USA doesn't show any signs of going metric in the forseeable
future. 1 mile = ~1.6 kilometers. Sorry, y'all.
(2) Or 72 months.
(3) Inspect and adjust at 30,000 and 60,000 miles.
(4) 2.2L Turbo III, yes.
(5) Some engines have two belts.
(6) Or 144 months, whichever comes first.
(7) Has front and rear belts.
(8) Or 48 months; inspect at 15,000 miles or 12 months.
(9) Check tension at 2000 miles, then every 15,000 miles.
(10) Inspect at 30,000 or 45,000 miles per model.
(11) At high engine speed.
(12) Inspect every 15,000 miles. Engine service schedule ends at
50,000 miles.
(13) Depending on cam position when the engine stops, the engine
may escape damage, as opposed to most others, which are always
damaged. A compression check will tell if there was damage.
<tommy.wilson@chaos.lrk.ar.us>
(14) info from James Matthew Kokernak <kokerj@rpi.edu>
(15) info from Steve Anthony Nilsen <sn1k+@andrew.cmu.edu>
(16) info from Richard Welty <richard.welty@balltown.cma.com>
(17) info from Mike Jones <jonesmd@crd.ge.com>
(18) with the possible exception of the 4-valve version, the B234F.
info from <sbn@unirsvl.rsvl.unisys.com>
(19) owners manual says 60,000, but this engine wears out belts
due to vibration damping problems, so the manufacturer now
recommends 30,000 mile replacement. <sbn@unirsvl.rsvl.unisys.com>
(20) In his book "Hot to Hotrod Your 2.0 Liter OHC Ford" David Vizard
mentions belt life is often related to temperature. He has seen
belts last over 80,000 in cool climates, less than 20,000 in hot
climates. He mentions race engines with stiff valve springs can
get less than 1000 miles from a belt, and recommends belt change
intervals of 30,000 miles on street motors with stiff springs.
<dave.williams@chaos.lrk.ar.us>
(21) Ford wanted $14 for a new belt last time I checked. It hardly
seems worthwhile to go for an off-brand parts-store belt.
<dave.williams@chaos.lrk.ar.us>
(22) water pump slides left to right to adjust belt tension, drooling
antifreeze everywhere. <dave.williams@chaos.lrk.ar.us>
(23) Recently the belt end of my crankshaft broke resulting in a pretty
good simulation of a broken timing belt. This happened at around
4500 rpm. The car is an '88 Mazda 323GT with a 1.6 liter 16v
turbocharged engine. There was *no* head damage. This leads me to
believe that on this engine at least there is no interference.
- broaddus@sword.eng.hou.compaq.com (Jerry Broaddus)
(24) from trent!djm@jolt.att.com
(25) Road and Track, April 1990
(26) info from ccw@slee01.srl.ford.com (C. C. Warren)
Comments:
"Although some manufacturers do not specify a belt replacement, it's
a good idea to plan for one at the 50 to 60 thousand mile mark."
- Tommy Wilson
"Typical failure mode is for the belt to shear off several teeth, so
that it no longer moves. Belts rarely break in service."
- Dave Williams
"The belt idler pulley may be a source of noise, sounding much like a
bad alternator. For some older engines such as the Ford 2000, these
idlers are no longer available and there appear to be no aftermarket
sources. In this case you may have to find a junkyard part or adapt
a replacement."
-Dave Williams
"A common question is, 'Why do manufacturers design engines which will
self-destruct if the belt breaks?' There are many reasons - most of
them have to do with combustion chamber shape and valve arrangement,
which are dictated by mileage, power, and smog design goals. Most
old-style chain-drive engines will also bend valves if the chain
breaks or stretches until it jumps a few teeth, and it's not *that*
uncommon for it to happen. Also, if people would change the belt
when the manufacturer said to, they probably wouldn't have any
problems."
-Dave Williams
=======end of file================================================
From: Dave Baker
Subject: Re: 94 Ford Escort LX - Blown Head Gasket - Reasons
Date: 06 Aug 1998
Newsgroups: alt.autos.ford
>Some US Escort engine's water pump is driven by the timing belt. The theory
>is to replace the water pump while it is aready apart, thus saving labor
>when it does fail. Im not sure if the 90 and newer ones have this type of
>water pump, but it sure is with the 81-89 1.6 and 1.9 engines
You are quite right that the waterpump is driven by the timing belt on the 1.6
and 1.9 engines. We have the 1.6 over here and that is the engine I tune most
for road and track. The 1.9 was never fitted in the UK but is very similar and
some firms do import second hand motors from the US as a basis for large
capacity conversions.
However the water pumps are extremely reliable in service and both they and the
timing belt are very easy to change. A timing belt should take no more than 30
minutes to change and the pump is even easier because you don't have to get the
crank pulley off. Of course you may have a tighter installation in US vehicles
with emissions equipment and stuff but any work in this area should still be a
doddle. I would never suggest to a customer of mine to spend money on a pump
just because the belt needs doing.
As an aside and after re-reading the original post it seems that this was not a
routine belt job but the result of a broken belt. This engine has always had a
belt life problem and over here the recommendation is change every 30,000
miles. When they break they ALWAYS bend the valves and it is a head off and new
valve job which is not fun. If the engine in question went 70,000 miles on the
original belt (which it may not have done and it doesn't really say) then it
should have been changed ages ago anyway.
Also if it broke and no valves got bent then that would be a first in my
experience. Mind you it sounds as though the head has to come off now. They
warp like you wouldn't believe when the engines overheat. It could even be new
cylinder head time.
Any CVH motor owners out there who haven't changed their timing belt for years
- you are living on borrowed time. Get it done.
Dave Baker at Puma Race Engines (London - England) - specialist flow
development and engine work.
From: David Stockton <david_stockton@hp.com>
Newsgroups: alt.autos.nissan,rec.autos.4x4
Subject: Re: Pathfinder: Timing Belt or Chain
Date: Fri, 20 Feb 1998 10:16:39 +0000
Jerry Bransford wrote:
>
> As much as I'm not a Pathfinder fan, I seriously doubt Nissan would use
> a 'zero-clearance' type engine where engine damage would result from a
> broken timing chain. I don't think many manufacturers use that design
> anymore since they quickly developed a bad reputation. If the timing
> chain/belt broke, the Pathfinder's engine would probably just stop
> running without further damage. Am I not correct on that guess???
> Jerry
I don't think this deduction is valid, your conclusion might be right,
but only someone with specific knowledge of the engine type concerned
could really know. There are engines in current production that suffer
terminal or merely expensive damage when a timing belt fails. One
particular gasoline engine from the orient is supposed to be designed to
survive, but what Dad found with a few he got in for rebuild was that if
the cam belt slips a tooth or so, some people keep on driving despite
the ignition timing being off (it's usually the crank sprocket that
slips). With a bit of carbon deposit on the valve and piston faces,
light contact can occur. Valves get minutely bent by the contact, and
get knocked slightly back as they hit their seats. The result is
fatigue. When the valve head comes off, the engine is history. I've seen
units with a valve head stuck edge-on into an aluminium cylinder head,
with the piston as schrapnel in the sump, and with slots chewed through
the liners by the gudgeon pin still in its conrod.
I don't know whether the Nissan engine under discussion is safe from
damage, should a belt fail, or not. I do know that some other engines
are not quite as safe as they're supposed to be. Personally, I always
replace belts a little before their scheduled mileage, and I make a
point of getting the original manufacturer's belt, too.
A lot of small European Diesel engines use timing belts. Because of the
compression ratio needed, positive clearance with a stationary camshaft
isn't an option. With our fuel prices, Diesel cars are on our roads in
growing numbers and command premium prices. Around the world, I think
there are a lot of engines that need care with timing belts.
Cheers
David
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