[Tim M]

We are adding OEM Ti LT4 intake valves to my LT1 heads as well as new OEM exhaust valves to replace my current young 30K mile units.

I like new parts to reduce machining since LT engines are not a common sight in Germany. We do like the German machinist - he does seem to be very adept and skilled based on our experience and variety of machinery always present in the 'to do' line.

I briefly discussed the addition of Ti valves to the heads and he was commenting there were special valve seat prep that would need to be followed.

Might anyone have some experience of Ti valves install? Possibly valve seat angles, etc?

I do have the intake valve shims...

Thanks!

[ZL14ever]

When I installed LT4 Ti intake valves in my LT1 heads, all I did was use BTR SK008 valve spring kit that insures you would have the correct install height.

If you don't want to go that route, just make sure your install height for the intake valve is 1.780". Add/remove shims to achieve this installed height

[6spdhyperblue]

Did you install bronze guides?

I know the lt4 has guides specific for Ti valves but not sure yet if the lt1 is of the same material.

[ZL14ever]

Originally Posted by 6spdhyperblue

Did you install bronze guides?

I know the lt4 has guides specific for Ti valves but not sure yet if the lt1 is of the same material.

No I did not install bronze valve guides. I kept whatever was in the head previously

[Tim M]

Appreciate the responses!

ZL14ever: Did you update the valve seat angles? Or did you just install?

Cam Motion recommended the PSI 1516 beehive spring for my camshaft with specs of 150 pounds on the seat and ~400 open.

I had not thought about the guide material differences.

My seats look usable as is, but will defer to the machinist:



Thanks.

[oldman]

TI is very aggressive, and I was unsure of it (guide wear) on a LT1 so I just went with proflows. If I did do TI, I probably would either go bonze guide or see if I could press in stock LT4 guides. Reaming can help as it allows so oil to flow deeper into the guide. I have heard that Z/28 do have guide wear issues stone stock. Could be just urban legend.
Cam Motion in general has gentle ramps and I would run with the minimum of seat pressure considering you have light valves from the get go. I think the next spring I run will be the weakest conical I can find.

[Tim M]

oldman: Appreciate the response. Overseas it is a risk between letting the locals attempt what they think is right and not doing anything (or ship to the US to the LT specialists). CNC porting was in the cards the following winter, but with this car down already 12 months longer than expected...;-)

The lightweight models are like a feather next to the OEM LT1's...awaiting on a digital scale to see the difference:

[ZL14ever]

Originally Posted by Tim M

ZL14ever: Did you update the valve seat angles? Or did you just install?

I just installed them. Don't forget the required lash caps for Ti valves

[oldman]

found this: https://powersports.wiseco.com/media...ve_Install.pdf

Looks like Wiseco likes light springs, intresting about lapping compound, I would have already messed up.

Katek says to use these
https://katechengines.com/i-30497925...e-springs.html
"This 65g lightweight beehive spring is Katech's default for all engine packages. Optron valvetrain dynamics testing revealed this spring was the best choice to keep lightweight valves such as LS6 and LS7 in control."

little lighter than the camotion rec here is the PSI spec sheet:
https://www.psisprings.com/products/1500-series/

I'm going to these, now I need to find smaller retainers as I toss the stock ones when I went to dual springs.

Katech does spec the 1516 for their stage 4 supercharged package LT1, don't think you need it as your valves are really light. Let me check their stage 4 ZL1..... it also uses the 1516. I'm guessing the stage 4 has a higher lift cam or it is shimmed.




They do list different part numbers for their LT1 vs LT4 guides and the LT1 guide says:CHE manganese bronze valve guides.

Works with LT1, L86, and L83 heads.

Does NOT with with LT4 heads. You probably can call CHE and see why there are two different guides.

[Tim M]

oldman: Great info. The valve seat info was especially useful although the concerns over finger contact with the titanium valves means I shouldn't been been ogling them out of the box!

Cam Motion suggested the 1516 springs, which I purchased along with tool steel retainers I have from BTR. May look to go with a relaxed seat height to work toward the lighter side of things.

Depending on the machinist comments, we'll just the run the heads as is with OEM guides. I may even pull the heads again in the near future for porting - will do a status check then.

Thanks!

[oldman]

apr studs of course, I have a big issue with their torque using their torque grease, I think I'm at 10 or even 15 ft-lbs less then what apr calls for, I did all the calculations 5 years ago, apr is just too tight say from memory 105 and I did 90 and I think the LS1 with thinner bolts was 70 or 65, anyway I like the stud but their spec is for maybe a race car engine and I felt it was too much on to my mind a relatively shallow threaded area. I don't know what others have done, it has been years and no leaks, blowouts etc.

[Katech_Mike]

Originally Posted by oldman

They do list different part numbers for their LT1 vs LT4 guides and the LT1 guide says:CHE manganese bronze valve guides.

Works with LT1, L86, and L83 heads.

Does NOT with with LT4 heads. You probably can call CHE and see why there are two different guides.

The difference is about .010 in the guide bore between LT1 and LT4 heads. The material is the exact same.

[Tim M]

Katech Mike - very helpful - appreciate the post. We will install the valves as is into the LT1 heads knowing we have 30K miles on them already (likely a bit more clearance than when new!).

Adding more detail on the LT4 intake valves - starting with OEM LT1 valve weight:



New OEM LT4 Ti valves:



Even though the LT1 valves are carboned - at least a 20 gram drop in weight which is impressive!

My next question is the valves spring height. The OEM LT4 intake valve lock groove is ~.200 lower than the LT1 valve. So all else equal, the spring pressure is much higher. For the 1516 springs at 409 pounds an inch = 82# increase. Seems excessive. It appears the OEM LT4 retainers are same for intake and exhaust. Likely I'm doing something wrong...

Comments?

[ADM PERFORMANCE]

d based on our experience and variety of machinery always present in the

Originally Posted by Tim M

We are adding OEM Ti LT4 intake valves to my LT1 heads as well as new OEM exhaust valves to replace my current young 30K mile units.

I like new parts to reduce machining since LT engines are not a common sight in Germany. We do like the German machinist - he does seem to be very adept and skille'to do' line.

I briefly discussed the addition of Ti valves to the heads and he was commenting there were special valve seat prep that would need to be followed.

Might anyone have some experience of Ti valves install? Possibly valve seat angles, etc?

I do have the intake valve shims...

Thanks!

Give me a shout as I have your answer and we need to chat - 214-228-8782

Andy