Something Knocking on Start-up

[fsmall23]

hey there,

I recently just bought a 88 ranger with a 2.9 in it with only like 70,000 miles on it. Great deal for a 1000 bucks. But every morning, well almost every morning, ill go to start it up and something knocks like crazy for about 5 seconds. Its coming from multiple places. So i figured it was lifters, just like any other engine. Well i have tried a multiple weights of oil, filters with anti-drain back valves, oil additives but nothing seems to help. i am going nuts trying to figure it out. All i can think of is something in the valve train.

Any ideas? Solutions?

 

[IMenriched]

Some have had sucess with removeing the valve covers and valve train from the head, rockers and common shaft and cleaning the common shaft, which is a precision tube. this tube, over time, can fill with crud and limit oil flow /distribution.

While this, rockers and common shaft, is out you may want to dissassemble it & carefully noting what goes where and in what sequence, and meassuring the areas where the rockers pivot. this area on the shaft may have excessive wear or the bore on the rockers too could be worn excessively as well.

If there is excessive wear on either shaft or rockers bore, then new componets maybe in order. If parts are still within specs then you might get lucky with just a cleaning and reassemble.

If you want to know more weather this noise is coming more precisely... an old trick is to get a very long srew driver, place the srew driver (drive end ) on the engine, (just not on rotating things), where the suspect noise is coming from, and place ones ear on the handle. {Be sure to not to have loose clothing on & the longer the screw driver the better}...then move screwdriver to new location and see if the noise is quieter or louder.

A compression check could also help determine the trouble spot.

 

[fsmall23]

Thank you very much, that actually makes sense to the problem. And since i found out yesterday that the guy who owned the truck before me was using crappy gas station oil, maybe i do have some crud up there that needs to be cleaned out. And i do need to replace the valve cover gaskets, so maybe i should venture and clean the valve train.

 

[RustedRanger]

I might be wrong but I think I read that if you remove the rocker shafts you have to unbolt them evenly or they could bend.

 

[fsmall23]

Yea, I wouldn't know. All i have dealt with were chevy's. Mainly smallblocks. I do love this 2.9. Its a fun little V-6. Guess I should take the valve covers off, replace the gaskets, clean the rocker shaft, and check the heads for any visible cracks. Heard that the early model 2.9's were notorious for that.