TR6 PI rev's

[John G]

Hi chaps need a little advice on my TR6 PI engine. I'm nearly done on a total restoration, engine is up and running ect but when setting up timing and doing my running in i notice that the engine when i rev it up to 2.5K ish, it seems sluggish to return to tick-over. This is my first PI engine so i'm not 100% on what to expect.

 

When i say sluggish it's 4 to 5 seconds before she settles back to tick-over almost as if the throttle linkage is slow in closing otherwise it's spot on.

 

Everything is either new or rebuilt any ideas on what it may be or what i can expect with a PI.

 

Many thanks JG

[Steves_TR6]

Hi JG

 

It should return promptly to idle.

 

Ive had a similar issue with my car, when i bought it the engine would sometimes not return to idle.

 

Traced to sticking throttle cable.

 

Could also be an air leak, but then probable it would never return to idle!

 

Steve

[John G]

Thanks Steve i'll double check that, i'm sure its going to be something simple but not having ever even heard it running it's easy to question the logic.

[aardvark]

John. Are the throttle bodies aligned properly? Did you use a jig?

 

Good luck

 

Dave

[John G]

Not sure what you mean but throttle bodies are located on the alignment stud to the head, how else can you do it ?

 

i'm running one of Malcolm's under slung linkage's

[mike3739]

Where about are you located John? Somebody local to you may well be able to offer assistance.

 

Cheers

 

Mike

[Spit_2.5PI]

JG, I don't know how applicable this is to TRs, but bicycle brake cables are very low friction and cheap as chips! Even available with outers in blingy colours and finishes - mine match my armoured injector hoses! Try quickly revving by manually pulling the linkage in the engine bay - this removes the cable from the equation.

 

i'm running one of Malcolm's under slung linkage's

 

Well, I've got one of his overhead linkages. I believe this uses the same adjustment links as your under-slung. Can you make your TR idle sooner by *gently* pushing each throttle body after a quick rev? I found mine were a bit "sticky" and wouldn't reliably return to idle. Despite Malcolm assuring me they shouldn't be like that and, after going through the possibilities, saying I should return for fettling/replacement (very good telephone support) I decided to replace the nut of the adjustment links at the throttle body end with a nyloc (invert if necessary as LH thread nylocs are rare!) and a crinkle washer, tightened so the miniature rose joint wasn't doing the work, so to speak. Bingo! It would idle straight away. I did this so the (Prestige) re-conned throttle bodies themselves could bed in and everything could just loosen up a bit. My reasoning was that the throttle bodies have pretty light springs in them and any stick-tion on the link *at that end* would have greatest effect. Now I've reverted to the original format, balanced the throttle bodies, and everything's fine.

 

Cheers, Richard

[Peter Cobbold]

Check pedal return spring works - lift pedal with foot to see if rpm then drop promptly..

Peter

[TriumphV8]

Although throttle is the most suspect as said above

also take a look at ignition timing.

 

It should come back with the dropping rpm.

[John G]

Thanks all great advice as always i'll try with the basics first and work my way through from the linkage back. I'll let you all know how i get on.