408 hyd roller, too much spring pressure?
Hi!
I have finished my 360 based 408 stroker with good result so far!
I am however starting to worry about my spring pressure...
The engine is based on a -89 roller 360.
I used stock replacement roller lifters with the stock spider like plate to hold down the "figure 8 shaped" anti rotation plates.
The cam is a Lunati VooDoo 20200712
As far as I can see, this is a cast core cam.
231/239 degrees @0.050"
.535/.550 lift
I checked during installation, and there is a good margin to the "figure 8" plates at max lift.
I use bronze bushed steel 1:1,5 shaft rockers, very similar to Comp cams ultra pro magnum rockers
Lunati recommended a spring kt for the Eddy heads I planned on using. Before I got them I ended up buying Trick flow heads instead.
The spricg choices for the Trick Flow heads ended up being lower than recommended with the 1,46" diameter spring, and a bit over recomended for the 1,55" spring. After recommendation from Trick Flow I went with the 1.55" diameter spring heads, p.n. TFS-61417802-C00.
According to the specs I end up with 138 lbs seat pressure and 369 lbs open pressure (on the exhaust lobes)
- Is this too much for the stock replacement roller lifters?
- Is this too much for the cast core roller cam?
The engine runs great! But the valvetrain noise is a bit more than expected. When starting up, there is a few seconds of rattle befor the lifters fill up. I guess they drain during standstill? I would consider this normal with hydraulic lifters, but I'm surprised what short time is needed for them to drain.
/Magnus
Hi!
I have finished my 360 based 408 stroker with good result so far!
I am however starting to worry about my spring pressure...
The engine is based on a -89 roller 360.
I used stock replacement roller lifters with the stock spider like plate to hold down the "figure 8 shaped" anti rotation plates.
The cam is a Lunati VooDoo 20200712
As far as I can see, this is a cast core cam.
231/239 degrees @0.050"
.535/.550 lift
I checked during installation, and there is a good margin to the "figure 8" plates at max lift.
I use bronze bushed steel 1:1,5 shaft rockers, very similar to Comp cams ultra pro magnum rockers
Lunati recommended a spring kt for the Eddy heads I planned on using. Before I got them I ended up buying Trick flow heads instead.
The spricg choices for the Trick Flow heads ended up being lower than recommended with the 1,46" diameter spring, and a bit over recomended for the 1,55" spring. After recommendation from Trick Flow I went with the 1.55" diameter spring heads, p.n. TFS-61417802-C00.
According to the specs I end up with 138 lbs seat pressure and 369 lbs open pressure (on the exhaust lobes)
- Is this too much for the stock replacement roller lifters?
- Is this too much for the cast core roller cam?
The engine runs great! But the valvetrain noise is a bit more than expected. When starting up, there is a few seconds of rattle befor the lifters fill up. I guess they drain during standstill? I would consider this normal with hydraulic lifters, but I'm surprised what short time is needed for them to drain.
/Magnus
