hi, please need help on this one, i'm not a mechanic i like just to fix any things that is not working properly, some knowledge but not good as a mechanic. we pulled out the engine of our forklift caterpillar with 4g64 engine smoking and hard starting found the problem ring worn out, valve seals and cylinder worn out, change the piston and ring rebore was done and machine shop did decking also (not sure if right word decking). me and our maintenance guy assembled the engine back together and it fires easily idles good like its a brand new engine. so we let run for like 3 days in row some sort of a break in. then we did a change oil then tried to use it, however we notice that when the driver revs it to lift the forks the engine is somewhat choking or its starts to shake like your running out of propane but not stalling or dies. and also when there is heavy load it cant go up the ramp as it was before we have almost 15 to 20 degree ramp, so what we did i tried to adjust or turn the distributor to point that it max adjusted already, i check with the timing light and confirm it in 7 +- 3 degree which website say for 4g64 1994 engine. is there any possibility that i was bore out and needs more propane to the sense that we need to adjust the impco 100 carb or propane carb to say, are we missing something out on our rebuild or some sort of a vacuum issue that we need to check, however i turn the distributor retarding it stalls advancing it revs up to certain point then engine starts to shake and like its lacking propane or chocking.
please we need the forklift running or i'll be in deep trouble to my supervisor and manager.
any insight and help in advance i'm already thanking you guys.
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What ever happen with this problem?
the timing marks on the 4G63/4G64 are indicated on the gears, there are pointers casted into the timing cover and head, on the slinger washer behind the crank gear that has a half moon cutout.
Now when you set the crank timing mark, when you look at the mark on the gear it will be pointing at the casted pointer (or pin) which is about 10 or 11 o clock when looking straight at the front of the engine.
As for the timing mark on the cam gear , there are is a dot, it should be lined up with a casted indicator in the head which is about 9 o clock. This will be close to the seam where the head meets the block so look carefully, its easy to overlook if you're not used to doing timing on these engines.
And last but not least, the oil pump sprocket has a dot on it that should be lined up with the casted pointer in the timing cover. This mark will also be about 10 or 11 o clock.
Now according to the manual a 4G63/4G64 engine timing is as follows:
Gasoline engine: 4deg BTDC @ 740 rpms
LPG engine: 9deg BTDC @ 740 rpms
hope this helps
thanks l1tmech, we will check the timing back again.
here is the link that is the same as our engine
http://www.mightyram50.net/vbulletin/showthread.php/1856-2-4L-timing-marks-confusion
which one is correct. the nipple line up to the cam gear or about 1 tooth or half up. the is a play on our cam gear which i think if clockwise the valves will open soon counter will delay the valve opening.
thanks for the input this is a big help
thanks guys i will check this one on tuesday my work start tuesday to friday.
yes swoop223 when we assemble the engine the maintenance ignored the oil pump because he said it was a free rotating gear and any position is ok, i will check this one. as for the mixer we will try to disassemble it and clean it.
yes double check the timing
one mistake i see alot when guys change out belts trying to set timing is they get it a tooth off OR they dont bother timing the oil pump sprocket. Yes the oil pump need to be timed also, it will not keep the engine from running but it will cause a harmonic vibration at certain rpm's if not timed correctly.
As for the power loss under load?
-make sure the mixer is clean and it's diaphram is ok
-check and clean out the converter
-make sure the dwell setting is correctly set (via the mixer, this is not an electronic setting like it was with the points system, this is a air/fuel setting on the mixer hidden behind a expansion plug)
-make sure the fuel lockoff is opening completly when energised
-double check vacum lines, make sure they are connected to the mixer correctly to the right ports (yes the vacum advance being connected to the wrong port will keep the timing from advancing correctly when accelerated)
just a few thoughts that come to mind
Simply boring out a worn engine will not increase its needs for more propane. The actual increase in total displacement is insignificant insofar as the fuel system is concerned.
But, the engine may not be timed correctly regarding the timing belt. One tooth off and the engine will barely run.
An issue I ran into on a 4G63 in a Mitsubishi forklift was that the vacuum advance unit on the distributor was packed completely full of dirt and debris to the point that the vacuum advance was not working at all. So you want to double check that the vacuum advance is working.
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