302 Top end clatters!!!

H8tulooze · Jun 26, 2007

I have a fresh 1990' 302 long block I bought. It had a stock 302 cam and I opted for a 351w comp extreme cam. I lubed it with the install lube. Fired it up with no mufflers and broke it in for 15-20 mins.I rebuilt the Holley 600, to find out I had a bad gas tank with crap in it(Gell like crap). I got the saddle tank to work(new one), replaced the plugs and carb. The carb is now a Edelbrock 600.

She was reving fine before the Edelbrock was put on,but I couldnt hear any valve train noise till I got mufflers on it. Well now I got it all quiet and sounds like I was getting no oil to the top end. I took the valve covers off and started the motor up. Plenty of oil as it got all over(70 PSI). Still clatter like a mother. think the cam is the prob? Should I go back a RV 302 cam? The motor is real lazy now too. I tried adjusting the timing all over the place and it sounds like a 4 cylinder.

scotts77 · Jun 26, 2007

Are the rocker arms tight? Is this an H.O. motor ? If so, did you install a roller cam ? The cam would be the prime suspect I would think.

H8tulooze · Jun 26, 2007

none roller motor. I put an aftermarket Comp cam for a 351w in it. Do I have to change the push rods? Maybe they are shorter for a 302 vs 351 cam?

broncnaz · Jun 26, 2007

Some aftermarket cams require shims to be placed under the rockers due to having a different base circle. Some cams come with the shims just in case. I would call Comp cams and see what they say.
Also a 1990 block is a roller block not sure of the exact differance it think its just bearing side.

76Broncofromhell · Jun 27, 2007

Personally, I think you have the firing order off. 351W cams use the "1-3-7-2-6-5-4-8" firing order as dictated by your cam. You have no idea how common of a mistake this is with small block Fords.

Only high output 5.0s have roller cam. Conveniently they also share the 351W/C firing order. Post '79 heads are non adjustable pedestal-style rocker arms. You have to shim them to get the lifter plunge correct, however; I have never had a set that were out of the specs of the lifters.

H8tulooze · Jun 27, 2007

76Broncofromhell said:
Personally, I think you have the firing order off. 351W cams use the "1-3-7-2-6-5-4-8" firing order as dictated by your cam. You have no idea how common of a mistake this is with small block Fords.

Only high output 5.0s have roller cam. Conveniently they also share the 351W/C firing order. Post '79 heads are non adjustable pedestal-style rocker arms. You have to shim them to get the lifter plunge correct, however; I have never had a set that were out of the specs of the lifters.

I didnt get shims with my cam. I will triple check the firing order when I get home tonight....Whats wierd is the thing RPM'd great early on and now it sounds like a turd...Not sure the bad gas(like gel) hurt anything.I havent even driven this dang thing....

minimatt · Jun 27, 2007

Sounds like the cam went flat to me. Did you use the comp cams cam break-in oil additive in addition to the cam lube?

H8tulooze · Jun 27, 2007

minimatt said:
Sounds like the cam went flat to me. Did you use the comp cams cam break-in oil additive in addition to the cam lube?

Yes I used their oil, I think you might be right. Flat cam..

Skiddy · Jun 27, 2007

Did you put new lifters in at the same time, if not it probably did flatten the cam lobes.

minimatt · Jun 27, 2007

If you had trouble getting it fired up and running at an elevated RPM (2000-3000) due to the bad gas situation, you may have wiped all the cam lube off and you were doomed from there on out. Also, did you prime the oil pump? Not doing so can cause the cam to go flat, too. With a new cam and lifters it is imperative to get the thing running almost immediately (with good oil pressure) to keep from killing the cam. Open headers sound cool, but as you found out, make it difficult to listen to what is happening with a new engine. On the bright side, you have gained "wisdom". Good luck.

H8tulooze · Jun 27, 2007

No prime on the oil pump... Tempermental engines FORD has.... Chevy seem to be way easier to build and work on IMO....I think this is the last FORD i'll ever own...

Thx for the help guys.

BwoncoHowie · Jun 27, 2007

Did you check your valve lash? When the lifter is on the heel of the lobe you should feel a little bit of resistance when you spin the pushrod between your fingers.

76Broncofromhell · Jun 27, 2007

H8tulooze said:
No prime on the oil pump... Tempermental engines FORD has.... Chevy seem to be way easier to build and work on IMO....I think this is the last FORD i'll ever own...

Thx for the help guys.

I'm sure reaching over the back of the engine with a flat head screw driver is a lot easier than putting a 1/4" socket up front with a drill motor.

Priming the oil pump DOES NOTHING FOR THE CAMSHAFT! The cam lobes are splash lubricated hence why you rev the engine to break the cam in. First step is to check the lash on the valvetrain then determine if the cam went flat. This is Ford, so flat cams aren't as big of a problem as you're used to....

minimatt · Jun 28, 2007

76Broncofromhell said:
Priming the oil pump DOES NOTHING FOR THE CAMSHAFT! The cam lobes are splash lubricated hence why you rev the engine to break the cam in.

Ha ha! That's funny.

Didn't he say it was a fresh engine? If all of the oil galleys are empty, don't you suppose it will take longer for the oil to start splashing onto the cam lobes? You prime the oil pump for the same reasons that you try and get the thing to light off immmediately - so you can get the oil splashing on the camshaft as quickly as possible.

H8tulooze · Jun 28, 2007

Isn't that why Comp cams supplies the cam lube for the initial break in period?

minimatt · Jun 28, 2007

No, the cam lube is designed to stay on the cam and lifters and not run off like motor oil would. This lube starts getting wiped off as soon as the cam rotates. The cam lube is to lubricate the cam during valve adjsutment, cranking and immediately after intitial start up when no oil is being splashed onto the cam. In short, the cam lube prevents a dry start-up on the new cam and is the only means of lubricating the cam until the engine oiling system starts splashing oil. The longer the engine runs without oil splashing onto the cam, the more time there is for the cam lube to be wiped off the cam by the lifters.

Don't take my word for it. Call Comp Cams and tell them you started a fresh motor up without priming the pump, had trouble getting it running because of bad gas, it ran fine initially, but now has poor response and valve train noise. See what they think the cause of problem is.

302 Top end clatters!!!

H8tulooze

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