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Severe engine overheat = now overheating oil???

General engine tech -- Drag Racing to Circle Track

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jasonn
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Severe engine overheat = now overheating oil???

Post by jasonn » Mon Jun 29, 2020 7:05 am

This may bet a bit long, but really need some help. Trying to give all info up front.


Just rebuilt my engine over winter with new bearings, rings, honed, gaskets etc, just a refresh after 6 years of beatings. But old pistons and valve springs. (he checked springs and they seemed still good)
My brother drove my car and stopped gas station. Took off and did not turn water pump and fan back on. He said he drove through a town 30 mph but probably 2 miles. turned round and drove back through town again till noticed temp was pegged!! (so don't know exactly how hot, but can't even imagine after driving that far with now pump and fans. Flipped them on and drove home but temp was going goofy and oil pressure was goofy. (his words)

70 mustang with a 427 dart sportsman blocked 10.5-1 compression.

Now, what it actually does -

Start car up and has 60 psi oil pressure. Warm it up and leave town. I start just making 2nd gear, then 3rd gear pulls under open throttle. Temp stays right around that 160-170 and normal oil pressure. Get around 10 miles on, and oil pressure drops to maybe 40 going down road and 15! at stop sign. Now, every time i make a small pull, I can watch temp going up by 5-8dg or so. Normally oil pressure would only drop to round 30 or so when at stop sign. Cant seem to get temp over 210 which is good, but never seen it increasing with a short time load and oil pressure so low when hot. Absolutely not normal for this engine. No water coming out of pipes, No water in oil, or vise versa. Everything else seems to run like normal

So things i have tried.
Again, head gasket, same thing
New electric water pump
Flushed water both ways through radiator, has very good flow
Seems plenty of air flow.
Tried new temp gauge.
Took engine out, took to local engine guy. He took completely apart and found the oil pan was clean as a whistle
Checked all rod bearings, (I know he checked some mains, don't know if checked all), but said every bearing looked like brand new (which they should after rebuild. Did not take crank out or front of engine apart, so didn't check cam or cam bearings or anything like that. Found a piston which was what he thought was a bit collapsed. So I ordered new but same exact wiseco pistons, new rings. Also, found one broken valvespring and replaced all with new. Checked head and no warp. He assembled and it STILL does same thing. Had 10-30 cheap convention oil in for quite a few miles testing things, changed to 10-30 mobile 1. Same thing.

Almost can't be cooling system. Only seems to start getting warm when making a pull, then cools right back down, so I am thinking it HAS to almost be oil temp?? But what could be causing oil to start overheating now under a load?? I would have bet on a bearing but he found nothing when going thought it. No debris whatsoever.
You would thing it was a spun cam bearing or something it wouldn't have a very good 60 psi at cold idle??

Could really need some help. Thanks so much!!
1970 mach with mild 351w
11.60's@117
1970 prostreet fastback with pump gas 427
8.81@154

BigBro74
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Re: Severe engine overheat = now overheating oil???

Post by BigBro74 » Mon Jun 29, 2020 8:07 am

What oil pump- new/old? What are the bearing clearances? If it is NOT a high volume/pressure pump and has wide clearance - with 10/30 oil it is probably not too bad...IMO. If you are worried about the oils temp that will take a gauge or you could use a temp gun on the pan when you stop .....
Maybe try some 10-40.....

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Re: Severe engine overheat = now overheating oil???

Post by Kevin Johnson » Mon Jun 29, 2020 8:26 am

WAG that pressure relief valve in oil pump is damaged in some way (spring, etc.).

Don't forget now -- good lesson. You should set up the coolant pump and fan so that they reset to being on every time the ignition is turned off. People have many distractions and you must protect your ride against the most distracted or forgetful person that might borrow it (with or without your permission).

jasonn
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Re: Severe engine overheat = now overheating oil???

Post by jasonn » Mon Jun 29, 2020 8:33 am

BigBro74 wrote:
Mon Jun 29, 2020 8:07 am
What oil pump- new/old? What are the bearing clearances? If it is NOT a high volume/pressure pump and has wide clearance - with 10/30 oil it is probably not too bad...IMO. If you are worried about the oils temp that will take a gauge or you could use a temp gun on the pan when you stop .....
Maybe try some 10-40.....
Put brand new oil pump in over the winter refresh. It is one of the select blueprinted better melling regular volume
http://www.flowtechinduction.com/mellin ... ce-series/

Did not change it after the overheat though. I think u r correct, i am going to try some 10.-40 and see if it changes, but seems odd, in 6 years (and after the rebuild but before the overheat, temp and oil pressure was absolutely perfect),, so something from the over heat changed something for sure. Do you think that a severe overheat could have affected the oil pump??
AND if so, would that make the coolant temp rise on a 2 - 3rd gear pull?? Thanks so much for the reply!! I need some ideas.
1970 mach with mild 351w
11.60's@117
1970 prostreet fastback with pump gas 427
8.81@154

jasonn
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Re: Severe engine overheat = now overheating oil???

Post by jasonn » Mon Jun 29, 2020 8:36 am

Kevin Johnson wrote:
Mon Jun 29, 2020 8:26 am
WAG that pressure relief valve in oil pump is damaged in some way (spring, etc.).

Don't forget now -- good lesson. You should set up the coolant pump and fan so that they reset to being on every time the ignition is turned off. People have many distractions and you must protect your ride against the most distracted or forgetful person that might borrow it (with or without your permission).
Yea, wife even drives the car, so working on solutions to fix the switch issue. maybe even add temp warning lights using a shift light but for now, gotta figure out the engine. good ? on the pump spring. But would you be able to see the coolant temp rise during a short pull??
1970 mach with mild 351w
11.60's@117
1970 prostreet fastback with pump gas 427
8.81@154

6.50camaro
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Re: Severe engine overheat = now overheating oil???

Post by 6.50camaro » Mon Jun 29, 2020 9:39 am

Are they mechanical cap tube gauges or eletric with sensor gauges . Did you replace sensors if electric . If mechanical were they the same make and model gauge . Havng works as an HVAC tech for 35 yrs I have seen a lot of variances in supposed calibrated instrumentsbetween differnt brands and models . Just a thought. Dan

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Re: Severe engine overheat = now overheating oil???

Post by dannobee » Mon Jun 29, 2020 10:17 am

First thing to do is to wire the water pump/fan switch to a 210 degree snap switch near the upper radiator hose. Wire it into the hot side of the switch so that if you forget to turn on the switch it'll still turn everything on at 210.

If it overheats at anything over about 30 mph (and the engine is ok), it's a radiator problem. Just because it flows water doesn't mean that some of the tubes aren't plugged. Quick way to diagnose: If it overheats at idle, it's a fan or belt problem. If it overheats down the highway, it's a radiator problem. Assuming of course that it's full of water/coolant without any leaks. With the engine warmed up, reach down and feel the radiator core. You should feel a gradual cooling from the upper radiator hose side to the lower radiator hose side. If any areas are cool to the touch, there's no flow in those tubes and those tubes are plugged.

jasonn
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Re: Severe engine overheat = now overheating oil???

Post by jasonn » Mon Jun 29, 2020 10:21 am

6.50camaro wrote:
Mon Jun 29, 2020 9:39 am
Are they mechanical cap tube gauges or eletric with sensor gauges . Did you replace sensors if electric . If mechanical were they the same make and model gauge . Havng works as an HVAC tech for 35 yrs I have seen a lot of variances in supposed calibrated instrumentsbetween differnt brands and models . Just a thought. Dan
Mechanical gauges. ones in car are autometer. Tried a cheap mechanical temp gauge. I still see very similar temps and also can see the temp rise when under load. So I think i can safely rule out temp gauge. Didn't try another oil gauge. but under cold conditons pressure is real normal. And it would still not explain why coolant temp goes up under load so i think i can rule out that gauge also. Almost has to be somehting in engine?
1970 mach with mild 351w
11.60's@117
1970 prostreet fastback with pump gas 427
8.81@154

jasonn
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Re: Severe engine overheat = now overheating oil???

Post by jasonn » Mon Jun 29, 2020 10:45 am

dannobee wrote:
Mon Jun 29, 2020 10:17 am
First thing to do is to wire the water pump/fan switch to a 210 degree snap switch near the upper radiator hose. Wire it into the hot side of the switch so that if you forget to turn on the switch it'll still turn everything on at 210.

If it overheats at anything over about 30 mph (and the engine is ok), it's a radiator problem. Just because it flows water doesn't mean that some of the tubes aren't plugged. Quick way to diagnose: If it overheats at idle, it's a fan or belt problem. If it overheats down the highway, it's a radiator problem. Assuming of course that it's full of water/coolant without any leaks. With the engine warmed up, reach down and feel the radiator core. You should feel a gradual cooling from the upper radiator hose side to the lower radiator hose side. If any areas are cool to the touch, there's no flow in those tubes and those tubes are plugged.
Good idea on the switch. Just wondering, does that backfeed to the switches somehow though?

See that is the thing, I can't really say it is Over heating now.. Just that the temp rises under a load. Seems to me that the cooling system is working as i back off throttle and it immediately starts going down. I guess it IS running hotter than normal, but not over heating if that makes sense. Before the switches incident, it always has run 160 down the road. Maybe 190 on a super hot day sitting running in pits. (this is a nitrous car so wondering how much it will rise when i put the 350 shot to it.) So highest I can now get temp by running it hard for a bit is 210 maybe? then back off and get it to 190. So I dont' THINK that is hot enough to overheat the oil to the point that is losing that much pressure? But u may b correct? Could it possibly be two seperate but related things? Maybe the rad got clogged when it was so hot then flipped switches? But with the super overheated oil took tension out of oil pump spring?? I just ordered a radiator and bungs to try. will have tomorrow. then i can eliminate that.
1970 mach with mild 351w
11.60's@117
1970 prostreet fastback with pump gas 427
8.81@154

jasonn
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Re: Severe engine overheat = now overheating oil???

Post by jasonn » Mon Jun 29, 2020 12:57 pm

Just got off phone with friend of mine who is a close friend of couple other very respected engine builders in area. One is Lance Line who is VERY good. (jasons brother)
Both these builders have seen with an engine overheat, that the cam bearings will squish? Causing excessive clearance?
Thoughts? Would you see something in oil pan if cam bearing issue? I suppose not if it squishes? Guess i haven't heard of this but sounds like a possiblity?
1970 mach with mild 351w
11.60's@117
1970 prostreet fastback with pump gas 427
8.81@154

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Re: Severe engine overheat = now overheating oil???

Post by 427dart » Mon Jun 29, 2020 1:41 pm

Is it mostly a street driven type car? I gladly give up a few HP to run the stock clutch fan and a good engine driven water pump for street use.
Now I do have a 12 inch electric pusher fan hidden low in front of radiator for those summertime melt downs at a long traffic light!

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Re: Severe engine overheat = now overheating oil???

Post by Dan Timberlake » Mon Jun 29, 2020 7:04 pm

The couple of engines I've known that had low oil pressure only after warming up each had excessive bearing clearances.
Like, down to the copper.
The rod bearings often suffer first, so the inspection of a few main bearings might have missed that.

I don't understand the cam bearings "squishing", but my bud's dad had a low oil pressure problem when he most uncharacteristically neglected to check the Sunbeam's cam bearings during a freshen up overhaul.

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Re: Severe engine overheat = now overheating oil???

Post by ProPower engines » Mon Jun 29, 2020 7:42 pm

Does the cam bearing have a groove on the back side of the bearing??? That and 3 feed holes so they can be clocked correctly??
Been using the Dart supplied bearings lately up here and that is how they are made. Have not tried any others so I am guessing the ford uses the same style as the GM block does.

I would cut the oil filter apart and check for bearing material. If the clearances were correct not any extra then really needed it may well be the mains have been abused enough as well as the rods to open up the clearance to drop the oil pressure.
Or as mentioned the oil pump may have shit the bed and the relief is screwed thus reducing oil pressure.

Time to pull the pan and check the lower end for issues.
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Re: Severe engine overheat = now overheating oil???

Post by af2 » Mon Jun 29, 2020 7:48 pm

jasonn wrote:
Mon Jun 29, 2020 12:57 pm
Just got off phone with friend of mine who is a close friend of couple other very respected engine builders in area. One is Lance Line who is VERY good. (jasons brother)
Both these builders have seen with an engine overheat, that the cam bearings will squish? Causing excessive clearance?
Thoughts? Would you see something in oil pan if cam bearing issue? I suppose not if it squishes? Guess i haven't heard of this but sounds like a possiblity?
Tapping out!! WTH?
Every flippin engine I have ever run will gain temperature. You must have had a special one?
Cam Bearing's? No could be the muffler bearings.
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Re: Severe engine overheat = now overheating oil???

Post by mt-engines » Mon Jun 29, 2020 7:51 pm

Same lifters? What's the bore clearance?

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