Have just put in rebilt 58 235 chevy engine in 48 chevy truck. No oil is getting to top rocker arms. Have put groove in head bolt next to return line, still no oil. Used Air compressor to blow out oil line hole. Have plenty oil where mechanical lifters are. Oil pressure guage on dash registers 60. Any suggestions as what to check next.
thinking from memory now, but it’s possible to install the rocker shaft wrong on these old engines. There are feed holed in the shaft force oil pressure to the rockers. The shaft will have to be removed and checked before you can know if they’te right. LEE
Agree; many years ago (summer 1958) I overhauled a stove bolt 6 Chevy engine and the mechanic helping me cautioned me to put the shaft back correctly. We assume here that the holes in the shaft are not plugged.
Oil getting to the rocker arms was a problem with these 235 engines of the 1950’s. If the other suggestions don’t solve your problem, it could be that the oil passage in the block is plugged. Outside oil lines that bypassed the passageway in the block were made for these engines and sold by auto parts stores and J.C. Whitney. Someone into old cars may be able to point you in the right direction if this is the problem and rather than pulling the cylinder head, you elect to go this route.
This problem of the lack of oil not getting to the rocker arms was not confined to the Chevrolet 235 engines. The 6 cylinder Ford engines of this vintage (I think these engines had a 223 cubic inch displacement) and the 292 cubic inch Ford V-8 engines seem to have had this problem, as outside oil line kits to lubricate the rocker arms were available for these engines as well. I had this problem with a 1965 Rambler with a 199 cubic inch 6. I had to have the cylinder head removed and the mechanic was able to ream out the passage in the block. My total bill was under $40 including the head gasket. Wasn’t life great when things were much simpler?
When the rocker arm shafts disappeared and were replaced by the ball and stud mounted rockers, outside oil lines couldn’t be fitted to these engines.
In your case, if the engine was recently rebuilt, the passageway in the block should have cleaned out. However, if all else fails, this may be the problem.
all the other people are correct. you could try oil clearnig solvent. make sure you do not leave engine to long then let it set for a day
did you check the new head casket with the old one to see if all the hole was punched . I got head gaskets that was for an engine that the same but different year but gasket had less holes . this is a common problem that many people never though of heart sick over a minor thing.
like my friend had a amc car put on new water pump and car over heated. the car was from california and because of an emmison pump they ran
an extra pully and the pump had to ran backwards. never though of a thing like this.
Where is this oil passage located? On my 56 235 there was a copper tubing coming from the block to the head, but on this rebuilt 58 235 there is no tubing. It just comes up straight. There is no hole in block to insert tubing.