PDA

View Full Version : Pulling engine this winter, what should I do to it?


jfw432
10-25-2012, 10:10 PM
I have an 86 351W engine with the 4160 carb. Since I'm pulling my engine this winter to replace the floor in my boat, I'm wondering what all I should look at while it's out and everything is readily accessible.

I don't know how accurate the hour gauge was on my boat when I got it but I'm guessing this boat has roughly 900-1000 hours on it. I've already done the GT40p heads and an Edelbrock intake. I can tell my engine is either burning oil or leaking it which is my biggest concern. I've added about an 3 quarts of oil in my boat in the last 50-75 hours and the bilge always has some oil in it. My compression numbers range between 128 psi low and 136psi high but I don't know what normal is supposed to be.

j.mccreight@hotmail.com
10-25-2012, 10:46 PM
I have an 86 351W engine with the 4160 carb. Since I'm pulling my engine this winter to replace the floor in my boat, I'm wondering what all I should look at while it's out and everything is readily accessible.

I don't know how accurate the hour gauge was on my boat when I got it but I'm guessing this boat has roughly 900-1000 hours on it. I've already done the GT40p heads and an Edelbrock intake. I can tell my engine is either burning oil or leaking it which is my biggest concern. I've added about an 3 quarts of oil in my boat in the last 50-75 hours and the bilge always has some oil in it. My compression numbers range between 128 psi low and 136psi high but I don't know what normal is supposed to be.

Based on your compression numbers you are in spec. The lowest cylinder reading should not be less than 75% of the highest reading, and typically not 10% differences from ajoining cylinders, anything above 100 psi is acceptable, typically they are 125 to 166 psi . If your really concerned about the condition of the engine do a cylinder leakdown test, this test will give you a better idea of the overall condition of the internals, ie rings, head gaskets, valves, valve stem seals etc. You could try and squirt some marvel mystery oil in the cylinders and see if the compression comes up, diagnosis only. its more important to have consistent compression in all the cylinders than just having some high compression numbers and some lower compression numbers.

FrankSchwab
10-25-2012, 11:52 PM
If you have oil in the bilge, then somethings leaking - a valve cover gasket, a rear main seal, etc. Figure it out, so you know what to replace. Burning oil from a valve seal or worn rings won't, in general, end up in the bilge - it'll go out the exhaust into the lake. That doesn't mean you aren't burning oil; you may have both problems.

petermegan
10-26-2012, 07:10 AM
If your boat has done 1000hrs and the motor is 25years old, coupled with OCD, I would pull it down for an inspection. Maybe run a hone through the bores, new rings and crank bearings. New seals and gaskets and you are good to go for the next thousand. Depends whether you want to spend a $100 or $500? Only problem is you may find something you didn't want to find :) Just my .02c

occva
10-26-2012, 07:31 AM
What is wrong with your floor? 86 should be all glass.

mikeg205
10-26-2012, 07:57 AM
3 quarts every 50-75 hours? And no puddles of oil in bilge? Engine will be out? Hard part is already done. Probably a stuck ring(s). +1 on the leakdown test j.Mc... recommends... Get it on an engine stand have fun... :D...26 years old...time for some lovin' for the inside of the engine... A little investment to get 1000+hours of fun in return. If you have the means you can have some real fun now.

1redTA
10-26-2012, 08:32 AM
Is this a 240 hp engine? If so a cam is in order :-)

Kyle
10-26-2012, 01:27 PM
Cam, roller rockers, rod and main bearings, new high volume oil pump, pan gasket, and main seal.

Supercharger would be nice

Lumbergh
10-26-2012, 01:32 PM
Awe yeah. Spending other peoples money. Everyone is good at that!

Kyle
10-26-2012, 01:48 PM
Awe yeah. Spending other peoples money. Everyone is good at that!

Tell me about it. You guys have spent plenty of mine along the way :D

jfw432
10-26-2012, 04:16 PM
Yeah I'm assuming the rear main seal is leaking but right now I don't know for sure. Nothing is leaking from the top half of the engine that I can see. I definitely plan to pull the oil pan off and at least replace the oil pump. I'm sure there is tons of sludge because it takes 10-15 minutes to drain the oil despite my best efforts to clear the lines. I'm considering a new cam to get the most out of the GT40p heads but I don't think I really want to spend the money to get a new crank, pistons, etc unless I really need them.

If I don't get new pistons, are new rings really going to help?

mikeg205
10-26-2012, 05:04 PM
Yeah I'm assuming the rear main seal is leaking but right now I don't know for sure. Nothing is leaking from the top half of the engine that I can see. I definitely plan to pull the oil pan off and at least replace the oil pump. I'm sure there is tons of sludge because it takes 10-15 minutes to drain the oil despite my best efforts to clear the lines. I'm considering a new cam to get the most out of the GT40p heads but I don't think I really want to spend the money to get a new crank, pistons, etc unless I really need them.

If I don't get new pistons, are new rings really going to help?
Depends how the cylinder walls look. Rings should be a tad softer than cylinders walls I hope - so they take the beating not the block. If the cam is worn - I would check the lifters to see how they are wearing... just sayin'...

Your MCOCD just might get the best of you... considering it will be so easy to get at parts... :D

j.mccreight@hotmail.com
10-26-2012, 05:30 PM
Yeah I'm assuming the rear main seal is leaking but right now I don't know for sure. Nothing is leaking from the top half of the engine that I can see. I definitely plan to pull the oil pan off and at least replace the oil pump. I'm sure there is tons of sludge because it takes 10-15 minutes to drain the oil despite my best efforts to clear the lines. I'm considering a new cam to get the most out of the GT40p heads but I don't think I really want to spend the money to get a new crank, pistons, etc unless I really need them.

If I don't get new pistons, are new rings really going to help?

Personally I would do the cylinder leakdown test FIRST, then if all is good I would replace the camshaft/ lifters to match your other upgrades and then reseal the entire engine (which is not many gaskets anyway).
You have good compression I highly doubt there is any internal damage.
Yes re-ring can be done without changing out the pistons, if the pistons aren't damaged.
I doubt there is sludge in the engine drain hose, these inboards typically take a good long while to gravity drain the oil through the drain hose.
Also check your damper plate for cracks or loose springs if you remove the engine from the transmission.

jfw432
10-26-2012, 10:44 PM
Ok thanks. I do plan to split the tranny and engine to see if anything is going on with it too. I can probably do the leakdown test and see what's up before I even get the engine pulled.

byronic
10-28-2012, 09:33 PM
I would still like to know what problems you're having that makes it necessary to replace floors in an 86 ?

j.mccreight@hotmail.com
10-28-2012, 09:38 PM
I would still like to know what problems you're having that makes it necessary to replace floors in an 86 ?

He owns another brand (Dixie?), not a MC

byronic
10-28-2012, 09:43 PM
He owns another brand (Dixie?), not a MC

Thanks , sorry I missed that.

jfw432
10-28-2012, 11:05 PM
He owns another brand (Dixie?), not a MC

Yeah it's a Dixie. Sorry I didn't clarify that. The engine guys here have been incredibly helpful so I keep checking in from time to time. My floor is actually wood surrounded by fiberglass and it's holding up ok. It'd probably last another year or two but I'd rather tackle it this winter than potentially deal with a problem mid summer.

thatsmrmastercraft
10-29-2012, 10:39 AM
Yeah it's a Dixie. Sorry I didn't clarify that. The engine guys here have been incredibly helpful so I keep checking in from time to time. My floor is actually wood surrounded by fiberglass and it's holding up ok. It'd probably last another year or two but I'd rather tackle it this winter than potentially deal with a problem mid summer.

Good choice. Putting your foot through the soft spot on the 4th of July would not be good.