The Stovebolt Site Forums The Shop Area Engine Shop Expected Life of 235?

My dad's 1946 has a 1961 235 in it. The engine was fully rebuilt way back in 1994. Since then it doesn't quite have 15,000 miles on it.

It runs absolutely fantastic, but for how long? I was just curious what the average life of one of these engines is if it's properly maintained.

Light-duty cruising- - - -virtually forever. If you work it hard, maybe 30,000 miles between overhauls. I mean long periods of high-RPM full throttle running like in a fully-loaded 2-ton or a dump truck, etc. Most of us don't use 'em like that anymore.
Jerry

The most "severe" service it might see currently is on the parkway between my house and my dad's house. That's 9 miles of 60-65mph cruising. My math puts that in the 3000-3250 RPM range and it's most certainly not heavily loaded.

I don't know how many miles it had on it when he had it rebuilt... Well I know the odometer reading but since the engine is not original to the truck and likely neither is the odometer... not to mention I have no idea how many miles were on the donor car. I'm betting it was well over 30,000.

I know straight 6's are tough, I have a '95 F-150 with the 300-6 and it's pushing 200,000 miles with nothing but oil changes.

In the old days these sixes were good to about 60 K until they started to smoke, or that is what my impression is. I am not talking about heavy duty use. I wonder now with modern oil and maybe a PCV system if they would last a little longer.

I have a 1958 235 with over 140,000 miles on it. I do change to oil every 90 days regardless of the mileage accrued. I change out the coolant and thermostat every year too. It still starts every time and has done very well. Like too or not, I tune every year also. The only changes are an HEI, 8 mm plug wires and a set of High Lift rocker Arms.
Normbc9

Where did you get your high lift rockers? Did you have to upgrade your springs to accommodate the extra lift? Did you notice any power increase?

Severe service is starting the engine from dead cold, and short trips.
Lightest severe is high vacuum low rpm non-stop cruising.
"Fully rebuilt" means different things to different people. Under $2,000 they may not have replaced the cam bearings, rebuild all rockers, etc.

Well, if the receipt is to be believed, full rebuilt means all the parts were checked for wear and replaced as needed. It's a little hard to read but it looks like the valves were checked and some were replaced, all new valve seals, springs, seats. New rings, new cam and bearings, lifters, new timing set, new crank and bearings, etc, etc.

It's a fairly comprehensive list.

Nathan, that "rebuild" might be good for many miles. It does not sound like it was what would be called a full rebuild, unless the cylinders were bored (and/or, honed and measured; and, the crankshaft was ground or measured; and, unless the head had the valves and valve-seats ground/dressed.

Other people here are experts and they have already provided better and clearer responses. They will probably/hopefully comment on your "full rebuild".

Have you checked the compression and checked the oil pressure on a warmed up engine.

Nonetheless, check out and use the engine. Maintain it carefully. These engines are robust - it could easily last you many years and many 1000s of miles.

If I am reading the receipt correctly the crankshaft was actually replaced. There is a section of the receipt dealing with the valve seat replacement, certainly a good idea for our modern unleaded fuels, and subsequent valve job.

I know it wasn't over-bored because there is no line item for new pistons. It does have new rings so surely he would have honed the cylinders first! I'm betting the honing falls into the "labor" portion as this doesn't actually require parts but I wouldn't swear to it.

Honestly though I have no reason to believe that anything was done incorrectly or poorly. I haven't done a compression test but I haven't really had need to. It makes good oil pressure, fully warmed up at idle it's somewhere between 15 and 30 and with any RPM's at all it pegs the old '46's 30 PSI gauge.

It starts great, idles great, and runs great. It seems like all the major wear items were addressed in the rebuild and I know the engine has less than 12k on it since then. In my mind that's really low mileage, only just now getting full well broken in. But then again my view is skewed by modern engines that will go 300k with no problem.

I was just curious if they tended to only last 30 or 50k best case, or if they really were pretty robust. It's sounding like they're pretty robust and I don't have anything at all to worry about.

Depends, when they were built they were heavy work engines, sometimes with little or no oil filtration. Today, with modern oils, full flow filtration and light to moderate loading, 100,000 plus would not surprise me, given a high quality professional rebuild. You're not planning on using it to drag overloads up a gravel mountain road, are ya?

My Grandfathers and Father owned a fleet of Chevrolet trucks and have always told me the first problem that showed up was the need for a valve job. Then they would run good for a while but usually after getting the top end back in shape the rings would fail relatively soon, usually within a year to the point of doing a overhaul of the engine. He also said that the driveline would outlast the body of the truck. So, with care and service how long it lasts will be up to you.

That's an interesting suggestion, since he says he's got a 1961 235 in it already.
Jerry

Oops! missed that!

Yeah the engine is a '61 with hydraulic lifters. It does have full pressure oiling, but it does not run an oil filter. Dad always thought the partial bypass filter was more trouble than it's worth.

This is partially opinion, but is certainly based on research. If I were you, I would find a bypass filter. Any filtration is better than no filtration. If you choose not to run a filter, I would recommend using non-detergent oil. It would be a shame for detergent oil to drag all of the crud it is holding across your new bearings.

Just my $0.02...