Need Someone Smarter Than Me
#1
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Location: MI
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Need Someone Smarter Than Me
Long story short...... I recently had my twin 540's rebuilt, basically valve job, new cam, lifters, bearings ect.....basic rebuild. Everything is exactly the same as it was before (same exact cam, lifters, just new from the same manufacturer's....same emi exhaust) (have ran these 540's for 8 years) . Get them all back together, run them on the stand and the one is getting reversion pretty bad. The other engine is fine. The cams were degreed when installed.
I am running EMI thunder exhaust, if I dump the water from the top of the manifold out (basically skipping the tails) it runs great. If I hook up water on one side and run the other dry all good. If I put water through the other side (left side looking at the engine) and run the other dry it gets reversion so bad it won't idle. I switched the manifold from the other engine and it didn't help still same results.
I really don't know where to go from here. Any Ideas would be appreciated. I didn't get into all the specs because I have run this exact setup for years.
Thanks in advance
C
I am running EMI thunder exhaust, if I dump the water from the top of the manifold out (basically skipping the tails) it runs great. If I hook up water on one side and run the other dry all good. If I put water through the other side (left side looking at the engine) and run the other dry it gets reversion so bad it won't idle. I switched the manifold from the other engine and it didn't help still same results.
I really don't know where to go from here. Any Ideas would be appreciated. I didn't get into all the specs because I have run this exact setup for years.
Thanks in advance
C
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Did a Compression test, all the cylinders were within a few lbs of each other. Could the ignition timing cause reversion? I could swap the whole distributor from the other engine if it's a possibility?
#6
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If it's a hydraulic cam you may have a lifter a little to tight (back the adjuster off for maximum compression with the compression tester. If it's a solid cam tightening lash 4-5 thousandths is like advancing the cam 2 degrees. You if it's solid try giving it a few more .001's lash. You can also try backing the cam up a few degrees. What were the cams put in at? Did the same guy degree them with the same wheel originally?
Last edited by Black Baja; 06-05-2015 at 09:20 PM.