The timing on my 165hp IL 6 will not hold..update 07/28

[Skipster1]

.... It's as simple as that. I set it just right, shut down the engine, and the next day it is way out again.<br />At the same time my oil pressure has dropped to near zero.<br />All of this happened just after I replace the oil filter.... which may, or may not, have a d...n thing to do with it??<br />It's a 1976 Mercruiser engine and has been running great for the past six months that I've owned her.<br />Any ideas??????

 

[Blk-n-Blu]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

Bad advance springs in distributor???

 

[gspig]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

Timing chain slipping?

 

[Skipster1]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

I don't believe this engine has a timing chain.<br />As to advance springs..... I dunno. Where would I look to find that. It's the old fashioned distributor with points, etc.<br />I've set it up twice and the rotor always ends up having jumped to number 4 cyclinder wire. The shaft is solid. The engine never did this before. Timed it easily and it would hold????

 

[Boomyal]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

Sounds like the timing chain is jumping the gear, to me. If the distributor timing keeps changing in the same direction, that is all that it can be. The chebby six cylinder marine engine probably uses the same fiber timing gear, on the cam, as it's automotive counterpart. It's not like you have to break or wear steal gears to have the chain jump.<br /><br />If, by chance, your centrifugal advance was sticking and releasing, your idle timing would jump back and forth as the advance mechanism would stick then release at different times. This is not likely.

 

[Skipster1]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

Okay.... and thanks Boomyal. Is there some way I can check the advance mechanism?????<br />Also, how can I get at that "fiber timeing gear"???<br />Or, are you saying that I will have to replace the timing chain?<br />If so, can you give me a quick rundown on how I do that? <br />(I've maintained a Datsun 280 XZX Turbo for 6 years and it ran like a top and have worked on other 6s and 8s .... so I'm not a klutz when it comes to engines)<br />Thanks,<br />Skiph

 

[Boomyal]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

I assume you have a marine distrib w/ centrifugal advance, not an auto distrib with a vacuum diaphram canister mounted on the side of the distrib. To check the advance you really have to remove the point plate. You will see the levers and springs that allow the top part of the distrib shaft to rotate with rpm. It will be easy to apply torque to the rotor shaft and watch the mechanism move within it's slots.<br /><br />But, as I said I doubt that is your problem. The distrib/rotor shaft can only advance 30 degrees or so.<br /><br />The only way to visually check the timing gear is to pull off the water pump then remove the timing chain cover. That will expose the crank gear, chain and cam gear. It will be kind of obvious if the chain has a lot of slop and or there are broken teeth on the phenolic cam gear. Replace it with an all steel double chain set.

 

[Skipster1]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

Great info Boomyal, and thanks.<br />One question puhleez: Wouldn't the water pump fail to work if the chain were shot?<br />I only ask because my temp stayed pretty normal.<br />skiph

 

[Boomyal]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

Negative, they are not attached in any way. They just happen to be stacked on top of one another. Also, a slipped timing chain would have nothing to do with oil pressure. I'd hold off on tearing it apart until someone responds to this question. " what drives the oil pump on an inline chevy six. Is the oil pump shaft, in any way, connected to the distrib drive gear on the camshaft?" You may have two unrelated issues here. I don't think that an oil filter would cause a pressure issue.

 

[Skipster1]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

Thanks again..... I am hoping the two are connected.<br />The sequence of events indicates they are.<br />Oil pressure dropped to about 15psi about the same time I was able to re-set the timing (first time after it jumped.)<br />Oil pressure dropped to 0 about the second time I reset the timing.... but the engine was running really bad)<br />Third time... where I am now..... cannot get it to start at all, even after re-setting timing. Nada.<br />So we shall see..... again, mucho thanks.<br />I am now hoping I can replace the timing chain by myself. Never had to before and am worried that I might have to strip down half the engine.<br />If so - considering the 90++++ heat - I will hire Jimmy the Mechanic at $35/hour and smile ...

 

[Boomyal]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

Well with best intentions, Skiph, I was wrong, you were right. The IL 6 has no timing chain. It is a direct gear drive. So that invalidates a lot of what I have said. It is definitley back to the camshaft distributor drive gear and possibly related issue to the oil pump. Sorry!<br /><br />I'm not sure what the cam timing gear is made of but it may be unlikely that it has broken or jumped the gears. Hopefully someone else will weigh in here.<br /><br />ps I wish I had access to a competant $35/hr mechanic.<br /><br />also, I thought that 'hot' was a common commodity in FLA?

 

[Skipster1]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

Darn! After writing the sequence it seemed obvious that it was a chain or belt coming apart.<br />Could it be something in the "direct gear drive"???<br />(The gear on the distributor shaft is solid and shows no markings or aberrations.)

 

[Boomyal]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

If the cam timing gear is phenolic, it could shear teeth. Maybe call your local autoparts store and ask what the cam timing gear is made of on an IL. That still wouldn't address the oil pressure. Even if the cam gear jumped teeth before it quit starting, it would have had no effect on the oil pump drive. All the oil pump needs is rpm to pump oil. It could care less if the cam was out of time. This is all to say that I'd find out how the distrib drive gear is affixed to the cam. If that is slipping or broke a locating pin or missing teeth, that'd answer both questions.

 

[FreeBeeTony]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

I have an IL6 and it's correct saying it does not have a timing chain. The gears on mine were metal, not phenolic. When the timing changes does the rpm at idle change? The oil pump is turned by the distributor shaft. Is it possible the distributor is not seated properly? If it wasn't all the way down it wouldn't turn the oil pump and probably would jump gears. The distributor is turned by a gear on the camshaft. Hope this helps.

 

[Yepblaze]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

It is possible that the harmonic balancer is slipping, either on the crankshaft due to bad or missing key, or within itself the ring slips around the main portion of the balancer on the rubber band section.<br /><br />Just crank the motor by hand with a screwdriver or wooden stick down the number one plug hole and find when the piston is all the way up. At TDC the lines (TDC Timing marks) should line up.

 

[Skipster1]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

Hey FreeBeeTony.. thanks. I double-checked to make sure that the distributor is tight and seated properly ('cause I too thought that this is the problem.)<br />I did notice that the distributor shaft has up-and-down play of about 1/8" and now.... after all the replies and suggestions ..... believe that this play should not be there.<br />I think I'll just go ahead and replace the distributor and go from there.

 

[Boomyal]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

Whoa Skiph! Don't rush out and buy a new distrib. Up and down play is normal. Lateral play is not. 3/32 nd, or so, play is normal and will not be the cause of your problem.<br /><br />Something else is going on. Start from the beginning again. Get a diagram with pictures. Something is wrong that we're not striking on. No oil pressure has nothing to do with distrib play, neither does radically changing timing.

 

[snapperbait]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

Yep.. Oil pressure is the biggun'!..<br /><br />(far out. Boomyal and I agree on something!)<br /><br />Lets drop Skiph's other thread and keep it here.. Gets confusing..<br /><br />To sum it up, Skiph's been having problems...<br /> For starters, Skiph's fuel pump was causing noise from broken spring, since been repaired.. Oil filter change drops oil pressure, timing is now out of wack and won't stay adjusted, cam distriburtor drive gears are chipped, and now no oil pressure.. <br /><br />Skiph.. When you replaced the fuel pump, were you able to account for all the pieces of the old fuel pumps broken spring? <br /><br />Have you tried replacing the K&N filter with another new filter (not k&n)?<br /><br />And, please tell me you have a service manual of some kind...

 

[Skipster1]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

Okeydoke.<br />I've actually been trying to re-build the progression of events and the things that I've done.<br />I wanna nest on this tonite and then, tomorrow, do as you suggest.<br />What has troubled me all along is my inability to make adjustments to the pushrods while the engine is running.<br />I have had to settle for the "dry" method.... turning the engine until each cylinder is up and then adjusting the rocker arm. <br />I assume that this method is accurate, but feel that adjusting during actual running conditions is the superior way.<br />For one thing you can hear the engine's reaction.<br />One reason I mention this is that someone suggested that a pushrod might be tightened too much and pushing the gear drive away from the distributor gear.<br />The other concern that bugs me is the seating of the distributor. I have triple-checked this and the distributor IS cinched down tightly. But, what if the oil pump slot has some junk in it that prevents the distributor from being all the way "in"????<br />Anyway.... exhaustion is making me stupid.<br />Again thanks a whole lot.<br />skiph

 

[Airpacker]

Re: The timing on my 165hp IL 6 will not hold..update 07/28

How far does the timing "move" by itself after you set it? It is possible that some of the old fuel pump spring made its way to the oil pump, locked it and broke the roll pin the secures the distributor drive gear to the shaft. Index and pull the dist. Very closely inspect the gear and pin. If theres any doubt, support the gear and try to knock the pin out. If you can, put it back in because thats not the problem.If yo can't, pull the motor and replace the oil pump. Next,draw the oil pump drive shaft up and check it for twist. If it is twisted, pull the motor and replace the oil pump. If all checks well there, the distributor will need to be disassembled and inspected becaust the advance mechanism is probably sticking or rusted.