Vortec MPI injectors "click"?

[Skip Fix]

So swapped in a Blueprint Engines aluminum head 383 in my '97. Used a new Delphi intake and used the Delphi MPI "spider". Used JBA header and new Magnaflow convertors. The engine had a terrible lifter type "tick". Pulled valve covers their "self aligning" stamped rockers were able to pop side to side and you could hear a big click just doing it by hand! They sent me GM rocker but still too much side especially since there are no guideplates and no slots in head like the iron heads have. Got some Harland Sharps and they have a nice tight self aligning roller. Lifters did not really bleed down when resetting lash so they seemed good. Improved the noise considerably. But there is still a slight "clicking". it can totally go away usually when coasting no throttle, and con not hear WOT. But slow throttle increases with rpm. It does sound like an LS motor injector click, not really "header sounds". Neither me nor my mechanic buddy can pinpoint it. Motor runs smooth no misses.
He has never put the MPI injectors in a Vortec so not sure if that is it. Any ideas?

FWIW the welds on the Chinese OBX SS headers were nicer than the US JBAs! But their port was huge and no EGR connection.

 

[Schurkey]

Strange hearing you talk about 383s instead of 389s.

I can't really help with the injector tick, except having it go away during coasting does seem to confirm it's not lifters. I suppose the tick could be an exhaust leak, but I bet you're on top of header gaskets and other exhaust issues. The injectors seem the most-likely suspect to me.

 

[L31MaxExpress]

Strange hearing you talk about 383s instead of 389s.

I can't really help with the injector tick, except having it go away during coasting does seem to confirm it's not lifters. I suppose the tick could be an exhaust leak, but I bet you're on top of header gaskets and other exhaust issues. The injectors seem the most-likely suspect to me.

Headers emit kind of a ticking sound even when they are not leaking. The thinner the gauge of tubing the louder this tick will be. On the Thorley headers I have run it was barely noticeable. On cheap shorties and the GM tubular manifolds from the 80s it can be very noticeable. My old 83 305 with the factory tubular manifolds sounded like it was pinging under acceleration because of the tubular manifold design.

 

[Schurkey]

I know I have some hearing loss + tinnitus.

I've never heard tubular exhaust manifolds (headers) tick or ping unless there was a leak.

 

[Skip Fix]

Headers do have a "ting" as they fire each tube but this is more of a click/tick. No header leaks. Going to drive it til it breaks! Then we'll know.

Mu dog like the 97 as he sits in the passenger floorboard. My 2015 there is barely room for a single bag of grcoeries and the whole back with the seat flipped up is too much room and he never relaxes. Even when he was a puppy he would curl up in the passenger floor board of my 04 GTO vs just sitting in the seat. Tight fit for a Doberman!

 

[Skip Fix]

Plus the 97 has no throttle lag like the 2015 6.2 gas motor does!

 

[L31MaxExpress]

Short rod, long stroke engines do have more pronounced piston noise. The worse the rod ratio the more noticeable it becomes.

 

[L31MaxExpress]

Plus the 97 has no throttle lag like the 2015 6.2 gas motor does!

The gas 6.2L or even 6.6L gas do not make 500 ft/lbs before 3,000 rpm like a 383 SBC can either.

 

[Skip Fix]

Not piston noise factory 350 did and they even had a service bulletin if you brought it in for that!

i don't know my 6.2 gas motor sure pulls a trailer with a race car way better than the 350 ever did. But a quick stop and go the throttle lag is about like launching off a trans brake!

 

[L31MaxExpress]

Not piston noise factory 350 did and they even had a service bulletin if you brought it in for that!

i don't know my 6.2 gas motor sure pulls a trailer with a race car way better than the 350 ever did. But a quick stop and go the throttle lag is about like launching off a trans brake!

Guess GM got away from the abrupt, jerky, almost impossible not to spin the tires throttle mapping they had in the 8100s at some point. 1/2 pedal was 3/4 open on the stock 2002 8.1L van tune that is in my 99 Tahoe. I really cut down the throttle opening through half throttle on the stock mapping. There was zero delay, it gave you all the beans instantly.