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Discussion Starter #1 (Edited)




Well what do you think?
This is after about three times going out to the lake. All other plugs look fine. Ive done a comression test and it came out just a little low than the others, but within 10lbs of the highest cylinder.
Im running a stock 454 with new dizzy and wires and NGK R YR5 plugs.
Im burning about a 1/2 quart of oil in 3 trips to the lake also. Only thing I can note as far as changes was I added a dual plane mid rise performer intake. Im pretty sure that the gaskets are in ok but I am not sure as if the gasket matched up or not. (im not sure why I skipped that)
Im wondering what I should do. This is my only motor that I have right now and its running fine. I dont want to miss out on the season but dont want to be stupid either and cause further harm.
Ive got it narrowed down to leaking intake, Mis matched gasket, valve seat worn, maybe bad rings. Any help would be greatly appreciated. I trust the knowledge here than any local shop that I have around.
 

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No pix. try again!
 

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Discussion Starter #4 (Edited)



Ive owned the boat for 3 seasons now and it was burning fine. I added intake last season and at the end of the season I noticed it burning oil and a fouled plug. Replaced the plugs at the start of the season and now I am here. I never had an oil issue before the intake but also never drove it as hard as when I got the intake and diverter on.
Forgot to mention that its #8 cylinder. Whats my next course of action?
 

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All I see is red Xs no pix. But here is my .02 worth! If your compression is good then there is a possibility of a valve guide or a valve guide seal. WT:)devil
 

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If it started after you added the new intake, thats where I would start to look. there is a possibility that the intake gasket did not seat correctley, maybe some crud under it, and oil from the lifter valley is getting sucked into the intake causing the plug to foul.

If the boat did not burn any oil and did not foul plugs before the intake swap, thats where I would start. It is cheap, and shouldnt take you all that long.

I would check the valve seal after that.

Ryan
 

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Discussion Starter #10
Thanks for the link. Best webpage on plugs that Ive seen. I just got back from the tool store and picked up a leakdown tester. Now time to go figure out how to use it.
 

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Discussion Starter #14
Thanks for the advice. Im going to do the leakdown check but after reading up on that test, it doesnt seem like itll show a bad valve guide. Maybe after I do the test and if it comes out ok, it eliminates a bunch of stuff.
Say its a bad valve guide, is it head pulling time? I know im getting a little ahead of myself.
Lastly, what should I be looking for when I remove the intake? I mean how can you tell if the gasket is leaking?
 

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Thanks for the advice. Im going to do the leakdown check but after reading up on that test, it doesnt seem like itll show a bad valve guide. Maybe after I do the test and if it comes out ok, it eliminates a bunch of stuff.
Say its a bad valve guide, is it head pulling time? I know im getting a little ahead of myself.
Lastly, what should I be looking for when I remove the intake? I mean how can you tell if the gasket is leaking?
It wont show a bad guide. It will tell you if you have bad valve seals.
If you do a leak down and its in the valves you will hear the air coming out the carbs or the exhaust. If its bad rings you will hear the air in the valve covers. Do a leak down first. If you hear nothing pull the intake manifold. Check to make sure the gaskets on right. And the intake runners are not blocked at all on the heads or intake manifold.
 

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I would bet that when you set down the intake, the gasket dropped a little bit, causing an opening from the intake runner to the lifter valley. This is very easy to have happen, especially on an end cylinder.

But, it could be a valve seal as well.

Ryan
 

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I would bet that when you set down the intake, the gasket dropped a little bit, causing an opening from the intake runner to the lifter valley. This is very easy to have happen, especially on an end cylinder.

But, it could be a valve seal as well.

Ryan
I agree with Ryan on this, you can also check your oil, it could possibly have fuel in it as well. If the manifold gasket slipped when installing it, the fuel can leak into the valley of the block just as easy as the oil finding its way into the intake port.
 

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Discussion Starter #20
bad valve seal or guide almost always happens to #8 cyl
Im leaning towards it being that too myself but just a gut feeling on it. Buddies were heading out on the lake for an afternoon run so I threw a plug back in and hit the lake. Im gonna try to do the leak down test today.

Say its a valve seal. Whats involved replacing that?
 
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