is my 91 an interference engine?

dillon1340 · 10-20-2008, 06:41 PM

is the 4.0 in my explorer an interference engine?

boggs1227 · 10-20-2008, 08:31 PM

interference ?

POS Camaro · 10-20-2008, 08:35 PM

When the timing belt or chain breaks, the pistons hit the valves.

I don't know about the Ford 4.0.

James909 · 10-20-2008, 08:49 PM

I believe the 4.0 OHV (which is what's in your '91) is a non-interference engine.

dillon1340 · 10-20-2008, 08:53 PM

i've tried to google it but was unlucky. anywhere i can find out for sure?

**Maniak** · 10-20-2008, 08:55 PM

The 1991-1994 are non interference (use 90tm or 93tm head castings). I can't comment 100% for sure on the newer ones (diff piston/head configuration)..

~Mark

dillon1340 · 10-21-2008, 06:28 PM

awesome. i think i will postpone my plans to change the timing set then.

*EMG7895* · 10-21-2008, 10:03 PM

usually the timing chain is good for the life of the motor, under normal circumstances theres no reason to mess with it.

*mechjames* · 10-22-2008, 11:57 AM

it will stretch over the life of the motor, but I believe the ECU will compensate for that.

i don't think its an interference engine, actually i don't think many V shaped engines are interference. I think its just a problem on straight 4's.

marragtop · 10-22-2008, 01:40 PM

Gates has a great Timing Belt Replacement Guide on their website that you can download. It tells you what engines have belts, if they are interference or not, and the recommended replacement interval. Go to www.gates.com and click on the Timing Belts link.

dillon1340 · 10-22-2008, 06:32 PM

but my engine doesn't have a timing belt. also they may not break but the explorer has nylon tensioners that i'm sure wear out. i've had v8's that were interference and when the chain broke i had to replace valves. i just had the heads off to put on new head gaskets and do not want to take them off again that's why i was thinking of replacing the chain, in case it breaks. if it's not interference i'll still replace it just not as soon as i was thinking.

*EMG7895* · 10-23-2008, 09:42 AM

honestly I wouldnt even touch the timing chain unless your doing a full blown rebuild, do a quick search on ohv timing chains. You wont find many issues, the much more common fix for internals is replacing the worn pushrods.

**Maniak** · 10-23-2008, 10:34 AM

I'd have to agree.. In the past 10+ years being on EF (wow, its been a long time) I can't remember seeing anyone that needed to change the timing set on an OHV.

I replaced/rebuilt our motor at 355k miles.. nothing in the timing chain area looked overly worn. I didn't replace the timing chain set becuase I rebuilt my spare motor which had 150k or so miles (in that range).. I didn't change the timing set on that one either as it showed very little wear.

~Mark
~Mark

stifler27870 · 03-28-2009, 06:50 PM

was wondering if a 96 explorer 4.0 was a interference engine or not can`t seem to find it in searches. my vin letter is x.

**james t** · 03-28-2009, 06:53 PM

No, it is not an interferance engine. 4.0 OHV timing chain virtually lasts forever (life of engine) and if it were to break (almost unpossible) it would do no harm.

FYI it would be so stretched out it would barely run long before it broke.

stifler27870 · 03-28-2009, 07:09 PM

thanks alot.

10-20-2008, 06:41 PM	#1
dillon1340 Wannabe Elite Explorer greenville, south carolina 1991 explorer 4x4 Join Date: Sep 2008 Posts: 97 Vehicle Specs (Original Poster)	is my 91 an interference engine? is the 4.0 in my explorer an interference engine?

10-20-2008, 08:31 PM	#2
boggs1227 Wannabe Elite Explorer Flowery Branch , Georgia, 1994 sport 2wd auto 2005 colorado 2wd 5spd Join Date: Feb 2008 Posts: 1,521 Vehicle Specs	interference ? __________________ Scott .

10-20-2008, 08:35 PM	#3
POS Camaro Wannabe Elite Explorer Groton, CT 1999 XLT Join Date: Mar 2007 Posts: 45 Vehicle Specs	When the timing belt or chain breaks, the pistons hit the valves. I don't know about the Ford 4.0. __________________ 1999 XLT, 5.0, A4, AWD 1986 Chevy Z28 Camaro, 5.7, T-5 2003 Chevy Suburban LT 1500, 5.3, A4, 4WD

10-20-2008, 08:49 PM	#4
James909 Wannabe Elite Explorer Long Island, NY 1994 GMC Yukon 2 Door Join Date: Jan 2008 Posts: 685 Vehicle Specs	I believe the 4.0 OHV (which is what's in your '91) is a non-interference engine. __________________ -James 1992 Ford Explorer XLT 4x4 - Sold 1994 GMC Yukon 2 Door 350 TBI

10-20-2008, 08:55 PM	#6
Maniak Moderator-Stock 91-94 Vail, Arizona 1992 XLT 4x4 Join Date: Feb 1999 Posts: 10,741 Vehicle Specs	The 1991-1994 are non interference (use 90tm or 93tm head castings). I can't comment 100% for sure on the newer ones (diff piston/head configuration).. ~Mark __________________ Click HERE to see our Explorer Specs

10-20-2008, 08:53 PM	#5
dillon1340 Wannabe Elite Explorer greenville, south carolina 1991 explorer 4x4 Join Date: Sep 2008 Posts: 97 Vehicle Specs (Original Poster)	i've tried to google it but was unlucky. anywhere i can find out for sure?

10-21-2008, 06:28 PM	#7
dillon1340 Wannabe Elite Explorer greenville, south carolina 1991 explorer 4x4 Join Date: Sep 2008 Posts: 97 Vehicle Specs (Original Poster)	awesome. i think i will postpone my plans to change the timing set then.

10-21-2008, 10:03 PM	#8
EMG7895 Elite Explorer '91 xlt, 93 Join Date: Nov 2003 Posts: 1,715 Vehicle Specs	usually the timing chain is good for the life of the motor, under normal circumstances theres no reason to mess with it.

10-22-2008, 11:57 AM	#9
mechjames Triangle Beach Explorer Richmond, BC 1994 Explorer XLT Join Date: Sep 2007 Posts: 461 Vehicle Specs	it will stretch over the life of the motor, but I believe the ECU will compensate for that. i don't think its an interference engine, actually i don't think many V shaped engines are interference. I think its just a problem on straight 4's.

10-22-2008, 01:40 PM	#10
marragtop Wannabe Elite Explorer balt, md 91 xlt, 92 xlt, 95 xlt Join Date: Apr 2001 Posts: 2,074 Vehicle Specs	Gates has a great Timing Belt Replacement Guide on their website that you can download. It tells you what engines have belts, if they are interference or not, and the recommended replacement interval. Go to www.gates.com and click on the Timing Belts link. __________________ '88 F150 4x4 '91 Explorer XLT 4x4 '92 Explorer XLT 4x4 '95 Explorer XLT 4x4 If it don't = 16 (4x4), it ain't worth driving...

10-22-2008, 06:32 PM	#11
dillon1340 Wannabe Elite Explorer greenville, south carolina 1991 explorer 4x4 Join Date: Sep 2008 Posts: 97 Vehicle Specs (Original Poster)	but my engine doesn't have a timing belt. also they may not break but the explorer has nylon tensioners that i'm sure wear out. i've had v8's that were interference and when the chain broke i had to replace valves. i just had the heads off to put on new head gaskets and do not want to take them off again that's why i was thinking of replacing the chain, in case it breaks. if it's not interference i'll still replace it just not as soon as i was thinking.

10-23-2008, 09:42 AM	#12
EMG7895 Elite Explorer '91 xlt, 93 Join Date: Nov 2003 Posts: 1,715 Vehicle Specs	honestly I wouldnt even touch the timing chain unless your doing a full blown rebuild, do a quick search on ohv timing chains. You wont find many issues, the much more common fix for internals is replacing the worn pushrods.

10-23-2008, 10:34 AM	#13
Maniak Moderator-Stock 91-94 Vail, Arizona 1992 XLT 4x4 Join Date: Feb 1999 Posts: 10,741 Vehicle Specs	I'd have to agree.. In the past 10+ years being on EF (wow, its been a long time) I can't remember seeing anyone that needed to change the timing set on an OHV. I replaced/rebuilt our motor at 355k miles.. nothing in the timing chain area looked overly worn. I didn't replace the timing chain set becuase I rebuilt my spare motor which had 150k or so miles (in that range).. I didn't change the timing set on that one either as it showed very little wear. ~Mark ~Mark __________________ Click HERE to see our Explorer Specs

03-28-2009, 06:50 PM	#14
stifler27870 Wannabe Elite Explorer Northeastern, NC 96 ex Join Date: Jun 2008 Posts: 41 Vehicle Specs	96 xlt 4.0 was wondering if a 96 explorer 4.0 was a interference engine or not can`t seem to find it in searches. my vin letter is x. __________________ 96 XLT Rollin on 33x12.5 Mastercraft MT, TT, Shackles, 3" PA 883, and still scrapin soon to have superlift suspension kit and lockers 80 Jeep CJ5 on 44`s and chevy 1 tons Break It, Fix It, And DO It Again!!!!!!!!!!

03-28-2009, 06:53 PM	#15
james t moderation Texarkana AR/TX 94 SAS sport Join Date: Jan 2002 Posts: 11,258 Vehicle Specs	No, it is not an interferance engine. 4.0 OHV timing chain virtually lasts forever (life of engine) and if it were to break (almost unpossible) it would do no harm. FYI it would be so stretched out it would barely run long before it broke. __________________ my rebuild

03-28-2009, 07:09 PM	#16
stifler27870 Wannabe Elite Explorer Northeastern, NC 96 ex Join Date: Jun 2008 Posts: 41 Vehicle Specs	thanks alot. __________________ 96 XLT Rollin on 33x12.5 Mastercraft MT, TT, Shackles, 3" PA 883, and still scrapin soon to have superlift suspension kit and lockers 80 Jeep CJ5 on 44`s and chevy 1 tons Break It, Fix It, And DO It Again!!!!!!!!!!