Inliners International Forums General Discussion Engines Lifter bore center-center

Is the lifter bore center to center distance the same for a 292 as for the 250? I cannot find the dimensions for this on either. I'm going to run a hydraulic roller lifter from Morel if they make one. Does anyone know what will work?

The 250 and 292 cams will swap out. The fuel pump lobe will be in the wrong place so you have to use an electric pump. They use the same lifters.rockers, and heads So I'd say the lifter bores would have to be pretty close.

Yes, lifter bore spacing is the same on both engines. What engine are you going to be building. As Beater said, the camshafts will interchange, but most cam companies don't have cores for a 292 engine, and swapping a 250 core into a 292 can cause other issues as well, like rod to cam interference, 250 cams aren't notched for the rods like a 292 cam is. Also, since no one offers a hydraulic roller cam or lifter specific for these engines, there are many critical issues that need to be considered before someone just trys to make something adapt to the 6 cylinder engines. The lifter length is important, because it has to have the oil groove passage in the correct location to supply oil to the rockers or they will starve for oil. And usually using a reground cam makes the base circle too short to put the lifter in the correct location, so both cam and lifter design together are very important to making a hydraulic roller setup work correctly for these engines. If they have never made a roller lifter for the Chevy 6 before, chances are they will try to adapt a SBC lifter because it has the same GM diameter, but because of other criteria, it will not work in the 6 cylinder engines.

There has also been previous discussion on this subject here before, so you might be able to find additional info searching the archives that might help out.

Thanks beater. I figured some stuff would swap. It seems the 292 isn't mentioned a lot of times when it says it will work for a 250.
CNC, I'm new to the forum so I didn't know exactly how to search specifically. But i'll keep looking. I've been working with Ed Curtis of Flow Tech Induction, he says he can get a roller core for the 292; it will be billet. So I know we need a 292 specific core especially due to the fuel pump eccentric lobe. I've seen mechanical roller lifters for a 250 with the link bar between (Crower and Isky both make one); that gives me a center to center reference but like I said it's for a 250. Thus the question if it would changeover to a 292. I think I heard on here that an Olds V8 hydraulic roller lifter would work for center to center but I don't know about the height. That was a good point CNC.

So I found this older thread on here that spoke about installing an Olds length link bar onto a Chevy Hydraulic roller link bar lifter, if I understood that correctly. Morel lifter company makes a very nice hydraulic roller lifter to convert an Olds to a hydraulic roller cam. http://www.flowtechinduction.com/lunati-hr-link-bar-lifters-oldsmobile/

This could possibly would work right? Or would it need to be a Chevy lifter still?

Easiest way to check: put an Olds hydraulic lifter into a 292. If the oil band is the right height (oil gallery is never vented to the valley in any position you will use - this depends on cam base circle and lobe height) it should work.
You'll need pushrods, and the bottom must fit the new lifter.

Oldsmobile solid roller lifters have been used in these engines before, but the link bar length still isn't 100% correct for the 6 cylinder, and its lifter body length is not correct either, and I have seen instances where they wont work at all because the link bar location is too far down on the lifter body, the hydraulic version is still a totally different story and whole new can of worms that will open up. The best solution is to find and install a lifter made for these engines to begin with. The Iron Duke of the late 1980's had factory hydraulic rollers, thats where I would start searching.

The solid roller lifters made specific for these engines by Crane and others worked 100% of the time, even with small base circle cams, etc... they were just never made in the hydraulic roller style unfortunately.

CNC, thanks for verification. At least that gives me some more ideas. I've seen the replacement lifter for the Iron Duke and it doesn't have a link bar on it. So I guess it uses a dogbone and a hold down of some kind. I'm not familiar with that engine at all. So the problem with lifters I'm mentioning from Morel are that the body isn't tall enough?

Olds tappet centers (per Comp Cams) are 1.877" apart.

Panic, Thanks! Is that the same distance apart as the the 250 and 292?

No, the Olds bore center-to-center is not the same as the Inline 6 bore centers, but it can and has worked in some apps as I mentioned previously, but its not going to work 100% of the time. And whether your instance is one of those cases, its hard to say because it is dependent on other variables, such as the cams base circle, and how the oil groove in the lifter body aligns with the oil galley in the block, and several other crucial items. But again, it goes back to someone trying to make something work in an application it wasn't designed for originally, and no lifter is going to work in the 250 or 292 100% except one that was intended or designed for it be used that way. I know of someone that has successfully used hydraulic roller lifters from a Iron Duke in several 250 and 292 engines, and that is where you should turn your attention.

Just did a quick search. Click the highlighted text here to view some previous discussion on the subject. Hydraulic Roller Lifters

CNC, thanks. Yeah, that was the thread I referenced earlier. Which is also the one where I got the info about using an Olds roller lifter or at least link bar on a Chevy lifter. BTW, I called Isky today, they don't have a roller core anymore or at least the person I talked to said they didn't. I chatted with a rep from COMP that said they can get a billet core for the 292 but haven't in years. He's supposed to email me. I didn't check with Crower or Lunati. Not yet at least.

Roller cams have been discussed a lot here also. Also, the fuel pump eccentric is really irrelevant with a roller cam because mechanical fuel pumps aren't compatible with a roller cam to begin with, so a 250 core can work if they remove the pump lobe. They just need to notch it for rod clearance.

Yeah, sorry if I'm treading over old ground. This is probably old hat to you guys but I have a lot to learn about this. COMP shows a different core for the 230/250 motors and one just for the 292. I think that's encouraging. Now if someone would just make a link bar Iron Duke hydraulic roller lifter...

Maximum link length is the difference between 1 lobe up and 1 down, plus the angle between these points, so it's greater than the lobe itself.
The minimum link length is when both lobes are at equal height, and not too far from the inter-tappet distance.
The amount of slack in the link is partially based on the maximum lobe height, so if what you're trying to do has more lobe than the Olds model (Comp should be able to tell you) you need more slack.

Panic, thanks for that. I thought about the length in those terms. I'm more concerned about it binding when they are at equal height than anywhere else. Mainly due to this not being some crazy grind with a lot of lift. I'm going to see what COMP can do in the way of grinds. I HOPE they can use some modern technology lobe like an Extreme Energy cam.

There is still a lot of R&D that needs to been done before you settle on a cam and lifters. I had Comp quote me on finish grinding some round lobe roller cam billets I made, and they were way too proud of themselves for me to let them do it. Several critical dimensions have to be met before the Olds lifters can potentially work. The cams base circle has to be large enough to make the lifter body set in the lifter bore high enough to allow the oil groove to get a constant oil supply, or the lifter wont pump up, and oil wont get to the pushrod tips. Having too small of a base circle is where the link bars have a problem, that is where they will physically contact the block and have interference issues. Since no cam company has ever explored making a hydraulic roller cam for these engines as a production part, there is no engineering data available for what works and what doesn't, they will be taking a shot in the dark as to what base circle is correct, and whether or not the Olds lifter will even meet the criteria required to work, since it isn't made for this engine to begin with. Comp quoted me over $800 to finish grind my blanks, and I was supplying them with the cam core. Just do some R&D before you pull the trigger on this project, you might get stuck with parts that wont work and aren't returnable.

Oh yeah I've been searching but the info has been limited. COMP quoted me about $835 for the billet core. So I guess it would be wise to err on the side of the largest base circle I can. Any potenial dangers in that? I would rather do this actually to raise the lifter high enough to prevent interference problems between the link and the block. Isky makes lifters with interchangeable link bars but only offer a mechanical lifter for this. BTW, why isn't a mechanical fuel pump compatible with a roller cam?

The 8620 billet steel that the cam is made out of will wear the fuel pump arm completely in two in a very short time, it is only compatible with the softer cast iron material flat tappet cams are made out of. An electric fuel pump is going to be your only option when using a roller cam in these engines.

Also, a bronze distributor gear is also going to have to be used, the stock gear will disintegrate in a few minutes of running on a roller cam if you don't.

As far as base circles go, in a V8, I know the biggest base circle that can be used the better. I think the more potential for lobe design and ramp technology can be used on it. If it's a small(er) base circle, the lobe doesn't have as much distance to use a particular ramp or ramp rate correct?

I did find this. http://schneidercams.com/SOLIDROLLERlifter5211.aspx
I know it's solid roller but does anyone know anything about it? It may not be anything different that what Crower and Isky offer.

There is really only one or two companies that make lifters in the US, and all the cam companies buy from them and repackage them as their own, so its probably one in the same with someone else's im sure.

So I figured out the Iron Duke hyd. roller lifter is just like all of the other factory Chevy hyd. roller cam stuff. The part number I have is a Sealed Power number HT2148. That cross references to pretty much all of Chevy's OEM roller cam engines and any other GM motors that are "Chevy Gen I" motors. Whatever that means. Trouble is, these motors use an OEM tie bar or hold down and don't have provision to mount a link bar on them. So like I say, maybe this is old hat. Sorry if it is.

The OEM tie bar stuff will have to be removed from 80's iron duke motors with roller cams. I have tried getting the parts from GM, no longer supported.
The used parts can then be used in a modified 250 block ( same deck height) a 292 will require something all different.

The tie bar parts bolt to the side cover bolt boss and are made from thin hard spring steel plate.

The Iron Duke came in Fiero's, S-10 and many other GM products, and were all roller equipped by 1986, so finding a used engine core shouldn't be too difficult. We looked at this project a few years back, and determined the Iron Duke lifter was the way to go with this conversion, it was just the other components were the challenge. If you could just find even a picture of these parts, I can make them, and then the conversion would be completed.

Well, honestly, I would rather use a retro-fit link bar lifter if I could. Not that I'm against using the OEM Iron Duke lifter. It just seems that the retro-fit one has all of that taken care and I don't have to hunt what it looks like or how to connect it etc. I talked to a guy from the Lunati tech line today. He says the lifter bore spacing on the I6 family is the same as a V8 Ford. He helped a friend put a roller cam in a 292 using a link from a their Ford lifters.

Back from the dead thread. I finally got Leo Santucci's book for Christmas. The lifter bore center measurement is 1.900 in case anybody was wondering.

I know Kike Kirby had Isky make one or two billet hyd rollers camshaft & lifters for him or a customer.

I never heard of how it worked out, but they were made.

MBHD

That's who I was referring to a couple of posts back. He said the lifters were almost as expensive as the cam.

Yeah guys, I'm pursuing this. I talked to Dave Crower awhile back and they have cores and can make us any link bar lifter we want. However, I rather let Comp grind it so we can use one of their lobes. I have a copy of their Master Lobe chart. Honestly, I would like to use the Morel lifter but don't know the center to center on them.

I would go with the Crower stuff over the Comp simply because Crower has the most premium quality products available, and they have been doing the 6 cylinder stuff longer than Comp, and has more experience and knowledge for these engines and can provide any lobe you want. They have over 9000 lobe masters in-house. And their cams are less expensive. So less money for better quality is always a plus.

Well, Dave and I batted around a few ideas for lobes. We won't use a Comp lifter by any means. It's just my opinion that Comp has more impressive, faster ramp lobes, not necessarily that they do. Talking to Dave, you can tell he knows his stuff.

I talked to Dave quite a bit myself thru the years, and he does know cams very well. They have made more 6 cylinder cams than all others combined in the last 15-20 years, and they know Chevy 6's well also. I think the fact that you can call and talk to him in person or Richard Iskenderian @Isky says a lot about their companies.

I talked to Richard too. He was going to get back with me but didn't. Some preliminary numbers for lobes that Dave ran were 217* .525 I think. I have the numbers at work. I told him I rather use more lift and less duration than that. We may settle on something like 211* .565 or something like that. He was even able to give me a rough estimate on HP and torque with the 217* lobe. It came in a about 287 HP and 320 on torque If I'm remembering right.