Measuring Engine Case Hydraulic Lifter Bores - Lost a Tool

[Lane66Monza]

This is discussion is about what happens when you lose one insignificant tool from your tool box and what it can develop into afterwards.

Lately, I have been trying to measure the hydraulic lifter bore diameters on 2 FC configured cases I have. I had no luck with just a digital caliper, as the movable jaw straight bar would hit the engine case before jaw could set into the holes. I went to using a telescoping gauge to trap the dimension on it, then I would measure it with the digital caliper. That process always resulted with a dimension below the hydraulic lifters dimension I had nearby as a check tool. The SBC lifter OD is 0.840" and the Vair lifter is 0.839". I was reading 0.838" on the lifter holes I checked. Seeing the readings were smaller than the lifters, I suspected the telescoping tool is not fully contacting the lifter wall, due to the differences in their contours.

Below are the tools I was using. If I could find my mechanical inside measuring tool, there would be no issue. A intensive search of 1 workshop,2 garages, 3 storage sheds for equipment, 5 tool boxes and a for sale bin with tools did not turn up the tool. Onto buyinga new toolas I wasted to much time for a low dollar tool.

Telescoping Gauge Set.jpg (21.57 KiB) Viewed 982 times

6 in. Digital Caliper.jpg (16.47 KiB) Viewed 982 times

Technical Measuring Set, 6 Piece.jpg (17.39 KiB) Viewed 982 times

I found this inside digital caliper, I am going to try on this task. It should be here by Monday. The range of this new caliper is 0.50' - 8.0". Acceptable for the task, but I am looking to get to the 0.0001 resolution. For that capability, my plan is to use a digital micrometer to read the inside digital caliper legs after measuring each lifter hole. The digital micrometer has that increased accuracy range. We shall see how well my plan works. If Plan A doesn't work, Plan B is to get a new Measuring Tools set.

8in Inside Caliper Digital Calipers.jpg (28.92 KiB) Viewed 982 times

Digital Micrometer.jpg (18.08 KiB) Viewed 982 times

If the hydraulic bore measuring technique is successful, I can also use it on the other bores in the case.

[vairmech]

There is a small bore gauge that you can get as a kit that will fit as small as .4"

I think this is the one I have; https://www.shars.com/0-7-1-5-dial-bore-gauge-0-0001

[Lane66Monza]

Ken:

That is a very nice digital bore gage. I wish I saw that 10 years ago. I would have added it to my tool box. Now it is a do you really need it and can a less expensive tool work? I could have gone and got another mechanical measuring tool set for $10 with tax. But I wanted the digital gageI found, as it would give me a initial go-no go indication when locked in the bore.

[Frank DuVal]

I could have sold you a nice three point internal micrometer, but... it only does .5 to .8" Dang!

Good for wrist pin bores, but too small for lifters.

[Lane66Monza]

Nice to learna bout other tools, but you didn't add a photo or a link. Thank you for the info, though. I probably can look it up in my spare time.

[isucorvair]

Seeing some of those gages pictured makes me twitch.

Junk gages give you junk measurements, and for some, you'd be rather off guessing the size than using them...

At work, I manage small Gage Calibration system (small for the company) - with around 7000 hand gages.

Eric P.
DeWitt, IA

[isucorvair]

I could have sold you a nice three point internal micrometer, but... it only does .5 to .8" Dang!


3 points are good for size, but I always use a 2 point as well, for roundness.


Eric P.
DeWitt, IA

[Lane66Monza]

.......
Junk gages give you junk measurements, and for some, you'd be rather off guessing the size than using them...

Eric P.
DeWitt, IA

You buy what you can afford. Major companies can afford high dollar accurate tools. Tools with accuracy home mechanics can only drean of holding. Home shops have to buy the accuracy with what the budget allows. So I am guessing, you borrow tools from work to do project measuring at home. I could borrow for while I was workingat Gulfstream Aerospace. You know, those home mechanics that build $65 million dollar jets. It got stopped around 2004 when something occurred and Gulfstream stopped loaning tools. I only borrowed twice from 1985 - 2004. Now I am retired and on retirement funds, funds are not as lucrative to buy the high priced tools. So I get what will do the job within budget and work with my other tools. So please twitch away, as I show low cost tools I get or home made ones I make to get a job done on my home, land or cars. A twitch is minor exercise, but still exercise.

[tomkeo]

I had a similar problem many years ago while building a 180 turbo motor. The crankcase came from one of my friends who took very good care of this motor however it broke a piston and he put in a new motor. I was very careful to check all the bearing clearances, including the camshaft.
When I started the engine on the bench, it was kind of noisy but I was sure it would quiet down when I adjusted the valves--but it didn't. The oil pressure was low at idle but when I increased the idle speed, the oil pressure came up but the lifter noise continued. I tried a new set of lifters, rocker arms, checked pushrods, even checked rod clearance again with Plastigage. Everything was good.
So I tore down the engine and tried to measure the lifter bores and had the same problems as Lane66. The bores measured maybe 0.5 thousands larger than a normal crankcase, but it was difficult to get a consistent measurement using a telescoping, inside tool. So I cleaned all the oil from the bore and lifter and I could feel the new lifter was SLIGHTLY looser in the noisy crankcase.
So I re-assembled the engine with a different crankcase and started it up. After adjusting the valves, it was quiet as a mechanical mouse. No lifter noise and the oil pressure was normal at idle. I still have that crankcase and can't bear to scrap it. We need some way to internally knurl the lifter bores, then hone them to the correct size. The knurled bore will retain oil better than a smooth surface and should last a long, long time.
This problem will surly become more frequent in the future.
TomKeo

[Lane66Monza]

Thanks, Tom. I am glad I am not the only one who has run into this issue with telescoping dimesional measuring gauges.

[vairmech]

I had a similar problem many years ago while building a 180 turbo motor. The crankcase came from one of my friends who took very good care of this motor however it broke a piston and he put in a new motor. I was very careful to check all the bearing clearances, including the camshaft.
When I started the engine on the bench, it was kind of noisy but I was sure it would quiet down when I adjusted the valves--but it didn't. The oil pressure was low at idle but when I increased the idle speed, the oil pressure came up but the lifter noise continued. I tried a new set of lifters, rocker arms, checked pushrods, even checked rod clearance again with Plastigage. Everything was good.
So I tore down the engine and tried to measure the lifter bores and had the same problems as Lane66. The bores measured maybe 0.5 thousands larger than a normal crankcase, but it was difficult to get a consistent measurement using a telescoping, inside tool. So I cleaned all the oil from the bore and lifter and I could feel the new lifter was SLIGHTLY looser in the noisy crankcase.
So I re-assembled the engine with a different crankcase and started it up. After adjusting the valves, it was quiet as a mechanical mouse. No lifter noise and the oil pressure was normal at idle. I still have that crankcase and can't bear to scrap it. We need some way to internally knurl the lifter bores, then hone them to the correct size. The knurled bore will retain oil better than a smooth surface and should last a long, long time.
This problem will surly become more frequent in the future.
TomKeo

I have looked into doing lifter bore inserts. They are available from several sources, but I just haven't had the need yet with the number of blocks available. Keep in mind I will do a street engine with any block but for the race engine I look for the 95 hp engine or a PG engine code. If you have a 140 or a turbo engine, how do you run it? Probably like you stole it! The blocks are worn out.

[Lane66Monza]

You just missed 2 LM RH cases (PG) that went to the scrapyard. Both those had about 64-67K on them when dragged into my yard.

[vairchet]

I too, scrapped out a bunch of RG, RH, and a couple RN blocks (cases) 'cause no one wanted them.

[Wittsend]

I know a lot of people speak against the high volume oil pumps but in the case of the block that had low idle oil pressure perhaps the volume would have overcome the pressure loss at idle and quitted the lifters? As the days going forward will bring less parts availability workarounds might be needed.

Curious, with the attempt to measure the lifter bores and seemingly producing a .0005 clearance (and still having issues with that) does anyone know how tight the factory clearance would have been? Also any chance that the cut for the oil flow around the lifter might have bleed pressure in one block and not the other? Especially if a higher lift cam was used, or the base circle was cut in a regrind?

[joelsplace]

Good thoughts. I have a case that has sleeved lifter bores. Might have been factory like the welding we all see.

[Lane66Monza]

Just some info from the SBC 350 owners,when they are checking their steel lifter bores.

A standard Chevy SBC 350 lifter bore size is typically around 0.8437 inches in diameter, with most engine builders aiming for a clearance between 0.0012" and 0.0025" when checking lifter bore-to-lifter clearance; a tighter clearance could seize the lifter, while a looser one might lead to oil pressure issues.
Key points about Chevy SBC 350 lifter bores:
Standard size: 0.8437 inches
Clearance range: 0.0012" to 0.0025"
Important consideration: Ensure lifter bores are straight and not tapered

Here is info about aluminum block LS# lifter bores from a performance forum. Some reading on the aluminum block, if anyone is interested.

.0012 is pretty standard on performance engines. A little larger will work but you have to watch out and not get sloppy with the clearance as it costs you a lot of oiling capacity with such an internal oil leak basically. If they are tighter than .0012 they are prone to gall and/or stick. Any looser than about .0014-.0015 I would bush them, and if that's the case it's a no brained to go to a .904 or even .937 lifter to get the benifit of a larger wheel and load capacity. Hope this helps.

No help really for the Vair.

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