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Narrow Deck V Wide Deck

mike newall

Well Known Member
Sponsor
We have been offered an O-540 narrow deck engine that is inhibited, around 900 hours and was sent to the shop for an IRAN 'overhaul'.

Any issues with this motor on an RV10 ?

It is a basic O-540 260hp unit out of a BN Islander, O-540 E4C5 which should convert easily to our spec.

Please discuss and advise, as it is being offered at a rather attractive price ;-)
 
No problem with a narrow deck other than there is a little extra work to make the standard baffle kit fit. I know several folks (including me) who have narrow deck -540's from BPE.
 
Narrow deck

I'll agree. I have a narrow deck built by Barrett on my -10 and the only hassle is tweaking the baffle kit. It's not that hard but a little time consuming. I think it specs a little lighter than the wide deck so you have that going for you as well.

Mark Easton
 
Narrow deck

Does it have the cylinder hold down plates and internal socket nuts holding the cylinders? If so, a cylinder change is a little harder in my opinion

I have a narrow deck O320 on my Hatz
 
I have a narrow deck in my Rocket. Some believe the narrow deck is stronger. It’s the preferred option for high performance versions.
G
 
Mine is a Barrett narrow deck IO-540. I'm not a mechanic or engine builder but someone in a position to know told me when I was shopping that over the lives of a thousand engines, the ND's would have more cylinder base issues and the WD's would have more case crack issues but neither would be common or significant enough to specifically choose one or the other.
 
Sump fitting

Mike

I brought a Aztec c4b5 and changed to d4a5 configuration.
Looking at the e4c5 spec it may have a different sump so you need to find out if it will fit the vans engine mount and cowl.
From the Lycoming operations manual-

Oil Sump (O-540, IO-540-C, -D, -J, -N, -R) – The sump incorporates an oil drain plug, oil suction screen, mounting pad for carburetor or fuel injector, the intake riser and intake pipe connections.
Oil Sump and Induction Assembly (Except O-540, IO-540-C, -D, -J, -N, -R) – This assembly consists of the oil sump bolted to a mated cover containing intake pipe extensions for the induction system. When bolted together they form a mounting pad for the air inlet housing. Fuel drain plugs are provided in the cover and the sump incorporates oil drain plugs and an oil suction screen.

I checked the parts catalog and noted any difference. In my case it was mounting ears and some studs for the prop governor.
As for narrow deck vs wide deck I was told by my engine shop to be more concerned about how many rebuilds the engine had.

Regards

Peter
 
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Mine is a Barrett narrow deck IO-540. I'm not a mechanic or engine builder but someone in a position to know told me when I was shopping that over the lives of a thousand engines, the ND's would have more cylinder base issues and the WD's would have more case crack issues but neither would be common or significant enough to specifically choose one or the other.

I would expect a good portion of the cyl base issues on the ND, is from mechanics not honoring the radius clearance on the base plates or using the early plates without the reliefs cut into them, as called for in the SB. Lyc requires the use of spacers during installation to ensure a proper clearance. These problems can likely be avoided with attention to detail in that area.

Larry
 
I've had both on my -10 and didn't find any significant difference. When switching the baffles from one to the other, the only thing I think that I ran into is a slight difference in the position of the center hole that holds the 2 aft baffles together, and maybe a tiny bit of trimming needed when going to the wide deck. Really nothing significant at all. If it weren't for the cylinder bases, you wouldn't easily be able to tell one from the other.

Another interesting tidbit: The IO-390 comes with internal 12-point nuts, like a narrow deck IO-540, yet the IO-390 is a wide deck engine. That caught me off guard as I thought that if you had regular hex nuts it was a wide deck, and internal nuts it was narrow, but turns out that's not a 100% hard and fast rule once you jump to different engine series.

Also, I agree with the post above where to me, it appears that the narrow deck with the backing plate would actually be stronger in the bases, but the gap spacing would be critical to get right, but would perhaps then be stronger. At any rate, there are probably over 1000 RV-10's flying with each, so you're not going to find any real operational or installation difference.
 
I agonized this decision as well when looking for a rebuild engine. I ended up with a ND from an Aztec and I'm part way through the rebuild process with yellow tagged parts. While the ND's are older engines, there are lots of them out there and if you look at the hot rod shops sending out really nice modified engines (like BPE), you'll see many ND's in the mix.

Because of the age of them, there might be a higher risk of something like a crank/cam being rejected - but the price might justify it. I had to replace all my connecting rods, but came out OK on the crank/cam/case (although it might be this engine's last run per spec).
 
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Weight difference

I bought a WD core from a high-performance engine builder who happened to have it laying around but had experience building up both.

He mentioned that the WD's were about 10 lbs heavier than a ND when configured the same.
 
Just note the slight difference in the prop governor drive ratio between ND and WD engines, not a big deal, just be aware when ordering your governor.
 
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