[Fot] Spitfire Misfifre Part 2

[Jamie]

Experienced this today with a tr6 engine startup.  Check your valve clearances
on 1 and 4.  Lack of compression = lack of firing.  We had valves too tight.
Took us 3-4 hours to figure it out...

Jamie Palmer


On Aug 4, 2012, at 10:51 PM, "Tim Murphy" <timmurph at fastbytes.com> wrote:

> Have you tried the old trick of spraying carb cleaner around the intake
> manifold and carb mounting on #1 and #4 to see if you somehow have a
massive
> intake leak causing a very lean mixture and the misfire?
>
> Tim
>
> -----Original Message-----
> From: fot-bounces at autox.team.net [mailto:fot-bounces at autox.team.net] On
> Behalf Of robertten1 at aol.com
> Sent: Saturday, August 04, 2012 6:55 PM
> To: fot at autox.team.net; net at newenglandtriumphs.org; nedyno at gmail.co
> Subject: [Fot] Spitfire Misfifre Part 2
>
> Thanks to all who responded to my problem here.  I'll be heading to the
dyno
> shop on Friday next, hopefully to get baseline and a/f readings.  This in
> hopes of solving the misfire problem a a little break-in time on the new
> engine.
>
> To recap :  Removing the #1 or #4 plug wire there is no difference in
engine
> note.  If remove the #2 or #3 plug wire the engine stumbles.  I've checked
> the
> timing, tried rotating 180 degs ( will not start ).  Swapped the plugs
> around
> and the same 2 cylinders misfire.  Swapped the plug wires around and no
> change
> in results.  Checked and cleaned all the engine grounds and the connections
> at
> the battery.
>
> I have swapped out complete ignition systems, one is Mallory Dual Point the
> other is a PerTronix conversion in the factory Delco Distributor.  The
> PerTronix is all new parts the module, cap rotor, wires and coil.  The
> Mallory
> is as was before the engine rebuild.  There was no noticeable change in my
> problem with either system.  Re-checked all connectors and connections for
> both complete ignition systems found nothing faulty.
>
> I have done a compression test and all cylinders seem OK.  I did a
leak-down
> test and nothing stood out there either.  I had hoped If there was a
problem
> I
> would get some direction in one of these tests.  Next I removed the valve
> cover brought the crank to top dead center, removed the plug to #1 cylinder
> to
> verify and checked the lifters for #1 - both are loose ( suggestion from
Kas
> )
>
> I re-torqued the head, checked the valve clearances ( nothing out of place
)
> reassembled.  Then changed from Platinum plugs to NGK V-Groove plugs and
> started the engine.  Still a misfire at #1 and #4 ???
>
> I have checked the Weber carb, knowing it will need some tuning as I made
> some
> changes to the engine during the rebuild.  The biggest is a custom cam from
> Rick Cline.  I found I need to lean the Idle Jets as both Idle adjustment
> screws could turned in all the way without changing the idle note.  A 2
step
> leaner jet did result in backing these screws out almost 1 full turn.  But
> no
> change to effect the misfire problem.
>
> And yes, in all kinds of testing there is spark going to #1 and #4 plugs
> just
> no change in engine note. A couple good zaps made me feel wide awake
> performing those tests,   Hmmmm ??
>
> So I am going to order another rotor for the Mallory dizzy ( at some one
> here
> suggestion ) as I grasp at straws for a solution to this misfire problem
>
>
> Engine - .'73 1500 Spit  Bored .040" over  (recessed blocked)
> A/E flat top pistons  +.040
> Head -  Milled .125" ( big valve head )
> 6.5 to 1  roller rockers   Race Push Rods
> 10/10 crank polished and balanced
> Lightened flywheel  @ 12 #
> Duplex timing chain set-up
> Cline Cam  lightened and drilled lifters
> Tri Y  Headers   2" exhaust
> Single Weber 45 DCOE 13 carb   Cannon Manifold
>
>
> Stumpdified,
> Bob T.
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