power drop problem

dibs · Post by **dibs** » Fri Oct 15, 2010 6:27 pm

ok guys n girls

A mate of mine runs a 1600 suby on his pump truck .

He tells me its dropped power after it got hot . When it loads up, it drops in revs and keeps slowing down . Before, it used to drop in revs and pick up again.
We ran it this arvo and if I heard this motor running on the floor, I'd buy it. It runs sweet as it revs clean, no smoke. I did a carbon test in the radiator - none. Pulled the plugs, looks great. No steam cleaning evident. No bubbles. Not rich or lean.
My thoughts are its too far advanced, points stuffed or maybe even could be shit in the carby. He's going to do a comp test to get a better idea.

Any ideas guys?

P.S. - if ya got a 1600 ya wanna get rid of let me know. He was going to put a 1800 in it but he's gotta change too much due to the difference in adaptors and mounts.

dibs

Post by **TOONGA** » Fri Oct 15, 2010 10:34 pm

what is the oil pressure like

if the oil pump is stuffed then when the engine heats up the oil pressure will drop away and cause a big drop in power

seen this in quite a few ea81 motors

TOONGA

RSR 555 · Post by **RSR 555** » Sat Oct 16, 2010 2:48 am

First would definately be the compression check followed by the timing checks

dibs · Post by **dibs** » Sat Oct 16, 2010 5:59 am

heaps of oil press aroud 55 psi and forgot to say when it starts its sounds high on comp or to far advanced .we checked all the driven pumps and there free to so i dont realy know waiting on more info
dibs

Post by **TOONGA** » Sat Oct 16, 2010 9:54 am

plenty of oil pressure is good

definitely get the cylinder compression checked

and as well check the ignition timing, the valve timing, the rotor button, the cap, points, condenser and the high tension wire that runs from the points to the power input of the dizzy

TOONGA

tony · Post by **tony** » Sat Oct 16, 2010 7:29 pm

had the same thing with my L series, eventually turned out it had cracked the heads did not show up with bubbles in radiator but did affect the power and did have symptom of too much advance, maybe the cracks heat up around the edges and get hotspots which cause preignition and starting difficulty with apparent high compression. or could have water in the cylinder.

GTlegs · Post by **GTlegs** » Sun Oct 17, 2010 8:48 am

cracked heads sound plausable actually. Also check the electricals like mentioned above as they sound most likely. The carb may or may not play a role too.