Timing chain guide limits

[lilmarauder]

Had my engine refreshed and had a few things done to make it more suited for my turbo setup. The engine only had 25k on it so the engine builder recommended re using the timing chains, guides and tensioners. He also used new OEM cam bolts.

I did buy the upgraded tensioner from cobra engineering.

I'm going to try to be pushing around 800rwhp through a th400. Maybe more depending on how the combo does. My question is are the factory guides good for this power? I had a helpful member advise me to upgrade to billet guides. I value his opinion, but I'm asking others as well now that it's a question.

10:1 comp
Mild bowl port head clean up
Bullet turbo cams
Wiesco pistons
Stock crank
Stock rods
ARP studs, mains, side bolts


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[ctgreddy]

I've never seen a 4.6 one fail, I'm sure it's possible but I haven't seen one. I know 5.4's are what have the issues. I wouldn't worry about it at all. I mean just think about how many stock engines are making 750-1000 hp and when a stock motor fails it's never the guides/arms that fail.

 

[lilmarauder]

I've never seen a 4.6 one fail, I'm sure it's possible but I haven't seen one. I know 5.4's are what have the issues. I wouldn't worry about it at all. I mean just think about how many stock engines are making 750-1000 hp and when a stock motor fails it's never the guides/arms that fail.

What's up colin? Yea you do have a good point on that. Turbo is lower stress than a blower too.

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[MalcolmV8]

Never seen an issue with stock guides either. The only time I've seen them destroyed is when someone was 2 stepping with the metal ratchet tensioner and it locks out in an overly extended position and the excess constant tension destroys the guides. But in those cases even a billet guide will get destroyed.

As far as keeping stock tensioners if you have the plastic ones replace with the metal. Also grind off the bottom four teeth on the tensioner ratchet arm so it can't lock out in the most overly extended position from 2 stepping or possibly hitting the rev limiter to much.

Stock chains are fine too. I replaced mine with new chains just since I was in there and they're not overly expensive. It was suggested to me that I get the GT500 secondary chains with aftermarket cams and springs as they're stronger chains. I've only heard that from one source so I don't now how valid that is.
I was buying new chains anyways so I grabbed the GT500 secondary. It looks identical in every way except for a different part #. For all I know it is identical.

 

[lilmarauder]

Never seen an issue with stock guides either. The only time I've seen them destroyed is when someone was 2 stepping with the metal ratchet tensioner and it locks out in an overly extended position and the excess constant tension destroys the guides. But in those cases even a billet guide will get destroyed.

As far as keeping stock tensioners if you have the plastic ones replace with the metal. Also grind off the bottom four teeth on the tensioner ratchet arm so it can't lock out in the most overly extended position from 2 stepping or possibly hitting the rev limiter to much.

Stock chains are fine too. I replaced mine with new chains just since I was in there and they're not overly expensive. It was suggested to me that I get the GT500 secondary chains with aftermarket cams and springs as they're stronger chains. I've only heard that from one source so I don't now how valid that is.
I was buying new chains anyways so I grabbed the GT500 secondary. It looks identical in every way except for a different part #. For all I know it is identical.

I do have the metal tensioners. Can I take them off without taking anything else apart? I know everything is degreed.

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[MalcolmV8]

I do have the metal tensioners. Can I take them off without taking anything else apart? I know everything is degreed.

Yes you can remove them easy enough. Just use something to tie down the tension on the chains so they don't jump a sprocket or anything while you have them out. I use these ratchet clamps from Harbor Freight. Works great to clamp down on the guides and apply tension when the tensioner is not there.

http://www.harborfreight.com/12-in-ratcheting-bar-clampspreader-68975.html

 

[lilmarauder]

Yes you can remove them easy enough. Just use something to tie down the tension on the chains so they don't jump a sprocket or anything while you have them out. I use these ratchet clamps from Harbor Freight. Works great to clamp down on the guides and apply tension when the tensioner is not there.

http://www.harborfreight.com/12-in-ratcheting-bar-clampspreader-68975.html

Yea I have a ton of those around the house. Grind the last 4 off?

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[MalcolmV8]

Yes. There's a release pin you have to pull back with a pick or small screw driver to be able to slide the ratchet arm out. The bottom 4 teeth you grind down. Be careful the metal is surprisingly soft. I use a Dremel and just go slow and then a hand file to make it very smooth and straight when done.

That way when it's fully extended there's nothing to ratchet on. It'll slip back down and catch on tooth # 5 allowing it to release tension from a fully extended position.

 

[jrgoffin]

Grind the last 4 off?
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An even better option is the spacer from SHM. You can then completely toss the ratchet.

If you want to do the modification, all the details start in p.14 of this build thread (with more on the spacer that I ultimately went with):

http://www.modularfords.com/threads/236857-Aluminator-Gibtec-Build

 

[lilmarauder]

Thanks for the help guys. I'll mod the tensioners

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[MalcolmV8]

An even better option is the spacer from SHM. You can then completely toss the ratchet.

I added a spacer but kept the ratchet with the lower four teeth shaved off. So essentially the spacer just sits there doing nothing but if ever the ratchet where to somehow fail the spacer will come into play and stop the tensioner from totally collapsing and would push out with oil pressure and the car would still function.

 

[lilmarauder]

I added a spacer but kept the ratchet with the lower four teeth shaved off. So essentially the spacer just sits there doing nothing but if ever the ratchet where to somehow fail the spacer will come into play and stop the tensioner from totally collapsing and would push out with oil pressure and the car would still function.

I couldn't find the SHM spacer on the website. I will for sure file the last 4 though.

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[badcobra]

If you are on FB, message Keith Rhea, he has the spacers for sale. I run that spacer and the teeth filed off the ratchet also.

 

[jrgoffin]

I couldn't find the SHM spacer on the website. I will for sure file the last 4 though.

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You have to call SHM - that info is in my build thread. They are about $20 for the pair and worth it. If you are just going to file the ratchet, then no sense is getting the spacers.

 

[lilmarauder]

You have to call SHM - that info is in my build thread. They are about $20 for the pair and worth it. If you are just going to file the ratchet, then no sense is getting the spacers.

OK I'll look more carefully in your build thread for it.

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[badcobra]

If you are just going to file the ratchet, then no sense is getting the spacers.

Not true, the spacer will keep the chain tensioned if you lose oil pressure.

 

[MalcolmV8]

Not true, the spacer will keep the chain tensioned if you lose oil pressure.

Actually when you loose oil pressure you still have tension due to the upper teeth still remaining on the ratchet. It's one of the reasons I don't delete the ratchet as good tension is held all the time even when oil pressure goes away which ensures no issues of teeth jumping or chains slapping on start up as oil builds pressure.

However should the ratchet setup fail the spacer is a good fail safe at that point to keep the system working.

 

[lilmarauder]

I messaged Keith Rhea about the spacers. I guess I'll buy them and be done with it.

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[jrgoffin]

Not true, the spacer will keep the chain tensioned if you lose oil pressure.

Actually, I meant to type "If you are going to add the spacer, no sense in filing the ratchets". I had the modified ratchets installed while my build was in progress, but once the spacers went it, I tossed them. If oil pressure were ever to drop, the chains aren't going to lose tension with the spacers in place.

 

[lilmarauder]

Actually, I meant to type "If you are going to add the spacer, no sense in filing the ratchets". I had the modified ratchets installed while my build was in progress, but once the spacers went it, I tossed them. If oil pressure were ever to drop, the chains aren't going to lose tension.

So when I put these spacers in, I should take the ratchet arm out completely? That's what I'm picking up on, just trying to be clear on it.

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