I did a leak down test on my engine because the car slowed up a bit with out explanation, about a tenth. No mis-fires or any thing obvious just slower . It is a 440 topped with trick flow 270 heads. What I found was cylinder #1 and #8 have 30-35% leak down #4 has 15%. The rest of them are less than 5%. The air is escaping passed the exhaust valve. Tried tapping the valve with mallet and and adding a shot of oil with no change. I'm surprised with this as the engine only has 45 runs on it. Has anyone seen an issue like this with the trick flow heads? I don't have the heads off the engine yet, that is going to be my project this weekend so I can get a close up inspection of what is actually going on with the valves.

Did you back off the rockers on those cylinders for the test ?

You said the car slowed down, so I suspect the leakage wasn’t present initially.

Until the heads are removed and inspected it’s all speculation, but my guess is the valves got tagged and are now tweaked.

Yes, I removed the rocker assemblies altogether.

Yes , you are correct there was no leakage when the engine was assembled

That is what I am suspecting too. But why only the three valves? If I remember There was .090" piston to valve clearance. I used the clay method of checking clearance.

Those valves might have gotten a little hang time and made light contact.

When my timing set came apart all the valves held water but when I pulled them 12 were bent. 4 survived. All the pistons had tiny eyebrows.


The tiny tolerances stacking up can make all the difference.

I’ve inspected a few TF heads that had pretty minimal guide clearance.
If yours are like that, it might have pinched the valve a bit and allowed contact.

At high rpm, it doesn’t take much contact at all to tweak a hot exhaust valve.

What rpm, and what valve spring?

You wouldn’t be the first person to get fooled by that.

Please expound on the issue - Thx

Engine assembler used clay, came up with .060” intake clearance.
Breaks new Ferrea 6000 intake valve in burnout box of first pass.
Post blow up inspection reveals all intake valves making hard contact with pistons

I mock everything back up and manually measure with checking springs, with lash set.
I get “zero” clearance.
He kept good notes during assembly. The notes showed .060 , checked with clay.

I only use clay to check for radial clearance in the pocket.

I watched this one a few weeks ago, and he goes over how the valve is not always where people think it is relative to the piston when it's near the top of the cylinder.

https://youtu.be/o_Oln_ik0vw?si=H-vxgkMQwL59kqsb

Did you check all 16 valves for piston to valve clearances and valve to block clearances with checking springs? I do

Then that guy was an idiot, he probably did it with a hydraulic lifter or something stupid like that.
I use both methods for different reasons and have run engines twice in the .050's(using checking springs) and we never hurt a thing. That being said I am not suggesting everyone go out and do it for the reasons above.

If the heads are off you should already know why and what happened. There should be contact marks and bent valves, next would be look at top of valves for x pattern wear for valve float, then stem clearance.

My point being .090 with clay would be fine(clay always shows more) ., but now that I read the post he says I think it was .090

And yes after typing this I can see where .060 with clay could be trouble. Takes me a second. Clay usually adds about .030 or more. (deflection in valvetrain).

If the rocker shafts are off put a straightedge across the valve stems to see if they are all the same height?

Greg how much did you pick up changing from the 240s to the 270s?

The car went from 10.7s to 10.4s and 124mph to 128mph with just the cylinder head change. I am quite happy with the results.

I got the heads off the engine and checked the valves and to my surprise the valves are not bent but the seats are deformed on the high leakage cylinders #1, 8, and 4. I can see light behind the valve. When checked with bluing dye there is a gap on the seat. I have no idea what could have caused this , I'm going to call trick flow tomorrow and see what they have to say.

Time to put that warranty to the test.

Thats great, it sounds like you hit your goal then. Did you keep the same carb and intake and port it or did you make a change?

I changed the manifold to the matching trick flow max wedge port manifold and used the same carb. I added an adaptor / spacer under the carb.

Has a plan for the repair been decided on yet?

How short of a adapter/spacer were you able to find? I am looking for this solution right now, due to limited clearance... I have a scoop, but not very tall. So I am concerned about my options in this scenario. thanks in advance.

That's a nice pickup. Whats the rest of the engine combo?

I called Trick Flow customer service. I was asked to write an email letter explaining my issue with the heads, the test I've done and to send pictures of the heads, engine and car. Trick flow wanted see and inspect the heads, they sent call tags for the heads. The heads are now in their possession and I am waiting on the verdict. Their customer service has been reasonable and so far helpful.

The spacer I'm using came from AR Engineering, I bought it from Brad H here on Moparts, he was kind enough to sell me his because AR Engineering doesn't make it any more. Its 1/2 inch tall and has a taper to the bores kind of like a shear plate. It seems to work well. My carburetor has a dual pattern base plate.

It's a .030 over , stock stroke 440. 11.7 to 1 cr. 260/264 Hughes engine cam. 1.6 rockers. 2" hooker headers .

In Response To: "Re: trick flow head exhaust valve leak"
gregcharger72
The spacer I'm using came from AR Engineering, I bought it from Brad H here on Moparts, he was kind enough to sell me his because AR Engineering doesn't make it any more. Its 1/2 inch tall and has a taper to the bores kind of like a shear plate. It seems to work well. My carburetor has a dual pattern base plate.

Thanks. I know of that spacer, but unfortunately it is not available anymore. I am trying to find something that will be comparable to that setup. Haven’t had any luck yet. Thanks again and good luck with the TF warranty, I hope they do right by you.

I'll sell the design rights and the CAD file to someone who wants to make those low profile spacers.

Yep, I had Andy's last one that I purchased when I was a still interested in an MP RB 4500 intake to test with a 4150 carb. The OP needed one about the same time that I gave up finding an intake that wasn't already hacked on or way overpriced (IMO). Nice part, which what I've come to expect from Andy's products.

Did the top of the pistons show either contact or a pattern in the carbon at the valve? Can you post a picture ?

This is cylinder #1. The one with the most leakage. There is no sign of contact that I can see.

Hmmm, what does that leave as a cause ? Inconsistent or insufficient seat harness ?

Sounds like defective heads to me

Talked with Trick Flow today and spent some time answering questions about my combination in an attempt to figure out what happened to the heads to cause some of the exhaust valves to leak.
Bottom line is my heads are getting fixed and should have them back in a week or two. I'm pleased with their customer service so far it's been easy dealing with them.

Awesome!

That is good to hear Thanks for posting your results.
I'm thinking of buying a set of their 270 soon

Did TF concur that there was an issue with the seat sealing surfaces?

He didn't say, just told me that the heads were being fixed. He did comment that they were were not that bad, but from the line of questions I was asked, such as shift rpm , spark plugs used , total ign timing, type of fuel used, rocker arm used, cam part# and who made it, that there was definitely an issue.

It's highly commendable they are fixing them for you. Most places I don't think would do much to help you once their parts have been installed and used.

Good to hear, but what the problem was, if it's happened on other heads, and the steps to solve the issue would be things I'd want to know.
Hopefully it's just a freak deal and other customers don't have to anticipate teardowns & repairs.

I received a call from Trick Flow and the final inspection of my cylinder heads showed valve float as the cause of my sealing issue. He told me the seats, keepers and locks were beat up, BUT, not on all the cylinders only a few. The remedy is installing titanium retainers and adding some shim to increase the spring pressure to help the spring control the valve. They replaced all the valves, resurfaced the heads, touched up the seats and are installing the titanium retainers. He is thinking the cam may have aggressive opening and or closing ramps that the spring was not able to control.

So, the obvious question at this point is……what’s the cam?
And what rocker ratio are you running?

[/quote]
It's a .030 over , stock stroke 440. 11.7 to 1 cr. 260/264 Hughes engine cam. 1.6 rockers. 2" hooker headers .

This is from the Huges site.

Thanks Doug.

Fast rate .904 cam with 1.6 rockers.
Not a match made in heaven for high rpm stability.

The cam I have has a different part #
What would you do to improve the stability? I really would like to not have to deal with this again anytime soon!

Flat tappet valve float didn't knock your seats out of whack. They probably weren't installed just right and moved.

That picture above has a spring error on it DVW's looks right.

1128 has a 146lb seat pressure. at 1.87 (supposedly pac)

and closest pac is a 1924 which is spec'd by them at 144 at 1.900

Yes, I'm inclined to agree with you. There were signs of valve float like an X wear pattern on the valve tips and the retainer and keepers were super difficult to remove. But was it enough float to create seat damage? I don't know. I can only go by what I was told. If float is the cause it happened very quickly, as there is only 45 passes on the heads. On the bright side Trick flow repaired them at their expense and I'm very pleased with that.

The card that came with the cam has different spring specs than the cards for the same cam on the Hughes website, I'm going to call Dave and get his take on what to use with his cam and Trick flow's evaluation. Which should prove to be an interesting conversation.
Even the trick flow spring specs are different from what is listed on the cylinder head instruction sheet and what the spring part # list in their catalog. The numbers are all over the place. What do you trust???
To know what you are getting you have to check everything yourself, which mean buying spring checking tools, fun stuff !!

The TFS-16094 spring that comes on those heads is a PAC-1294.
In the paperwork that comes with the heads, the specs for that spring are incorrect.
However, they are correct in the TFS spring chart(specs the same as the PAC catalog).

If the lobe profile isn’t stable enough to allow the springs to maintain control without excessive force, that’s when the tough decisions get made.
Don’t rev it as high, add spring force and hope for the best, change the cam, etc.

The spring has a rate of 427lbs/in, so with .650 net lift, you’re going to have 277lbs on top of the seated force.(such as 155+277= 432).
It’s a lot of force for a cast cam and lifters.

Thanks for your input it is helpful and appreciated.

The comp 928 spring with installed height 1.87 to 1.900 is my choice