ACL rod bearings?

[deansbimmer]

Originally Posted by Helmsman

Thanks mate. Did you check HX clearance with plastigage by any chance, or leaning towards STD based on gut feeling?

I can't remember exactly. I think those were showing between the .002/.003 marks. Plastigage is more of a guideline to make sure nothing is seriously wrong than a way to determine with absolute accuracy.

[Helmsman]

Originally Posted by deansbimmer

I can't remember exactly. I think those were showing between the .002/.003 marks. Plastigage is more of a guideline to make sure nothing is seriously wrong than a way to determine with absolute accuracy.

Thanks man, I'll try a reach out to ACL to see what they have to say about HX vs a possible mix with STD. Heading of to the shop next week.

[steven_s]

Interesting, I thought the consensus for the ACL would be to get 8B1580HX model for the extra clearance as that was measured the same as BE's ?

[Green-Eggs]

Originally Posted by steven_s

Interesting, I thought the consensus for the ACL would be to get 8B1580HX model for the extra clearance as that was measured the same as BE's ?

Negative. BE measured STD shells, not HX. Pure HX shell would be too much clearance IMO.

[steven_s]

Thanks, I saw the other thread but kinda went over my head. Was the clearance on the STD the same as BE's offering? Because the HX is the one that's supposed to be "extra" with the 0.001" on par with BE.

[groovetek]

Originally Posted by deansbimmer

I have a few sets of ACL bearings here. They’re good lead/copper bearings, preferrable to oem imo but don’t provide the ideal clearance that BE does. They also make a .25 oversize set.

Sigh I've had my HX bearings running for over a week now.

Engine sounds quieter.

So, this earlier comment was in relation to ACL bearings not offering increased clearance to BE, I'm assuming based on the standard H model, but also now people are saying the HX has too much clearance?

What is the downside to that?

[deansbimmer]

Not sure yet what practical consequences might be in an S65 with slightly too much clearance. Probably nothing to worry about with 10w60. With something like 0-40 the oil pump may not be capable of the volume to maintain pressure.

[Honda]

Originally Posted by deansbimmer

I've used both but would probably lean towards sticking with the std size shells unless you bought the std and hx sets and made a custom upper/lower set..

I am about to buy a set and torn between going with which type. If I am planning to supercharge in near future, would extra clearance (HX) would be better or would you think STD is better choice?

[groovetek]

Originally Posted by Helmsman

Thanks man, I'll try a reach out to ACL to see what they have to say about HX vs a possible mix with STD. Heading of to the shop next week.

I already went through this process as you will see from earlier on. It is possible to mix shells, but this is mainly for the purposes of measuring each journal etc. And using mixing to match all cylinders....

The issue here is "STD" is misleading.

The part numbers in question for those with OEM crank (not machined down) is either 8B1580H-STD or 8B1580HX-STD.

[wingzee]

Originally Posted by deansbimmer

The H-STD is the standard set with OEM clarance.
The HX-STD is the "extra clearance" set (.001 per journal inch)
The H-.25 is the oversize set

Don't confuse extra clearance with oversize. In this context oversize means the shells are thicker to compensate for repaired crankshafts that have had their journals ground down.

I've installed 7 or 8 sets of ACL bearings in engines so far because of BE's inconsistent supply. No issues.

Thanks. I did further research throughout the night:

The Nominal Clearance size for the H-STD (according to Wiki) is 0.0508mm (BE is 0.0610mm), the BMW OEM 702/703 are 0.0432mm - so this actually means the H-STD bearings already offers additional clearance vs OEM?

HX-STD has thinner size walls which mean additional clearance, on top of H-STD (+0.0125mm each or +0.025mm per pair) so I guess if I match a H-STD and HX-STD as a pair that should bring me closer to BE’s: 0.0508mm + 0.0125mm = 0.0633mm?

Any downsides of running a mixed set? I reckon it’s fine as long as they been installed correctly? My feel is a pure HX-STD set might offer too much clearance too as that would be 0.0508mm + 0.025mm = 0.0733mm (vs BE’s 0.0610mm). That said, 0.0508mm is the measurement for a H-STD (none been measured for HX-STD so far).

[pbonsalb]

The factory often uses mixed sets — you order upper and lower separately.

[Green-Eggs]

Originally Posted by wingzee

Thanks. I did further research throughout the night:

The Nominal Clearance size for the H-STD (according to Wiki) is 0.0508mm (BE is 0.0610mm), the BMW OEM 702/703 are 0.0432mm - so this actually means the H-STD bearings already offers additional clearance vs OEM?

HX-STD has thinner size walls which mean additional clearance, on top of H-STD (+0.0125mm each or +0.025mm per pair) so I guess if I match a H-STD and HX-STD as a pair that should bring me closer to BE’s: 0.0508mm + 0.0125mm = 0.0633mm?

Any downsides of running a mixed set? I reckon it’s fine as long as they been installed correctly? My feel is a pure HX-STD set might offer too much clearance too as that would be 0.0508mm + 0.025mm = 0.0733mm (vs BE’s 0.0610mm). That said, 0.0508mm is the measurement for a H-STD (none been measured for HX-STD so far).

There is no downside to running a mixed set of STD and STD-HX. You would be copying BE when you do this.

[groovetek]

Bummer... surely I can't be the only one who is running the higher clearance HX bearings right? This recommendation/consensus of mixing the shells is so recent that I have missed the boat it seems...

I think there's some misleading info over nominal clearance; yes someone measured the ACL 8B1580H-STD and came up with 0.0508mm. I don't believe however this is ACL's "design nominal clearance".

According to the tech data/PDF they sent me before I decided, their 8B1580H-STD nominal clearance is 0.0355 mm and their 8B1580HX-STD nominal clearance is 0.0615mm.

I understand if there's some difference between their intended/targeted nominal clearance vs the actual resulting product's measured nominal clearance (albeit a sample size of only 1 set, and using 1 person's measuring equipment), but from a design perspective ACL aren't targeting 0.0508mm with their 8B1580H, and therefore not targeting 0.0758mm with their 8B1580HX.

[wingzee]

Originally Posted by groovetek

Bummer... surely I can't be the only one who is running the higher clearance HX bearings right? This recommendation/consensus of mixing the shells is so recent that I have missed the boat it seems...

I think there's some misleading info over nominal clearance; yes someone measured the ACL 8B1580H-STD and came up with 0.0508mm. I don't believe however this is ACL's "design nominal clearance".

According to the tech data/PDF they sent me before I decided, their 8B1580H-STD nominal clearance is 0.0355 mm and their 8B1580HX-STD nominal clearance is 0.0615mm.

I understand if there's some difference between their intended/targeted nominal clearance vs the actual resulting product's measured nominal clearance (albeit a sample size of only 1 set, and using 1 person's measuring equipment), but from a design perspective ACL aren't targeting 0.0508mm with their 8B1580H, and therefore not targeting 0.0758mm with their 8B1580HX.

Do you have the literature that shows the nominal clearance for H-STD being 0.0355mm and HX-STD being 0.0615mm?

Problem is ACL don’t specifically measure their RBs before shipping out unlike BEs hence numbers could vary vs BE who does.

[Helmsman]

Originally Posted by groovetek

Bummer... surely I can't be the only one who is running the higher clearance HX bearings right? This recommendation/consensus of mixing the shells is so recent that I have missed the boat it seems...

I think there's some misleading info over nominal clearance; yes someone measured the ACL 8B1580H-STD and came up with 0.0508mm. I don't believe however this is ACL's "design nominal clearance".

According to the tech data/PDF they sent me before I decided, their 8B1580H-STD nominal clearance is 0.0355 mm and their 8B1580HX-STD nominal clearance is 0.0615mm.

I understand if there's some difference between their intended/targeted nominal clearance vs the actual resulting product's measured nominal clearance (albeit a sample size of only 1 set, and using 1 person's measuring equipment), but from a design perspective ACL aren't targeting 0.0508mm with their 8B1580H, and therefore not targeting 0.0758mm with their 8B1580HX.

ACL seem reluctant to quote a Nominal clearance. Their Race bearings are assumingly targeted built engines where clearance are individually measured anyhow which may be a reason.

In my communication they however state the STD shell was targeted around the OEM 702/703. With the housing and shaft tolerances (they use hsg 56.000-56.013, shaft 51.975-51.991, haven’t double checked BE’s numbers), it according to them result in a possible clearance range of 0.013-0.058mm where 0.0508 is ending up towards the top of the range. The assumptions and methods to measure seems different between the vendors which is puzzling but hey, at least we learn a little something along the way.

Chatting with my shop in parallel: They state that even a 0.0758 clearance is nothing strange for an high power engine, and even advantageous for our Nordic climate using 10W60. These guys are engine builders since many years so their opinion counts in my book. Next week I'm off to get HX in, and I feel good about it.

PS. No you are not the first putting in the HX shells - look further up in the thread - so you don't need to feel alone...

[Honda]

Originally Posted by Helmsman

ACL seem reluctant to quote a Nominal clearance. Their Race bearings are assumingly targeted built engines where clearance are individually measured anyhow which may be a reason.

In my communication they however state the STD shell was targeted around the OEM 702/703. With the housing and shaft tolerances (they use hsg 56.000-56.013, shaft 51.975-51.991, haven’t double checked BE’s numbers), it according to them result in a possible clearance range of 0.013-0.058mm where 0.0508 is ending up towards the top of the range. The assumptions and methods to measure seems different between the vendors which is puzzling but hey, at least we learn a little something along the way.

Chatting with my shop in parallel: They state that even a 0.0758 clearance is nothing strange for an high power engine, and even advantageous for our Nordic climate using 10W60. These guys are engine builders since many years so their opinion counts in my book. Next week I'm off to get HX in, and I feel good about it.

PS. No you are not the first putting in the HX shells - look further up in the thread - so you don't need to feel alone...

What if we use oil 0w-40, would the STD shell be better for our engine?

[Helmsman]

Originally Posted by Honda

What if we use oil 0w-40, would the STD shell be better for our engine?

No idea mate. Just trying to build puzzle for my own rb change based on available information.

FWIW the ACL S65 shells are designed for 10W60 like most others so personally would stick to that oil regardless.

[deansbimmer]

Originally Posted by Honda

What if we use oil 0w-40, would the STD shell be better for our engine?

Yes. 0w40 is too thin for any clearances beyond stock. Personally I think it's too thin anyway unless you're in a northern climate.

[wingzee]

Originally Posted by Green-Eggs

There is no downside to running a mixed set of STD and STD-HX. You would be copying BE when you do this.

Great. Looks like I will opt for the H-STD and HX-STD mixed sets then.

[Honda]

Originally Posted by wingzee

Great. Looks like I will opt for the H-STD and HX-STD mixed sets then.

Which one would be the H-STD and which one would be HX-STD ? (lower or upper shells)

[wingzee]

Originally Posted by Honda

Which one would be the H-STD and which one would be HX-STD ? (lower or upper shells)

I am not sure if that matters - yet to order mine so happy to be guided by the experts here.

[deansbimmer]

Thicker shells (H-STD) on the top, thinner (HX-STD) in the cap... You should make sure this combination measures out OK before slapping it into an engine.