HkPlinker

I have the 76 Talbot Yellow 911s that Stephen Kaspar built with the 67 911 sand cast block. It is bored out to accept the 2.7l heads. I know some (little) mechanical skills on this car. My engine is making a skipping, popping noise (much like popcorn in a microwave bag) when I am accelerating in any gear. It only makes this "popping" and skipping while under a load. At a stand still I can rev it up to redline and it sounds and the responce is great, but when I roll away and give it ANY moderate or heavy throttle I can hear a rather loud popping and the RPM needle is jumping all over the place. A P-car friend noticed the coil had a slight wet spot like leak, so I replaced it. No change.
I was told to try to lean it up or richen it, so I used a 3mm allen wrench and "leaned" it out a little, but no help. I moved it up a little rich and caused a "bouncing idle", still no help with the driving noise.

I am trying to find Stephen, but can not find his number.

Any suggestions??

cscrogham

Take the lower valve covers off and see if there is a head stud with a nut still attached to it swimming around in there. That sound is often associated with broken head studs, I hope for your sake it is something really simple like an exhaust leak or misfire.

theiceman

Sounds like running to lean under load or has exhaust leak as mentioned .. head studs are undoubtedly a great place to start .... I don't know this car .. is it someting special we are supposed to know about ? I am not being a ***** but your post suggests it is something special we should know about . My point is if in fact it is a special car i would suggest getting it to a Specialized P shop and don't monkey around too much .

All the best

HkPlinker

Its not a special car, but one that is known by a few around here. The noise sounds like a mis-fire to me. I just had the valves done and tranny pulled for new sincs. The plugs (the two easy ones I pulled) look good. and it has been converted to a pointless system.
I guess it's time to take it in, sucks cause it's a 60 mile drive to get to the shop. If I ginger the throttle, it drives fine.

theiceman

Wow that is one sweet looking motor ... sounds like a bit of a custom job for sure and should be looked at by pros. if you have updated the ignition and timing anything we tell you would be pointless ( excuse the pun )

Steve Weiner-Rennsport Systems

If you really have an early aluminum block, you should not be having head stud issues,.........

I'd follow Cole's advice and have someone pull the valve covers to make sure the head nuts are all at specified torque. Beyond that, its a tuning problem: fuel or ignition.

WPOZZZ

I had a similar sound in my Carrera and it was the head studs.

whalebird

HK....all good advice here, but may I suggest you post the picture of that lovely car to remind us. Fun car to look at. In the mean time get it looked at and consider having it flatbed-towed to the shop.