Lifter bore clearance?

[bherman]

Hi Guys' I have some questions about lifter bore clearance. The engine I'm working on is a "B" and I would like to run a solid flat tappet cam with approximately .550 lift. Maximum RPM would be 6000-6200. The block I'm working with has lifter bores that measure .9064. A couple may be a little smaller but not much. All of the aftermarket lifters that I have measured are pretty much spot-on @ .904 that would give me .0024 clearance without touching the bores in the block. I've checked several blocks and this seems about typical. I would think just cleaning the bores with a very light hone I'd be @.003 clearance. I don't want to bush the lifter bores unless I absolutely have to. Any thoughts, thanks Brian.

 

[wyrmrider]

bherman
I can ask my machinist tomorrow, they do a lot of lifter bores
I'd send mike jones an e-mail and ask him- It may depend on how near the edge the cam lobe OPENING is to the side of the lifter
The amount of lift does make a difference
what lifters?
if you are going to hone with a brake cylinder hone I'd hit the sharp edge of the oil galley very lightly first and do a couple of strokes and see the pattern
taper and out of round should show up
you really just want to put some cross hatch on the lifter bore not make it any bigger- do you have a small rigid hone?
What were the D.C. lifters undersized or oversized- damn I forget

 

[bherman]

bherman
I can ask my machinist tomorrow, they do a lot of lifter bores
I'd send mike jones an e-mail and ask him- It may depend on how near the edge the cam lobe OPENING is to the side of the lifter
The amount of lift does make a difference
what lifters?
if you are going to hone with a brake cylinder hone I'd hit the sharp edge of the oil galley very lightly first and do a couple of strokes and see the pattern
taper and out of round should show up
you really just want to put some cross hatch on the lifter bore not make it any bigger- do you have a small rigid hone?
What were the D.C. lifters undersized or oversized- damn I forget

Thanks wyrmrider, I would appreciate any info that I can get. It would seem that this would be a common issue, I haven't found a used block that measures, on average, less than .9062. The lifter bore diameters are pretty consistent within a given block and vary more between blocks (small sample). Based on the measurements I'm seeing if you install a new lifter in a good used block bore clearance is probably .0025-.003. Do you think that will cause a problem? Thanks Brian.

 

[wyrmrider]

I did not get down to the shop today- Brothers Cirrus has a P0305 code not plugs or wires, compression's good sooo
i'll go down tomorrow and let you know
I need to ask when the Serdi will be free so I can do my Magnum heads- can't get to it till the end of the month though

 

[Hemirunner]

Anything over .0015” is nothing but excess oil flow and lower oil pressure in my opinion, but sometimes it can’t be helped.

 

[wyrmrider]

That's what HV pumps are 4

 

[dvw]

As long as the lifters rotate it shouldn't be an issue. As far as oil pressure my 572 has .0025 lifter bore clearance. with 45-60 @ idle depending on temp.
Doug

 

[bherman]

Hi Guys', I appreciate your input, thank you. I guess I'd like to know what you think, should I bush the bores or let them go? If I go down the bushing path what issues do I need to be careful of? dvw, do you know anybody in the Detroit area that you would recommend to do this? Thanks again, Brian.

 

[not so famous bob]

Thanks wyrmrider, I would appreciate any info that I can get. It would seem that this would be a common issue, I haven't found a used block that measures, on average, less than .9062. The lifter bore diameters are pretty consistent within a given block and vary more between blocks (small sample). Based on the measurements I'm seeing if you install a new lifter in a good used block bore clearance is probably .0025-.003. Do you think that will cause a problem? Thanks Brian.

I am not a professional engine builder, but after a couple of 426 hemi`s, a couple of sbc`s, and now a 440/505 stroker, I`ve never had that much clearance !!

 

[bherman]

I am not a professional engine builder, but after a couple of 426 hemi`s, a couple of sbc`s, and now a 440/505 stroker, I`ve never had that much clearance !!

not so famous bob, thanks for the reply, if you don't mind me asking what kind of clearance did you have in your 440/505 and how much oil pressure does it have? Thanks, Brian.

 

[wyrmrider]

machinest says 2.5 very usual would not spend money on FT in less than .003
rollers are more critical (also due to more lift usually) bushes them tall
HV oil pump

 

[moper]

More of the issue to me is the potential issues with the cam's lobe and lifter face. Anything that allows the lifter to cock sideways can cause a flat lobe. Oil pressure's easy to control. But the bores are worn - they are trash. In my opinion, for a mild build based on the cam choice, find another block. Otherwise it's a pricey deal to bush the bores.

 

[not so famous bob]

not so famous bob, thanks for the reply, if you don't mind me asking what kind of clearance did you have in your 440/505 and how much oil pressure does it have? Thanks, Brian.

I had about .001 clearance, had too have them straight to even get them in , but they work freely. I did an oil mod. when building my engine , wish I hadn`t, 85 cold, 25/28 idleing when hot. Have to watch it a little closer than I`d like.

 

[bherman]

I had about .001 clearance, had too have them straight to even get them in , but they work freely. I did an oil mod. when building my engine , wish I hadn`t, 85 cold, 25/28 idleing when hot. Have to watch it a little closer than I`d like.

not so famous bob, would you share with me your oil mod and if you believe it causes your low hot oil pressure. The original block that I used for my engine had very similar oil pressure numbers to yours but I discovered that it had huge lifter bores .9095-.910. I assumed that was where my low (hot) oil pressure came from. I'm currently inspecting blocks to find a suitable replacement. Thanks, Brian.

 

[Hemirunner]

I had about .001 clearance, had too have them straight to even get them in , but they work freely. I did an oil mod. when building my engine , wish I hadn`t, 85 cold, 25/28 idleing when hot. Have to watch it a little closer than I`d like.

What oil mod?

 

[wyrmrider]

cam is tapered and lifters have a crown face more than enough to cover the angle that .003 cocked each way top and bottom would generate on a .904 lifter
rollers however do like to roll straight
remember Isky's torridal crowned rollers?
before that everyone ran cylindrical rollers with just a little chamfer on the edges

.910 that's a bunch .006 clearance
remember the cam lobe will push the lifter over the same way
looking for a good block- lotsa luck looking for perfection- just do the lifter bores find a shop with the tooling
more accurate than a steeped reamer- I've had to fix some horrible DIY lifter bore jobs- mostly in BBC- Figures
too bad the Olds lifters are not readily available- I could see reaming to .921
BTW used to use a vertical mill with the block tied down and lined up- much better than trying to locate a reamer in an oval hole

 

[not so famous bob]

What oil mod?

I read about an oil mod on here, guy claimed to be an engine builder . Seemed like a good idea at the time, for full time oiling to the top end. Drilled thru the lifter feed tubes going to the heads , to the main oil galleys running around the lifter galley, and tried setting the full time oiling to the heads, w/ (pills I made) SOME USE JET TYPE ORIFICES in the head surface,TO CONTROLL HOW MUCH. In my opinion this is just plain bullshit, a better and easier way would be to just groove the #4 cam bearing about .020/.030 so oil could pass thru the bearing all time , instead of being timed. It could be eliminated w/ a cam change if it wasn't right for you too. I ended up cutting some alum. rod down to fit in the drilled holes, and tapped the drilled up tubes out bigger for 1/8" pipe x 1/16" compression fitting screwed in and tied together w/ copper line to the other side to feed both sides thru the 1/16" copper tube. The fittings hold the alum. rods in to almost plug the holes in the up tubes to the heads. I think it is probably why I don't have hot oil pressure to suit me. I probably didn`t word this where u can understand it , but that`s what I did. Many don`t like full time oiling to the heads, but it keeps things oiled and cooler up there. Fine line between not enough and too much!

 

[5.7 hemi]

If it’s wet, there’s plenty.

 

[Hemirunner]

Put clear valve covers on and watch how much oil flys around under them. Even with the factory timed oiling, it’s a ton. We also ran clear valley trays and the amount of oil hemorrhaging up around the lifters is amazing...

 

[wyrmrider]

problem with grooving the bearing (we tried the housing) is that you take oil away from the main bearing and the rods it feeds
there are other ways to oil the rockers and shafts