Thread: Cam timing problem
12-24-2010, 09:52 AM #1
Cam timing problem
I just finishes rebuilding my engine and am having trouble with cam timing. I have read numerous threads about this especialy Verns but i still can"t get this right.I set the cam timing went for a ride and could only manage 7000rpm and idle was rough with no power.I figured had the cam timing too advanced so CAme back and locked cam , undid small bolts on cam gear and rotated engine ccw (retard) then went and re tested ski. Rpms came up to 8000rpm but still well short of the 8600 was doing prior to rebuild.I also noted that it only had 110 psi retarded and 130psi advanced which is strange on a fresh engine with new pistons and rings.I could not retard the timing any further so i moved the cam gear 1 tooth clockwise and reinstalled cam pin and no3 at TDC thinking was maybe a tooth out and still only get 105 psi advanced and 80 psi retarded. THe 1503 marks don"t line up as good as before i moved a tooth cw. I am lost now on which way to go!!! BElow is a photo of how it sits now and any advice would be appreciated...
12-24-2010, 10:08 AM #2
12-24-2010, 10:13 AM #3
looks like hes finding front cyl tdc on the money with a dial indicator....
12-24-2010, 10:15 AM #4
what tooling is that ur using to lock the cam? never seen that one.... been using my factory seadoo one from like 5 years ago, never seen that one like you have pictured.... or your just using something out of your toolbox at home?
12-24-2010, 10:18 AM #5
12-24-2010, 11:06 AM #6
My cam tool never turned up in time so i machined one up to fit snug!!! I took it to a local Seadoo dealer and he verified i had the cam timing right aswell with his tools . we used his crank and cam tool aswell but when i took it out for a test could only get 8000 rpm , would rip out the hole but nose over just on 8000. Nothing else was changed like prop or charger or anything. Before i did the rebuild i had mid 135 in all three cylinders. When i had about 130 psi after rebuild would only turn to 7000 and was dead, so like i said i retarted the cam timing as far would go in the slots got the seadoo dealer to check it and he could see about 1/3 moon through the crank hole in the block , so retarded but only got 110 psi but went to 8000rpm ,,, weird!!!
12-24-2010, 11:16 AM #7
Dial indicator should be great for finding TDC on #3, but that cam tool looks really thick ... it must neck down a lot where it goes into the motor? In a pinch you can use a medium/large sized Phillips screwdriver for a quick check of cam timing, but honestly, getting the cam timing perfect even with the S-D cam tool still takes some playing sometimes.
Here is my .02 ... since you are definitely OFF right now, just keep the compression tester on, mark your current setup on chain and sprocket, then take sprocket bolts out, go one tooth different, reinstall sprocket and bolts, test compression again, and keep doing this until you get good compression readings. Your compression will be low if you are advanced a tooth or retarded a tooth, so the easiest way now is to keep moving a tooth in the direction of better compression.
Keep an eye on the 1503 marks too tho ... they should be pretty close to dead even if the sprocket is on right. If they are not close to level, you might be two teeth off, and you can 'tickle the valves' ... not good.
When you are on the right tooth, you should see compression more in the range of 140 retarded 160 advanced, depending on battery, plugs in or out, gauge, etc. But when on the right tooth, on a healthy motor, you should never see it down as low as 110.
12-24-2010, 11:18 AM #8
I just double checked my supercharger slip too just to eliminate that and no probs there either!!! was seeing 13.9 psi at 8040 rpm set at 18ft/lbs slip!!!
12-24-2010, 11:19 AM #9
If you haave the crank locked with the OEM tool and the cam locked with the OEM tool you cant get it wrong hardley. Get the right tools
12-24-2010, 11:22 AM #10
FWIW, a friend and I just did a little playing with an '08 motor he has ... we pulled the head off, did some checking, reinstalled the head, used the same head gasket and just tightened the head bolts to 60 psi, purely to just roll it over and test cranking compression (will tear it down and use all new stuff or part it out as is). With just the longblock on the garage floor, no spark plugs in, we had compression of 140 in all 3 retarded, 160++ in all three advanced. 1503 marks were perfectly parallel with the top of the head with chain tensioner in.
Oh, and make sure your chain tensioner works great and you can pinch it fully with your fingers.
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