933 Pressure Relief - just pulled off seat at 5lbs.

The old 933 runs again!! Had some difficulty with the fuel bleeding but resolved that. While turning over, the starter wanted to disengage once it fired but the engine did not fully start. I used a small sniff of ether and it ran. I ran it for about 1-1/2 hours as directed in the manual for running in the rings. Engine ran well. NOTE: RADIATOR CAP LOOSE.

Problem that still exists: Engine will blow white smoke if radiator cap is tight. After running up and down my drive one pass I stopped and checked for leaks and tightened the radiator cap as it was not tight. After about 45 seconds the engine started blowing white smoke appeared out of the exhaust. I immediately opened the cap and back to running perfect. I continued on my brake in time and checked it one more time before putting it back into the shop, same result.

Synopsis of work completed to date:
Head removed and reconditioned, surfaced and magna-fluxed.
New head gasket and seals along with all new brass ferrels. Installed with Permatex 300 coated both sides (not on fire ring)
Pre comb seals replaced
Number 2 liner and rings replaced
All liners removed reinstalled w new o-ring seals as well as new brass seal ring
Water jacket of block cleaned
4 new cylinder head studs replaced

I will be retorqueing the head this morning
I removed the pressure release valve and cleaned last night
What would be my procedure for pinpointing the location of the combustion gasses getting into the coolant?

Pressurize the cooling system with the engine stopped. It would maybe be best to do it with engine cold and then with it warmed up.

You may need to take off the exhaust manifold to check which one the coolant is coming out of. I’m thinking it’ll be clean. May be able to do the same with an infrared “heat gun” thermometer after it gets hot. Coolest one is probably it but that could be confounded by other factors.

ALWAYS TURN ENGINE OVER BY HAND 2 turns or more before starting it after you pressurize the cooling system. You don’t want to bend a connecting rod.

I’m thinking you might have a crack in an exhaust port/runner, but it might be a leak in the cylinder area if you’re getting bubbles in the radiator as well as the white smoke. If no bubbles, I would try a dose of block sealer.

In thinking though the process of identifying which cylinder is leaking.....
Remove injector
insert rubber tipped air chuck set for 6 lbs pressure
Pressurize cylinder at TDC
Listen for air leak

Is there a specific tool for this? Would a standard cylinder pressure tester thread into the injector retainer and hold pressure against the v-seat of the injector?

Only OUTSIDE EVIDENCE of leakage is a small series of bubbles at the base of the glow plug next to the o-ring of the injector retainer. Number one cylinder

Pressurizing the cylinders one at a time is a great plan.

However you should use as much air pressure as your shop compressor can build. Note it’s a good idea to lock brakes and put transmission in high gear to prevent the engine turning if you don’t have it exactly on TDC (if it turns and you do have it exactly on TDC mark, that may be opening up another can of worms!)

In any event, lock it down and disengage the hand clutch to allow you to position the engine at each TDC and then engage clutch to hold it there.

"ccjersey" wrote:

Pressurizing the cylinders one at a time is a great plan.

However you should use as much air pressure as your shop compressor can build. Note it’s a good idea to lock brakes and put transmission in high gear to prevent the engine turning if you don’t have it exactly on TDC (if it turns and you do have it exactly on TDC mark, that may be opening up another can of worms!)

In any event, lock it down and disengage the hand clutch to allow you to position the engine at each TDC and then engage clutch to hold it there.

Can you direct me to a tool that would be used to attach to the precombustion chamber to hold the air in?

Cat offers a 1P5569 drilled plug that replaces the nozzle for air testing.
The injector body thread is a 9/16-18 tpi, same as a 3/8 JIC nut
The seat taper in the injector body is 60 degree, the JIC is 37 degree
It is possible to make up a connection even though the seat angle and tube sizes are different
or
Use a piece of old 1/4" injection pump line with ferrule.

Retorque went well. Ran for about one hour with cap on radiator without the white smoke. At start up there was considerable white smoke but within about 30 seconds it leveled out and ran perfect the rest of the time. I do have a video of the precombustion / glow plugs with a bit of a bubbling action that I will post tonight. What is the proper torque for the retaining nut for the injectors. Wondering if I torqued them correctly.

105 ft lbs on the nozzle retainers.

"rehpig" wrote:

Can you direct me to a tool that would be used to attach to the precombustion chamber to hold the air in?

I have found that a tapered rubber tip that comes on an automotive compression gauge will fit on 1/4" pipe on a blow gun will seal and hold against air pressure for leak down testing on Cat engines with capsule type injection valves.