ACF cylinders

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flat38
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ACF cylinders

#1

Post by flat38 » Wed Jun 05, 2019 10:01 pm

I bought a set of U cylinders from American Cycle Fabrication in August of 2017. A parts supplier in Europe told me of his experience with ACF cylinders so I started looking more closely at mine. I would like to report what I have found so far so that anyone else with these cylinders will know what to look for.

I ordered my cylinders with fitted pistons. The honing looked good in most of the cylinder but at the top of the bore there was a large drag mark that was rough enough to catch a fingernail on. Further inspection found that the head surface and the base flange were not parallel. I then found heavy clamp marks on the base flange showing that they were not bored and honed with a torque plate. The distortion from the clamping caused the bores to be .015" out of round in the base flange area. The bore was round and the correct size for the pistons at the top of the cylinder. I will have to machine the base flange parallel to the head deck and bore the cylinders at least .020" oversize. I was also warned that the intake nipples may not be sealed very well. I have not checked that yet. The valve seats were far enough out of concentricity with the guides that by the time they were cut to full cleanup, oversize valves were needed.

There were many other annoying and disappointing flaws but they were quite visible. I would not have even thought to look for issues with the bore without the warning I received. The ACF website seems to have gone dark so there is probably no recourse from them.



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Re: ACF cylinders

#2

Post by Andygears » Wed Jun 05, 2019 10:29 pm

First off, thank you for posting and helping someone else avoid their cylinders.

Could you keep us updated on further problems and maybe post some pictures so we could identify them on the secondhand market? Fact is, they're out there now and poor quality deserves to be shunned, especially with many of the people who are out to just make a buck.

My two cents
Andygears

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Re: ACF cylinders

#3

Post by RUBONE » Wed Jun 05, 2019 11:36 pm

If you do a search on ACF you will see that they are not communicating with many customers struggling to get their parts returned, work completed, etc. Not a good thing. Too bad as they were building a good rep and it is all down the tubes right now.
Be careful out there!

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Re: ACF cylinders

#4

Post by flatheadmatt » Thu Jun 06, 2019 2:10 am

I had a complete engine build done by them in late 2016. My cylinder nipples started to leak badly after about 100 miles. To be fair mine had the brazed in KR nipples. I tried many things to seal them but fixes only held temporarily. I have a feeling the paint was why they didnt leak right off the bat.

I spoke with Paul after 6 attempts to reach him. He said to return the cylinders for a new updated set with new fitted pistons. (This was is October 2018). I sent them back hoping I would get a set in return. After 3 months of waiting I got a text response from Denise. After another six weeks and a call from Paul, my cylinders arrived. The new ones are much better castings. They have all the correct casting hallmarks on the base flanges as well. The fins look much better than the previous set. Also I pressure tested the nipples....no leaks. Overall, a much better looking quality set. I have 1000 miles on them and everything seems good so far. Flat38, I wonder if you have an older set like my original ones.....?

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Re: ACF cylinders

#5

Post by Holtvintage » Thu Jun 06, 2019 2:16 am

I was corresponding with a rep in the US for FHP cylinders. He said it would be $1440 for the cylinders bare, 200 for pistons and honed to fit. No valves installed. But suggested kibble brand. I have seen mototechnic from Germany makes and sells cylinders. I think that they are aluminum. I am on the hunt for a set of cylinders and was leaning towards a ACF set. I have had limited experience with them but the items I bought on Ebay were shipped out immediately and were described properly. Any other suggestions for Aftermarket cylinders would be appreciated. Thanks .. PS. I never had any luck getting ACF to answer the phone number from their website.

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Re: ACF cylinders

#6

Post by flatheadmatt » Thu Jun 06, 2019 2:55 am

Personally, I won't do business with ACF again.

What about the new v-twin big twin cylinders? They say Made in the USA.
Anyone try those yet? The price is under a grand I think.

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Re: ACF cylinders

#7

Post by Larry » Thu Jun 06, 2019 1:33 pm

I purchased ACF cylinders directly from ACF about 2 years ago. There was a lot of core shift, which I cleaned up with a die grinder. The cylinders were finish machined to +.003", so that was OK. When bolted down, the manifold didn't line up properly, and I needed to drill the base holes oversize to get it to work. A bubble test showed a bad leak at both nipple rivets. One rivet had been seated poorly with a hammer and punch. I phoned and talked to Paul (I got lucky) who told me it was a common problem that he solves with wicking Loctite. Needless to say, that approach doesn't work. I used JB Weld on the heads of both rivets and that is holding up.

These cylinders are cast in India and finished, I believe, at ACF. They are of a quality that I would expect from V Twin.

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Re: ACF cylinders

#8

Post by Buddhahoodvatoloco » Thu Jun 06, 2019 3:55 pm

""Eloquently stated, gracias..""
Larry wrote:
Thu Jun 06, 2019 1:33 pm
I purchased ACF cylinders directly from ACF about 2 years ago. There was a lot of core shift, which I cleaned up with a die grinder. The cylinders were finish machined to +.003", so that was OK. When bolted down, the manifold didn't line up properly, and I needed to drill the base holes oversize to get it to work. A bubble test showed a bad leak at both nipple rivets. One rivet had been seated poorly with a hammer and punch. I phoned and talked to Paul (I got lucky) who told me it was a common problem that he solves with wicking Loctite. Needless to say, that approach doesn't work. I used JB Weld on the heads of both rivets and that is holding up.

These cylinders are cast in India and finished, I believe, at ACF. They are of a quality that I would expect from V Twin.

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Re: ACF cylinders

#9

Post by chuckthebeatertruck » Thu Jun 06, 2019 9:54 pm

Indeed, at least one run were the India cast cylinders. These same cylinders were also sold by a few different groups for a 7-10 year period in the mid 2000s. Paul claimed to have "fixed" the issues with the last run of cylinders; but with everything, who knows. A couple of years ago, I would have bought what he was saying -- today, I wouldn't trust his word; at all.

Speaking of which, I was one of the first out of the box last year to complain about them. I took a TON of flak over calling them out on the internet. I got threats, nasty phone calls, and a bunch of emails from people who told me I was nuts and just trying to trash Paul's business for self-gain.

Do some reading on the AMCA forum (you don't have to be a member to read; just to post) and you'll see even guys who had been singing Paul's praises have stopped and his "friends" have even posted how they won't continue doing business with him.

As for new cylinders; why would you NOT pay $1440 for brand new FHP cylinders? Anders is one of the best and these are NEW, all NEW, cores and castings. In fact, if you can hold off a few months; Anders will likely be at Davenport (he's been there the last few years) and likely will have cylinders to inspect. I've found messaging him via facebook to be the most reliable these days. drop him a line and see if he'll be there. I know I prefer to see a part before I spend a mortgage payment on it.

As to aluminum cylinders; there are two sets in market or in development.

The one's indevelopment are from Enfield Racing. Bruce A. I likely will buy and put on the shelf a set of enfield racing's aluminum cylinders when they become available -- provided they are 80" and not 74" cylinders.

The ones in market are the mototechnic cylinders. Unless something has changed, they only come in 74"

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Re: ACF cylinders

#10

Post by Holtvintage » Fri Jun 07, 2019 1:56 am

I will be at Davenport come Labor day . I plan on buying a FHP set . It is what it is. It should be the only set i ever have to buy

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Re: ACF cylinders

#11

Post by Blind Melon » Fri Jun 07, 2019 9:52 pm

In 2003 I had a local shop order me a set of FHP cylinders.. They arrived in March of 2004.. I noticed that the outside cylinder diameter
near the flange is 0.125" larger than my original 13 fin ULH cylinders.... The engine seemed a bit more peppy @ lower rpm... I'm guessing
that the ring seal is better with FHP cylinders.... Here we are 15 years later and I'm still running those cylinders and they still don't need
to be oversized... They cylinders weren't cheap @ nearly $2,000 including a bore job to 3.50" but were worth it.. They definitely are as
good, maybe even better than brand new OEM cylnders... Just my opinion ........Oh, I using these cylinders on VL cases with a set of 5 1/4"
stroke flywheels... So their life ain't easy..........

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Re: ACF cylinders

#12

Post by Frankenstein » Sat Jun 08, 2019 1:16 am

Enfield racing's cylinders are 3.4375" bore, Ted's and I believe Mototechnic's are 74 bore only. They have an Iron sleeve, not possible to go to 80" bore with that configuration.
Enfield racing's are a Nikasil treated bore, allowing them to be full sized.
DD

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Re: ACF cylinders

#13

Post by RooDog » Sat Jun 08, 2019 5:04 pm

Blind Melon wrote:
Fri Jun 07, 2019 9:52 pm
..... They cylinders weren't cheap @ nearly $2,000 including a bore job to 3.50" but were worth it.. They definitely are as
good, maybe even better than brand new OEM cylnders... Just my opinion ........Oh, I using these cylinders on VL cases with a set of 5 1/4"
stroke flywheels... So their life ain't easy..........
Wow!!! a 101 Cubic Inch Flathead is more than impressive.
.......RooDog....

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Re: ACF cylinders

#14

Post by Mark44 » Mon Jun 10, 2019 1:46 am

Woody, sorry to hear you're stuck with such poor quality cylinders. I've been wondering how things are progressing on the '38.
Mark

flat38
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Re: ACF cylinders

#15

Post by flat38 » Mon Jun 10, 2019 5:21 pm

Mark, not so much "stuck with" as just figuring out how to fix my way out of a poor choice. It does make for some interesting machining challenges. Other than having a rough appearance, the castings seem to be ok. The problems are from machining processes that were not done properly. I would highly recommend that saving a bit more coin and going with FHP cylinders is the way to go.

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