Topic: Simple question - Cam chain tensioner blades.

[Dimitri13]

Just a simple question: should these blades be replaced?

[dave500]

if you can see cracks and can pick bits off theyll be ready for replacement,if they are the factory ones id replace them,ive reused plenty though.

[Wobbly]

Considering that you are already there, and that they are still available and thus very reasonably priced, I say: by all means--replace them. And while you are at it, spend another ten bucks on a new cam chain roller unless it has been recently replaced. Rubber doesn't do so good with the years.

[dave500]

no rollers in 500/550s.

[Wobbly]

no rollers in 500/550s.

Be default, I always assume CB 750 

[dave500]

ha!yeah its 500/550s for me by default.

[Dimitri13]

Thanks guys. I'll be replacing them. Might just get the whole tensioner assembly since I kinda bent mine up a bit.

[flybox1]

Thanks guys. I'll be replacing them. Might just get the whole tensioner assembly since I kinda bent mine up a bit.

one too many PBR's while wrenching.
happens to the best of us 

[Dimitri13]

Lol, that was before I started drinking.

[dave500]

you know all about making sure the bottom tang of the tensioner locates into its little slot in the lower case half?

[Dimitri13]

I see that's where it goes, but how do I make sure it seats?

[dave500]

i remove the pan to be sure,its hard to spot it properly from above even with a good flash light,if your fully rebuilding an engine the pan would be off anyway?

[Dimitri13]

Yeah the pan is off, but the engine is on the bench, so I have to lift it up to see.

[dave500]

heres an engine i pulled down only to find this?sheesh,i wouldnt be surprised if even back in the day a dealership could foul this up.

[Dimitri13]

I know cmsnl and dss have all the tensioner pieces, but is there anywhere less expensive?

And since we're on the subject, what problems does a worn tensioner cause?

[dave500]

it wont tension the chain enough.

[Dimitri13]

Thanks dave.........

Better question: what problems are caused by a loose cam chain?

[dave500]

floppy whippy chain flailing about,on 750s itll chew into the tunnel,never seen it on a 500/550 yet but it could.

[Bodi]

loose cam chain is nasty noisy, cam timing gets a bit wonky (not really a problem); loose enough and it can skip on a sprocket - performance is hurt by one tooth out and more will eventually have the valves hitting the pistons; the blades wear fast and can be chipped by the whipping chain; I think all the "four" engines have the main oil gallery across the engine in front of the crank and a loose chain can rub on the inside of the case where the gallery is - if it wears through you have oil pressure drop/loss; on the 350/400 engines a loose chain damages the adjuster horseshoe pivot making it lock up so the cam chain tension is unadjustable - I can't say for sure that a loose chain causes chain failure, but the only four I've seen with a snapped cam chain was a 350F with its adjuster locked up by this damage. After a cam chain breaks, it's best to look for a good used engine. The carnage in the cylinders is prohibitively expensive to fix.

[Dimitri13]

Ordered new blades from DSS. $150 goes bye bye.

[Tews19]

Glad I checked this out. Dimitri, I noticed the cracks in yours so I went to check mine out. The smaller blade got a knick and that will need to be replaced on mine. The top blade with the cam tensioner nut on it looks good though

[DustyRags]

My 550 started chewing into the cam tunnel, but wasn't too bad. Place install the tensioner in the jugs with the jugs a few inches off the case, and then drop the whole assembly down together. Once the jugs are in, you can't get the tensioner in correctly.

[Dimitri13]

I was able to get the tensioner in with the just mostly on (about 1/4" up, enough to get the small blade in).

The big tensioner had cracks at both ends, enough so that I could break it with little effort.