Mofoco Head Problems, Fixes, and Perfomance- Post it all here

[jpaull]

We need a place to keep track of performance, progress, and also problems that happen with these heads. Its nice to have one spot to report back. This is not a feedback thread. Its a technical place to share issues and solutions regarding performance of these cylinder heads.

I'm working on my second set that I have ordered bare, and simply paid to have a shop (Headflowmasters) start from the bare casting and install seats, guides, cut for dual springs, 94's. Also porting and cc work. They worked great, and got my first 12 second quarter mile time in a bug with a very mild setup. They have survived many trips down the quarter mile, abuse llike running without the belt and beating the crap out of it all night, then driving it home after.
But problem is, others see mine working decently and order a set, and dont have the best luck. In fact, 4 samba members/friends got heads that were rendered into door stop material. Door stop could mean that it failed within 100 miles, or it was deemed not worth using on the engine as is because the money/time/effort is more then the heads cost. 4 might not seem like alot, but thats 100% of the folks that I know that wanted a set to try out all ended up total loss and scrapped or salvaged with a price of the amount of work/time/money equal to the cost of the heads.

There are a few different types of situations when this happens. Some get the feeling that the type of work that was done, its not worth the risk to send it back. The sick feeling sits in, and they think, "if i received a cylinder head with the valve spring seat/boss machined totally off-center, and nobody knows what a circle is supposed to look like, or where the center is, i dont trust them to fix it and send it back correctly machined. See this for example, they were so off-center that the pressure from the spring pushing to one side wore the guides in less then 100 miles:

Same head, none of the valves were fully sealing:

For this gentleman, he never complained. He has the means to remachine all the boses, install new guides, and it was more important to do it right then to risk sending it back to the people that did this in the first place. He did this, plus did a full valve job and got things set up right. All is well now. It just cost him 8 hours of work, but he does have a good running set of heads now.

For this one below, the valve guide came loose and the little guide boss that was leftover let go all together. The owner was so disgusted he didnt want anything to do with it and just moved on and spent the money again on a set of heads that just worked, no issues. Sometimes life/time is more important then the lost money.

My second set, There was some valve seat over hang that I could not work with for a performance head. Roy exchanged that set no problem, and i just requested a bare set(3rd set now) to be sent off to be done at headflowmasters and they are being completed now.

Set #2 seat overhang that has been sent back and exchanged:

Im sure there are more. What happend to yours? Pictures? if you fixed them, how did you accomplish the fix?
Or if they worked, how are they running now?
Anyone do any heavy work to them and make some good power/timeslips?

I really want to have a productive thread, from people that have experience with Mofoco heads or do their own cylinder head Machine work/Service/Porting
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[email protected] MPH 1/4 Mile & 8.1 @ 83.7MPH in 1/8 Mile with Mild Type 1 VW Mag Case 2234cc commuter engine in stock weight bug w/only .491 total lift(CB2292 Cam), 42x37 heads, 48idf's, Street tires, Belt on, Mufflers, Pump gas, video of the run here: https://youtu.be/M3SPqMOKAOg

Transmission by MCMScott:
Rhino case, Klinkenberg 4.12, Superdiff, 002 mainshaft with 091 first idler. Weddle 1.48 Third & 1.14 Fourth.

[Alstrup]

As posted in the thread we more or less hijacked

Off set valve guide bosses and incomplete spring seats

Seat from 40 to 43 mm valve to barely clear overhang. Also, bowl only touched.

Correction of valve guide angle to seats
https://fb.watch/6NtXMluwy8/
Exhaust seats pulled and ports welded for enough support, new seats installed. I sadly do not have pictures of that. I forgot.
Also, with these particular heads, 2 valve guides were very loose, only about 1 maybe 1,5/10 mm. pressure. The floor in the rocker box is too high, so the entire spring area is out of whack. Intake ports are located too high so it is was not possible to cut the seat deeper than we could juuuust get a fair spring seat. Had to use shortened Type 4 valves (115 mm) to get 1,5" installed spring height.
The other set I got for another customer almost at the same time were not as bad as these, but we still had to pull seats and weld for proper seat support and lower port shape. (The port shape is an individual opinion, but thats how I wanted it)
I later fixed a set for a Lee something (GB) Forgot his last name. He is a user on here. Basicly the same story.
So, there is room for improvement.
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https://www.thesamba.com/vw/forum/viewtopic.php?t=435993

[jimmyhoffa]

Looking back at my history with my 042 heads (mid 2019 production) now compared to others, I would say I have a moderate case of seat overhang, and a moderate case of guide axis/seat misalignment.

According to the Sunnen VS-1005 valve seat gauge at my local hot rod shop, the contact area of the valve seat ran out about .005" on the worst seat with respect to the guide, and about .002" on the best seat. The .002" seats didn't worry me quite as much as the .005", but in the name of completion I recut them all and had the contact area of the seat stone-finished by the local shop. You can see how my GM gear marking compound printed an uneven pattern on the contact face of the seat. If the spring was installed, it drew the valve down into the seat, printed the full contact pattern, and held acceptable vacuum at my local machine shop. They stated that they have seen heads with similar levels of seat to guide runout that worked, but they would personally try to correct it if it was their build.

In fairness to Roy, he did offer to vac check the heads for me to ensure they met his specification- the decision to re-work the seat geometry to true it to the guide axis was MINE and mine alone. At that point, I was in one of the situations jpaull painted a verbal picture of: I wanted control of the outcome, regardless of the vendor offering assistance. It so happens that I am going to trust this engine to carry me through the mountains of Colorado and the deserts of Nevada and California in less than a week, so I needed to personally ensure that everything was sorted to my liking. I wasn't about to go bouncing through the desert imagining the valve head flexing over to find the seat 60 times a second.

I did not remove the valve guides, but I did paint-mark the spring side of them and made tooling to press on them after I heated them in the oven to see if they wanted to budge, and they did not. I pin-checked the guide diameter after that and re-measured seat runout to ensure I didn't disturb anything. It was all good.

The real beef I have left is that he states that the seat overhang issue essentially only happens on 040 heads, and that us folks with 041s, 042s, 050s essentially shouldn't see that, and if we do, it's something of an anomaly. So, that begs the question: Did all of us "unlucky people" just happen to find each other? Even if the seat overhang was mild and consistent every time (which it is not!) if I'm paying upwards of $700 for anything, I'd like a straight answer as to what it's going look like when it shows up.

Alstrup posted a picture of my exhaust valve seat overhang. That was the worst one dimensionally speaking, but all the others were visually similar. My intake valve wasn't that bad, but did exist. Here's a picture of the intake valve seat, undisturbed out of the box.

I would be in a different mental state with the heads on my engine if the statement was "Yeah there's some seat overhang, but I'm clever about it and the way it presents itself doesn't really matter to flow or head life/seat retention" but that is NOT the way a prospective customer would interpret Roy's statements on this forum. A customer ordering 041's or above would expect, 95-99% of the time, to get heads with minimal or no seat overhang.
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1974 Chenowth 2RL #1244 Street Legal
My other car isn't ridiculous.

[Nightshift]

First I would like to say, hats off to someone that wants to build and sell made in the USA. Problem is just because it is made in the US doesn't always make it better. I am the owner of the heads with the picture of the non-sealing valve and offset guide boss.(100 miles) I chose to do all the required repairs myself as I own a machine shop with the needed tools. I am not in any way a VW expert. That being said I have been doing engine machine work for 4 decades and know what is not correct. I also got tired of dealing with the %^& who answers the phone. If you feel good and need a downer call and get belittled by him. It is free of charge. Dealing with Roy himself has been very good. I can not say anything bad about it. Returns calls and emails and is easy to deal with. I believe he does care.
The reason I did everything myself was the proprietor who owns MOFCO had his "employee" do the work and not correctly. I could not trust it would be done correctly if given a second chance. It is not personal, believe me. Below is the list of what was done to make the heads correct.


Disassembled, cleaned and inspected.
Welded and machined under valve seat area.
Installed new seats and guides, (Bullitt nose)
Machined and welded spring seat area, Machined for dual valve springs.
Installed new springs and set for my cam specs(pressure , coil bind and installed height checked)
Machined head for additional air flow between cylinders.
Quality 3 angle seat and valve work and some nice bowl blending.


Yes they had les that 100 miles on them. Yes I like the port flow and design.

[texastomeh]

I currently have a set of the "new" 042 cylinder heads on order from MOFOCO. I already have a set of their "old" 042's that these will replace on a new build

Since placing the order, I have corresponded with Roy and Paul several times via email checking on the status of the build and with various "technical" questions.

They have always been very responsive in answering my concerns. Per the latest correspondence with them, I should receive the heads within the next few days.

I know that Roy frequents the Forum and has been very active in addressing questions re his cylinder heads. Given the time that has elapsed since I placed the order and the assurances that I have received from Roy regarding my "technical" concerns, I am trusting that I will receive a quality set of cylinder heads. I have no reason to believe otherwise.

If I do have issues, I will contact Roy and attempt to resolve them.

Be assured that I will share the results/outcome - GOOD or BAD.

As I said earlier: I have always been pleased with Roy's responsiveness and willingness to address my concerns - even with my "old" 042's installed by the PO.

THANX and STAY WELL!!

Tom
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A new engine build won't solve ALL of life's problems - only those THAT REALLY MATTER!!!

GETTING old was GREAT - BEING old SUCKS!!

Too bad that the guys that know how to solve all of the WORLD's problems are too busy working on old Volkswagens!!

[Ohio Tom]

I have used several sets of MOFOCO heads.

I have seen a bit of seat overhang. I always clean up the ports anyways so I blend them out.
Crooked valve seats can happen on any head. Especially after a few heat cycles.
CB heads are famous for seats moving after a short time.

Re-cut the seats and then they are good for the long haul( MOFOCO or CB's). Seems like you need to run them for while, then re-do the valve job.

My biggest complaints are:
1. the valves and hardware seem lesser quality. I always buy CB single groove valves, keepers, retainers, and springs. Three groove valves and keepers don't do well in race motors anyways.

2. Although they have more cooling fins, they don't really have much airflow "thru" the head. Hold it up to the light and try to look thru the fins. Most areas are blocked with casting flash. I usually drill out the areas around the exh ports as they need the most cooling flow of any part of the head. CB's Panchito head is far superior in this regard.

3. I wish they would cut the spring seat deeper in the head for more surface area, and the ability to add shims to tune install heights with.


The good:
Never seen a MOFOCO head drop a seat.
Never seen one crack.

[Rome]

[Ohio Tom]

I use a carbide burr ball shaped to knock off the step and blend the seat.
Trying not to make the port any bigger. Just cutting steel only.

[Nightshift]

[Ohio Tom]

[Motor7710]

It's not a "Hey, lets bash MoFoCo"
This thread needed to happen.
As a former quality assurance manager I can tell you the best data that you can get is from real world use. This is like gold! Because it allows you to correct and improve the product. In house testing may not reveal these deficiencies.
Again the best DATA comes from real world usage.

Here's my learning experience.
This about 5miles use. luckily it happened in my garage as I burped the engine.
Could have been worse if I been driving.

The head was repairable just added a new valve guide and I replaced all valves with CBs High rev valves and HD springs with new retainers and keepers
Luckily the piston was fine but I did have to replace the cylinder.

Currently on those Mofo 042 heads I have about 70kmiles of revving the piss out of that 2234cc engine. Those heads are still going strong!
Again it's all about real world DATA DATA DATA
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If it stopped dripping oil you’re probably out of oil!

[jpaull]

In just one page, I have seen the most information complete with pictures and real life evidence then all the pages of arguments and "heresay" in the last 6-10 years. There are many others that have not spoke yet also. Be it fixes, repairs, or success.

Nobody is bashing here. We all want, or wanted to have success with these heads. Some, so badly they are willing to not say a word that they would not work for them. They dont want to raise a fuss, and hope their deal was simply a fluke. Some, so bad they were willing to buy the heads, bare and then spend $1200 extra($2,000 total) to take control and make sure they were done right with all seats/guides and setup done right. Then lots of porting/chamber work to get the performance level up. Then, they got them home and flow tested them more, and spent another 15 hours carefully making more improvements to squeeze out a little more. After that, they turned a blind eye to all their friends that were having issues with heads that were coming out of mofoco that accepted them and tried to run them as is.

The fixes here are priceless to know. Also when its too bad to fix. The valve seat overhang is not a deal breaker for function. But no matter if it will work, i dont have the heart to take a carbide cutter to a seat and blend it down to the port. I just cant. My limit is a cartridge roll blend of the seat to port. If it needs more then that, it needs to be fixed right, or start over. But its nice to know seats didnt fall out because of that for some.

The offcenter guide boss, being off center, its nice to know it can be fixed if there is enough meat left.

Alstrup is one of the most tactfull, and "forgiving" guys ever. When he shows things and mentions them, its really time to take notice.
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[email protected] MPH 1/4 Mile & 8.1 @ 83.7MPH in 1/8 Mile with Mild Type 1 VW Mag Case 2234cc commuter engine in stock weight bug w/only .491 total lift(CB2292 Cam), 42x37 heads, 48idf's, Street tires, Belt on, Mufflers, Pump gas, video of the run here: https://youtu.be/M3SPqMOKAOg

Transmission by MCMScott:
Rhino case, Klinkenberg 4.12, Superdiff, 002 mainshaft with 091 first idler. Weddle 1.48 Third & 1.14 Fourth.

[texastomeh]

Alstrup wrote:

[chrisflstf]

I assume any issues here with mofoco heads are common to all head manufacturers.

Maybe someone can make a list of simple common fixes to improve them. I don’t know how often problems are found. If 4 guys complain it seems like a lot, but out of how many heads did Roy produce? Typical error rates are easy to find, usually in the single digits is common

Can Roy sell bare castings and let someone else finish them? Can he do more detailed work at a higher cost? Maybe there could be more profit in selling heads that were given special treatment? He wont make changes that will cost him time and money. Go ask Burger King to make a better burger and see what you get.

[clonebug]

[jpaull]

[Dauz]

Some years ago, I saw a pair of built 050s that appeared to be worth their weight in gold. Adrian told me they were sent to him bare. He had made a work of art out of them.

[Alstrup]

[DerrickfromNC1]

[Lo Cash John]

A kid near me was talking about MOFOCO heads for his 2 liter build. I personally have had great results from CB CNC heads and have generally pointed folks that way. With that said, I'd love to learn more about the MOFOCO heads and maybe give them a shot if Roy can address these issues.
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