Kent Head Gasket Failure?

[-pru-]

I've experienced a fair number of Kent "issues" over the years, but this is a new one for me.

Attended a Test & Tune for the purpose of chasing down a high speed stumble / lack of power.

Began the day thinking I was chasing a spark related issue as car (DB1 w aluminum head) started, idled, and ran fine below 5000 rpm. After warming up and making a few runs, I did a plug inspection and noted Cylinder #1 was fouled. Cleaned plug and swapped out wires as several times over the years I've had a burnt wire arc out against the header which result in the same type of high speed stumble.

Another couple of test runs revealed that new wires did not fix the issue. While letting car cool so I could do another plug check, I recalled the "odd" temp swing I was seeing while warming up the car; car jumped from ~95 to ~195 degrees. I though I just mis-read the dash when it first read ~95 but then it occurred to me to check the radiator (i.e. air pocket?). Sure enough, rad was down ~1/2 gallon of water. Next plug check of Cylinder #1 revealed a wet plug (water dripping off).

Pulled head and gasket (Ford) looks fine; that is, I cannot see any gaps, cuts, tears, etc.

Next step is to ship head to Ivey for check as well as (overdue) service. Hoping that it is just a gasket failure and nothing more.

Anyone have similar experiences / thoughts on the cause? This one has me puzzled as I have never had issues with air pockets in rad or overheating in the 13+ years of running this car.

[BeerBudgetRacing]

pull the plugs and pressurize the cooling system. see if it holds pressure or bleeds water into a cyl.

also rotate the engine while pressurized.

any watér in the oil?

[Garey Guzman]

On my DB6, I had a water leak in my rad that I didn't see, engine temp spiked up so I finished the lap and went to my pit. After a lot of checks, found my aluminum head was warped. I don't recall how the head gasket looked.

[-pru-]

pull the plugs and pressurize the cooling system. see if it holds pressure or bleeds water into a cyl.

also rotate the engine while pressurized.

any watér in the oil?

Great idea. Already pulled head so I'll have to try that next time...Yea, there's water in the oil.

[-pru-]

On my DB6, I had a water leak in my rad that I didn't see, engine temp spiked up so I finished the lap and went to my pit. After a lot of checks, found my aluminum head was warped. I don't recall how the head gasket looked.

Thanks for the feedback. Sounds very similar to my failure but I'm not seeing / finding rad leaks. How did you determine warped head? I don't have access to a surface plate and my "straight edge test" isn't really that precise / showing a warp.

[mark elder]

Most engine shops can do a water pressure test on the head. This will tell you if the head is cracked (I have seen it in the alloy heads).

If it is OK, I would be looking very closely at the block between the water galleries and the #1 bore.

[-pru-]

Most engine shops can do a water pressure test on the head. This will tell you if the head is cracked (I have seen it in the alloy heads).

If it is OK, I would be looking very closely at the block between the water galleries and the #1 bore.

Appreciate the feedback. Honestly, my greatest fear is that block is cracked second only to a warped and/or cracked head...

[Garey Guzman]

Thanks for the feedback. Sounds very similar to my failure but I'm not seeing / finding rad leaks. How did you determine warped head? I don't have access to a surface plate and my "straight edge test" isn't really that precise / showing a warp.

This was several years ago and it was raining when I was trying to repair (and 90 degrees in Alabama ). As I recall, My friend helped me put on a new head gasket and when we restarted, found water coming out of the exhaust. Pulled the plugs and found water going into a cylinder.

[-pru-]

This was several years ago and it was raining when I was trying to repair (and 90 degrees in Alabama ). As I recall, My friend helped me put on a new head gasket and when we restarted, found water coming out of the exhaust. Pulled the plugs and found water going into a cylinder.

Appreciate the follow up. Based on advice, I'm considering putting the engine back together using the spare Ford gasket I have on hand and then doing a leak down / other tests to see where I stand. Also, trying to figure out if I'm looking at a scratch or a crack in cylinder #1 (see attachment).

[Thomas Wirtz]

Try This to see if it's a crack or a scratch.
https://www.amazon.com/Dye-Penetrant.../dp/B00XLW4BRC

Appreciate the follow up. Based on advice, I'm considering putting the engine back together using the spare Ford gasket I have on hand and then doing a leak down / other tests to see where I stand. Also, trying to figure out if I'm looking at a scratch or a crack in cylinder #1 (see attachment).

[DaveW]

Appreciate the follow up. Based on advice, I'm considering putting the engine back together using the spare Ford gasket I have on hand and then doing a leak down / other tests to see where I stand. Also, trying to figure out if I'm looking at a scratch or a crack in cylinder #1 (see attachment).

That, IMO, would be a really odd crack - absolutely straight up and down in the cylinder. probably a bit of sand or something got in there and scratched it while running.

[-pru-]

A big thanks to all that have responded both in private and to the thread. LOTS of great input on how to move forward. At the moment, my plans are as follows:

~ Have head pressure checked / checked for true (FAILED due to pin hole leak in #1 intake runner)

~ If head okay, reinstall w spare Ford gasket and then pressure check cooling system while rotating engine wo plugs
~ If cooling system holds pressure, run engine up to temp and then do leak down / check plugs / cooling system
~ If leak down checks, plugs, and water okay, then swap out oil/filter, water, plugs
~ Run a local event to confirm all okay then pull head for (overdue) service.

[-pru-]

I had the head tested today and the results were not good; pin hole leak in #1 intake runner.

On a positive note, head gasket was okay / head was not warped / remainder of engine seems to be okay / no reason to believe my prep work led to failure.

Head is 6 year old RFD that was freshened (i.e. NO porting or polishing) as part of engine rebuild by Ivey 4 years ago.

Currently investigating multiple replacement options.

Thanks again to all to have responded; I really appreciate all of the comments, suggestions, and offers of assistance.

[mark elder]

Why not get it welded? If you are about to throw away the head, its worth a go. A simple ultrasound test will tell you if here is much metal thickness nearby. Once it is welded and ground back, pressure test again. There is also a filler (epoxy stuff) also made for this job. I would weld it. Save you a fortune.

[-pru-]

Why not get it welded? If you are about to throw away the head, its worth a go. A simple ultrasound test will tell you if here is much metal thickness nearby. Once it is welded and ground back, pressure test again. There is also a filler (epoxy stuff) also made for this job. I would weld it. Save you a fortune.

Thanks. That idea had crossed my mind as well as being suggested by multiple other folks. I will see what the shop has to say when I pick it up; that is, if welding is an option.

[Earley Motorsports]

On my DB6, I had a water leak in my rad that I didn't see, engine temp spiked up so I finished the lap and went to my pit. After a lot of checks, found my aluminum head was warped. I don't recall how the head gasket looked.

I do. The head gasket looked fine if this is the time we were at Barber and we swapped the head out.

[Garey Guzman]

I do. The head gasket looked fine if this is the time we were at Barber and we swapped the head out.

Yup. I didn't want to mention your name and bring back that haunting memory. I think it was about 90° in the rain when we were working!

And as I saw a lot, Thanks for your help!

[-pru-]

Spoke to the folks at RFD. They are open to trying to repair the head via welding or epoxy (they have a great results using "Splash Zone"). Turn around roughly 7-10 days. Cost estimate (including refresh) was very reasonable. I'll be sending it out shortly...

[-pru-]

Photo of the hole on lower portion of right yellow mark. Hard to see in photo but visible to eye.

[-pru-]

Good news - head back from RFD; hole welded / repair blended / full valve job. All in costs just under 1/2 of new. Installed head and adjusted valves (when cold and warm). No leaks / ran great!

Not so good (but not totally unexpected) news - water in oil. Will let drain overnight and refill with “low hour” oil before swapping out for the “expensive stuff”. Planning a filter inspection as well...

Thanks again for all of the input!