Loadstar 1600 with 345

Well I take some of what a I wrote back. Looks like the base circle varies. That would not be attributed to wear but to being reground. The lobe lift values you gave us are basicly 2 values .224 and .254. Good from a wear indication standpoint. The taper is evident on the heal of the lobes and the lifters were rotating. I hope you maintained the order in which you removed them as they must be retuned to the exact same lobe they were running on or you risk eating the cam. If not new lifters should be installed.

My opinion is to replace the cam in either case. Just not enough money to go through the teardown again.

Robert
 
Appreciate your input Robert, a couple of questions, this info is deeper than I am familiar with such as rocker arm ratio? The lift values of .224 and .254, are you saying that is right? Or am I missing the connection or calculation for valve lift? The manual shows more .44 and .395. Or is it the fact this is from a 1600 loadstar instead of a Scout?
To answer your question, yes I have kept all lifters organized with cam, lifters and push rods. But this rebuild is a long term project so I will take my time and replace parts that need to be replaced, if, and it looks like it is, the cam needs to be replaced. I agree nows the time to do it. It will be interesting to see what the machinist has to say about the block.
As I write its getting clearer, your taking the .254 x rr say 1.75 to get valve lift is that correct? Nevermind you had 2 posts I missed the first one until now, yes I am slow!
Thankagain
ron
 
Ron,

you are correct. Valve lift = rr x lobe lift. 1.75 x .224 =.392 @ the valve. 1.75 x .254 = .444. This is only close because the rr is really unknown. It looks close but you still show a lot of variation in your lobe dimensions.

Rk
 
IH sv's have different rocker ratio's for the intake and exhaust. Depending on style they are either 1.5 intake (early welded), 1.7 exhaust, or 1.6 (later boat style) and 1.7 exhaust. The lobes with .25x" are intake lobes. The lobes with .22x" are exhaust lobes. Sv v8 cam lobes go I, e, e, I, I, e, e, I, I, e, e, I, I , e, e, I, from one end to the other.
As others have said the shop manual is referring to valve lift, not cam lobe lift (or lifter lift).
 
Thanks for the info "71", since I have boat style rockers and your info. Rr for this would be 1.6 intake and 1.7 exhaust.
Just averaged the measurements and I have .404 intake valve lift, spec says .44 and .3809 exhaust valve lift spec says .395. The manual does not give an acceptable range for valve lift but I am sure less valve lift means less hp. This just verifys what we've said; time for a new cam.
Ron
 
Ron,
in a very general sense. Lift = torque and duration = hp.
Now while duration makes hp it also effects where the hp and torque will occur. So for a truck/Scout you want the most lift in the shortest time(duration) to give you big torque numbers.

If you compare the cams Jeff sells you can see that the isky cams have better lift velocities than the comp grinds. More lift in a shorter duration.

Next we need to flow a set of sv heads on a flow bench I have access to and see what really effects the flow numbers. The flow of the port valve in is important to how we cam it. No reason to over cam a set of heads. That can kill torque curves.

Rk
 
Looks to me like you have a sloppy re-grind. The stock IH sv cam is a one size fits all, 266-392, Scout to loadstar.

It is a dual pattern cam, and they also use different rocker ratios for intake and exhaust due to the canted valve arrangement. 1.6 intake and 1.7 exhaust iirc so if you apply that to your cam you give you a net avg lift of ~.410 int and ~.383 exh.

The fact that the pattern on the base circle is so wide and the fact that those lifters pictured have about doubled from their initial pattern means the cam and lifters are toast.
 
Robert, I don't know all the differences in cams but I am learning. That's why I am here, the best knowledge base for IH on the web! I know ihon has a favorite they sell:
isky-190125-26 when I buy one it will be from here.
I appreciate all the advice I am getting here it's great!
Ron

eric, the more I tear into this motor the more I find what appears to be a bad rebuild. It does not appear to have very many miles on this rebuild. Cam bearings and rod bearing show uneven wear. Parts of these bearings show no wear where other parts are nice and shiny. I will try to post some pics later.
 
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ronmc1954 said:
Eric, the more I tear into this motor the more I find what appears to be a bad rebuild. It does not appear to have very many miles on this rebuild. Cam bearings and rod bearing show uneven wear. Parts of these bearings show no wear where other parts are nice and shiny. I will try to post some pics later.
Click to expand...

You need to keep in mind when examining the bearings that there is a "load side" that will wear more. The bottom of the cam bearings and the top half of the rod bearings will wear more. What you are looking for is for the shinny areas to be pretty much the full width of the bearing. The concern would be if they were off to one side or where they aren't supposed to be, which could indicate a bent or improperly machined component.
 
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