Here are my compression test numbers from July when I'd found the broken rocker arm. So I'm wondering what happened to #6 since then.

 

Lotsa things could be contributing... including physical damage. Of course, WHERE the compression is going would be good to know. Can you do a cylinder leakdown test?

 

Yes I have a leakdown tester. Just moving slow this morning but will be out in the garage NLT noon. Great way to spend Thanksgiving... I'll do the leakdown test and then start getting things ready to pull the heads. That way maybe by Monday I can take them to the machine shop and get them working on them.

 

OK interesting times....

Leakdown test on cylinder #6



For Grins & Giggles after doing the leakdown test I did a compression test on #6 again and got 215 lbs of compression... So sticky valve? Not sure what but that cylinder is good but the head is suspect?

This is cylinder #5. No issues with it but I could hear a little air leaking thru the intake. So again I think it's the heads.



This is cylinder #7. It still has 175 lbs compression but you could hear air coming through the intake during the leakdown test. All this seems to point towards the heads.



I seem to have been here too many times... Dang Nab it..

 

Yep, time to pull the heads, and go thru 'em. Still need to check bearing clearances and such, for the oil pressure issue. Do you have another tune coming as well??

 

I bought these heads in 2013 or 2014 so 10 years ago.
When I bought them I'd had them drilled for 3/8" studs and used this conversion kit from Crane. Crane Rocker Arm Guideplate Conversion Kits 36655-2 Crane Cams 36655-2 Crane Rocker Arm Guideplate Conversion Kits | Summit Racing
But it is now discontinued... It seems that most of the stud kits I can find now all have 3/8" upper & 7/16 lower threads. Just wondering if anyone knows why this was done? Stock the heads came with 5/16": threads so I thought going to 3/8" was a big plus.
If I can't find anyplace to get new 3/8" studs from I might have to have the heads drilled and tapped for 7/16" threads.

 

Is there something wrong with your existing studs that is requiring you to change them?

 

The one on that one cylinder is bent. I've got the heads off and the valve slides in the guide fine but IMO there has to be something wrong with the guide or it's spring bind? But why only that one spring? I'll have some pictures of everything to post later.

 

Check installed height of the spring, then compress it all the way, and measure height. Is the difference more than your calculated valve lift?

 

This is the stud off cylinder #5 intake valve. You can see it's bent just a little. It might have been bent after the rocker arm broke? But it needs to be replaced.



Heads are off.



Got to pull the studs and get them cleaned up so I can take them to the machine shop Monday.



You can see that the valve guide is just bored in the head which from some reading I'm finding this isn't the best so I am going to have bronze installed.



Heads are cleaned up.






Will get all the springs checked for the amount of lift on the cam plus that I'm running 1.7 rockers instead of stock 1.6.