I have a rebuilt 390 fe that burns oil on right side only. good compression someone suggested that its the intake manifold leaking. we put a used aluminum one on when we rebuilt it. how would you check it or any other suggestions. uses a quart in 100 miles but doesn't show like lots of blue smoke like a broken ring.
Could also be worn valve guides.If it smokes right after cranking it up it could be oil seeping past the valve seals and guides and burning.
More than likely its an intake leak...sometimes hard to seal if you are not used to working on those FEs.....check that first. M.
Yeah, you'd have some seriously sloppy valve guides to be burning a quart every 100 miles. Those intakes can be a pain to get seated correctly, look there first.
When you get the intake off, put a good straight edge along its ports & the same on the mating head surface. I had one warp on me, caused a vacuum leak, had a hard time finding the problem. In later years I worked in a shop that had a smoke generator machine just for such troubleshooting. Had adaptors to go over the carb top & you run back all the valves. As stated above, a valve guide leak or piston ring problem will also do it. Doug
had a valve job when engine rebuilt so guides and seals "should be good" just did a quick compression check and it was 150 lbs on all the four right plugs all looked clean whitish brown
Sorry, I somehow missed the one qt./100 mi. in my 1st reading. Recovering from a stroke a couple weeks ago is why I've got the time to get on here more now. With that amount you should have oil dripping out the head pipe flanges I'd think. Is it possible the oil was checked while on an incline one of those times? Or maybe the filter can bled out some air at higher RPM & dropped the level. Doug
inline that's why im asking for some suggestions it may be a quart in 200 miles still way to much. at idle you can see blue smoke once the engine heats up, but going down the road you don't notice it? it didn't do this before we installed the alum intake so I kind of suspect that thats the problem I was just looking for a way to check before we buy and install a new intake. and any good ways to put a new one on to prevent future problems
Had a fresh rebuild here burn oil because of too long of rocker rail bolt letting oil shoot into the head. Also check for no baffle in valve cover pcv side.
I would check the intake manifold seals and gaskets first of all. It's a VERY common problem with Ford FE engines especially with that big HEAVY mother of a stock intake manifold. And they are hard to check from the outside because it's usually the lower inside edge that hasn't sealed.
At one time we had some problems with FE engines if we installed a high volume oil pump. The oil drain back holes in the head were not big enough and the valve cover would fill up with oil. The oil would drown the valve guides and seals. Maybe the head with the problem has shorter guides or smaller drain back holes or some such problem allowing the oil level to be over the top of the guides. Just an idea. We quit using high volume pumps in these engines.
How many miles are on the engine now? Mine used an unusual amount of oil for awhile till the engine fully broke in.
I've had a bit of experience with FE's in medium trucks.They would suck in an intake gasket sometimes and get a bad vacuum leak.But I don't remember if they used more oil when it happened.Might be guides or a ring problem on some pistons.
OK you had a fresh valve job and did the OH on the motor and burning a quart every 100 mi. I would start with the used intake. Some of the old Buddy Barr intakes had a 1 inch pipe plug and I have seen them come loose. Thats a good place to start by removing the intake and checking the intake /head mateing surface.If your heads have been milled and the intake hasn't you have a mismatched gasket surface. Another point of interest is with a bad scrapper ring you can have 200 LB compression and still burn oil with an FE motor.Bought a Holman Moody 427 in 64 and installed it with my heads. Blew oil like no tomorrow but ran good. Tore the new motor down and there were absolutely no scrapper rings on the pistons. Ford gave us a set of rings and gaskets and that fixed our hi dollar motor . Weird but true.
Remove the pcv valve and plug the hole. Also plug the breather hole. Try to seal the crank case as much as possible and put a vac gauge on the dipstick tube. If you have a bad intake leak you should see a vacuum reading sitting running at idle or fast idle.
A gasket leak in the bottom of a port will suck in a bunch of oil, I have had the same trouble before. Also, If you put a high volume pump on it is a good idea to use positive guide seals at least on the intakes. The valve springs flood with oil up to top of the guide and they will pull oil through the guides. Having plenty of oil on top is a good thing because it keeps the springs cool. Also, there were two kinds of baffles that went under the rocker stands, one was flat across the top, and the other had little drip rails that fed up to the intake valley. The drainbacks in the head are kind of small and placed pretty high, with an intake bolt going through it to boot. Any silicone used while installing can block this drainback.
Loosen the intake bolts on the side that isn't smoking, and retighten the ones on the other side. This will pull the intake over and seal that side. It might start pumping oil on the other side, but at least you'll find the problem. Some aftermarket intakes for FE's are too deep where they seal at the ends of the valley, holding the intake too high to seal correctly. One solution is to chuck the gaskets and use silicone on the ends.
ok we are going to try some of this stuff. Has anybody tap the intake manifold and put a pcv valve in it? I know some of the old chevs did this
A lot of the earlier FE's used a spacer under the carb that had a fitting for the pcv connection. Some carbs also had a large port in the rear of the base. If you tap into the manifold you need to get into both runners if you have a dual plane manifold. You don't want to lean out one ot two cylinders with the pcv.
I guess i was wandering if you could tap into the manifold not in the runners but to get in to the valley pan and then hook that up to the port at the carb to relieve pressure under the manifold instead of off the valve cover. then there would be less chance of drawing in oil.
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