Logo
FULL SITE MENU

Mercruiser Ford 302 winsor

H

harryjay

New member
"I have a pr of old 1973 carb

"I have a pr of old 1973 carb Mercuiser 5lt inboards. The port motor has developed a tapping sound that sounds like loose tappets. They are not loose, replaced all the hyd. lifers, no difference. With the rocker cover off the sound is not from there. Using a stethescope it sounds like it's coming from No. 2 but top end not from the big ends. Sort of piston height. It's a light tap like a tappet knock. It's been suggested I've worn a lobe off the cam. Any suggestions would be welcome. Really don't want to have to pull the engine if i don't have to.

Thanks

Rob"
 
pull the valve cover and measu

pull the valve cover and measure the lift or see if they all move the same height when you turn it over
 
Rob Harrington-Johnson
Take a

Rob Harrington-Johnson
Take a good look at the mechanical fuel pump. Sometimes they drop the spring on the lever and sound like a lifter.
Bert
 
Maybe years of carbon builup o

Maybe years of carbon builup on the valves and esp. the piston tops. I've had it sound like a hammer pounding while the engine shook violently in my truck; swore I threw a rod but just a chunck of carbon.
 
doubtful on the rod knock. I&#

doubtful on the rod knock. I've had fords act that way when run low on oil and air gets in the oil galleries. Make sure you have good oil and quantity. Add a quart of ATF to the oil (which has detergents)... sometimes that frees up stuck lifters or collapsed lifters. I like Bt Doctur's suggestion on diagnosing a worn lobe.
 
"Rob...

I agree with Bert a

"Rob...

I agree with Bert about that fuel pump. I've heard alot of them have that high pitch clicking sound from the arm bouncing around on the cam eccentric. The pump will still work normally, but make that tappet noise.

A carbon knock will make a slightly deeper sound, but still clicky. Get some liquid combustion chamber cleaner. Not the spray can type, but the kind you pour down the carb while it is running. Dump the whole can down the carb while holding the throttle open to give the motor some rpm. Make sure not to dump it in so fast that you will get hydraulic lock up, but pour it in fast enough that the motor won't just burn it off. At the end of the can, you should be able to stall the engine while pouring it in. Now let it sit for the whole day so that the carbon will soften up. Then fire it up and rev her up to burn all the carbon out of there. It'll smoke big time untill it's all out of there. Then change the oil as some of that stuff will have leaked down past the rings and into the oil pan.
(we used to do this at Ford)

You said that you recently changed the lifters. If there was a bad cam lobe, one of the lifter bottoms will have been badly worn, and the lifter would have been very difficult to get out of the block. Was this the case?

A wrist pin knock will be a quick double knock while it is running, but usually be a deeper sound again than a clicking noise.

Let us know how its going

Wrench"
 
Thanks for all the great comme

Thanks for all the great comments.
To ans. the various suggestions.
The sound seems to be around top end of No 2 the fuel pump is on the other side would it transfer across? I'll try the stethescope on the fuel pump and see how it sounds.

If it's carbon I'd be very happy.
The lifters all came out ok and no obvious sign of damage.
We did do a compression test some time ago but can't remember if that one was any worse than the others.
The oil while I've owned the boat (a year) has always been at the right level. After we did the lifters (due to the noise)we drained it and replaced.

Guess I got a whole lot of suggestions to try this weekend.

Thanks
 
"I beleive the rocker studs on

"I beleive the rocker studs on the Windsors are press in. One may have come partially out, which results in rocker slop and will give you that noise. Not uncommon.
Something to check; easy with the valve cover off.
Rod"
 
"Thanks Rod, the noise isn&#39

"Thanks Rod, the noise isn't evident at the rocker level. had the cover off and it's not in that vicinity.

Rob"
 
Back
Top