435 Cats

[ChrisP]

No not a pet problem.

The engines are fitted with a flap valve in the exhaust after the turbo. I understand that this was added as an emmission control, controling the turbo boost through the rev range by restricting the exhaust flow through the turbo. These have become stiff to move and are affecting the movement of the throttles. We've been told to disconnect them and fix them in the open position. From the stupid answers to other questions we are getting from the present "expert" we are loosing faith in his abilities in all things mechanical with the exception of the production of astronomical bills are increasingly regular intervals. Prehaps you can throw some light on the matter.

What effect will this have on the engine apart from the fact it now smokes more?

Are we likely to damage anything by running the engine with what is now a free running turbo over boosting the engine at low revs? (the valve position is directly proportional to the throttle movement).

I know later engines wern't fitted with the flaps. Were the engines modified in some other areas to make the flaps unecessary.

Is my assumption that Catapiller wouldn't fit an valve unless it was needed illfounded?

Comments please

ChrisP.

<hr width=100% size=1>What do you mean the sea gull in front's walking !!!

 

[DepSol]

Chris I know this sounds obvious but is there no way of stripping them, cleaning, greasing and putting them back in easily?

<hr width=100% size=1>Dom

<A target="_blank" HREF=http://www.soltron.co.uk>the website</A>

 

[Deleted User YDKXO]

Its certainly true that some engine manufacturers had to resort to quick bodge fixes in the 1990's to meet spurious emissions regulations. The fueling on the Cat 3208 is not electronically controlled so it was impossible for Cat to remap it electronically; in fact, the engine has now been withdrawn from sale because it cannot be made to meet current emission regulations which is a shame because its a good engine
I'm not qualified to say whether wiring up the exhaust flap will damage the engine but I do know a company that may be able to help. Who are you using now? Have you tried speaking to Finnings?

<hr width=100% size=1>

 

[adarcy]

No won't matter. As Deleted User says it was just a bodge to restrict emissions and probably mainly smoke. After all, with a diesel at a steady throttle setting (not full bore or acceleration) there is always an excess of air rather than a stochiometric ratio so allowing more boost up to the boost limit (blowoff valve which is still there) is not going to make any difference. The flap will only affect full throttle acceleration emission/smoke by limiting the airflow then. At WOT it is presumably fully open.

On reflection, limiting the airflow without "remapping" the fuel flow is going to make it run richer and smokier so it must have been nitrogen oxides they were trying to reduce.

Rip them out/wire them up whatever you are not being pursued by men with emission and smoke meters like wheeled CAT engines are and let the exhaust dump whatever. I can't see it damaging the engines as they are protected by the boost limiter.

<hr width=100% size=1>

 

[adarcy]

Re:Get it right you idiot

If I've told you once, I've told you a hundred times.

It's stoichiometric or stoicheiometric, even stoechiometric is acceptable but not <<stochiometric>>
from the Greek 'stoicheion' - an element.

Have you forgotten all your Greek?

<hr width=100% size=1>

 

[adarcy]

Re:Thank you kind sir

but Greek forgotten - never did any, my humble apologies

BTW - If I've told you once, I've told you a million times - don't exaggerate!

<hr width=100% size=1>