Engine and Transmission Tech

tips, technology, tools and techniques related to vehicle driveline components

Go to Thread: PreviousNext
Go to: Forum ListMessage ListNew TopicLog In
Goto Page: 12Next
Current Page: 1 of 2


Moderator
Curtis Jacobson
Portland Oregon
(4308 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Hydraulic Lifter Preload (Buick/Rover)
Posted by: Moderator
Date: May 17, 2009 02:46AM

How much lifter preload is really too much for a street-driven BOPR aluminum V8?

I'm measuring 0.072" to 0.080". I know that's significantly more than Des Hammill likes to see on a "power tuned" engine, but is it really too much for a modest-budget street motor that only VERY rarely sees 5000rpm?

Background:
- this week I bolted Rover 4.0L heads onto my Buick 215 (to move from ~ 8.4:1 to ~10.1:1 compression)
- the Rover heads weren't flat, so 0.010" was skimmed off them.
- using Fel-Pro Permatorque head gaskets (compressed thickness ~ 0.040" to 0.045", right?)
- stock Rover springs and valves (reground)
- stock Buick rockers/shafts
- new but ordinary Sealed Power hydraulic lifters
- well broken-in Kenne Bell ("1XA") cam
- my budget for this job is very low
- I need to get this engine together really quickly if I'm gonna make it to BritishV8 2009

Here's what Hammill says in his book:
Quote:
The average amount of preload equates to between 0.020in/0.5mm and 0.050in/1.25mm of lifter plunger travel, with 0.020in/0.5mm being the optimum. Hydraulic lifters can actually operate successfully with a self adjusting working range of between 0.020in/0.5mm and about 0.160/4.0mm and, as a consequence, are able to compensate for any minor discrepancies, such as cylinder heads or block decks that have been planed.

0.020in/0.5mm is the optimum preload because exceeding this figure can result in lifter "pump up" at above 5000rpm, although its worth bearing in mind that lifter pump up can also occur if the oil pressure is above 65psi/44.8kPa.

Should I worry about this, or just torque everything down and get on with life?

Probably the easiest way to reduce the preload is to add shims under all eight pedestal bases... but where does one find (or how does one make) appropriate shims? (They would obviously need holes to accommodate oil passage.)

How do you guys measure preload? I measured by tightening the pedestal base bolts to 15lbf and then backing the bolts back off evenly until I could just barely/almost wiggle the lifters off the camshaft with a fingernail - then measuring the gap between head and pedestal bases with feeler gauges. Is that a reasonable technique?


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5343 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: BlownMGB-V8
Date: May 17, 2009 10:25AM

Well, sort of but not really. You might get by with it though. Not sure how that measurement will translate to preload considering the rocker ratio, it won't be 1:1. One recommended procedure is to torque down the rocker shaft and then using a wire type feeler gage you check the distance between the retainer clip at the top of the lifter and the top of the piston, with the lifter on the heel of the lobe of course. Another method involves using an old (not deformed) lifter and putting a nut and bolt inside instead of the spring to set it to the desired preload height and then substituting that and checking clearance at the valve tip. Most common is to use an adjustable pushrod, take up the play, do a direct length measurement, add your preload and order the next longer size pushrod. Typically they come in .050" increments, that should be a clue.

But the bottom line is, you're doing a delicate balancing act between preload distance, leak down rate, valve spring pressure, redline, and oil pressure. Some of those factors are unknowns. If you had the luxury of always using the same lifters, always the same build, same valve springs, same redline, same oil pressure and multiple re-do's you might be safe in saying, ".020 is optimum" and it might be perfect for a racing engine. But for a street engine it is not, not by any stretch of the imagination. It only takes one of those unknowns to be off by a little and you'll have lifter noise at idle because .020" just isn't much of a safety margin. Much better to rely on your valve springs to control pump up at redline and use a little more preload to eliminate lifter tap at idle in my book. It might mean a little better quality springs than you otherwise would use, but not all that much more, and I don't know about you, but I despise lifter noise. Unless I'm running solids, which I seldom do.

Also, seldom will all 16 come in at the same height and it shouldn't be a real surprise to see as much as .030" in variation unless you have been extremely precise in all of your build up to this point. So it's best to check every one. With that range of values you can bracket your preload values. A common range is .020-.060". I prefer to shoot for the center point of that range for the lightest preload, often clustering the range around the upper value. With moderate springs I've never found those values to be restrictive of a redline below 6 grand. HTH

Jim


Bruce Mills
Bruce Mills
Vancouver Canada
(71 posts)

Registered:
11/28/2007 09:31PM

Main British Car:
1974.5 MGB Roadster 3.5 Rover

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: Bruce Mills
Date: May 17, 2009 12:02PM

Curtis

I just went through this on another bulletin board
[www2.mgcars.org.uk]

I found the some of the lifters seemed to be within tolerances and some were not. What to do when the auto parts distributors in my area are unable to provide me with shims??

Keeping what Paul H had to say in mind (in the other posting).....
I probably have 30000 + on the engine and it has worked just fine so far so I put it back together and figure the hydraulics will take up the variables.

I have run the car at the drag races several times but seldom run her up to 5000+


FWIW


Bruce



Edited 3 time(s). Last edit at 05/17/2009 12:06PM by Bruce Mills.


MGBV8
Carl Floyd
Kingsport, TN
(3232 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: MGBV8
Date: May 17, 2009 12:07PM

I think the range is .020-.060". Shoot for .040.

Is the intake still off where you can measure it at the lifter like Jim says?

You can make shims out of .020-.040" brass stock trimmed to fit & matching holes punched.

The non-adjustable valvetrain on this engine is one of my biggest beefs, I don't like it!


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5343 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: BlownMGB-V8
Date: May 17, 2009 06:40PM

Curtis, it'll probably run just fine for you with what you've got. .080 x 1.6 = .128", a little heavy but still within the range of your lifters and you aren't wringing it out. Pump up is usually not a problem below 5400 rpm unless your springs are weak to begin with. But check your rocker tip to stem contact for the full range of lift to make sure it's reasonably well centered. That's every bit as important and sometimes requires other changes to correct.

Jim


Moderator
Curtis Jacobson
Portland Oregon
(4308 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: Moderator
Date: May 17, 2009 09:17PM

Thanks guys - very helpful responses indeed!

Carl's range matches what Hardcastle has in his book, "Tuning Rover V8 Engines" (e.g. shoot for 0.040").

I don't have wire-type feeler gauges, but here's a tip: In a pinch, you can use MIG welder wire!
(The two most common sizes are 0.023" and 0.035".)

A tip about motivation:
I was unenthusiastic about this until it occurred to me how rarely I get to create handmade performance parts to go inside my engine. I usually dread engine work because it seems to break down into just four mundane tasks: 1) tedious measurements, 2) scrubbing parts (and inhaling solvents), 3) buying expensive parts, 4) bolting stuff together. Even though pedestal shims aren't remotely challenging to make, at least they're something you can make yourself.

Rover-Buick-Pedestal-Shims.jpg

16ga (0.063") copper shims seem to have gotten me to a preload between 0.020" and 0.040", measured at the lifter. I haven't checked all 16 lifters yet... but the handful I checked were in the range. Jim's points about ratios (1.6:1 vs. 1:1?) are well taken, but something about the geometry doesn't seem quite right to me. I need more food and sleep... but right now I'm headed back out to the garage to check valve tip contact per Jim's suggestion.




Next question... what sort of sealant or gasket maker does one use with a Rover composite (rubberized) valley pan?


Bruce Mills
Bruce Mills
Vancouver Canada
(71 posts)

Registered:
11/28/2007 09:31PM

Main British Car:
1974.5 MGB Roadster 3.5 Rover

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: Bruce Mills
Date: May 18, 2009 12:24AM

It's to late for me now as the engine is almost ready to fire up. but Curtis has given me a couple of great idea's for next winter.

I didn't have much luck with the wire-type feeler gauges I bought but I do have welding rod and should be able to source some copper by next winter to fabricate some shims.

Thanks Curtis


Bruce



BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5343 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: BlownMGB-V8
Date: May 18, 2009 09:05AM

That Rover lifter valley pan will work just fine without any sealant whatsoever, as the rubberized coating will make a perfect seal. Unfortunately it is a one use item, (the rubber compresses) so even if you smeared a little silicone or hylomar sealant on it to make it come back off easily it's real questionable on re-use, but I think I might try the hylomar (sticky, waxy, non-hardening) if I thought I might want it back apart some day. Otherwise the rubber will tear away from the substrate when you remove it.

Jim

Edit: Forgot to mention, I really like your custom made shims. Copper isn't the easiest material to work with and they look real good and ought to work just fine. But I hope you're close to .040 than .020" on your preload.

J



Edited 1 time(s). Last edit at 05/18/2009 09:15AM by BlownMGB-V8.


Moderator
Curtis Jacobson
Portland Oregon
(4308 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: Moderator
Date: May 19, 2009 05:41PM

A couple more comments - and another question.

Measuring rocker preload takes some practice! I was just starting to get the hang of it about time I was done. I think it might have been a little easier if my lifters had come with proper circlips instead of wire retaining springs. The welding wire did work great as a go/no-go gauge. I bent little "L" shaped bends at both ends, and then also bent the overall wire into a bigger "L", which made a pretty handy tool to get into tight places. I think fourteen of the lifters showed slightly more than 0.035" preload/gap, but two or maybe three had less. All of the lifters had more than 0.023".

I only used copper for the shims because I spotted a piece in my scrap bin that seemed nearly the perfect size. It was kinda fun to work with. (One note: especially if you use a saw to cut copper, make sure there are no steel chips around or they can easily get embedded into the soft copper surface.) I hardly ever use copper for anything - just about any metal would be cheaper if you had to buy it special for the job. I started to use steel, but the softer metals are a little easier on my Roper-Whitney hand punch. I punched 1/4" diameter holes, and then drilled the bolt holes out to 3/8".

I'm almost ready to start this engine up. I still need to make a new alternator bracket, and... but I went ahead and spun the oil pump drive with a (1200rpm) drill motor to make sure everything is getting lubed.

I found that I was getting a small river of oil flow from the rocker shaft on the driver-side of the engine, and only an occasional drip from the rocker shaft on the passenger-side. That concerned me, so I called Mark at D&D for advice.

Mark's first suggestion was to remove the slower-flowing rocker shaft assemblies and SLOWLY spin the oil pump. Sure enough, it's getting fed a fat stream of oil and it only took a couple rotations to start flowing.

Next, Mark suggested I check to see if the rocker shafts were assembled correctly. That's when I discovered, to my surprise, that it was the free-flowing driver-side shaft that was assembled wrong. I've marked up a Rover shop manual illustration to show how Mark told me the lube holes in the rocker shaft should be oriented on all BOPR engines. (Mark said to disregard Rover's note about the identification groove.)

BuickRoverRockerShaftAssembly.JPG

It only took a moment to correct the problem on that shaft because all I needed to do was rotate the pedestals 180 degrees relative to the shaft itself and to the rockers. I reassembled the shaft assemblies to the engine...

And I'm still getting a river of oil on the drivers-side compared to a slow drip on the passenger-side. Mark said that actually a drip is closer to normal considering that the drill's speed is a lot slower than the engine's operating (non-idle) speed.

What do you think? Do you think the driver-side oil flow indicates worn rocker bores? (The shaft itself doesn't appear worn, and the push-rod & valve-stem contact pads look good.) What would you do about it if it were your engine?



Incidentally, Mark said that D&D never shims rocker pedestals to reduce lifter preload. They've probably rebuilt as many of these engines as anyone in North America, and they believe the hydraulic lifters are perfectly capable of handling larger preloads than the British books specify, even on relatively high-performance engines. Very interesting! (I assume that on full-tilt race engines they're not using stock lifters.)


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5343 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: BlownMGB-V8
Date: May 19, 2009 06:38PM

On full race engines you would normally use roller rockers and those would be adjustable, making Carl very happy.

I would try pulling the spring away from the rocker and try to wobble it on the shaft. Any wear will be at the bottom of the bushing so twisting it or trying to move it up/down would be the approach, or you could pop a couple of them off and take a measurement. It's pretty common to get wear, and normally loss of oil control does not result from that because the contact area around the oil holes is held tightly together by the valve spring and the lifter preload. However if you've got old rockers on a new shaft the wear patterns in the bushings can open up clearances. Does it leak at all of the rockers or just a few of them?

Jim


MGBV8
Carl Floyd
Kingsport, TN
(3232 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: MGBV8
Date: May 19, 2009 10:56PM

Swap 'em side to side & see what happens.

Adjustable roller rockers & a solid roller cam or even a regular solid lifter cam would be heaven on these engines!


NixVegaGT
Nicolas Wiederhold
Minneapolis, MN
(659 posts)

Registered:
10/16/2007 05:30AM

Main British Car:
'73 Vega GT 4.9L Rover/Buick Stroker

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: NixVegaGT
Date: May 20, 2009 08:50AM

Our engines send way too much oil to the rockers.

Anybody convert to using pushrod oiling? I'm just about to do that. I got my new lifters the other day from TA. They have tiny oil holes on the face of the lifter and it has the oil hole through the top to the rod. I figured I'd oil my rocker shafts that way instead, like the Buick 350, and just plug the oil holes to the heads. I was planning on limiting the oil to the rockers anyway.

I'll have the setup you're talking about, Carl. Solid cam and adjustable roller rockers. I'm pretty excited… well… and nervous to see what happens.


Moderator
Curtis Jacobson
Portland Oregon
(4308 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: Moderator
Date: May 22, 2009 10:57AM

Everything's back together and I put 30 quick miles on the engine last night. It ran great, but would run even better with some carburetor tuning.

To close out this thread, I thought I should report back about the rockers.

Upon close inspection, I found (and remembered) that the rockers themselves are slightly different on the two rocker arm assemblies. Both sets came from the NAPA parts store almost twenty years ago, but apparently one was older stock than the other. One set was date coded 1970 and the other was date coded 1973, but moreover they had slightly different castings for the rockers themselves and different width oil grooves parallel to the bore. (Shafts appeared identical and neither shaft showed any wear at all. Pedestals had different markings, but were dimensionally identical.)

So... it's not clear if the difference in oil flow rate is due to the small design difference, a manufacturing difference, or different amounts of wear.

To at least even out oil flow between the two cylinder heads, I took the reckless decision to reassemble the two rocker shafts such that all the free flowing rockers are lined up with exhaust valves and all the less free flowing rockers are lined up with intake valves. I don't know if that really made sense to do, but at least there's some symmetry to it.


NixVegaGT
Nicolas Wiederhold
Minneapolis, MN
(659 posts)

Registered:
10/16/2007 05:30AM

Main British Car:
'73 Vega GT 4.9L Rover/Buick Stroker

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: NixVegaGT
Date: June 03, 2009 09:40PM

My turn…

shims1.jpg

I figured I'd use these to block the oil passages since I'm converting to pushrod oiling. I made mine out of aluminum... They seem to work great.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5343 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: BlownMGB-V8
Date: June 04, 2009 01:38AM

Hey Carl, what's the recommended preload for a stock Chevy, something like 1 to1-1/2 turns after the lifter stops tapping? At 24 tpi (fine thread) that'd be .040-.060". Now if you add say maybe as much as 20 thou to get it to stop tapping to begin with (which is consistent with the recommended minimum) you're at .060-.080". FWIW.

Jim



ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(974 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: ex-tyke
Date: June 04, 2009 09:13AM

Jim,
When I owned my "65 SB Corvette, the preload was about 2/3 turn after the lifter rattle elimination (done while the engine operating).....this coming from a local Chevy mechanic.


MGBV8
Carl Floyd
Kingsport, TN
(3232 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: MGBV8
Date: June 04, 2009 05:38PM

One full turn, 1/4 turn at a time with a pause in between. A few models require only 3/4 turn.

I didn't really like any method of adjusting hydraulic lifters, so I went with a big, solid lift cam (& roller rockers), many years ago.


NixVegaGT
Nicolas Wiederhold
Minneapolis, MN
(659 posts)

Registered:
10/16/2007 05:30AM

Main British Car:
'73 Vega GT 4.9L Rover/Buick Stroker

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: NixVegaGT
Date: June 04, 2009 08:09PM

How'd that turn out? That's what I'm doing now.


MGBV8
Carl Floyd
Kingsport, TN
(3232 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: MGBV8
Date: June 04, 2009 09:47PM

That was on my '68 Camaro (.560 solid lift, Harland Sharp roller rockers), not my MG.

Harland Sharp has shaft mount roller rocker that probably could be made to work, but they are expensive.

[www.harlandsharp.com]


castlesid
Kevin Jackson
Sidcup UK
(361 posts)

Registered:
11/18/2007 10:38AM

Main British Car:
1975 MGB GT Rover V8 4.35L

Re: Hydraulic Lifter Preload (Buick/Rover)
Posted by: castlesid
Date: June 05, 2009 04:32AM

Both TA Performance and YellerTerra ( Australia) do Rover/Buick specific roller rockers but not worth the money unless for a high revving engine ie over 6500 RPM.

BHP gains to normal rev limit are neglible but reliability is increased and power can be gained for use up to 7500RPM on a race spec engine.

Valve gear geometry still needs to be accurately set for correct alignment of the roller over the valve stem which requires approx 60 thou. off the rocker pillar bases for high lift cams over approx .450 lift and push rod length carefully selected even with the adjustability of the rockers.

Kevin.
Goto Page: 12Next
Current Page: 1 of 2


Sorry, only registered users may post in this forum.