Quote:
Originally Posted by donut
-I'm assuming that the carb float level is correct or a tad low?
-That ignition timing is correct?
-The advance springs and weights you used were plotted and not just thrown in because "the internet said so".
-All 8 cylinders are firing? (for that matter, why keep the dizzy that was set up for propane instead of replacing it with a new one?)
-break in was properly done.
Set the carb back to stock, iirc your about 2 stages leaner now.
Take truck to engine shop, ask them why would those two cylinders are acting like that. One of the techs should be able to diagnose the problem (compression, leak down ...) and decide which direction to go.
This way, you both can decide whose problem it is. (if it's not an engine problem, they can probably test it cheaper than you can.)
|
ok I'll give as simply as a breakdown as i can to tell you everything i've tested/redone
- engine ground
- full voltage at distributor
- new high output msd distributor
- new spark plugs
- new spark plug cables
- heat protection boots on cables
- new holly carb, professionally dyno tuned by a guy who im told is the best in western canada
- redid the intake manifold gaskets, the originals did not have any leaks
- re-torqued the heads
- tried removing the vacuum advance and bumping initial timing to 20 degrees to see if that would help with the off the line failures. it was worse if anything
- tried running sea foam through the carb and in the engine oil. seemed to change the running a little bit, but not necessarily for the better, and it was a short lived change
- did a vacuum test (at the dyno shop) checked out fine
- fuel pressure test (also at the dyno) also fine
- air/fuel ratio checked out fine after the new carb
- re-did all the valve lash stuff. 3/4 turn with hydraulic lifters
- checked to make sure the timing mark on the harmonic balancer did in fact match up with TDC on the marking plate - it was bang on
- did a leak down test. all cylinders were around the 15-20% mark, which i was told is fine for a cold motor.
- compression test, all cylinders fired approximately 70-90-120-150... so im all good there.
other things of note, i've never had any oil show up in the radiator, no rad fluid in the oil except the one time my heads came a little loose, but i fixed that. i've never had any metal shavings come out with the oil. the break in process was done exactly as they told me to. I had the proper oil with the zinc and everything, ran it for 20-30 minutes varying the rpm from 1500-2500 every few minutes.
any thing else I should check on?