Head Gasket leak?

[JSM]

Dave keep the gauge. Looks great!

You could always go grab the n47 block from the maxima. You got most of the work done already and we’ve been rain free for weeks now. 

[Dave WM]

I grabbed that a while ago, installed it today, new head gasket, all buttoned up but I was to wasted from working in the heat that I decided to wait till next week to fire it up. I did adjust the valves and made sure my pump was still working (so the fuel pump relay and all the wiring was still hooked up.

I used my cherry picker to help with removing not only the head but the manifolds as well (did I mention it was hot today? prob feels like temp in the low 100's true air temp was in the upper 90's).

The cherry picker is proving its worth. I also made a wood timing chain jam tool, worked great! cold compression was about 165 on all but #6 which was about 155. I did not notice any thing valve issues on that one, but will check again after running it some.

If this does not fix it I will just tear down the motor an take it to a machine shop for evaluation of the block and heads, use which ever one looks better. I would like to do a full engine build anyway.

[Dave WM]

same results with the MN47 head, even burped up a bunch of water before the Tstat opened (although at this point I think that is unrelated). chem still turns green, no other symptoms of a problem. I hot checked the compression, 175psi on the nose for all cylinders, even forgot to open the throttle. (checked again a little over 180 on all with throttle held open)

Anyway I am guessing I have two good heads and one bad block, but that is a guess. I am saying this since changing the head had NO effect on the chem test. So I guess my next course of action will be to pull the engine apart and take the block off to be tested. I have some pics of the cylinders I will share soon, some odd looking stuff at least to me. I took them between head changes.

Edited June 5, 2019 by Dave WM
tested with throttle open

[Dave WM]

The guy at the machine shop really thinks its more likely just a bad sealing head. So the plan will be to bring it all to him (block and both heads) and let him do his thing. check the block and refinish the better of the two heads.

[Dave WM]

putting this link is so I can find it again

Amtex Cylinder Head and Casting, 1412 N 22nd Street, Tampa.  (813) 248-9429

http://www.amtexcastingrepair.com/?fbclid=IwAR2bOxuzAdbRoqd-MhHtBmvAwtvoy_0PXxx34TCJLai-bz6K_adTjzONZCY

 

 

[JSM]

Did you check out revmaster off of Kirkman and Old Wintergarden rd?

Tampa is a hike. Make sure you check the 3 LKQ JY out that way in Tampa!

[Dave WM]

I think I am going to take the block to rev master, do a hot tank and magna flux before doing anything else. The Tampa guy seems to really know about L28 heads.

Time for your turbo to take a ride on the test stand!

[240260280]

Sometimes leak happens in timing cover or thermostat housing bolts.  Maybe drain the coolant and pressurize at the rad cap with 13 psi of air and listen?

[Dave WM]

5 minutes ago, 240260280 said:

Sometimes leak happens in timing cover or thermostat housing bolts.  Maybe drain the coolant and pressurize at the rad cap with 13 psi of air and listen?

there is no apparent loss of coolant, so the leak you refer is for an exhaust gas to water leak? I did pressurize to about 15psi, is dropped down in about 15 min, but I think that is more my old pressure tester not holding than a leak. I did the same to my 75 which does NOT have the issue, same result, pressure drop off about the same amount of time.

I carefully cleaned the under side of the orig head, can see NO defects around the combustion chamber.

seems to me in order to get gasses into the coolant, It would have to be

1. cylinder wall to coolant passage block crack
2. cylinder head to coolant passage crack (no evidence of by close visual exam).
3. fire ring seal fail (warped head incorrect clamping pressure).
4. corrosion from combustion chamber to coolant hole (looks fine to me, no corrosion) allowing gas to seep under fire ring.

there are NO signs of water in oil pan, or under oil filler cap.

I don't see the oil slick in the rad but there is something floating about, but does not look like an oil film. I figure is just residual trash but could be wrong.

The chem test passes until the water begins to flow thru the T stat. then a very slight change to green will show after several pulls on the rad top. The tester is well away from the actual water (no contamination of water to test fluid).

I rechecked the orig head, I found some 1" bar stock alum to use as a straight edge about 2 ft long ( I had been using a 3ft metal ruler). with the bar stock turned up on its edge I was not able to get even a .0015 between any 3 cylinders, so I am pretty sure its not a warpage issue. this was checked longwise and diagonal two ways.

the surface as very clean, not perfect, but clean enough to see the orig machining marks, and marks made by the OE gasket digging in (very small divots).

I would assume that if the fire rings seal and the alum combustion chamber shows NO crack, then it has to be the block. But that is my in experienced guessing.

 

 

 

[Dave WM]

I still need to post up some pics that maybe clues to exp eyes. there was def something going on from the staining I say on the cylinder walls. I looked like the fire ring seal was not perfect. I will post up as soon as I get the darn cameral to work.

[Zed Head]

Any chance there's something off with clamping force?  Bad bolts, bad threads, funky torque wrench.   Are the fire rings crushed flat, like they should be?

You're putting a lot of faith in that "chem test".  Test products don't sell well unless they show results.

[Dave WM]

1 hour ago, Zed Head said:

Any chance there's something off with clamping force?  Bad bolts, bad threads, funky torque wrench.   Are the fire rings crushed flat, like they should be?

You're putting a lot of faith in that "chem test".  Test products don't sell well unless they show results.

I know that chem test is the only thing showing a problem... but it shows the no change in color on my other engine after it warms up and is flowing too. If it were not for that I would be more skeptical about it. all the bolts went in fine, I used a cheap HF torque wrench. The other thing to consider is the orig head came off with an OE head gasket that looked perfect, no issue at all on it. So I was hoping it would have been a smoking gun. The change to a different head was kind of "a lets see what happens" rather than a "I am pretty sure this is it". It was easy to do so I took a shot.

This is a 1st for me (pulling heads) so I may have missed something or could be doing something completely wrong, live and learn.

Edited June 6, 2019 by Dave WM