Hey folks,
Several weeks ago I posted that my truck was in the shop due to a burnt valve. My code was that it was lean in both banks. It surged at about 2500 RPM. The shop manager told me that it was probably a bad injector.
Well, both heads had to come off. One cylinder on each side was low on compression.
When I picked it up Tues. they told me that my underdrive pulleys caused the harmonic balancer to come apart, thus causing it to jump time and bend two valves.
This mystifies me. It just doesn't sound right. I'm not complaining about the quality of the work. My truck runs better than it did at 25k miles when I bought it. It now has 66k. I also don't feel cheated, as the dealer is a friend who did not charge me for the high$$$$ fix. I just don't get the connection between the pulleys, harmonic balancer and jumping time.
Can anyone help me understand this issue?

 

yeh UD pulleys if not properly balanced with the harmonic balancer will throw it off and cause hella roblems

 

HI!... IMO your dealer friend just fed you a line of bull *****. The UD pulleys won't effect your timing at all. You probably had a worn timing chain guide or a malfunctioning hydraulic guide adjuster. It is very hard for one of these modular engines to jump a tooth on the timing. Unless one of the above happens or one of your actual timing chains stretches. With your low miles, I highly doubt it was the timing chains. I have run UD pulleys on every vehicle I have owned from all different manufacturers. Never had a problem with them causing any sort if engine damage.

 

I second what Neal posted. The underdrive pulleys don't speed up the balancer, they slow down the accessories. Our engines are internally balanced and the timing chain is behind the front cover.
If you had a worn timing chain guide or a malfunctioning hydraulic guide adjuster it could allow you to jump timing on one bank but I can't imagine how that would allow both timing chains to jump at the same time. They each use a separate tensioner. The likely hood of both failing at the same time is non-existent.
Here is a picture of my engine with the timing gear uncovered.

I think there is something fishy about what your service friend told you.

 

Actually, his service manager was the one who told me that. I listened, but was a bit taken back, so I didn't think to question what he was saying.
Thankfully, it's fixed. He did say (though it wasn't on the ticket) something about the camshaft position sensor and that the timing chain idlers were replaced because they were messed up. He attributed that to the UD pulleys messing up the harmonic balancer. That's what I need to get explained to me. I don't see how that could be. I've talked to two friends of mine who (1 a machinist with vast knowledge, and the other a diesel mechanic with years of experience) don't think it makes sense to attribute the problem to the UD pulleys.
Anyway, they replaced the UD pulleys with stock and got rid of my UD pulleys.
SIgh...

 

Yeah, I think, from what I posted above, you will find that you are correct. I don't know why he would attribute it to the UD pulleys, though.
Maybe they don't want anyone working on them????

 

HI!... What brand of UD pulleys to you get? A 2 piece or 3 piece set? Every UD pulley set I have ever seen for the modular engines replaces the factory crank pulley (harmonic balancer) with one from the kit plus the water pump and alternator pulleys. So how can you mess up the stock crank pulley with your UD kit if you replaced the stock crank pulley with one from the UD kit???????? Sounds like the service manager is grabbibf excuses out of his A$$. I hope they gave you your UD pulleys back. If not their probably on some mechanics truck right now.

 

Perhaps that's where the problem came in....not sure.
They were UD pulleys for a Mustang, so the alternator pulley didn't fit. I used the crank and water pump pulleys. I'm told I should have heard lotsa noise if the harmonic balancer went out, though.
Is the harmonic balancer actually on the pulley? Someone told me that the pulley actually bolts to the harmonic balancer. I didn't install the pulleys myself, my dad did that while I worked on another project.

 

HI!... On the older engines the pulley bolted to the harmonic balancer. The modulars are internaly balanced. So the crank pulley is incorporated into the harmonic balancer. It's one piece.

 

ha my harmonic balance is better!

 

HI!... But is yours SFI approved? I bet not.

 

haha yes mine is.. its a BHJ

FO-IB5.4V8-7 6.9" 5.4L FORD MOD. V8 Internal Balance
(8-Rib) $ 464.94

but i didnt pay 464 for it... ill have to find a picture of it.

 

HI!... Well mines from MMR (Modular Mustang Racing). It's a 6 rib and is 25% under driven and SFI approved.MMR uses it on their 1500H.P+ 5.4L Mustang drag car. MMR sells it for $199.00(U.S)

 

i paid a wopping 45 bucks for mine. a guy had it on his lightning and went to the lighter weight aluminum one. so he had this one setting in his garage for a year. i think this one is 6.9" in diameter. so im not sure if its under driven any. but i cant complain for the price and also not having to switch to a 6 rib belt. and change over all the accessory pulleys

 

HI!... Well I got all my 6 rib pulleys for free and I needed a new belt anyway so it really didn't cost much to do the swap. 6.9 INCH is got to be the stock crank pulley size. Mines like 5 inches in diamter.