What is the thought on bushing the lifter bores on a block and installing SBC or other make roller lifters for these inlines? Good: Reduced weight of valve train. Readily available. Much more reasonable. Bad: smaller lifter Increased push rod length Bushing of block Reduced contact area (higher loading on camshaft) Waste of time???
Why would busshing the lifter bores be bad? ( I dont know.. Its why I am asking, but when I read it it seems like a smart ***, but I dont mean it that way.)
The V-8 guys wish they had a fat .990 lifter Rollers are good for some cam profiles and less worries about lobe wear. If you're using a typical reground cam for street use and will use the right oil, the flat tappet cam will last a long time.
What do you hope to gain? Roller lifters allow higher spring pressure and more aggressive cam action, not a big problem on long stroke slow revving straight six motors. You also reduce friction and free up a few HP. I don't see what you have to gain, that is worth the cost. Or that couldn't be accomplished easier some other way. And, where would you get a roller cam?
Roller cam blanks and roller lifters are available. Crower makes lifters. Cams I don't remember. The big thing is that if I am going to spend the money, would the be any benefit over tha stock size roller? With these sixes you look at $100 per Hp. The cam and roller lifters would run $1200-1500. Even with a good flat tappet cam and lifters you are looking at $600-800. I think the big problem would be the guide for the lifters with the small lifter. BTW: this will be on my 12 port jimmy.
That is what I was wondering how are you going to keep them from rotating ? I guess if you bush them the bushings could have a flat but you would have to make sure that they got installed correctly to keep the roller inline with the lobe on the cam!
The roller lifters that McGurk sold for these engines back in the dark ages had a flat on the backside, and you screwed a flat piece of strap iron to the inside of the lifter chamber for them to seat against to hold them in place.....yeah, I know, it sounds pretty cobbed up.
The new ones from crower have slot in them and a rail fits inside the gallery to guide them. Similar to SBC but more crude.
Crower ran a batch of GMC roller lifters a couple year ago that have a ball embedded in the side of the lifter. They sell a drill guide that allows you to slot the lifter bore with a drill bit for the lifter ball to ride in. Supposed to be current technology but not being a serious racer don't know for sure.
If anybody is looking for an original NOS McGurk roller Cam and lifters for a 235 or 261 chevy, I got one for sale on EBay. A steal at $600.
If I was using it on the street and some playing around I wouldn't go with the roller. If its a full race motor I would, and on my 302 I use the Fontana roller with the tie bar. I run monster lift and machined up a second lifter to use in the head to take up the angle to the rocker and run a two piece push rod. On these old engines the lifter bores are off and over half of them had to be bushed to align them. The cam and crank is a another story.
Never go smaller on lifter diameter when high performance is the goal. If one is going to spend the money, Jesel makes the world's best keyway roller lifters in .937”, 1.062” or 1.095” diameters. http://www.jesel.com/valvetrain/index.php/lifters/keyway jack vines
The Jalopy Journal
