3.6 on 50mm PMO Carbs sounds like a VW!!

[daltvater]

Questions for you experts.

1979 with a 1995 3.6 in the back. Carbs no EFI.

When I start the car from cold the car sounds like a VW. The thing shakes and sounds like its only running on 1 cylinder. After a few minutes is smoothes out.

Lots of sand crackle pop at 3,000 revs on very light throttle. Goes away once you "give it some jandal" (as they say out here in New Zealand)

Engine is freshly rebuilt, big cams, solid rockers. Last dyno carb tune was 6 years ago and 5,000 miles ago.

heading to the track this weekend and want to be sure all is normal. Cylinders not running on cold startup with carbs, is that normal?

[Jeff Alton]

Not normal. Pull jets and clean, ensure no debris. Change fuel filter, have the carbs properly set up.

[daltvater]

Originally Posted by Jeff Alton

Not normal. Pull jets and clean, ensure no debris. Change fuel filter, have the carbs properly set up.

Followed your advice Jeff. Carbs were gone through, car runs super smooth at this point. Starts on all 6, and even sounds much better!

However it lost some grunt, I'm confused as to why that would be. It runs a Link ECU for the timing, wonder if that has been thrown off? Car is noticeably slower. Guessing it now needs to be dyno tuned eh?

[Jeff Alton]

Get the timing curve data. It could be the issue.

If you can get it on the dyno, and the timing curve is adjustable, it can be made perfect,

Cheers

[safe]

Originally Posted by daltvater

Followed your advice Jeff. Carbs were gone through, car runs super smooth at this point. Starts on all 6, and even sounds much better!

However it lost some grunt, I'm confused as to why that would be. It runs a Link ECU for the timing, wonder if that has been thrown off? Car is noticeably slower. Guessing it now needs to be dyno tuned eh?

If you have a Link ECU sell the carbs and get some ITBs...

[daltvater]

Originally Posted by Jeff Alton

Get the timing curve data. It could be the issue.

If you can get it on the dyno, and the timing curve is adjustable, it can be made perfect,

Cheers

Thanks Jeff, I asked about the dyno and the carb guy said yep lets get it on there. Thinking of doing two timing maps so I can switch to the track map once I get there.

Really appreciate your help on this!

[daltvater]

Originally Posted by safe

If you have a Link ECU sell the carbs and get some ITBs...

Never! I love the full analog thing. Carbs are running so smooth now. Spend $10k for more hassle and similar power. So many benefits of the ITB's but nah. Old school car old school fuel delivery.