Monster 2786 Type 4 build

Hoffmann Automotive Machine (HAM) in Watkinsville, GA has been the go-to for Type 4 heads for a long, long time. Have your guy talk to Len.

That’s gonna be one hell of a sexy looking hot rod, Jimmy.  I gotta get a ride in it sometime.

Stan Galat

 Thanks Stan you sent me to the right place! I may consider ordering a pair of LE200 heads. According to Len Hoffman of Hoffman Automotive they are the most up to date highest performing type 4 head available with ceramic coated valve chambers and Thermobaric coated exteriors, with the highest flow and highest port velocity. They are made by HAM using AA head castings from China. According to his site the Chinese castings have improved since their launch. Hoffman Automotive stopped taking any used type 4 and 914 heads in to rebuild or repair in 2017 because they weren't getting any in that were in goo enough shape to repair. From 2017 forward they have only sold new heads built from first AMC castings (their quality declined) and now AA castings FYI. I love this forum, what a treasure of info and great people.

Ok, my engine builder now has all the parts in to build my 2786 Type 4 engine. He has started on the heads, taking them apart and checking everything. He is giving all the valves a competition 3 angle grind and cleaning up and cc'ing the combustion chambers and lastly cutting the heads open to fit the cylinders for the 104mm pistons. He will then install the old bearings on the new 82mm crank and rod assembly and mock it up in the engine block so he can rotate it to find the places that will need to be ground away to make clearance. The new crank, rods pistons,& flywheel will be sent out to be balanced together as a unit. Ask Alan how much this makes a difference in how an engine runs. The 2276 Type 1 that I just sold was balanced like this and it would zip up to 6k no problem and sound great doing it. I haven't trusted many type 1 engines to do this. I estimate that the engine will be finished by the 2nd week in Sept.. I have Rancho building me a Pro Suby transaxle just like the one in my Subaru powered Speedster. Why? the trans in the Puma needs work and it is a stock geared 4.12 R&P unit and I know and like the gear ratio of the Pro Suby unit built in a Rhino case and it will work well with the Type 4 for the time I run it and the Puma will be ready for this winter when Carey converts it to a 2.5L suby engine with heat and A/C. The monster type 4 will be placed on the market for sale. More to come soon.

... and so it begins...

Jake told me my valve-train was good to 7500. My crank/rods/pistons/pulley/pressure plate were all dynamically-balanced as a unit. My motor pulls strong and balanced up to 6500, peak power is at 6K though so I usually keep it under that.

But yes, what a glorious sound a well-balanced easy-revving motor makes!

My engine builder sent me some more pics and a video today. The cylinders will need to be cut down to get the correct deck height to make 9.5:1 CR. He has mocked up the crank, cam and connecting rods in the engine block to find out the areas that need to clearance ground. This has been completed, now the crank, pistons rods, flywheel and clutch assembly are all being sent out to be balanced at a shop that builds top fuel drag engines. This shop will also be cutting the cylinders down to the size we need. I am looking at 3-4 weeks before the engine is finished. I can't wait to hear the engine fire up. 

Just thinking about how, if you fused the crankshafts of two 1300cc Type 1s, the resulting FLAT 8 would still be smaller than this. 

 David at Rancho just called and they are shipping the Pro Suby Rhino cased transaxle they just finished building for me. It is a twin of the trans in my Speedster. It will work well with the torquey type 4 or a Suby engine if and when I go that route. I love the one I have in my Speedster so ordered one to replace the squealing transaxle currently in the Puma.  I should have the engine and Trans ready to go in before the months end.

Except for an IRS notation, that looks just like the tag on my transaxle!  Greg says I'm in the cue for some big work next week.  I'm all tingly.

Hey Michael, is Greg building you a coup? what engine are you running? Is it a Suby? If so you will love the gearing of the rancho Trans. It isn't an inexpensive item but worth every cent. Good luck with the build. Post lot's of pics.       

Hi Jimmy!

Yes he is.  Link to the thread in this post.  Short answer Suby 2.5, Z-head with porting, aftermarket FI (stinger), Rancho Pro-Suby w/Peloquin torsen diff, AirKewld Wilwood 4 pot discs (so I can easily change to 5X130...also not T-bone anything!). Lot's of other stuff (AC, heat defrost) too numerous to list.

I spent a lot of time researching before I designed and then pulled the trigger.  Listened to you, Stan, Danny, Alan, Art, Bob, Paul, Troy, Theon....everybody I guess.  I had been explaining choices in my last few posts there.  I'll continue that soon.  Been hellishly busy for a few months. 

Here's the link: https://www.speedsterowners.co...a-coupe-build-thread

Michael

The snowball keeps on a rolling. Instead of using the heads that we had with 42/36 valves and stock ports, My engine builder has ordered a set of hot cylinder heads with 48 intake and 38 exhaust, dual valve springs and stage 2 porting with welded up and match ported intake manifolds. The heads will now be more inline with the large displacement of the engine. Now I am thinking of going with 48 IDF carbs instead of the 44's I have. This thing has truly turned into a monster, mores ways than one.

HAM heads?

Hoffman, yes.

@Jimmy V. posted:

Hoffman, yes.

This one will be special. Cam?

I approve of the head/valve/port enlargement. You're going up 40 percent in displacement, after all.

I mean, 2.8 liters is well into what they used to call the "Big Bore Group" back in the early days of sporty cars. It's why you still see 240 Zs racing against five-liter Camaros on Labor Day weekend at Lime Rock. 

I am running what I think is a relatively mild cam but the engine builder tells me it is what I want. It is a Webcam 86A  it has 290 advertised duration and .435 valve lift with 1.1 ratio rockers( is 1.1 what bus type IV heads have?) the rockers in my heads are 914 type which are 1.3 ratio so that calculates to .514 valve lift    ( .435 divided by 1.1 =  a .395 lift at the cam multiplied by 1.3 = .514 valve lift.) 

@Jimmy V. posted:

I am running what I think is a relatively mild cam but the engine builder tells me it is what I want. It is a Webcam 86A  it has 290 advertised duration and .435 valve lift with 1.1 ratio rockers( is 1.1 what bus type IV heads have?) the rockers in my heads are 914 type which are 1.3 ratio so that calculates to .514 valve lift    ( .435 divided by 1.1 =  a .395 lift at the cam multiplied by 1.3 = .514 valve lift.) 

Thanks, Jimmy. That is a very mild cam for those heads, but it should be a torque monster with all that displacement. I'll be very curious how you like it.

Aircooled says this cam is .435 lift with 1.3 rockers. I think that is mild, as is the 252 degrees duration at .05. It also says the powerband goes to 6000 rpm, which ... how? 

By way of comparison, the Engle W125 in my little 1914 has an advertised lift of .460 with 1.1 rockers and 262 degrees duration at .05 lift. The dyno charts on these engines, as built by Raby with 8.5-1 compression, dual springs & Weber 44s, show peak torque (circa 125 ft-lbs) at 4000 and peak HP (122-ish) at 5500. Raby revved them to 6k on the stand, losing 2-3 hp off peak, before shutting down.

Judging by chatter on the forums, lots of Type 4 players love the Webcam 86A, and I would not challenge the judgment of a real, experienced engine builder, but I am curious to learn how such a small cam would be deemed optimal for such a large engine, as built for such a light vehicle as the Puma. 

Raby loved the 86b in Big Type 4s, back when he was sharing information. 

I also love my 86b in my type1. Along with the 1.5 rockers(cam designed for 1.4 or 1.5). I've got .575" lift at the valve, which is on the edge of maximum.

Conventional wisdom on a LARGE type4 such as Jimmy's is to cam them up, as they already have major torque built-in.

But at the end of the day, Len Hoffman knows far more than any of us armchair engine designers. I'll bet the motor will be great, as the man who built the heads is the man who knows the best cam for them.

All I can say for sure is that Jimmy is my spirit animal. He’s not shy about going big. 

We shall see. I have been assured the 86A is plenty cam with the 290 duration. I want an engine that makes plenty of power and torque in the 1500-5500 range not in the 3500-7500 range. The lower valve lift will make the stress on the valvetrain less. I will have plenty of valve size and cam duration to compensate for the lower lift. The combustion chambers will still fill plenty fast. If I don't like the way it runs with the 48/38 ported heads I will go back to the RAT 42/36 heads and use the big heads on a different build or sell them. My engine builder is the one who is saying the 86a is the cam to give me the end result I have asked for not Len Hoffman.

 The bottom end of the engine is together and waiting for the heads to be built. Once the heads arrive the cylinder bottoms will be cut down to give the desired deck height giving 9.5:1 CR. Now to be patient and wait...

Jim DuBois’ killer T1 in the silver lightweight outlaw Al Merklin sold a couple of years back was built similarly— huge heads, lots of displacement, and a very small cam (the same one, unless I’m mistaken).

That engine also flew in the face of conventional thinking, and was by all reports a monster.

As an interesting comparison, here is the tag I got with my Engle 120 cam - It's damn close to Jimmy's spec.   It sits in a 2,110 that pulls like a train from 1500 to over 5 grand and I'm very happy with it.

Oooo....   I have the Mofoco head specs, too.  Single HD valve springs (recommended by my solid tappet Hot Rod friends to save my cam lobes) and I'm supposedly running 8:1 C/R.

Nice mild combo and it's been going strong for like what? Two decades?

A W120 cammed 2100 with decent heads is the absolute sweet-spot for these cars. They are zero muss-'n-fuss, long lived, cool running perfection. I'd probably run more compression than 8:1, but we're quibbling here.   

Yeah, Ed - 20 years from day zero and running better than ever!

Well, it’s 8.3:1 C/R, but not quibbling. 
That was because I was asked if I might run 87 octane gas in it.  It runs fine with a tank of 87 but I usually run 89 or higher.  

But you’re right, Stan - Just hop in and drive it for 20 years with only minor issues.  

@Jimmy V.

I'm a little lost. You were on TheSamba yesterday asking about AA Stage 2 48x38 heads. I went to AA's site and saw a picture of the heads you put up a few posts above.

Are you getting AA heads, or Hoffman Automotive Engineering heads? Either way, I'm following this build closely, as the T1 engine you just sold was a masterwork and a screaming value. The cam choice is super-interesting, and I'm waiting anxiously to hear your thoughts about how it runs in your Puma.

Keep posting-- I love this stuff.,

@Gordon Nichols posted:

Yeah, Ed - 20 years from day zero and running better than ever!

Well, it’s 8.3:1 C/R, but not quibbling. 
That was because I was asked if I might run 87 octane gas in it.  It runs fine with a tank of 87 but I usually run 89 or higher.  

But you’re right, Stan - Just hop in and drive it for 20 years with only minor issues.  

I'll never forget your saga of the broken rocker adjuster on your son's wedding day!

Stan:  I was wanting to know if anyone has tried the AA heads because according to the Hoffman website their head castings come from AA Performance because the AMC heads starting having quality issues.( I just pulled a pic off of a search of images of type 4 heads that had porting work.) I was curious how the finished heads from AA ran in case we have to wait too long from Hoffman. What I got from Samba was a bunch of advice and criticism I didn't ask for or want and not anyone that answered my simple question. I made myself stop replying and haven't been back. I forget how good we have it here on SOC even with our small issues, it is still much better then most car based forums. 

That clears it up! Thanks, @Jimmy V. 

Yeah, TheSamba is super-good for picking everything apart. 

Dan wrote: "I'll never forget your saga of the broken rocker adjuster on your son's wedding day!"

Yeah, that was epic.  How many times do you hear about a rocker arm shaft breaking on a VW T-1?  In someone's wedding get-away car?  Like almost never, but there you go.  Occasional rocker arm, yes, but the shaft?  Never.

At least it made it through the off-site photo session before it completely died.  His best friend (who now lives in Sandy Eggo and drives some sort of Porsche dual-turbo thing) came back to the hotel after it died with the news and that he was having AAA transport it to the best Man's house, but the main uses for the car were over and as we all know, it's a mechanical thing and mechanical things can be fixed.  Fortunately, all of the guys in the wedding party are car guys.

That little drama didn't dampen his car-loving spirit, though.  He's still hopelessly in love with cars.  And his wife!  She has realized (probably early on) that he's just like his nutty father.......    

Wedding Escape car before disaster:

The bride, wondering just what the heck she's getting into (and a rare photo of Chris' sister, Anna, in the front on the left - she was used to the "car Guy" thing):

And the dead Pearl, after the hex was put on her......   That's Will, calling AAA:

@Gordon Nichols  Without the distracting cars in background. 

Thanks!   Wish I could do that, but my Photoshop abilities are non-existent.

I was excited to received after 6 weeks of waiting a new Rancho rhino case Pro Suby transaxle. After unwrapping the plastic I was disappointed to find they built it with the wrong length axles. I ordered a trans with long axles and they sent short. Upon contacting Rancho they said the would have it picked up and switched to long axles. The trucking company is going to make out on this $700.00 round trip from Indiana to California and and back. I am glad my engine isn't ready or I would be a little more upset. It gives me more time to clean and paint the underside of the Puma.