26120s on Iron Heads

[CTX-SLPR]

Howdy,

Since the search is down and before it died I couldn't find anything other than recommendations to use them. What is needed to run the 26120 beehives on iron heads?

I'm planning a "big" solid roller and I like the idea of beehives. According to Comp they will fit with a set of Ti retainers I found and they seat and open pressures look to be in the range I was advised for the cam. However the spring is nearly 0.2in larger at the base that the stock springs, how hard is it to open up the spring seats on the heads to fit the springs? Are shims or locators needed?

Thanks,

 

[bison]

It wouldn't be easy to get them to work on a stock head. I wouldn't use them with a big solid roller either. The springs needs to be located somehow. Shims are needed to adjust for the correct installed height. I have 26120 springs that are tested and individually bagged if interested but wouldnt be my choice for a big solid roller.

 

[turbodave231]

I have used a similar Comp cams spring 26995 on both stock iron and champion alum heads. Both hydraulic roller cams. Either spring will require a spring seat/locater on the head. I used spring seat p/n 4696 and had to modify the ID of the seat in a lathe to fit over the stock valve guide. The 26120 has alot more spring rate and a taller installed height. You will have trouble fitting the 26120 spring on the stock head with a spring seat (not enough room).

The beehive spring and small retainer give you lots of clearance between the retainer and underside of the rocker arm.

 

[CTX-SLPR]

The 26995's look promising but a bit soft on the seat. Shimming them to a shorter install height limits the lift and/or rocker ratio that I can use and still only gets me ~150lb on the seat. While that's closer to what I was looking for, I'm not sure it's enough.

bison, can you recommend a spring for a big solid roller on iron heads? If possible to work with 1.25 OD and 0.65 step retainers?

Thanks,

 

[bison]

I think I have something that will work. What net lift? You're going to need 3/8 pushrods no matter what. It will need to be a double spring. Locating the outer spring o.d. or the outer springs I.d. Will be required. If you locate the outers I.d. then the inner spring will be sitting on the locator for more pressure. If the net lift is under .620" what I have in mind should work but require machining the spring seat area around the guide a little. I'd also drill the rocker mounting holes deeper and use a bottom tap to get more thread and a good hard stud setup. There will be a lot of pressure on the 3 mounting pedestals.

 

[CTX-SLPR]

bison,

Sounds like you've got what I'm looking for. Max lift even with 1.65:1 rockers is under 0.60 at the valve. Will these work with the retainers I mentioned?

Sounds like I need to add a bottoming tap to my list of machine tooling to purchase. I'm sure I'll need to clearance the pushrod holes for a 3/8in pushrods. Don't solid lifter normally have oiling restrictors in them so I don't flood the heads?

Thanks,

 

[bison]

.600 is a small solid. The hyd i spec approach a theoretical .600" sometimes. What I have will get you about 200lbs on the seat and 520-540 over the nose. Plenty of spring for 6500rpm capability. If this is a stock block without bushed lifter bores you will need a shielded lifter. The reason for the 3/8 rods is because of the over the nose pressure and rpm. 5/16 will bend like spaghetti.

 

[CTX-SLPR]

bison,

It's set up for a stock block with sheilded lifters. I'll be using a set of KB 1.60 adjustable rockers with the cam. Please send me a PM on the cost for the springs and what locators I'll need to use.

Thanks,

 

[bishir]

I hope this means you're getting close to finishing that Riviera.

 

[davinci50]

Would the PAC 1518/1218 have to be located as well ? They have a similar spec, But I don't think they'd be good for a solid cam.

 

[CTX-SLPR]

I hope this means you're getting close to finishing that Riviera.

Working on it. Being cold outside makes it easier to search for parts for the new engine than to work on the Riviera. However I did get all of the modules and roughly 2/3 of the wiring that I no longer need out of the car, just have to finish detangling the stuff I do need to keep from the stuff I'm ditching. Oh and seal the holes where the wires used to go through. probably just use plugs for now, weld up at least the outside hole next time I have the fenders off.

Back on track, how much above coil bind should I run springs? 1.5x the wire diameter? 0.040in?

Thanks,