Broken timing guides/tensioners

[BruceH]

Is it improved or a cost effective measure, iron vs plastic ? Also have to wonder, I was told last night that the Coyote has the older style(iron with ratchet) hydrolic tensioners.

I have no idea. I do know that the plastic ones don't have the ratcheting mechanism.


There is a tsb on the 5.0 tensioners. I don't know what they are being replaced with. Plastic being replaced with metal? Metal being replaced with plastic? Replaced with the same style?

TSB 11-9-15
5.0L Engine - METALLIC RATTLE OR SCRATCHING TYPE NOISE FROM FRONT OF LEFT HAND CYLINDER HEAD AT IDLE - BUILT ON OR BEFORE 3/31/2011

FORD:
2012 Mustang
2011 Mustang
2011 F-150

ISSUE:
Some 2011 F-150 and 2011-2012 Mustang vehicles (excluding Boss) built on or before 3/31/2011 and equipped with a 5.0L engine may exhibit an intermittent metallic rattle or scratching type noise in the area at the front of the left hand (driver side) cylinder head at idle with the engine at operating temperature.

ACTION:
(Some diagnosis steps which will not help without pictures)
...
a. Yes - Replace the left hand primary tensioner and the left hand timing chain tensioner arm using the kit part number provided in this article. Refer to Workshop Manual (WSM), Section 303-01C, Camshaft-Left Hand , for removal and installation procedure.

NOTE:
FAILURE TO REPLACE BOTH THE PRIMARY TENSIONER AND TIMING CHAIN TENSIONER ARM MAY RESULT IN OVERLOADING OF THE TIMING CHAIN AND UNDER CERTAIN CONDITIONS COULD LEAD TO TIMING CHAIN FAILURE.

PART NUMBER: PART NAME:
BR3Z-6L266-AA Chain Tensioner Kit
ZC-30 Motorcraft Silicone Gasket Remover
ZC-31-A Motorcraft Metal Surface Prep
TA-30 Motorcraft Silicone Gasket and Sealant
BR3Z-8255-A Thermostat Seal
F1VY-8507-A Water Pump Gasket
BR3Z-6A340-A Crankshaft Bolt
BR3Z-6020-B Front Cover Gasket Left
BR3Z-6020-C Front Cover Gasket Center
BR3Z-6020-D Front Cover Gasket Right
BR3Z-6584-A Left Hand Valve Cover Gasket
BR3Z-6584-D Right Hand Valve Cover Gasket
BR3Z-8620-A A/C Stretchy Belt

 

[19COBRA93]

The 5.0L tensioners are cast iron as well. As is the replacement tensioner in that TSB. The cast iron tensioners have proven to be more durable. The plastic tensioners fail in a couple ways. As Lito mentioned, the o-ring on the back fails and because there is no ratchet mechanism they bleed down after the engine shuts off. Upon restart it rattles like crazy until the tensioner pumps back up. The plastic bodies crack as well causing similar rattling at start up.

The cast iron tensioners just don't seem to fail.

 

[crownaviation]

So how many people are running the steel bodied tensioner on their 4.6? I ordered some but would like more info on this. Atleast two people now with failure? Out of how many running them? I think I could deal with some rattling. That could be fixed. Harder to fix when the valves crash into a forged shortblock.. Especially since my car is driven on weekends/summer only. How many plastic tensioners fail and has it ever led to catastrophic failure?

 

[Corpo]

Last year I had a failure in my timing system. A bolt holding the passenger side of my tensioners sheared off in the head. The chain came loose but it never jumped a tooth. I was autocrossing at Tue time, on/off the gas.

 

[TurboX]

NOTE:
FAILURE TO REPLACE BOTH THE PRIMARY TENSIONER AND TIMING CHAIN TENSIONER ARM MAY RESULT IN OVERLOADING OF THE TIMING CHAIN AND UNDER CERTAIN CONDITIONS COULD LEAD TO TIMING CHAIN FAILURE.

I believe this is what caused my failure, I replaced the hydraulic tensioners to the old steel kind. I did not replace the guide or arm that swings, briefly looking at a old tensioner('99) arm I noticed the pocket is not as deep as it is on the 2010 guide/arm I used. If you look at the pictures I took of the tensioner arm, you can see where it took a beating. I didn't have enough time to compare the 2010 parts to '99 parts, I will check that on Tuesday and report back.

The only other thing I wondered about was, when I was degreeing cams and assembling motor I used a small screwdriver to put as much tension on the swing arm as possible. I wanted to eliminate as much slop/slack as possible to hopefully get the cams dead nuts on. I figured the worse thing to happen would be to wear out the nylon/plastic material prematurely.

 

[Rasmus]

Here's my damage:

 

[crownaviation]

I believe this is what caused my failure, I replaced the hydraulic tensioners to the old steel kind. I did not replace the guide or arm that swings, briefly looking at a old tensioner('99) arm I noticed the pocket is not as deep as it is on the 2010 guide/arm I used. If you look at the pictures I took of the tensioner arm, you can see where it took a beating. I didn't have enough time to compare the 2010 parts to '99 parts, I will check that on Tuesday and report back.

The only other thing I wondered about was, when I was degreeing cams and assembling motor I used a small screwdriver to put as much tension on the swing arm as possible. I wanted to eliminate as much slop/slack as possible to hopefully get the cams dead nuts on. I figured the worse thing to happen would be to wear out the nylon/plastic material prematurely.

So... The tensioner arms are different for steel vs plastic tensioners?

 

[TurboX]

Think so but will know for sure in a few days.

 

[maldoj2]

are this gears any good Cloyes Gear from summit racing or o.e.m. better

 

[Speed+Clinic]

It's something that came up when I was doing my first motor. It's been quite awhile.

FWIW I've never had an issue with the standard tensioners. I've read many posters state that they are no good. IIRC the plastic ones have been revised.



You see many more examples than the rest of us. Does your dealership see alot of the newer plastic tensioners fail? Have you seen the metal ones lock open before? A quick google search came up with cases of the metal tensioners locking open and destroying guides but it was mostly older explorers and F150s.

I had my stock R tensioner fail. It happened along with an oil pump gear falure. I dont know if the tensioner was bad before the pump exploded or not. Either way it eventually failed to bad rod bearing.

 

[Speed+Clinic]

Think so but will know for sure in a few days.

have you been able to figure this out?

 

[TurboX]

Sorry I've been busy and just got around to it yesterday. I took apart a old 2002 2V that was sitting around. It had steel bodied tensioners and the fixed and swing guides were the same down to part numbers. The 1 that I was laying around ended up being off a 4V.

I did call TSS about sending my pump in to be examined, after your post I think I'm going to open the pump myself before sending.

I've have exchanged emails with a very reputable engine builder and he states this only occurs when slack developes in the chains and causes slapping. I was asked if I banged the rev limiter and while I wish I could say yes and know I caused it, I wasn't on the rev limiter. The only other way slack would develop would be my adjustable cam gears slipping, I didn't see and scaring in the cam gears and don't believe that happen but I sent the heads fully assembled(to be ported)so Im not longer able to inspect.

Hope to post more this week even if I don't have a answer

 

[05stroker]

I took apart a old 2002 2V that was sitting around. It had steel bodied tensioners and the fixed and swing guides were the same down to part numbers.

Thats good news for me! Thanks

 

[tmcolegr]

Thats good news for me! Thanks

Me too!!

 

[Speed+Clinic]

Either way ill reinforce the guides by putting some material where the breaks are happening.

 

[Speed+Clinic]

Sorry I've been busy and just got around to it yesterday. I took apart a old 2002 2V that was sitting around. It had steel bodied tensioners and the fixed and swing guides were the same down to part numbers. The 1 that I was laying around ended up being off a 4V.

I did call TSS about sending my pump in to be examined, after your post I think I'm going to open the pump myself before sending.

I've have exchanged emails with a very reputable engine builder and he states this only occurs when slack developes in the chains and causes slapping. I was asked if I banged the rev limiter and while I wish I could say yes and know I caused it, I wasn't on the rev limiter. The only other way slack would develop would be my adjustable cam gears slipping, I didn't see and scaring in the cam gears and don't believe that happen but I sent the heads fully assembled(to be ported)so Im not longer able to inspect.

Hope to post more this week even if I don't have a answer

Could it be that you had it to tight? I always tighthen them up but not too tight.

 

[one eyed willy]

Wow!

 

[TurboX]

Could it be that you had it to tight? I always tighthen them up but not too tight.

It could be, I know I had them pretty tight when I degrees cams. The thing is that none of the pieces showed any wear, look like new. So I'm at a loss but open to any theories and suggestions.

 

[XtremeStang]

Are you using a two step because I was told that's the worst thing for timing chains components

 

[TurboX]

No 2 Step and like you, Ive heard the 2 Step does put huge strain on timing components.