Lbz heads on lly

[Wyatt.bilodeau]

I have an lly motor that lifted the heads last year and I’m finally getting around to fixing it. I have lbz heads that I plan on using for the repair which leaves me with a few questions. First, the lly has 120k miles and the lbz had 250k miles on it, does anyone know if I would have any issues using the lly pushrods and rocker assembly in the lbz heads? And second, is there any thing specific I have to do in order to use the lbz heads? Thank you!

 

[Chevy1925]

I have an lly motor that lifted the heads last year and I’m finally getting around to fixing it. I have lbz heads that I plan on using for the repair which leaves me with a few questions. First, the lly has 120k miles and the lbz had 250k miles on it, does anyone know if I would have any issues using the lly pushrods and rocker assembly in the lbz heads? And second, is there any thing specific I have to do in order to use the lbz heads? Thank you!

nope, lly rockers and pushrods will work fine. you must use LBZ glow plugs (lly wont thread in), im not sure if the lly GPCM will have an issue with that or if you will burn up glow plugs as they are different than LLY internally as well. i used glow plug deletes in my LBZ heads.

if you use the LLY intake clam shells and ybridge, shouldnt have any issues with fuel rails and stuff lining back up. LLY injectors will drop right in. Some say the o-rings on the injectors will be looose in the bore but mine were still plenty tight. it should be a pretty much bolt in deal besides the glow plugs.

 

[Wyatt.bilodeau]

nope, lly rockers and pushrods will work fine. you must use LBZ glow plugs (lly wont thread in), im not sure if the lly GPCM will have an issue with that or if you will burn up glow plugs as they are different than LLY internally as well. i used glow plug deletes in my LBZ heads.

if you use the LLY intake clam shells and ybridge, shouldnt have any issues with fuel rails and stuff lining back up. LLY injectors will drop right in. Some say the o-rings on the injectors will be looose in the bore but mine were still plenty tight. it should be a pretty much bolt in deal besides the glow plugs.

Guess I should have done more research before buying 8 lly glow plugs! Thank you for the info much appreciated

 

[Dallas S]

It will work just fine. Run the LBZ glow plugs. We do this swap often as we don’t see LBZ heads crack at the injector bores like the LLY can.

 

[1FastBrick]

I also have a buddy with LBZ heads and glow plugs on his LLY. We couldn't locate a set of LLY heads at the time.

 

[Wyatt.bilodeau]

It will work just fine. Run the LBZ glow plugs. We do this swap often as we don’t see LBZ heads crack at the injector bores like the LLY can.

Okay awesome. Is there anything special I should do to prep the mating surface on the heads?

 

[Dallas S]

Always recommend having the heads checked and decked at a minimum.

 

[Wyatt.bilodeau]

Always recommend having the heads checked and decked at a minimum.

So I noticed this little hairline crack on one of the water jackets of the lbz head. How concerning is this ?

 

[1FastBrick]

Hard to tell from the picture but if its an actual crack, it can propagate out ward from that point and be problematic for the sealing.

If it's just etched from something, it will clean up when they skim it. Your machine shop will be able to tell the difference.

Can you feel it going down ward if you run something fine metal like a pick or scribe over it?

 

[Wyatt.bilodeau]

Hard to tell from the picture but if its an actual crack, it can propagate out ward from that point and be problematic for the sealing.

If it's just etched from something, it will clean up when they skim it. Your machine shop will be able to tell the difference.

Can you feel it going down ward if you run something fine metal like a pick or scribe over it?

I can feel it if I run over it with a metal pick but there is no crack down the water jacket hole next to it.

 

[1FastBrick]

I can feel it if I run over it with a metal pick but there is no crack down the water jacket hole next to it.

I assume you will be visiting a machine shop for pressure check and possibly a surfacing of the decks?

They can inspect it and if it appears to be more serious then a surface issue, They could possibly repair it by welding it the area prior to machining.

They have a product for crack detection on aluminum, this will tell them if it's cracked or just some sort of surface defect.

 

[Wyatt.bilodeau]

I

I assume you will be visiting a machine shop for pressure check and possibly a surfacing of the decks?

They can inspect it and if it appears to be more serious then a surface issue, They could possibly repair it by welding it the area prior to machining.

They have a product for crack detection on aluminum, this will tell them if it's cracked or just some sort of surface defect.

To be completely honest I was trying to avoid the machine shop all together as I was quoted upwards of $700, but if I’m going to be sending heads out anyways would it make more sense to send the lly heads out with less miles? Those heads have a bunch of broken bolts in them as well

 

[1FastBrick]

I

To be completely honest I was trying to avoid the machine shop all together as I was quoted upwards of $700, but if I’m going to be sending heads out anyways would it make more sense to send the lly heads out with less miles? Those heads have a bunch of broken bolts in them as well

I was also trying to do the bare minimum on my LBZ heads. I only wanted to pressure check them and re seal the motor. But when the valves came out it was clear they needed more work...

1 cylinder was oddly wet so I was concerned about either the valve seals leaking, a crack in the casting, or maybe an injector issue.
I ended up needing 5 new intake valves, 13 new exhaust guides and 3 new intake guides...

I am told the damage to the intake valves is from water ingestion some where. My machinist says this is common on boats with a closed cooling system and leaking liquid intercooler. He says it's common on the Volvo diesel engine used in marine applications.

 

[Wyatt.bilodeau]

I was also trying to do the bare minimum on my LBZ heads. I only wanted to pressure check them and re seal the motor. But when the valves came out it was clear they needed more work...

1 cylinder was oddly wet so I was concerned about either the valve seals leaking, a crack in the casting, or maybe an injector issue.
I ended up needing 5 new intake valves, 13 new exhaust guides and 3 new intake guides...

I am told the damage to the intake valves is from water ingestion some where. My machinist says this is common on boats with a closed cooling system and leaking liquid intercooler. He says it's common on the Volvo diesel engine used in marine applications.

Interesting but that makes sense. Was it big money for the new valves/seals? Keeping my fingers crossed I don’t run into the same issue

 

[1FastBrick]

Interesting but that makes sense. Was it big money for the new valves/seals? Keeping my fingers crossed I don’t run into the same issue

Haven't got the bill yet... I purchased the replacement parts thorugh Brad and we sourced them through merchant. Guides were 1.95 each The valves were 19.95 Each I already have the Valve seals in the Gasket Kit I purchased to re-seal the motor. But I don't believe they are that much maybe around $40

Some places were $5 a guide and $25-30 a valve and I didn't want to over pay. Sometimes when the machine shop sources stuff the Prices can be higher depending on there sources. I also didn't want anything of a different quality.

 

[Wyatt.bilodeau]

Haven't got the bill yet... I purchased the replacement parts thorugh Brad and we sourced them through merchant. Guides were 1.95 each The valves were 19.95 Each I already have the Valve seals in the Gasket Kit I purchased to re-seal the motor. But I don't believe they are that much maybe around $40

Some places were $5 a guide and $25-30 a valve and I didn't want to over pay. Sometimes when the machine shop sources stuff the Prices can be higher depending on there sources. I also didn't want anything of a different quality.

Oh perfect not bad at all. Definitely a little worried given the high miles and everything is just so damn expensive for these motors lol. Thank you for the info I just called a shop about a clean, pressure test and surface test and they said around $110 for the pair so I think that will be the plan with crossed fingers

 

[1FastBrick]

Oh perfect not bad at all. Definitely a little worried given the high miles and everything is just so damn expensive for these motors lol. Thank you for the info I just called a shop about a clean, pressure test and surface test and they said around $110 for the pair so I think that will be the plan with crossed fingers

Yeah these had 227K miles on them. The EGR may be the source of the liquid contamination but I am not 100% Sure. My heads seemed to pressure check ok.