Hello, I own a 1958 Chevy 235cu.in motor and it has been completley rebuilt; I have the hydralic valves set at 0 lash plus 3/4 turn; At idle and the vac. adv. disconected The vacuum gauge reads "Late timing"( in the red), If I advance the timing at the distributor I can get approx. 15-16 pds, but it's hard to start when hot. My question is, Why does the gauge read late timing with the ball on the flywheel set at the pointer? Thanks for your information...Olgzer

Try backing off the valves you may have a lifter that is not bleeding down. Did you adjust your valves with it running? Are cam and crank timed correctly?

My thoughts-
The book calls for 1 1/2 turns on the 235 engine. Being on the loose side will not change vacuum but the proper setting is best for oil feed to the lifter plunger. If too tight there will be a rough idle....so doubt if its the lifters.
Its not necessary to disconnect the vacuum line on a 216/235 to set the timimg because at idle speed the vac. advance port in the carburetor is not recieving vacuum. No harm thought in disconnecting and plugging line.
What I would suspect the problem is, is the timing gears are off one tooth.
There is the proceedure for checking cam timing in the 1949-53 shop manual but I do not see it in the 1957 manual. If your 1958 has the original cam the valve timing would be the same for a 1954-55 Power glide engine or any 1956-58 with hydraulic lifters as they all used the same camshaft.
Have you driven the car on the road since the rebuild? If so how does it perform?
Any chance that the exhaust is plugged?

Hi Dens41 and Chevnut, thsnks for your reply, I don't think the valves are too tight, I set them acc. to the manual; The Idle is good and it performs well on the road, it's just that it's hard to start when hot. I don't know at this point if the cam and crank are lined up correctly or not as it was assembled when I got it back from the shop, If that is the case can I correct it by moving the distributor one tooth? I will check the exhaust for a plug though. I appreciate your advise...olgzr

No it can't be corrected by moving the distributor one tooth. The gears would have to be moved on tooth.
Note that the 3/4 turn is correct for V8 and the later model 7 main bearing 6 Cyl. engines. The 235 is 1 1/2 turns.
What year car is this engine insatlled in? If its a 6 volt car the engine being tight may be the hot starting problem. If so should improve with driving.

this brings up a subject a while back i rebuilt my 54 235 power glide engine in the overhaul kit there was new cam and crank gears i noticed that the gears were not marked as the originals in the instructions it said not to mismatch the gears only use in a set if a person did not use in a set and ony used one of the gears and lined the marks the cam would out by one tooth i never did understand why they did this it could cause a lot of hard work to correct after the engine is in the frame .

Guess the Chinese that made the gears could not count in English or something like that? Makes sense to me?