4eighteener
Well-Known Member
Could it be a reverse rotation water pump?
Overheating on run stand
- Thread starter 4spdragtop
- Start date
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TT5.9mag
Two atmospheres are better than one
Will your fan, shroud combo suck a piece of cardboard to the front of the radiator and hold it there while running? If not you need more airflow. And guessing at the timing is a recipe for disaster when breaking it in, get a light on it instantly after fire up and pull 40 degrees in at 3000rpm like everyone else has said.
Ant
Well-Known Member
You mean for like a marine engine?
Uh oh!
Oh my GAWD. Steve, just try pulling some more timing in it. It's FREE! LOL
I totally agree.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Just asking; you got a direct drive 7-blade fan on it for break-in, in a shroud?
1) Easiest way to get the right timing is to leave the timing lite in the toolbox, reconnect the VA to manifold vacuum, then with the rpm set to 2000, just advance the distributor until the rpm quits rising. If the rpm gets too high, crank it down to where you want it, then either RETARD or advance the timing, until the rpm again reaches max, whichever direction it needs to go. The goal is to get the rpm to rise to a peak, but not begin to drop.
Let the numbers be what they will be; it doesn't matter.
2) At the same time, there should be a temp difference between the hottest part on the stat house, and the bottom of the rad near the WP pick-up, of about 30 degrees. Twenty is not Enough.
3) If you still have overheat, with the pump known to be running in the right direction, and the belt NOT slipping, clamp the bypass hose to force all the water in the block to the stat house, instead of going round and and round inside the block!
4) If, after all that, you still have an overheat situation,
go back to your build sheet and check the skirt-clearance, the ring gaps, and the piston type.
With KB hypers, I followed the directions exactly, and had an overheat that could not be cured. I took the engine apart and increased the ring-factor from 065 to 080, put it back together, and Shazam, the engine ran cool as as a cucumber.
In fact, I had to install a hotter stat, just to get the heat up to where I wanted it.
5) Oh and BTW
At the new ring gaps,
the engine idled down to 550 in gear and pulling itself with a starter gear of 9.44 (manual trans), and with a 292/292/108 cam, and @5* ignition advance ....... with no temperature increase whatsoever.
Whereas in the earlier configuration, there was no way it would run on that tune nor would it even suffer idling at all; the car had to be moving at all times.
I learned a lot in that frustration, and, altho at the time I was not a happy camper, the experience was well worth the learning.
1) Easiest way to get the right timing is to leave the timing lite in the toolbox, reconnect the VA to manifold vacuum, then with the rpm set to 2000, just advance the distributor until the rpm quits rising. If the rpm gets too high, crank it down to where you want it, then either RETARD or advance the timing, until the rpm again reaches max, whichever direction it needs to go. The goal is to get the rpm to rise to a peak, but not begin to drop.
Let the numbers be what they will be; it doesn't matter.
2) At the same time, there should be a temp difference between the hottest part on the stat house, and the bottom of the rad near the WP pick-up, of about 30 degrees. Twenty is not Enough.
3) If you still have overheat, with the pump known to be running in the right direction, and the belt NOT slipping, clamp the bypass hose to force all the water in the block to the stat house, instead of going round and and round inside the block!
4) If, after all that, you still have an overheat situation,
go back to your build sheet and check the skirt-clearance, the ring gaps, and the piston type.
With KB hypers, I followed the directions exactly, and had an overheat that could not be cured. I took the engine apart and increased the ring-factor from 065 to 080, put it back together, and Shazam, the engine ran cool as as a cucumber.
In fact, I had to install a hotter stat, just to get the heat up to where I wanted it.
5) Oh and BTW
At the new ring gaps,
the engine idled down to 550 in gear and pulling itself with a starter gear of 9.44 (manual trans), and with a 292/292/108 cam, and @5* ignition advance ....... with no temperature increase whatsoever.
Whereas in the earlier configuration, there was no way it would run on that tune nor would it even suffer idling at all; the car had to be moving at all times.
I learned a lot in that frustration, and, altho at the time I was not a happy camper, the experience was well worth the learning.
Thanks, I would have to go back and check specs on build, but pistons are 30 over used TRW with new rings. Gaps were all within specs.
Fan/shroud/rad are all oem for ac car.
I know that the small water leaks(stat housing and timing cover bolt) are cured. So I can focus on timing. Damned fool outlet on carter pump still has slight leak. May need to get a new pump...
Thanks again all.
Fan/shroud/rad are all oem for ac car.
I know that the small water leaks(stat housing and timing cover bolt) are cured. So I can focus on timing. Damned fool outlet on carter pump still has slight leak. May need to get a new pump...
Thanks again all.
Newbomb Turk
Well-Known Member
Does your pump have female pipe or are they inverted flare fittings??
A rumor I heard (and now I’m spreading) that these inverted flare fittings are coming with the wrong flare.
I haven’t seen it myself yet but I’m hearing complaints that it’s true.
Thanks Tim, inverted flare. I thought maybe my flare was ****(nicop) so I bought a short pre-made chunk and altho less of a leak, it still leaks and I've snugged the beach down good. I may try a wrap of teflon tape(fuel resistant) to see if that "fixes" it.
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What rpm r u running it at? I usually do 3G but I had the same problem on 1 motor so I slowed it down to 2g and she was a lot better. What r ur ring end gaps? Kim
Place a large box fan on high speed directly in front of the radiator to simulate driving down the road. The smallish fan in the video is at an angle and not only too small but only used for a short period. The fan blade on the water pump is only sufficient at idle speed when stopped. Just my observation.
Thanks guys, no idea on ring gaps, they are within specs tho. Rpm was 2-2800
Yeah the fan in video is pretty lousy but when we broke in the 273 the rad was "good enough". Same rad too.
Yeah the fan in video is pretty lousy but when we broke in the 273 the rad was "good enough". Same rad too.
harrisonm
Well-Known Member
Damn, I hate it when I am wrong. I misread the initial post. I thought Steve was saying that it ran OK the first time but overheated the second time with the thermostat. I was basing all my thoughts along that line.
Hey, who knows whose wrong or right? We're all just guessing, really. I do KNOW 30 degrees is too retarded for break in. That's why I recommended pulling in more timing. He could well have multiple issues. Hard to diagnose over the internet.
Steve I'm not suggesting that the fan is the sole problem here but first off you need to re-create the scenario of driving at say 60mph at roughly 3,000 rpm. You need lots of air flow. The rad your using maybe adequate as well. Again just my 2 cents. Good luck
Inadequate
Wrong head gaskets blocking water flow????
By the way what compression ratio are you running? 10.5:1?
More compression, more heat and hotter fire.
Aged stock flowing radiator may not be up to task?
☆☆☆☆☆
By the way what compression ratio are you running? 10.5:1?
More compression, more heat and hotter fire.
Aged stock flowing radiator may not be up to task?
☆☆☆☆☆
Thanks Casey, I'd have to chk my build notes for compression, but pretty close to 10.5-1. I figured my compression played a part in it.
Head gaskets are correct.
My cheap *** should've bought a box fan.
I'm pretty confident the major contributor as Rusty and others mentioned was too little timing. Play time is Tuesday.
Head gaskets are correct.
My cheap *** should've bought a box fan.
I'm pretty confident the major contributor as Rusty and others mentioned was too little timing. Play time is Tuesday.
Thanks, hopefully do a walk around once I get it straightened out.
How long has it run, Steve?
MopaR&D
Nerd Member
You could just hook the VA up to manifold vacuum to pull in that extra timing if you don't want to add it in with more initial.
Half hour
Hell that beeotch is broke in.
Yeah, I figger as much but would like some more run time on it to be on safe side.
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