Head to Block Parallel flow vs series flow cooling

[Barth C.]

Re: Head to Block Parallel flow vs series flow cooling

The kit I borrowed has no adapters.

I also got a "loaner" kit from Autozone. No different except it had a "truck" adapter which was significantly different.

[Joe L.]

Re: Head to Block Parallel flow vs series flow cooling

I'm going back and verifying everything is working properly.

I friend suggested I do a cooling system pressure check to determine if I have a leak inside the engine. I borrowed a Stant cooling system pressure tester but unfortunately it does not properly fit the DeWitt radiator neck which appears slightly narrower than OEM.

Has anyone else experience this issue with DeWitt radiators. Or can anyone recommend another method of pressure testing the cooling system without attaching a pump in place of the radiator cap?

thanks

Barth-----


If an RC-15 radiator cap or equivalent thereof works OK on the radiator, then I can't see any reason why the proper adapter for the pressure tester will not work.

[Gene M.]

Re: Head to Block Parallel flow vs series flow cooling

Your head gasket looks way too big for the bore size. There is not much between the cylinders for sealing compared to what you would have if you use the proper size gasket. Also the head surface adjacent to the water port in the photo looks very pitted.

[Edward J.]

Re: Head to Block Parallel flow vs series flow cooling

Barth, with the engine running take a infra gun and check the temp. of the radiator from top to bottom and check the efficiency of the radiator cooling capability, or even the upper and lower hoses. from what your explaining of the slow temp. rise it sounds like a blockage in radiator. Have you read John H. article in this months restorer. gives a detail of the corvette cooling systems workings.

[Barth C.]

Re: Head to Block Parallel flow vs series flow cooling

Regarding the slow overheating problem I've been having with this 66 425 Hp L72 427 since rebuild, I double checked all the usual reasons given in the archives for overheating. Since everything seemed OK I pulled the engine and tore it down to investigate further.

#5 rod bearings had spun on the crank journal. The rod bearings all had obvious damage. The main bearings and cam bearings have very little wear.

My initial reaction was that the overheating problem led to the rod bearing failure or that the bearings had been starved of oil. BUt all the oil passages are free of obstructions and I had primed the oil pump before initial start and always monitored oil pressure when running.

Is it possible a problem with the rod bearings or rod big ends or rod installation is what was causing the overheating and not the other way around?

[Timothy B.]

Re: Head to Block Parallel flow vs series flow cooling

Barth,

That's terrible news..the rod bearings are oiled through the crankshaft so if the main bearings look OK check closely at the crankshaft holes that allow oil to pass and double check the size of the rod journals and rod bearings on the non damaged rods.

Could be a few of the rod journals were checked and someone called it good when actually there were some tight journals with the rod bearing size selected, are these rod bearings oversize? Did anyone replace the rods and were they checked for round?

Do you still have the package with the part # to double check size and is the crankshaft a GM part?

[Duke W.]

Re: Head to Block Parallel flow vs series flow cooling

I doubt if overheating damaged the rod bearings. The problem is probably in the oil system.

1965 and '66 big blocks used a camshaft with a groove in the rear journal and a three-hole bearing. The F-M replacement cam does not have the groove, so you have to have it machined, and, of course, use the proper three hole bearing.

Several cases have been reported in the past of using the '67-up cam without the rear journal groove and single hole bearing in pre-'67 engines. It usually results in no oil to the valvetrain, but I suppose if the engine is run long enough bearing damage could occur.

Duke

[Larry B.]

Re: Head to Block Parallel flow vs series flow cooling

Detonation could cause heating and bearing problems and #5 is prone to detonation. You never said it pinged tho. I'm sure you don't have a oil cooler in the radiator so oil temp won't heat the water.A bearing spinning just happened cause in a mile it could spin ,break the rod and fly out the side. I'm sure the bearing clearance wasn't right. The rods needed reconditioning ,side clearance,or crank needed work,or standard bearings on a 10 under crank all of which should have been caught on assembly.The rear cam bearing ,slot in the cam can shut the oil off to the valve train but that would just put more oil to the bottom end. What does the cam lobes look like. The main bearings could look good and the rods bad because the rods are last to get oil. Tell me your not using a $1.99 oil filter like a Fram as they won't flow the volume of oil needed .The heating could be head gasket .We can cure the heating with a little extra plumbing if you are not a purist cause it does show.

[Domenic T.]

Re: Head to Block Parallel flow vs series flow cooling

No one talked about the schroud seals!
The seals for the schroud are there so the whole radiator gets used. without the seals, or bad seals, the air won't be directed thru all the tubes and you will not get proper cooling at any speed.
When I installed my schroud in the 70's there was a warning in the box addressing the air flow that would not go thru the radiator without properly sealing the schroud. They were right, and the radiator is also at a angle and the air needs to be captured by the schroud & seals to direct the air thru ALL the radiator and limit the air that escapes around the schroud.

DOM