hi sages- this question has come up before. is the common red block 2.3 volvo 240 4cyl. engine interference or has it ever been? my understanding has always been that it is not. if the timing belt busts this engine will not self destruct by crashing the valves into the pistons. a colleague insists that this is exactly what will happen, causing joy at the dealer who after his eyes light up like a freshly polished cash register, can now soak the hell out of you to replace/rebuild the head and commit various other larcenies. have read here many messages about replacing busted timing belts . if the head or block top is planed down and modified this might turn it into an interference engine but if left stock no interference. car is a 92 240 wagon. confusion in some may be caused by the reality that today virutally all late model cars 4 and 6 cyl. have this interference characteristic, allegedly to raise mpg and cut emissions, but at least partly to enhance dealer profitability on repairs that shouldnt happen. so has anybody here been clipped to repair this boondoggle on the 2.3 red block? maybe ive been to the cleaners too often and have a bad attitude. thanks tons oldduke

It's non-interference.

The proof is that the valves are inset in the head and don't extend into the piston chamber when opened. Maybe somebody can provide a photo of the bottom of the head.

Conceivably, one could make interference engines non-interference by adding a thickened gasket or similar to keep the pistons from touching the valves.
--
1980 245 Canadian B21A with SU carb but electronic ignition and M46 trans in Brampton, Ont.

Okay, so this is a year-old thread, but I came across it searching whether my 740 was an interference engine. I've been following BB for several years and was pretty sure the 8-valve B230 was non-interference. However, my son has a 1999 Mazda Protege and I had never been able to find out what type it was searching the web. Today I found a Gates site and a document that said it was non-interference. However, when I looked up the 1992 740 engine, they say the exact opposite!

http://www.gates.com/common/downloads/files/Gates/TimingBeltReplacementGuide.pdf

WTF! Where would Gates get this recommendation?
--
1992 745 approaching 500k km

That Gates chart is a challenge as it is the "most" accurate guide out there so folks tend to think it is gospel.

The B230F is a non-interference engine period.

The Protege is most likely non-interference depending on which engine you have an if it is a US spec. '99 us just far enough back that you guys might have gotten a higher compress version of the same. The 1.8L in US trim was non-interference but not sure about 1.6L. My wife's 2.0L in her (long gone) 2003 Protege was also non-interference.

You didn't get it stock in the USA, but I can state from experience that a K cam from the early 80s, sold in the Canadian and other markets, can be interference. Marginal, but enough to do the usual valve-bending. Many have been sent from our junkyards to US buyers. Great cam otherwise!
--
67 144, 85 740T, 86 740T, 91 945SE, BMW R69S, R60/2

For those outside North America, I believe that the B200E is interference, and the B230E probably is an interference engine. I got this information from the UK Volvo forum. The B230E kicks butt in terms of performance when compared with the B230F, and the B200E is quite respectable too (even with an auto trans -- which is what I had) -- so while you can't just wait until the timing belt breaks before dealing with it, they are quite a nice red block set-up.

hi sages- this topic is an interesting one . everyone interested purchasing a new or used car should research whether their purchase includes an interference engine because the eventual cost can be a true shock followed by a ripoff repair. some observations(invite your comments)- 1. what happens when the timing belt busts and wrecks your interference engine(5-6k repair to rebuild the crashed engine). if the belt was just replaced within warranty will the dealer shop pay to fix the engine? what about if the belt is original but within the mileage frame? dealer will not pay in my experience and will disavow responsibility with double talk- remedy- get it in writing at the time of replacement that dealer will pay if failure occurs. each dealer ive talked to about this says it wont happen but refuses to answer whether he will pay it. letters of inquiry to the manufacturer were not responded to or were responded to with double talk. this remains a bad situation with unsatisfactory answers. 2. while the basic volvo 240 230F engine is non interference i have noticed that there is a depression of about 1/2-1 inch in the piston top. if the engine was interference this probably would avoid the crash of valves when the belt busts. 3. we are told engines have to be designed this way due to mpg requirements and emissions rules, but i have never seen in car mags or literature a rational
explanation for this. could it be bull queet?behind this may be the runup in prices for repairs and the make work programs followed by dealers. maybe i have a bad attitude. thanks oldduke

I am pretty sure the "requirement" to go to interference engines is one of many design choices when attempting to meet all the needs of a modern power plant:

HP and torque curves
Emissions
Cost and lifetime maint costs
Fuel economy

Many companies have chosen to use timing chains again. BMW is moving to no cam shafts at all (air actuated valves controlled by computerized timing like in F1 cars) some time in the next 5-7 years.

I doubt ANY manufacturer would choose an interference design over a non-interference to increase the income of the dealer service departments *from which they receive not a dime) or the parts sales. The customer ill will would NEVER make this financially worthwhile.

Do you think GM intentionally chose a bad design of their 3.4L V6 so they could sell intake manifold gaskets? They made a (in hindsight) poor design compromise.

hi onkel and jwalker- agree with your responses up to a point. i do not think gm or any other manufacturer would even prefer an interference engine nor go to it to upjack repair costs. the customer ill will is unavoidably enhanced by these engines though and their pricey repair costs. i have heard it, seen it and experienced it. actually there is often more damage than bent valves; pistons can be cracked or perforated and the head can be cracked. cost of that mess can lead to terminal sticker shock. timing belts can break before their mileage limits are reached. knew one guy who broke a new timing belt after 6mos which wrecked the engine and the dealer mechanic wanted to soak him for an engine rebuild. backed down when threatened with court action and publicity. so the oft heard " no problem if you replace the belt on time" is not always true. call or write a manufacturer of cars or belts and test the lip you will get with a healthy serving of double talk or no answer as to who bears the cost.what i am saying onkel is that there should be a much better answer than the interference engine to accomplish the worthy goals you set forth . my attitude must still be bad. regards oldduke

"what i am saying onkel is that there should be a much better answer than the interference engine to accomplish the worthy goals you set forth"

I think there may be as time goes by. Right now, this probably the lesser of many evils.

Keep in mind that the increases we have seen in fuel economy in spite of the massive increases in vehicle weight are federally mandated instead of organically occurring as part of the evolutionary process of technological progress.

OHC and DOHC engines existed in motorcycles as standard equipment for years (decades?) before they were commonplace in cars. One of the many reasons (in addition to manufacturing complexity, tall motor height, and low return on investment as torque was sacrificed for HP) was that it was difficult to find a reliable, space efficient and quiet method to drive the cams reliably.

In short, the existence of the interference engine is not the prime issue here. The fact that the cam drive can fail while engine is turning on an interference engine is the problem.

The production oriented experiments with air or electrical solenoid driven valves is aimed at further increasing efficiency over an extremely broad range of RPM's. The primary goal being an extremely flexible and powerful engine...high horsepower when needed and extremely high fuel economy the rest of the time. The side benefit is the virtual impossibility of a valve ever impacting a piston. No cams mean no cam drive to fail and the default position of all all valves if fully closed.

If these come to fruition I am sure other, very expensive, failure modes will emerge until the system is perfected.

Timing belts are at least cheap, easier to swap, easy to inspect.

Timing chains don't last forever, they fail too (or their tensioners fail, or their guides) - at which point you're still in the same boat, only with an even more expensive fix.

Still, it happens a lot. Byt the time a car is *way* past the replacement point for a belt, it's usually into it's 3rd owner, moving down the economic food chain quickly. And that owner is a lot less likely to 'invest' $$$ on 'preventative maintenance' - they're likely the type of driver that drives until it stops, then has it fixed or sent to a junkyard. And a broken t-belt on an older car is a ticket straight to the crusher in most cases. (Although once I saw an ad on CL for an S80 with a broken timing belt - they helpfully included the fact that a new timing belt only cost $25 at Autozone...)

In addition to my two Volvo's, our little home 'fleet' consists of two 3rd gen 4Runners, with a 3.4L V6. Which has a timing belt. Despite it being a more modern 4V/cylinder OHC engine, however, it is non-interference.

And of course, I've gone to considerable effort to may my 93 245 into an interference engine, by swapping the 16V head onto it. Oy.
--
'63 PV544 rat rod, '93 Classic #1141 245 (now w/16V turbo)

1. - Depends upon the extent of damage and the type of engine. Usually it is just the valves that need replacing. In talking with my friendly local independant (Volvo specialist), he quoted me $2-3k for a friend's Volvo S80. That engine is a 6 cylinder, 24 valve DOHC twin turbo. A basic 4 cylinder with similar damage would obviously be less. OTOH - I've also talked with 2 people with Honda Civics that threw timing belts and the engine was toast...

As I mentioned last year, the principle is pretty basic. If you have an interference engine (and most today are) simply change your timing belt on time.

--
95 855 GLT Sportwagon 217k, 90 244 DL 300k - after 11 years has a new home

Oldduke,


I really enjoyed your comment and writing. It’s always interesting to see another perspective. All too often we take for granted our own viewpoints, to leave in ignorance those of others.

Yeah, I’d whip out my socket set and crank holder, then change the belt out in a couple hours for $20, just for the educational reasons. However, you should also replace the oil seals and tensioner in reality.


Goatman

The USA B230F 8 valve is not an interference engine.

Here is a link to 10 pages of BrickBoard
results for this search: b230f interference engine?


--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

I broke a timing belt 10 years ago on my '92 740. Replaced belt and good to go. Rebuilt upper end 18 months ago. No sign of damage to pistons.

hello goatster, lucid and jack- thanks for your answers. curious to wit- what do you mean by usa 230? was there a european 230 which was interference? also you said all awd and fwd engines are interference- assuming those engines are timing belt and not timing chain engines- when that belt breaks it must be one hellacious expense to redo or replace that engine. bet you would get soaked 4k. as a general rule of thumb when one takes the timing belt off the 230 for any reason(head change or repair,etc.) does smart money say to always replace the belt since the old one would go through contraction and restretching to reinstall it thus weakening it? figure the belt must cost about $20. how would you rate the belt replacement job on the 5F scale(difficulty and aggravation factor)? blower motor replacement is a full 5F job, spark plug replacement would be only 1/2 F. dont ask me what F stands for. thanks tons oldduke

I'm with KENC 3F

2-3 hours.
--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.lyse.net/brox/TonyPage4.html http://cleanflametrap.com/tony/

"was there a european 230 which was interference?"

Indeed there was. The B230K (ca. 1986-88) was the last carburetted redblock engine. It had 10.5:1 compression and dish shaped pistons and a head without compression chambers. This engine is definitely an interference design. It's in my car.

All the best,
Erling, Norway.
--
My 240 Page

Yes, the bizarre 'Heron' head.







You'd have to imagine that those pistons were exceedingly heavy.

The last 8V head I had on my car was interference, a combination of a slight shave and a higher lift cam. But it was *barely* interference, odds are even if the t-belt broke it likely wouldn't have hurt anything.

The current 16V head, however, will cause huge amounts of damage if the valvetrain stops moving.
--
'63 PV544 rat rod, '93 Classic #1141 245 (now w/16V turbo)

What timing chain engines are you referring to? I don't know of any Volvo automotive engines
that used timing chains.
--
George Downs Bartlesville, Oklahoma

re: "...how would you rate the belt replacement job on the 5F scale(difficulty and aggravation factor)? blower motor replacement is a full 5F job, spark plug replacement would be only 1/2 F...."

I'd prefer to think of a spark plug replacement as 1/10 F (rather than 1/2 F), but I'd say the belt replacement is a 2.5 to 3.0F compared to the blower motor project. That is, a 2.5 if you've done it before, and a 3.0 if this is the first time; maybe a 3.5 if you don't have a good set of tools. And, if this is the first time, a good set of instructions and knowledge of interpreting the pulleys' timing marks (especially the crank's, where you have to "wrap the belt" around to see if it's positioned right) -- if it's the first time, you'll be rereading the instructions and looking at diagrams a lot; if you've done it before, it's a no-brainer, second nature.

I would also add that adding a water pump to the job is hardly a blip on the scale if (again) you've done it before (and well worth doing if you do a timing belt); otherwise it raises the task to a 3.5 because there are certain nuances to learn by trial and error (knowing how to install and seat the little seal for the heater return pipe without it leaking afterward, and the best way to pry the pump upwards to seal the larger O-ring).
Likewise, changing the seals under the sprockets is also wise if they've never been done before -- that, too, is hardly a blip on the scale if you have a good set of the right kind of "gear pullers" for the cam and intermediate sprockets (because they're usually pretty stuck on), and you also take the 1/10 F effort to remove the radiator to have the room to work the gear pullers.

All in all, the heater-A/C blower's 5F rating must stand alone as a big jump over just about all other projects on the car (although putting in the center arm rest with cup holders on a '93 was a tedious but not difficult 4 F, to me, only because it didn't come with instructions and I had to figure it all out from my head, and with the car's front seats and center console removed from the car).

Yes, *all* B18/B20/B21/B23/B230 redblock engines are non-interference. The only exception I am aware of is a redblock with a dual-cam 16V head on it.

All the FWD/AWD engines *are* interference.

To elaborate further, there was a red block interference engine with a 16 valve variant of the b230f called the b234f. To the best of my knowledge it was only available in the U.S. in the 740 GLE.

The basic principle with interference engines is change your timing belt on time! If you do, there should no problem. I'm on my 3rd interference engine with no problem..:)

See the URL below from 700/900 FAQ for more info:

http://www.brickboard.com/FAQ/700-900/BuyingUsed7xx.htm#BuyingaUsedGLEwithB234F

The oddball, '91 only 940SE also came with the interference 16v head.

Best,
Afton

'68 220; '88 & '92 245s; '92 945t; '98 XC

Actually, the 940SE is a turbo four with the usual 8-valve head. It was 91-only here, sold for many years in Europe. Basically a 960 with a B230FT.

The GLE models for a few years used the 16-valve head.

Edit: Guess I'm a year out of date on this response, oops!
--
67 144, 85 740T, 86 740T, 91 945SE, BMW R69S, R60/2