GROUP BUY MECHANICAL TIMING CHAIN TENSIONER

ATOM_X

I am hearing off and witnessing for myself an ever increasing number of failures associated with "chain failure"
Route cause analysis has reveiled two main issues

tensioner design & function
inadequate oil pressure or inability to mantain pressure

GM have partially addressed these with the introduction of the "SAAB" style tensioner, which I believe is now the new standard?
When building tuned engines especially with higher valvespring rates there is a much greater risk of the chain jumping if there is inadequate oil pressure or inability to mantain pressure, irrespective of whether VX or SAAB tensioners as both are reliant on oil pressure

I see two avenues to reduce this risk

1; Oil accumulator (accusump etc)
2; Mechanical tensioner similar to the item quoted in the tuner manual (citation to follow) To my knowledge no company manufactures or markets such an item which in affect is a modified standard part

MY QUESTION

Is there a market for such a product if professionally manufactured tensioner

BURT150

Its probably a good idea. I made one a long time ago but never used it i didnt really understand how to set it up properly :think:

The best part about using one would be that if its setup properly and checked every so often it cant physicly fail.

Is any one actualy using one at the minuit who can give some feed back?

pottsey

its good idea lee ,a few weeks ago my tensioner had seized up after 22k miles ,luckily no damage was done and cavaddict replaced it and all is good again

astra22bertoneauto

Would Karo be able to help? Maybe they have something like that in the States? possibly? notsure.gif

ATOM_X

I have come u with a design

Dhe hydraulic system as the primary function will remain the same
there is a internal threaded stop that will be set just clear (1mm) of the tensioner fully activated position
this will replace the weak springed ratcheting grooves & locking pin mechanism
The new threaded stop will act a back stop which if set up correctly and adjusted SHOULD remove risk of
tensioner failure
and/or
chain slippage

My other consideration is heat expansion

obviously all other items within the chaindrive system must be serviceable

I have sent off 5 saab tensioners for modification

on return I will post pics

2-20

Have you tried to contact them:

http://www.jbodyperformance.com/new/PartDetails.php?partId=997&catId=997&catName=JP0997

ATOM_X

there is no decent write-up & £200

reading between the lines probably just a stronger spring
I can do better than that

2-20

Not sure, their wild performance crate LSJ engine use a dead lock tensionner.

http://www.jbodyperformance.com/new/PartDetails.php?partId=912&catId=912&catName=JP0912

ATOM_X

The tensioner has a latitude of 15mm of play from fully depressed to fully relaxed
this should be enough to cope with all senario's

OAKMERE

I will be interested in one of these Atom. :thumbup:

Cheers Oakmere

alanoo

To be honest, I'm not sure if it's a good idea or not... as everyone must remember that as a fully mechanical one, you have to regularly check and correct the tension. For lazy people it could very well be worse than a OE z22se tensioner

OAKMERE

My understanding of this was it is still hydraulic but with an adjustable backstop too prevent slip if the adjuster fails?

Cheers Oakmere

alanoo

If it is a similar item to the one quoted in the GMR tuner manuals as Dr.Lee said, it is a fully mechanical item
basically an OE tensionner outer body, tapped in the middle for a bolt

astra22bertoneauto

alanoo said:
If it is a similar item to the one quoted in the GMR tuner manuals as Dr.Lee said, it is a fully mechanical item
basically an OE tensionner outer body, tapped in the middle for a bolt

It is exactly that. OE tensionner reworked to make it mechanical instead of oil pressure dependant

OAKMERE

Sorry I misunderstood. I think I will stick with the revised standard. I thought Vocky had one that used a spring rather than oil pressure to maintain tension from a later design?

Sorry looking again that just seems to be the Z20net one.

Cheers Oakmere

exmantaa

Quote ATOM:
The hydraulic system as the primary function will remain the samethere is a internal threaded stop that will be set just clear (1mm) of the tensioner fully activated position

ATOM_X

Just to clarify

my design is not the same as the one in the tuner build manual
that is just a simple removal of hydraulic plunger replaced with a theaded stud bar

mine retains the plunger which works the same way

the ratcheting spring system is discarded and replaced with close tolerence bar (threaded at one end)
this hold the plunger in close proximity
this provides a positive backstop should there be a hydraulic failure

I hope that helps