| Snakebit |
04-06-2009 12:02 PM |
Engine only warms up to 140
ERA FIA 302 Small block Ford stroked to 331 with Webers dual inlet manifold with Robert Shaw 180 inline thermostat. Test drive on Sunday temp guage only went up to 140. Partially blocked radiator with a piece of card board and it went up to 160. Running March street pulleys, not under drive. Any sugestions?
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| madmaxx |
04-06-2009 12:07 PM |
Your temperature gauge is wrong, your thermostat is defective. Excellent find, anything below 180f and you are wearing your engine out.
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| vettestr |
04-06-2009 12:30 PM |
look for the t-stat being bypassed with heater hose or the plumbing configuration somehow. Easy test is feel top rad hose from cold start up, is temp cold till t-stat begins to open or does temp come up before hand. With a cold system you should be able to feel where heat is coming from if you consider system as 2 sides. 2 sides are those on each side of t-stat and should be that cut n dried.
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| zimmy |
04-06-2009 12:49 PM |
Quote:
Originally Posted by madmaxx
(Post 937555)
Excellent find, anything below 180f and you are wearing your engine out.
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What does this mean? As long as the oil pressure is up and correct, why would a colder engine "wear out"? Actually you'll get better performance from a cooler engine. |
| patrickt |
04-06-2009 12:58 PM |
Quote:
Originally Posted by zimmy
(Post 937571)
What does this mean? As long as the oil pressure is up and correct, why would a colder engine "wear out"? Actually you'll get better performance from a cooler engine.
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You're not going to wear your engine out, but I do bet that your gauge is wrong. Get one of the little infrared pyrometers at Lowes or Home Depot or the like (they're also handy for checking temperatures across your tires). Then you just point and click at different spots on your cooling system to see what the temperatures are -- that will give you an indication as to whether your gauge is really off or not.
Clever Afterthought -- If you really were wearing your engine out, then the increased friction would create more heat, thus stopping the wear out process by getting your temperatures up where they belong. |
| Wayne Maybury |
04-06-2009 01:02 PM |
Quote:
Originally Posted by zimmy
(Post 937571)
What does this mean? As long as the oil pressure is up and correct, why would a colder engine "wear out"? Actually you'll get better performance from a cooler engine.
|
The engine is designed and probably built to run at 180 to 190 degrees. Operating it for an extended period of time at a temp well below 180 means that the tolerances are not correct. For example the pistons are aluminum and the cylinders are steel. The 2 expand at different rates with the change in temperature but are machined to operate at 180 not 140 degrees.
As a rule of thumb, your engine sustains more wear in the first 5 minutes of operation than it does in xxx miles (sorry, I can't remember the number of miles).
Wayne |
| patrickt |
04-06-2009 01:04 PM |
Just Remember...
... that 99% of the owners around here either die or sell their Cobra before they put 20,000 miles on it.:cool:
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| blykins |
04-06-2009 01:44 PM |
The direct temperature may not wear it out, but driving it at that temperature doesn't give the engine a chance to get hot enough to get all of the condensation out of the oil.
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| patrickt |
04-06-2009 01:45 PM |
Quote:
Originally Posted by blykins
(Post 937592)
The direct temperature may not wear it out, but driving it at that temperature doesn't give the engine a chance to get hot enough to get all of the condensation out of the oil.
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Just put some cat litter in the oil --- it'll dry it right out. |
| blykins |
04-06-2009 01:47 PM |
Or a chamois in the lifter galley.
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| patrickt |
04-06-2009 01:49 PM |
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| twobjshelbys |
04-06-2009 01:49 PM |
Quote:
Originally Posted by Wayne Maybury
(Post 937576)
The engine is designed and probably built to run at 180 to 190 degrees. Operating it for an extended period of time at a temp well below 180 means that the tolerances are not correct. For example the pistons are aluminum and the cylinders are steel. The 2 expand at different rates with the change in temperature but are machined to operate at 180 not 140 degrees.
As a rule of thumb, your engine sustains more wear in the first 5 minutes of operation than it does in xxx miles (sorry, I can't remember the number of miles).
Wayne
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I had to replace my thermostat and the closest engine catalog listed a 195. Mine was 180. Any advantage or disadvantage in going higher? |
| blykins |
04-06-2009 01:54 PM |
Old Vince from Sham-Wow got thrown in the pokey not too long ago for beating up a prostitute in Florida. I guess the fame went to his head.
*Clearing throat* Sorry....back to the topic.
The disadvantage to running a 195 over a 180° thermostat is the engine will run hotter. It doesn't say where you're located, but if you're somewhere like Arizona, that could be a bad thing as it may allow the temperature to creep up a little higher than normal.
Thermostats are easy to find....I wouldn't necessarily look in an engine catalog for one. I'd just go to Autozone and tell them what you want.
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| madmaxx |
04-06-2009 02:04 PM |
Thermostat just opens and a predetermined temperature, if you car will overheat with a 195 thermostat it will overheat with a 160 F thermostat, it will just take 5 minutes longer. Performance unlimited has an excellent write-up and corresponding graph. The problem with running below 180f is the cylinder walls stay cool but the pistons reach temperature and voila, excess cylinder wear wall. The optimium temp is 200F but the increased life between 180F and 200F is nominal.
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| madmaxx |
04-06-2009 02:07 PM |
Clever Afterthought -- If you really were wearing your engine out, then the increased friction would create more heat, thus stopping the wear out process by getting your temperatures up where they belong.
This would be correct if you had a "perfectly" sized cooling system. I assume like most yours is oversized to handle the variety of condition you drive in.
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| vettestr |
04-06-2009 05:13 PM |
Not so much that you are wearing things out as much as everything working harder. Oil is thicker so does not flow as well or evap contaminates and moisture off. The hyd. lifters want to pump up at high revs a little easier . A cold engine is missing any safety net that an up to temp engine might have.
PS>>>> Boat engines that are run cold do wear bores and rings etc.... at a higher rate than those will a good working cooling systems. I saw this working in boat yards.
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| Snakebit |
04-06-2009 05:46 PM |
I am not running any heater hose or bypass hose. If you sit and let it idle it will go up to 180 to 200. I checked the upper hose with a pyro meter and the temp was within 5 degrees. Should I try a higher thermostat or switch to an under drive pulley on the water pump? The water pump is an Edlebrock Victor pump. Here everyone is having an overheating problem and I am just the opposite!
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| madmaxx |
04-06-2009 05:55 PM |
If it is plumbed correctly the thermostat should modulate to maintain the 180f temperature. I would replace the thermostat first. They cost about $4.00.
vettst.
The lower priced marine engines without closed cooling system run 140f thermostats, if not the salt would plate out on the engine and the passengers would close off. Not all engines are used in freshwater.
If the engine has a closed loop cooling system it should operate 200f.
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| vettestr |
04-06-2009 06:56 PM |
Snake,
Your gauge is accurate as now verified and engine is not staying at T-stat value when running down the road.
Lets go step by step on a few tests. If you start a cold engine and you let her idle it heats up. When gauge or pyro shows about 120 or 130 shot the T-stat housing with pyro to verify. Now shoot top rad hose a few inches from the rad. What does it read on temp? If it shows something close to engine or the 120/30 on gauge your T-stat is already open or is being bypassed somehow.
If engine heats up to about 160 on idle but rad temp on a cold start up is still outside air temp the t-stat is closed and should be able to monitor the temps and see her open and heat coolant in the rad. T-stat should close now that cold rad coolant has entered engine and flow stop. With cooling fans running and t-stat closed you should see rad temps drop until cycle of t-stat opening and closing starts again but fans must be on to see the temps vary.
What happens when you watch this with your pyro?
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| vettestr |
04-06-2009 07:21 PM |
Hello Mad,
Boats are as bad as Cobras for ways they get modified or FIXED over the years! In a very basic overview of a lot of the systems I saw (maybe to basic a description) they were radiators in a box.
Fresh lake water was plumbed in and then out of the box around the rad. so an unlimited cold water supply. The engine or engines would swing wildly on temps as t-stat opened and closed if the AUTOMOTIVE t-stat was used and I saw a lot of that. The marine t-stats had holes in them to reduce this swing but as people figured this out they would drill holes in a car t-stat for pennies on the dollar. Problem was that hole corroded bigger or Joe FixIt only had a big or bigger drill bit at that moment. Many T-stats just got taken out all together because what the heck cold is better than hot.. right.
When fixed properly with the right parts they ran a little cool but ran well. Many of these boats were a work of art and engineered to perfection. OTHERS.... well???
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