CJ3b....That is what the vin tag says.

[inVERt'D]

Ha! You just dated yourself old man...

I got an early start

[jonah]

Well, I finally got it together and took it out for a quick run. Was running pretty good, definitely more power than the 225. Running at 190ish on flat ground. However, point it at the slightest hill and the temp starts rising, 200, 210, 215. Stop and idle and the temp comes down. Figure the cooling system is clogged up, there was evidence of bars leaks in the motor when I changed the freeze plugs. It was rinsed pretty good when I did the plugs but...

Flushed the system again, no change. Then noticed the coolant in the radiator was foaming, looks like a head gasket. Compression test and leak down test both looked good so I tore it apart. Everything looked really clean inside. Took the heads to the machine shop, the machinist said he could see leaking between the end cylinders and the water passages. The heads were not warped but he took 0.005" off to get the surface flat. The machinist recommended sanding the block with a hard sanding block and 220 grit paper. I had never heard of hand surfacing a block deck before, but I used to hand grind litho stones for printing within a few thousands so I gave it a go. It cleaned up quick and checking with a straight edge and feeler gauge of 0.0015 I couldn't find a low spot. Can't wait to get it going again.

[Tumbleweed13]

Good to see Opie got to stretch his legs a bit. Hope this salves all your issues. When your ready for a Cleghorn shakedown run, let me know.

[aw12345]

Good to see Opie got to stretch his legs a bit. Hope this salves all your issues. When your ready for a Cleghorn shakedown run, let me know.

I'll tag along for that, always up for a Cleghorn quicky

[jonah]

Heads and intake reinstalled. Should be done sometime tomorrow. If I do a shake down next weekend I will post something up!

[jonah]

I am having some serious cooling problems with my new to me motor. I am running a two row aluminum radiator, dual electric fans, new water pump, cap and thermostat. I have flushed the motor and rad. It will drive around town with no problems, it will sit right at 180 all the time. Yesterday I went up to Cleghorn with Kevin and the whole drive from Huntington Beach doing 60 (2800 rpm) on the freeway it was right at 180 until I started climbing the grade after the 15-215 merge a couple miles before Cleghorn. By the time I hit the Cleghorn exit it had climbed to 215. I let it cool down and started up the trail. I was at 220 by the time we hit the powerline tower play area. We parked it nose up and burped the system, a little air came out and we headed up again. Problem persisted and we turned back. Kevin thinks that my fans are too weak and I agree, but the fact that it was getting hot at highway speeds (granted on a grade) makes me think my radiator isn't working. I ran this set up with my old 225 and it would occasionally get a little warm on hard offroad climbs it never warmed up on the freeway. The new motor still a buick v6 but it is built up a bit more and a bigger bore, 252 cu in. It is probably making 50 more hp if I had to guess.

Open to ideas, fuel to air runs at 14.7 cruising on the freeway and 12.5-13 under full load. Total timing with vac advance disconnected is set at 24, with vac connected it hits 36. I did a block check and it didn't show any combustion leaks, I can see water flowing in the radiator. It isn't spitting out the cap when it gets up to 230. The recovery can seems to be working correctly. Kevin loaned me an extra pusher fan that I am going to try and see if a little extra air flow will help. I think it will since my fans feel a lot weaker than the ones Kevin is running (of course he is pushing 400 hp . But I still feel like the radiator is partially plugged or something, although when I flushed it the water seemed to be moving well.

Help, I am going crazy!

[inVERt'D]

Sorry to hear about your cooling problems. Besides the obvious thoughts like a bad thermostat, here are a few that come to mind in no particular order. Reverse rotation water pump? Impeller broken off of the WP shaft (has happened to me). Is your ignition timing retarded (no offense)? Is the motor broken in yet? Radiator hoses not collapsing?


EDIT: started posting before you posted above. One more thing: did you bleed the air out of the cooling system?

EDIT: okay you answered most of my questions. It does sound like your radiator may be inadequate. More HP generally equals more heat.

[jonah]

Timing may be a bit retarded but not my much, lol. My lower radiator hose doesn't have a spring but I haven't checked for a collapse but this happens at low rpm climbing too so I don't think it is that. Bad pump out of the box maybe? I am confident we had the air out, plus it doesn't jump around like when there are air pockets. Over an hour straight on the freeway and never moved off 180 heading up (until the hill of course).

Radiator seems like the most likely culprit but this radiator should easily do the job unless there is something wrong with it.

[inVERt'D]

No chance it's running lean on the climbs?

When you say two-row does it have two wide rows, or is it standard 2-row width? I used to have a Griffin 2-row that was as wide as a 4-row, but flowed more.

If your 225 was marginally cooled, and your 231/ 252 is inadequately cooled, and the radiator is the common component, I'm thinking your radiator is either too small, has insufficient airflow, or like you said, has something wrong with it.

[jonah]

The radiator is two wide cores, the core thickness is 2.25". Just checked the timing again runs at 28 degrees btdc at 2500 rpm with vac advance attached. I am running a wideband 02 guage on the dash, I am not seeing any lean readings and the plugs look good.

i have read that the wider core radiators like a higher flow. Some people overdrive the water pump to increase flow. I guess it causes more turbulence in the core that helps heat transfer.

I should also mention that I ran half of holcomb with the thermostat out and it acted the same, so I think that rules out thermostat issues.

[alittleoff]

First off, I'm no expert so I don't know where to start, but something to kick around. Do the fans operate at freeway speed and/or in town speed ? At freeway speed it has good air flow so the RPM of the water pump is ok, but at off-road engine RPM, is to high for the air flow ? Could the water pump push coolant too fast through the radiator and not allow sufficient cooling ? Is 4 narrower cores the same as 2 wider cores in effective cooling ? Would a full shroud too close to the back of the radiator be of concern ?

Steve

[jonah]

The fans do stay on at freeway and in town speed, they are set up to come on at 180 and off at 165. The only rpm thing I have noticed that when hot the quickest way to cool it down (outside of coasting down a large hill) is to bring it up to 1200 rpm while sitting. But on offroad climbs in low range it still heats up whether I run it at 1200 or 4000 rpm. On the freeway I tried a few different ways. Once I stayed behind a semi doing 40 in third gear and high revs, got hot (220). Then I tried 55 in fourth gear (1:1) and it got hot a little slower (only hit 205), then I did a fourth gear pull at 65 (3200 rpm) and it got hot a little more slowly (got to 197). Yes I went up and down the grade from cleghorn to the summit inn a bunch of times, that is how bad I want to figure this out, lol!

Not sure on 2 wide tubes vs 4 narrow tubes. I have read that the fins per inch is the most important thing, but I am not sure what is the ideal. I believe more is better up to a point where the airflow gets restricted.

[RAT]

Hey Jonah, after reading all the way through this, I suspect it may be the pump. At highway speed the pump is turning fast enough to provide adequate flow but at idling and climbing speed it is not. I doubt if it's timing. Does not fit the symptom. Radiator might be partially clogged, but if it's new I would say meh, probably not. You may need to replace it or put a smaller pulley on the one you have. And as far as the fans are concerned, maybe they're not up to the task. But normally if you aren't moving enough air acrss the radiator it should be running hot under most conditions.

[jonah]

I feel like it has to be pump or radiator. The radiator was new 2 1/2 years ago but this motor was expelling a bunch of crud at first but I flushed both the motor and rad a few times. The pump is new but you never know. I am about to pull it apart and take a look at the pump. The fans may be marginal but at highway speed it shouldn't matter.

[RAT]

I meant to ask. What is the dilution on your coolant? 50/50?