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302 problems....help please
I've bought a secondhand but "rebuilt" 302 engine for my Cobra.
I spent a couple of days fitting it, then tried to start it. Big fat spark, plenty of gas but no go. Took off the rocker covers and the fourth rocker on the l/h side (sitting in the car) is not moving as I turn the engine over! whats more the fourth rocker on the other side is moving only half the amount of all the others. I took off the rocker and looked down at the lifter, it seemed ok. I took a spare pushrod and gently tapped the lifter, it moved down but I'm not sure how much was oil seeping out and how much was the lifter moving. when I turned the engine over again with the pushrod in place but no rocker, it moved up and stayed there. What the h**l is going on??? The first thing I'm thinking of is a couple of lobes of the camshaft (just my luck) but could there be another problem/cure? Any help would be greatly appreciated. Thanks guys. ps, in the UK, so not many 302 experts around here. |
possible
It sounds like the lifter might be colapsed.
Remove the distributor ( after you mark positions on it ) and put an oil pump driver in and run the oil pressure up. Then, put the distributor back in and see if the rocker arm goes up and down. Make sure the distributor is in time. If the valve train is adjustable, you will need to run the engine and loosen the rocker arms one at a time and adjust the lifter for top travel. This will give you best RPMs. Just my $0.02 :3DSMILE: |
HHHMMMM, not sure if thats the problem, I turned the engine over without the plugs in after I'd put oil in it so I'd get some oil pressure before I started it.
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Flat tappet or haydraulic cam? I agree with Trularin, sounds like a collapsed lifter - ie not moving at all.
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Its a hyraulic cam/lifters
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Gawd Simon, you don't have much luck with your engines, do you??
I am unsure about the collapsed lifter theory, since even if fully "bled down" there should still be some valve lift left. I rather suspect that you have some cam lobe issues there. If the valve train is "ajdustable", try checking that first. Was there oil in the enigne when you got it? Was there any metallic debris in it whne you drained it? Also try cutting open your (old) oil filter to see what it has trapped. Any other valve train dmage you can see? Broken valve springs, bent pushrods, "bent" rockers etc? Get this pinned down before you even think of firing that engine up. |
Hi Simon,
When the lifter comes up can you push it back by hand after you turn the engine past where the high point of the cam on that cylinder? It should drop down with very little pressure. Poorboy |
Hi Wilf,
Maybe I should stick to bicycles eh? I've had the inlet manifold off and from what I can tell the cam is OK but a couple of the lifters are very tight in their bores, ie push them down and they'll pop up when the engine turns over but won't go down again. I managed to get one lifter out and it seems to me the lifter bore had a (very slight) burr at the bottom edge that I could feel when I put my finger in it. After a bit of work it now moves freeley and with the rocker on, has the whole range of movement. However I cannot get the other lifter out to check it! If I ease it donw gently with some taps from a drift, it pops up again ok when I turn over the engine but I can't lift it out of the bore. Any advice? It seems to me that MAYBE in a previous life, the engine had a cam problem that caused the two lifter bores to have this ridge on the bottom, and the problem was not addressed before the engine was built. There's plenty of assembly lubricant on the parts, and the lifters look new, so I think it has been rebuilt. Simon |
Poorboy,
No, see above, its really tight in the bore. I need some way of getting the lifter out to inspect it, any suggestions? Simon |
Remove the intake and use a magnetic pickup. If it is stuck, that might be a problem all by itself. If the magnet does not work, get a hydraulic lifter puller ( SnapOn or someone else ). This tool will "slide hammer" the lifter out of the bore.
I can only go by what you post, but I would pull both covers and check all of the valve train. If each one of the push rods can be verified that they go up, then the only part left is the lifter itself ( prior to the rocker arm ). Wiping out a lobe seems to be common lately. From what you say, the lifter bore or the lifter appears to be the problem. Please keep us posted. Hope this helps. |
Simon - you are going to have to get that "stuck" lifter out somehow. Maybe if you pulled the cam it would come out by pushing it out downwards? ( I can't remember the exact layout of the iron around the base of the lifter bores).
Then you can inspect the lifter bores (which should clean up with a hone, but that is going to mean complete engine strip down and clean to get the abrasive particles out) and the lifter, which sounds as if it is mushroomed at the bottom end - probably didn't get changed out for this very reason when the engine was rebuilt??? I can't see how else you are going to fix it - if the valve spring pressure wont push the lifter back down the bore it has serious problems. Boy - you are going to be good at Ford engine building by the time you are finished!! Bad luck old chap (that bit was for the benefit of our American chums) :LOL: |
stuck lifter update
OK...It's out.
I took the internal part of the lifter out with it still in the bore and put a rawlbolt in (used to secure things to brick walls by srilling a hole and then expanding by doing up the bolt...I'm sure you know what I mean. the lifter is undamaged but when I try to put it back in the bore it comes up agains a stop that I estimate to be the bottom of the bore. I think my theory of the bottom of the bore being damaged is about right. I'm trying to (gently) file away any burr that may be on the bottom of the bore with a magnetised and grease coveret small file. Just what the engine needs now...fillings ! I'll squirt it down with WD40 and change the oil before start and after a half hours running. Can't see what else to do apart from tearing the whole thing to bits. Simon |
I'm not following you, is the lifter out, or is it just the guts?
If you can pull the lifter casing, mic it out and see if we have a size problem. |
I would not use a file in the lifter bore. This is a machined surface. If you need to clean up the bore than use a hone.
Mike |
It might just save time and aggravation to just remove the 302 and refurbish/rebuild it once and for all...I think that would be worth it for the piece of mind that your engine is "Done well!" Costs a little more that way, but what price sanity? Do it once, it should last years...do you want to do some more work in a few months?
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