Bobacuda Posted July 16, 2016 Report Share Posted July 16, 2016 (edited) The most I have driven my truck since rebuilding it prior to today was 15 miles. Prior to this morning, I had put 89 miles on my truck. I had work to do in Fredericksburg (TX), so I warned my wife and the person I was going to work with that if my truck failed on the 25 mile (one way) trip, one of them would be getting a call. Lots of hills between here and there. It was about 85 degrees F when I left the house and 100 degrees F when I headed back home. Truck ran basically good - no top end over about 55...and I know this truck would go over 70 back when I first got it. After about 15 miles, I noticed my normally 40 lbs of oil pressure started slowly dropping. By the time I got to my destination, it was about 10 lbs, but it was starting to go up again (slowly). After the truck had cooled for about 3 hrs, it was back to 40 lbs again. The only stumble was about a half mile from the house - a small backfire out the carb as I went up a hill and it ran rough for a short distance, then smoothed out again. I am blaming the oil pressure on the fact that one qt in the crankcase is Marvel Mystery oil, as was recommended by the engine rebuilder for break in purposes. I will be draining it soon to go to straight 30 W or 40 W (damn hot around here). I am blaming the lack of top end speed and the stumble on timing, so I have to check that later this evening or tomorrow. When I timed it with a vacuum gauge, I had to advance the timing A LOT to get the vacuum "in the green." Now, the engine will spin, then slow down as the compression builds, then start. I will try just using the timing light and see how that works. One thing I was really impressed with is the new radiator from US Radiator. I purchased the one that is one step up from the OEM. What a difference. I am currently not running a thermostat and the temp gauge never got above about 105 degree F all the way to Fredericksburg. I couldn't believe it, so I opened the hood and touched the radiator and the block - neither was too hot to touch, only warm. On the way back, the temp never got about 130 degrees F. The radiator impressed me. On the way home, I stopped by the Gillespie County Livestock Auction facility to take a photo. I used the truck to pull a small cattle trailer there when it was time to sell calves. Edited July 16, 2016 by Bobacuda 5 Quote Link to comment Share on other sites More sharing options...
JBNeal Posted July 16, 2016 Report Share Posted July 16, 2016 How come ya ain't running a thermostat? My understanding was that it would help ya get to operating temp faster then basically stay wide open until ya shut'r down...as for the local heat, I heard that if ya get some ice gel packs and a towel that ya can have refrigerated seats for a few miles while the 2-55 AC was running 1 Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted July 16, 2016 Report Share Posted July 16, 2016 I agree, Install a thermostat. With my new radiator I went with a 180 degree thermostat. Much better to run the engine at 180 degrees than 105 degrees. 1 Quote Link to comment Share on other sites More sharing options...
Bobacuda Posted July 16, 2016 Author Report Share Posted July 16, 2016 I am planning on draining and flushing the cooling system and installing the thermostat prior to winter (rusty ant-freeze mixture currently). I am not running one now for that reason, as well as the fact I never had a flathead that ran this cool - it caught me totally by surprise. I thought I would put it off installing a 165 degree thermostat after the road testing. Anyone got a name and part number for a 165 degree thermostat for a 218? Quote Link to comment Share on other sites More sharing options...
NiftyFifty Posted July 16, 2016 Report Share Posted July 16, 2016 I put a thermostat in last year...ran 4 years before without, and no issues..but after the rebuild in 14/15 the engine showed it was running too hot for my liking...ended up being the new gauge was out because of a missing resistor...so I wouldn't be overly concerned. If you do, I recommend drilling two 1/8 or 1/4 " holes in it as a bypass...I put a brand new t-stat in after my engine rebuild, and it stuck closed and cooked my headgasket..that's when I went to no thermostat. Quote Link to comment Share on other sites More sharing options...
TodFitch Posted July 17, 2016 Report Share Posted July 17, 2016 I would not run straight weight oil, especially as heavy as 40, on a freshly rebuilt engine. 10w-30 ought to be good for all but the warmest weather. If you are really worried about it being too thin, go for 20w-50. You want the multi-weight oil to get everything lubricated quickly on start up. 1 Quote Link to comment Share on other sites More sharing options...
NiftyFifty Posted July 17, 2016 Report Share Posted July 17, 2016 I've run nothing but straight weight oil in my rebuild, other then the first 100 miles I ran a high zddp break in oil. The industrial motors all ran straight weight for their lives, and with 40 I have great oil pressure when hot, and I never notice any valve train noise....even after it sits for the winter. If you don't use it in winter or cold temps, you will never hurt a thing. Quote Link to comment Share on other sites More sharing options...
Phil363 Posted July 17, 2016 Report Share Posted July 17, 2016 (edited) I am planning on draining and flushing the cooling system and installing the thermostat prior to winter (rusty ant-freeze mixture currently). I am not running one now for that reason, as well as the fact I never had a flathead that ran this cool - it caught me totally by surprise. I thought I would put it off installing a 165 degree thermostat after the road testing. Anyone got a name and part number for a 165 degree thermostat for a 218? See post # 3 here. http://p15-d24.com/topic/30871-finding-external-bypass-thermostat/ Napa carried them last year and I bought both a 160 and 180. You may need to call them as I could not see them on the NAPA website this morning. My engine head has an internal water bypass. However, the thermostat housing I have is for an external water bypass .. so I bought both the THM 155 and THM 55 from NAPA on 29 Jan 2016. Edited July 17, 2016 by Phil363 2 Quote Link to comment Share on other sites More sharing options...
MBF Posted July 19, 2016 Report Share Posted July 19, 2016 Not that you asked, but an engine need to run hot enough to get the oil temp above 200 so that the condensation in the crankcase can vaporize and be drawn out through the road tube, or a PCV system if you have one installed. W/o reaching a high enough temp you're likely to have problems with sludge buildup, and dirty oil. I run 160's in all my flattys, and have a PCV system on my 1 ton. Keeps the oil clean looking longer than the road tube on the other two. Just my 2 cents. Mike 1 Quote Link to comment Share on other sites More sharing options...
Jeff Balazs Posted July 22, 2016 Report Share Posted July 22, 2016 Good to hear this about this radiator. I have been looking at doing this on mine. You should have a thermostat in place. They were part of the original design and build for some very specific reasons. The main reason is to regulate the temperature of the block. Without it in place you actually run a pretty high risk of doing some long term damage as the block will not run with an even temperature from one end to the other. Not trying to incite a riot here just stating the obvious. If they were not necessary the manufacturer would have left them out of the design. 20/50 works well in hotter climates. You may even notice a difference when you put a thermostat in place.........as this is will have an effect on the way the oiling system performs. You have put a lot of work into your truck. Don't undo it by not paying attention to some very basic engineering principals. These engines run fine at 165 to 200 degrees of coolant temperature. Lower than that is not better. Hth, Jeff Quote Link to comment Share on other sites More sharing options...
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