347 Burning oil on #5 cylinder bad

[Lex]

What do you think? Could this be the culprit? Good ol' Fel Pro 1250

[CraigS]

Yes it could. BTW the better Felpro gaskets for the Windsor blocks are 1250 S-3 (port size 1.20" x 2.00") and 1262 S-3 (port size 1.28" x 2.10"). Summit has them but they don't always show up in generic search so you may need to search by the number.

[Dan Babb]

I just bought the s3 gasket at auto zone...way more solid than the other felpros.

[Lex]

When I pulled the intake it looked like oil on top of the valve. I didn't build this engine so I'm going in blind. It's a DSS level 10 347 with Victor Jr heads and a wicked Anderson Motorsports N-71 roller cam. The dyno sheet shows 547 fwhp and 515 ft/lbs tq. To me it doesnt feel that strong. It has 150 lbs compression on all 8 cylinders but it uses about a quart of oil in 200 miles. Part of it is a bad rear main leak but #5 plug shows serious oil burning. It also puts out alot of oil smoke on the LH side after I've driven it normal for awhile and the get down on it. It puffs a little at start up but I had a friend following me the other day and said it didnt smoke at all just driving normal. One piece of history on this is when I bought it it had 14 lbs of fuel pressure on a Holley carb and the oil was 1/2 gas. I figured it had washed the bearings down but it carries 60 lbs of oil pressure crusing and about 20 at idle. I thought about pulling the piston out of that one cylinder but then I figure if I'm going to fix it to remove the engine and do it right. Do you think its worth the gamble of trying the intake gasket? That one corner sure looks like an oil track to me.

[ROADRACER83]

If the intake valve has oil on it, it must be coming from a couple of sources. 1. Down the valve stem because the seal is bad. 2. Down the intake port because the gasket is allowing oil to come from the valley area. If the port is wet with oil, then my guess is the gasket. If there is no oil in the intake runner or on the intake valve then the rings might be the cause and then the plug would be oil fouled and the exhaust valve and exhaust port would be gunked up but the intake runner would look like the others. It looks like the gasket is the wrong one and the possible suspect in the crime.

Ron

[Lex]

I checked the valve stem seals and they're ok. Cant figure out if its rings, why just the one cylinder?

[Wade Chamberlain]

I've recently had good luck with Felpro MS93334 intake gaskets, which is the stock replacement for a 5.0 motor. Same port size as the 1250, full open water ports, and steel core. Best of all....$10 a set at any auto parts store and always in stock.

[Dan Babb]

I'd go for the cheap fix first. If it doesn't work, then all you're out is a few bucks for the gasket and some time.

Maybe do this:

Clean the intake runner path on the cylinder head - just to get rid of any residual oil that could work it's way into the cylinder.
Put in a new spark plug - so it's squeaky clean and has no oil residue at all on it.
Put on a new gasket

Seal it up and take it for some spirited driving - where you would get the oil smoking out the exhaust for sure.

Take it home and pull the spark plug.

If it's clean, you're done.
If it's got oil on it, then it could be time to pull the motor for the more complicated ($$$) fix.

[Lex]

It hadn't been smokng out of the right side so I didn't even look at the RH plugs. Guess what? #1 plug is completely oil fouled. Guess I'm gonna jerk the motor and put some rings and bearings in it before the Chemo gets me too weak to work (see my post in OT) Wonder what the best ring to use is on a stroker? What about a shorter rod and custom pistons that the pin doesn't go through the oil ring gland?

[Racer 28]

Total Seal Gapless is all we use, they ensure great ring seal and limited blow by.

[ROADRACER83]

Originally Posted by Racer 28

Total Seal Gapless is all we use, they ensure great ring seal and limited blow by.

Racer 28 has got it right.

X2 on the Total Seal rings. I've used them for years. Better oil control, low leak down, more HP, low blowby. What's not to love? I would do whatever I could to get the pin out of the ring land. I know a lot of people have had no major problems with that setup, but that much ring flopping around in the air makes me nervous. I've always thought a 331 makes more sense.

Ron

[Greg_M]

Lex,
Do a leakdown test before you pull the motor. It might pinpoint something of interest.

Greg

[Lex]

Originally Posted by Greg_M

Lex,
Do a leakdown test before you pull the motor. It might pinpoint something of interest.

Greg

Greg, but will a leakdown tell me if the oil ring is not sealing?

[Racer 28]

Lex, it will give you a percentage of blowby, should be around 5%-8% on a fresh engine. If you have a major problem it will be around 15%-20% and you will hear it out of the dipstick tube. On the top 2 ring of course.

[Greg_M]

Originally Posted by Lex

Greg, but will a leakdown tell me if the oil ring is not sealing?

As stated it will pinpoint blow by or a leak from any source inside the cylinder. Might not be of any definitive use, just thinking it might be worth a shot.

Greg

[ROADRACER83]

Lex:

Here's the skinny on leak down tests and what they can tell you.

How to do Cylinder Leak Down Testing- Car Craft Magazine

Ron

[Lex]

Found the problem. On these pistons there's suppose to be an oil support ring on the bottom of the oil control rings. Whoever built the enging didn't put them on. There was so much clerance between the ring and the piston groove it pounded the oil rings. Theres no way this engine could have not used oil from the start. The guy I bought it from just forgot to mention this little problem.

[Racer 28]

Ouch yeah, that would cause it to use oil... at least you found it kinda early. Are you going to hone and replace the pistons and rings or buy a shortblock?

[Dan Babb]

I'm wondering why you'd only see the oil on the plug on two cylinders instead of all of them.

Sounds like you could just replace the rings and be good to go, right? Or is there more to it than that simple solution?

[CraigS]

Make sure to carefully check the ring groove in the pistons. I am thinking that those rings being in there loose may have worn the groove some.It must be perfectly square or the new rings will flex and eventually fail.

[Lex]

I'm checking everything. I only pulled #1 and #5 because they were the worst. #3 is burning as it should according to the plug. I'm going to pull it and see if the support ring is on it. The bearings are washed out pretty bad. I can't believe it was carrying 60 lbs of pressure and 20 at idle. Must have been the 20w50. Looks like the crank is going to need turned also. I was just looking at a new Scat creank for 250.00. Woner how much they charge to turn it?

[FFR5452]

Lex, I feel your pain.

I just discovered 5 of 8 cylinders of my Roush 427 have a leak down value of 35% or more. This engine was purchased new from Roush 3 years ago and only has 13,500 miles of street use on it. Same symptoms as yours. Needless to say, it's in for a full rebuild. Blow by was pushing oil out the dipstick and breather.

[Lex]

Jim, I've heard a rumor that a bunch of Roush 427's were doing the same thing at about the same mileage. You might want to call them to see if they're doing anything about it.

[FFR5452]

Thanks Lex.

I tried that. They didn't own up to any problems and I couldn't find any blogs about Roush engine problems online.

[Lex]

Completely tore down now. Trying to piece this puzzle together. This enging was orgionally built by DSS in 2004. I was furnished an invoice for that in all the papers I got with the Coupe. There also was an invoice for the enging being re-balanced in 2005 buy a private machine shop. Whoever re-assembeled it only put 3 rings on the oil groove. The flimsy top ring, the wafer middle ring then used the oil support ring on the bottom. Guess they didn't have a clue what they were doing. Anyway looks like the block is scratched up beyond honeing or even going .010 more. The piston skirts are bad enough I dont think I'd want to use them again let alone as earlier stated the ring gland is probably beat all to crap. The crank needs to be turned .010 under. The main reason I chose to buy this car was the $10k engine in it. Buyer beware, Spend the money for the plane ticket when you buy a car on line.

[dallas_]

Lex,
Sorry to hear that.

But could you have known any of that by seeing it in person?

[snapperlr]

I'm curious about the "rebalance". Was there an explanation as to why it was necessary?

[Lex]

Originally Posted by dallas_

Lex,
Sorry to hear that.

But could you have known any of that by seeing it in person?

It smoked bad when I got it. Couldn't have missed it with a test drive.

[Lex]

Originally Posted by snapperlr

I'm curious about the "rebalance". Was there an explanation as to why it was necessary?

No explanation. I would guess they had to do a rebuild or something. Probably due to the fact that it had 14lds of fuel pressure and washed out the bearings. Funny thing is if that was the problem it never got fixed because thats what it had when I got it and the crankcase was full of gas.

[Avalanche325]

Originally Posted by FFR5452

This engine was purchased new from Roush 3 years ago and only has 13,500 miles of street use on it.

OMG. That is worse than a Chevy Vega.