The Stovebolt Site Forums The Shop Area Engine Shop 58 235 distributor

The distributor on the motor (swapped... decoded engine to a 58/59 34-35-3700 truck) did not have a vacuum advance, just mechanical.

I cannot clearly read the part number on the tag, and even if I could, I don't know what the proper part should be.

Any idea what the proper (or what a 'working') distributor number would be, and must this engine have a vacuum advance?

Thanks!

You do not need the vacuum advance but it does increase the gas mileage & possibly the driveability.

Is the enhancement worth the expense/effort????

The only effort is in buying the parts and installing it. There is no effort after it is installed.

You will have to determine if it is worth the cost - about $25 for the line and $25 for vacuum unit. The parts are not difficult to install.

Ask how many people have eliminated the vacuum advance on an engine that came with one.

So I can get the vacuum advance and add it to an existing dist. or am I looking for a whole new dist?

My carb already has a port to tap (its got a plug in it now).

Just not sure what to look for.

I don't understand the concept of not needing one. That is the way it was designed to run.

to answer the original question, yes the engine should have a vacuum advance, which will be the same for any 235, and very simple to install - available from the vendors [scroll down to V]

Bill

The motor is not original to the truck, and does not currently have a vacuum advance on the distributor that is installed.

The rebuild guide that I have does not show the distributor, but does mention that setting the timing should be done with the vacuum port covered... so I guess I need one.

Its just new to me that you can simply bolt on a vacuum advance diaphragm and it magically works..... most of the dist's I've seen the vacuum advance was integral to the dist, and not simply 'added' to it.

Which year truck Shop Manual and Operator's Manual are you using?

The vacuum advance unit is shown in all the Shop Manuals.

And, it is shown in all the Operator's manuals.

I think that all 235 engines had a vacuum advance unit, but I am not sure about 235s on COEs. On some GMC trucks that used their 248/270/302 6 cylinder gas engine, there was no vacuum advance installed.

Also, there are at least two styles of vacuum advance units that were used on 235 engines. The illustrations in the truck manuals that I posted above are of the car's advance unit - this incorrect illustration was oddly used in all the truck manuals. The car's unit has a mounting plate that mounts the vacuum-diaphragm at a different angle than the angle of the vacuum-diaphragm on the mounting plate used for the truck's unit.

The shop manual does not advise blocking the vacuum port to set the timing. I would suggest using a proper shop manual and not whatever you have been reading.

Here is a copy of the rebuild manual I am referring to:
http://www.canadianmilitarypattern.com/1960%20235-261%20Engine%20Manual.htm

It states on page 7-16 Note 1 "spark vacuum line disconnected..."

Its not a complete guide, only the section that concerns the overhaul.

Most of the online guides that I have found are 57 or earlier. Since the motor is a 58-59 I was avoiding pre-58 manuals as from what I understand the 58 motor had hydraulic lifters vs mechanical.

where did you get the understanding 58 235 truck engines had hydraulics? did you read the section in the manual you linked about adjusting the valves? did you compare that to the adjustment procedure in the 55 manual? does your engine have hydraulics? maybe it's a car engine?

Bill

The motor SN (on the block behind the dist) is FIII9K which is a 59 motor for a 34-35-3700 series truck.

I have not found a complete 1959/60 shop guide online. And I am watching ebay for print versions.

There was no full 1959 Chevrolet Truck Shop Manual. There was/is a 1958 Supplement to the 1958 "complete" Manual and there is a complete 1960 Manual.

F1119K does not necessarily date it as 1959
F = Flint, MI
11 = Nov
19 = 19th
K = 34-35-3700 series truck
There is no year indicator.
1959 engine serial number
1958 engine serial number
1957 had the same style/format engine serial number.

You will need to find the block date casting code.

yes, as Tim says, there was no full manual in 59, and as seen in the 59 supplement, there was no change in the 235 other than the spark plugs called for .... the 58 full manual is really a copy of the 55 manual with the the last real changes concerning the 235 added from the 56 supplement [2 pages] - I don't think there was any other change until the engine was discontinued .... so back to the original question, add the vacuum advance on any year 235 distributor and it will work for your engine if properly installed, no magic involved

Bill

The block code is K 18 8 December 18th, 1958

From what I read the model year starts in September, so Sept/Nov/Dec of any year would be the next MODEL year.

All of the casting numbers match up to a 58-62 engine (block and head).

So I need the 55 manual with the 56 and 58 supplement.

Big ol THANK YOU!!!! for that

I did look over the vacuum hookup and realized they actually just rotate the whole dist. Man, that's some crazy thinking.

I'll hit up Jim Carter for the part... they have 10% off this month (and every month, it seems).

the 55 manual is free as well as the 56 supplement linked above, if you buy one get the 57 or 58 [engine sections the same] full manual and you need nothing else

funny your comment about crazy thinking reminds me of a time I was at a Chev dealer for parts and some young mechs wanted to see the 57's engine - I tweaked the throttle linkage to rev the 235 and one excitedly pointed "look your distributor is loose!"

Bill