I've got some pretty bad valve train ticking. I'm using the LT4 hot cam with springs with 135#@1.75 and 360#@1.20. I've already rechecked the lash(0 then 3/4 turn) and the lifters were out of a engine with 8k and no ticking. I'm wondering if anyone else has ran a spring this heavy with factory roller lifters without problems. I'm using comp pro magnum 1.6 full roller rockers also if that makes a difference.

 

That pressure is just right....don't see how that could be your problem. Might reajust them to 1/2 a turn from 0

 

Are you sure it's not just the fuel injectors ticking? They can be really loud.

 

Thanks for the replys. The injectors definetely make some noise but I didn't think they could be as loud as this is. Maybe I'll see if I can get it to run by spraying carb clean in it and unplug the injectors. If they're not it I guess the valve covers will come off again and I'll break out the stethescope. Good to know I don't need to change valve springs though.

 

If you're running the stock center bolt valve covers, you have to cut out the braces inside because the pro-mags hit. I had to do this with my wife's 89 TA.

 

took it apart again, found a broken inner damper spring this time, must not have looked close enough the first time

 

IMO, 135# seat pressure is way too much for a "factory" roller lifter. Retrofit roller lifters, this would be fine. Are the springs compatable with the hot cam? Id be suspicious of the broken damper. More just might pop too.

You must get the correct springs that go with that cam your using. Then they must have the correct installed height, to attain the proper seat pressure. IIRC, the "factory" rollers should not have more than 110 on the seat. I could be wrong though. Call GMPP, and get the info, if you do not have the cam card.

 

Yes your wrong.. 110lbs on the seat is not enough for a healthy hydraulic roller cam.

One of the most popular springs folks use for 'hot' hydraulic rollers are the comp 987s, which are I think 125lbs..

- Joe

 

I have the comp 977 springs with 150 seat and 430 open pressure with comp r lifters.

 

I decided to throw away the "claimer" (I know, I know, I had a new set left over from my oval track motors) valve springs I was using and ordered some crane 99846s. Wish I would have thought about this stuff more when the heads were getting the guides cut down, should have had the spring seats cut bigger also. the hot cam comes in a cardboard tube with no paperwork just like a stock replacement cam, so I figured I'd use what crane recommends for their cams that are similar to it.

 

I just got a set of these, too, as I'm adding a Crane Powermax to my 305 soon. One thing to consider is, however, that the numbers listed on Summit Racing's site aren't consistent with Crane's own numbers (on their site). To confuse things even more, the sheet that came with the springs gives the same numbers as Summit, so it all boils down to checking these things yourself, or having a machinist do it for you. Also, the Crane tech guy got a little flustered when I told him I was using these with the lower lift hyd. roller (.452/.429). I plan on using some offset locks to hopefully bring the pressure into the 110 to 120 range. If you're "fighting the clock" to get your project done, this is another thing to consider.

 

Yea, Joe 125 does sound right. I was just thinking back about a few years, and remembering that the OEM rollers are not as durable as retrofit lifters. I know that anytime you have to deal with spring pressure, its better to go with more, than less, to keep the lifter on the lobe at higher RPM. Just couldnt remember the correct number. Thanks.

 

Thats weird IMO. What if you wanted to degree it in?

 

I am running 175lbs on the seat and 400lbs over the nose. I am also running the Comp Cams R lifters. The stock ones would not let the motor rev past 5000rpm. Now it will rev to 7000rpm...