Rebuild for a performance oriented 6.5

[EWC]

So you and n8 had the same checking lifters and both of you had piston to valve issues . You have a different cam and he has a stocker , right ? Regrinds take material off the lobes and put a different profile on the " new " lobe . I lost .030 on the base circle and was worried that would need longer pushrods . Hydraulic lifters don't run up at the top of the clip , in the body , they kinda float in the housing . How many times have you adjusted hydraulic lifters , while the engine is running , and had to wait to do the 1 turn preload to not kill the engine ? That cam you have is not much bigger than a stock cam , can't see that being a problem . Now the ICL is a lot compared to my Crane @ 105 and I have more lift and duration than you . I didn't check anything , just primed it and crossed my fingers . Yeah , I know not the best way but it did turn over so I left it alone . Can you measure the base circle ? I have a stock cam and can check it .

 

[Hink]

Here's a two point FYI...
1 - I have nothing useful to add here : )>
2 - Just so you know, there are others out here that are learning a LOT from you guys. So, while I feel your pain in this, at least know that you're helping the rest of us boneheads out here to learn a little bit more so we may be able to return the favor some day.

Especially in the cam/ rocker arm area that seems so sparse in info with these engines.
@Will, did you guys ever do major work in this area?

 

[3500_6.5]

I wish I had sent you the length checking pushrods with those lifters. I didn't even think of that.

I'll probably just order one from Jegs. Looks like they have them for under $30. Problem is I don't know if I will even be able to find pushrods the length I need regardless. Stock length looks to be 8.822". So just taking the .075" off I'm at 8.747" and I can't find any that are even close to that length at the moment. I found some Chrysler ones, but I'm not sure if the ends are the same, plus it said that they are non oiling pushrods.

 

[3500_6.5]

So you and n8 had the same checking lifters and both of you had piston to valve issues . You have a different cam and he has a stocker , right ? Regrinds take material off the lobes and put a different profile on the " new " lobe . I lost .030 on the base circle and was worried that would need longer pushrods . Hydraulic lifters don't run up at the top of the clip , in the body , they kinda float in the housing . How many times have you adjusted hydraulic lifters , while the engine is running , and had to wait to do the 1 turn preload to not kill the engine ? That cam you have is not much bigger than a stock cam , can't see that being a problem . Now the ICL is a lot compared to my Crane @ 105 and I have more lift and duration than you . I didn't check anything , just primed it and crossed my fingers . Yeah , I know not the best way but it did turn over so I left it alone . Can you measure the base circle ? I have a stock cam and can check it .

Nate had clearance issues with an aftermarket cam. His cleared when checking with the solid lifters though. I'll have to pull the cam out to check the base circle.

 

[n8in8or]

I'll probably just order one from Jegs. Looks like they have them for under $30. Problem is I don't know if I will even be able to find pushrods the length I need regardless. Stock length looks to be 8.822". So just taking the .075" off I'm at 8.747" and I can't find any that are even close to that length at the moment. I found some Chrysler ones, but I'm not sure if the ends are the same, plus it said that they are non oiling pushrods.

I think when I was going through this I found in Summit that you could order custom pushrods in pretty much any configuration. I can't remember the brand, but I want to say it was Crane or Comp. I was lucky and didn't need different pushrods, but I didn't have any block or head machining done to mine.

 

[n8in8or]

So you and n8 had the same checking lifters and both of you had piston to valve issues . You have a different cam and he has a stocker , right ? Regrinds take material off the lobes and put a different profile on the " new " lobe . I lost .030 on the base circle and was worried that would need longer pushrods . Hydraulic lifters don't run up at the top of the clip , in the body , they kinda float in the housing . How many times have you adjusted hydraulic lifters , while the engine is running , and had to wait to do the 1 turn preload to not kill the engine ? That cam you have is not much bigger than a stock cam , can't see that being a problem . Now the ICL is a lot compared to my Crane @ 105 and I have more lift and duration than you . I didn't check anything , just primed it and crossed my fingers . Yeah , I know not the best way but it did turn over so I left it alone . Can you measure the base circle ? I have a stock cam and can check it .

When I had my issues it was with a Delta 202 cam and 1.6 ratio rockers. The rockers were the reason I checked my clearance - I hadn't heard of anyone running that cam with the higher ratio. I think the base circle on that cam was reduced .030 on the intake lobes but I can't recall for sure now. I checked my clearances with clay and had what should have been enough clearance when I used the solid lifters, but then when I opened up the engine for an unrelated issue I found light markings on the piston tops from the intake valves. I still have no idea why. At first I thought valve float, but an intake valve hanging open longer shouldn't hit the piston because the piston would be on its way down then. So I just don't know. I used solid lifters for checking because yes, the piston in the lifter does float, but there's a chance it could pump up so I wanted to check worst case - just to be safe. I didn't degree my cam like you guys did though, I just put it in and assumed it was ok because Delta told me it just goes in straight up. Plus I've never degreed a cam and I was more interested in getting the truck back on the road than figuring out cam degreeing.

 

[EWC]

OK , that answers a few questions . n8 , what did you do with the Delta cam ?

 

[n8in8or]

OK , that answers a few questions . n8 , what did you do with the Delta cam ?

I still have it. I haven't decided yet what to do with it.

 

[Husker6.5]

That does suck but glad you found it the easy way using a "solid lifter" (ok Husker I left myself open )

Free pass on that one, too late in the thread. Besides which, the solid lifter didn't suck, it blew, because it was the exhaust valve.

 

[Will L.]

Nate, if this is too much side track- have a mod kill it, just pm a copy to Hink incase he doesn't see it. My feelings don't get hurt that easy...

(edit for space by will)"... in the cam/ rocker arm area that seems so sparse in info with these engines.
@Will, did you guys ever do major work in this area?

This was in the 90's- no aftermarket cam or parts were available for h.p. Mods. We started with degreeing cam to see differences. Quickly after we chopped a head and mounted it. Determined what we figured was max duration and lift, an "all out" approach. Cut new cams from steel bars and after a few trials- had it. Played with lighter springs. Killed a few valves and Pistons along the way.
I've mentioned before that I don't think there is a ton to be gained by cams. If you are after every last bit of power- then ok. But if you are not starting with the biggest ip you can get and throwing propane in from idle to 250 rpm beyond the shift point- I don't see it. The $:hp ratio isnt there.
If you "invest" in a cam, you better have lightened and spun balanced your lower end, flowed and ceramiced your upper end, softened the intake springs, gear drive, and be pushing north of 125cc3.

Running a chain vs gear drive is part of the cam issue. We stretch chains, everybody knows it but it doesn't get addressed often. If you are building high power numbers and doing it with a chain you will loose your engine one day, not in acceleration, but the moment you ease off the throttle and BANG! That is where every engine I blew dropped it until we went gear drive. The slack will kill that valve clearance in a hurry.

For DD engines: if your running roller rockers you better still be running hydraulic lifters or a chain. If you run gear drive and solid roller lifters, you need non roller rockers. You have to have something take up the chatter. I ran gear drive, solid roller lifters, one off roller rockers (not as pretty as Harland's). We swapped the rollers on the rocker arms from chatter a few times. Hydraulic lifters are the easy part in theory- but if you aren't regulating the oil pressure to them, check your rollers once in a while. 2 piece valve covers are a good idea on a hot rod. Hydraulic shops sell fittings to extend fuel lines to bend and give clearence- you only need 8. Then with replacement rollers you can have it all...

 

[Burning oil]

Nate, have a picture of your pistons that you said had light valve contact? Ive seen so many pictures of pistons that look like there are two circles the size of the valves and people are thinking valve made contact. I don't know why the impression thing looks like it does, but I don't think there is contact (on the ones Ive seen anyway your may be different)
If you see actual deformed/dented piston tops the yes obviously they contacted.

 

[FellowTraveler]

Nate, have a picture of your pistons that you said had light valve contact? Ive seen so many pictures of pistons that look like there are two circles the size of the valves and people are thinking valve made contact. I don't know why the impression thing looks like it does, but I don't think there is contact (on the ones Ive seen anyway your may be different)
If you see actual deformed/dented piston tops the yes obviously they contacted.

Consider, floating valves @ higher rpms!

 

[n8in8or]

Nate, have a picture of your pistons that you said had light valve contact? Ive seen so many pictures of pistons that look like there are two circles the size of the valves and people are thinking valve made contact. I don't know why the impression thing looks like it does, but I don't think there is contact (on the ones Ive seen anyway your may be different)
If you see actual deformed/dented piston tops the yes obviously they contacted.

Here are a couple pics. The piston on the left is the original 1997 piston. The piston on the right is the piston with the Delta cam and 1.6 ratio rockers. I have seen what you are talking about and the 1997 piston kind of has it - it's like the carbon gets deposited a little differently under the valve heads. However the piston on the right is wiped clean of carbon under the intake valve. Also if you look close you can see swirl marks from the rotating valve head. I wasn't going to risk it, the pistons came out. That Delta cam was an expensive experiment despite my clearance-checking efforts.

 

[n8in8or]

Nate, if this is too much side track- have a mod kill it, just pm a copy to Hink incase he doesn't see it. My feelings don't get hurt that easy...



This was in the 90's- no aftermarket cam or parts were available for h.p. Mods. We started with degreeing cam to see differences. Quickly after we chopped a head and mounted it. Determined what we figured was max duration and lift, an "all out" approach. Cut new cams from steel bars and after a few trials- had it. Played with lighter springs. Killed a few valves and Pistons along the way.
I've mentioned before that I don't think there is a ton to be gained by cams. If you are after every last bit of power- then ok. But if you are not starting with the biggest ip you can get and throwing propane in from idle to 250 rpm beyond the shift point- I don't see it. The $:hp ratio isnt there.
If you "invest" in a cam, you better have lightened and spun balanced your lower end, flowed and ceramiced your upper end, softened the intake springs, gear drive, and be pushing north of 125cc3.

Running a chain vs gear drive is part of the cam issue. We stretch chains, everybody knows it but it doesn't get addressed often. If you are building high power numbers and doing it with a chain you will loose your engine one day, not in acceleration, but the moment you ease off the throttle and BANG! That is where every engine I blew dropped it until we went gear drive. The slack will kill that valve clearance in a hurry.

For DD engines: if your running roller rockers you better still be running hydraulic lifters or a chain. If you run gear drive and solid roller lifters, you need non roller rockers. You have to have something take up the chatter. I ran gear drive, solid roller lifters, one off roller rockers (not as pretty as Harland's). We swapped the rollers on the rocker arms from chatter a few times. Hydraulic lifters are the easy part in theory- but if you aren't regulating the oil pressure to them, check your rollers once in a while. 2 piece valve covers are a good idea on a hot rod. Hydraulic shops sell fittings to extend fuel lines to bend and give clearence- you only need 8. Then with replacement rollers you can have it all...

Interesting. I guess I'll plan on putting a gear drive in sooner than later.

 

[3500_6.5]

I think when I was going through this I found in Summit that you could order custom pushrods in pretty much any configuration. I can't remember the brand, but I want to say it was Crane or Comp. I was lucky and didn't need different pushrods, but I didn't have any block or head machining done to mine.

Thanks, I'll have to check them out and see what I can find.


My brother brought up a good point to me today while we were talking. .075" isn't a lot, not enough that I could even see it moving the valve when I tightened the rocker bolt down, but it is a lot when talking about the amount of material machined from the deck of the block or head, or even combining the two amounts. So I still had a hard time believing that it could have been solely from that. Then we started talking about the valve job and he mentioned about taking material off of the valve stem when you do a valve job to counteract the valve sinking into the head. Which, in these heads case, the valves stuck way out of the head. So much so that my machinist even called me and had me come look at how far out of spec they were. He said, obviously, that they had to be built that way bc wear would cause the valves to sink into the seats, not bring them up out of the seats. The valves stuck out so far that they protruded out of the head (I wish I had pictures so I could give everyone a visual of what I'm talking about).


So I'm thinking that if he set the valves back into the head where spec calls for them to be, that would have "lifted" the valve stem up in the head higher causing the rocker arms to go down on the pushrod side, making the pushrods too long. That would be under the assumption that he did not grind the valve stems down to counteract the valves dropping into the correct location.

I'll have to go back out and look at the heads again, but I'm thinking on either the intake or exhaust valves, you wouldn't even be able to take a whole lot of material off of the stems bc they sit almost flush with the valve spring retainer. But if this is the case, and the valve stems can be machined down enough, I may have the machinist just do that to get me back where I need to be. I'll probably call him in the morning and see what he says. Me get save me a lot of time and money if I can get this done.

 

[Husker6.5]

@NVW @bison Not to derail this thread, but I thought I'd throw this in for for their benefit. I took this photo yesterday afternoon just northwest of York, Nebraska. We had been having winds 30-40 mph out of the NNW for the past two days. It's not fog or blowing dust, it is the smoke from the Ft. McMurray, AB wildfire.

Ironically, this photo was taken while a group of landowners who refused to sign easement agreements with TransCanada, and associated allies, gathered at the Bold Nebraska New Energy Barn (which is a wind and solar powered barn that puts more power into the grid than it uses which we built in 2013 smack dab in the center of the proposed right-of-way of the Keystone XL tarsands crude export pipeline on the land of an easement non-signer, in defiance of TransCanada's edict in the easements prohibiting the construction of buildings or planting of trees in the easement ROW) to stain the barn and to plant trees in honor of Bill McKibben of 350.org, Climate Scientist Dr. James Hansen of NASA and one of the resisting landowners who passed away from cancer before the permit was denied, across the proposed ROW as a final act of defiance.

The smoke was so heavy, it cancelled the Navy's Blue Angels from flying at the airshow at Lincoln Municipal Airport yesterday due to low visibility.

 

[n8in8or]

Thanks, I'll have to check them out and see what I can find.


My brother brought up a good point to me today while we were talking. .075" isn't a lot, not enough that I could even see it moving the valve when I tightened the rocker bolt down, but it is a lot when talking about the amount of material machined from the deck of the block or head, or even combining the two amounts. So I still had a hard time believing that it could have been solely from that. Then we started talking about the valve job and he mentioned about taking material off of the valve stem when you do a valve job to counteract the valve sinking into the head. Which, in these heads case, the valves stuck way out of the head. So much so that my machinist even called me and had me come look at how far out of spec they were. He said, obviously, that they had to be built that way bc wear would cause the valves to sink into the seats, not bring them up out of the seats. The valves stuck out so far that they protruded out of the head (I wish I had pictures so I could give everyone a visual of what I'm talking about).


So I'm thinking that if he set the valves back into the head where spec calls for them to be, that would have "lifted" the valve stem up in the head higher causing the rocker arms to go down on the pushrod side, making the pushrods too long. That would be under the assumption that he did not grind the valve stems down to counteract the valves dropping into the correct location.

I'll have to go back out and look at the heads again, but I'm thinking on either the intake or exhaust valves, you wouldn't even be able to take a whole lot of material off of the stems bc they sit almost flush with the valve spring retainer. But if this is the case, and the valve stems can be machined down enough, I may have the machinist just do that to get me back where I need to be. I'll probably call him in the morning and see what he says. Me get save me a lot of time and money if I can get this done.

Interesting thoughts. Hopefully you can get things back in line with at least machining the valve stems, but you still have push rod length to play with too. Another positive is that by sinking the valves in the head you gained yourself some valve-to-piston clearance.....though possibly at the expense of flow from the valves being shrouded more now. All interesting developments.....

 

[Husker6.5]

Thanks, I'll have to check them out and see what I can find.


My brother brought up a good point to me today while we were talking. .075" isn't a lot, not enough that I could even see it moving the valve when I tightened the rocker bolt down, but it is a lot when talking about the amount of material machined from the deck of the block or head, or even combining the two amounts. So I still had a hard time believing that it could have been solely from that. Then we started talking about the valve job and he mentioned about taking material off of the valve stem when you do a valve job to counteract the valve sinking into the head. Which, in these heads case, the valves stuck way out of the head. So much so that my machinist even called me and had me come look at how far out of spec they were. He said, obviously, that they had to be built that way bc wear would cause the valves to sink into the seats, not bring them up out of the seats. The valves stuck out so far that they protruded out of the head (I wish I had pictures so I could give everyone a visual of what I'm talking about).


So I'm thinking that if he set the valves back into the head where spec calls for them to be, that would have "lifted" the valve stem up in the head higher causing the rocker arms to go down on the pushrod side, making the pushrods too long. That would be under the assumption that he did not grind the valve stems down to counteract the valves dropping into the correct location.

I'll have to go back out and look at the heads again, but I'm thinking on either the intake or exhaust valves, you wouldn't even be able to take a whole lot of material off of the stems bc they sit almost flush with the valve spring retainer. But if this is the case, and the valve stems can be machined down enough, I may have the machinist just do that to get me back where I need to be. I'll probably call him in the morning and see what he says. Me get save me a lot of time and money if I can get this done.

Setting up proper valvetrain geometry is a ticklishly fickle art/science where one little thing can throw off everything else. Likely the reason milling 6.5 heads is not recommended is just because of the tight valve/piston clearance and everything else that has to be changed to re-establish safe clearance tolerances. Throw in 1.6 rocker arms, different cam grind, timing chain stretch, etc, and suddenly the lower piston face of 18:1 pistons seem very friendly.

 

[Burning oil]

Here are a couple pics. The piston on the left is the original 1997 piston. The piston on the right is the piston with the Delta cam and 1.6 ratio rockers. I have seen what you are talking about and the 1997 piston kind of has it - it's like the carbon gets deposited a little differently under the valve heads. However the piston on the right is wiped clean of carbon under the intake valve. Also if you look close you can see swirl marks from the rotating valve head. I wasn't going to risk it, the pistons came out. That Delta cam was an expensive experiment despite my clearance-checking efforts.

View attachment 47989 View attachment 47990 View attachment 47991

Thats definitely not like the pics that were going around. Looks like you said, a light contact. Only on the one piston though?

 

[Husker6.5]

Interesting thoughts. Hopefully you can get things back in line with at least machining the valve stems, but you still have push rod length to play with too. Another positive is that by sinking the valves in the head you gained yourself some valve-to-piston clearance.....though possibly at the expense of flow from the valves being shrouded more now. All interesting developments.....

And hopefully not get less material away from the inter-valve coolant passage in the process.