Type4: Replace or rebuild

[Speedster72]

The type 4 CB (1700, dual pdsit, 66hp) engine of my bay has broken down. 1 of the valve-seats has been hammered into the head.
(Had some ignition issues on our holiday trip. Which probably overheated the heads as I could not do much troubleshooting while camping)

I took it out of the bus, and this is the situation:
Cylinders probably worn.
Crank has 0.3mm (0.0012") of movement.
Cam has the typical type 4 wear.
And off course a broken head.


I also bought another engine, W engine code (for a 914/VW411, 1700, 80hp)
So far it has no play on the crank (not 100% sure if someone readjusted this).
Similar wear on the cam+followers.
Heads and cylinders not checked yet on cracking, seating, or wear.

Preferably I would like to do full revision on the original engine, but buying all the parts (heads, P/C, cam, bearings) and have the case+crank+rods machined including type 1 cam followers is 3-3.5k.
Or can I save some money by just fitting new heads, 1910cc C/P, Web-cam cam+followers, and shim it to have the correct play?
Case has not been align bored before, but the crank had the 1st grind on main+rod bearings. I probably should get a micrometer instead of a digital calliper to have the full reading and see if they are still round, not oval.

Or am I better off by using the second engine? It has already more HP due to higher compression and different cam.
When checked the the heads+C/P to be OK I can swap the engine tins and carburettors and be ready for installation. But it has the cam wear and a different oil/ventilation setup.

It's not a daily, so it can probably last for a while considering the cam wear. But I should be able to trust the engine when we go on a trip, which is why I ordered a CHT sensor too.

[Alstrup]

You had detonation issues with the 66 hp engine? It must have been freakin´hot, or the ignition timing way off.
Anyway, the 80 hp is a much better set up engine, but If you plan on using the same carbs and ignition (from the 66 hp) you need to rejet.

[oprn]

The CB engine I rebuilt for my Buggy had been run too hot in a Bus as well. All it really needed was a cam (not related to overheating) and another head (one was cracked) and it would have been good to go. The pistons and cylinders, case, crank and rods did not need anything. Measure it all before making a decision or you will waste money.

[Speedster72]

[Multi69s]

Is this going back into a bus? If yes rebuild. I have about a 30 year background in Type 1 based engines. However, in my Squareback (see sig) I put a Type 4 in it. I know some of the physics, but not all. However, I can say this, The Type 4 based engine is a torque monster compared to the Type 1. I believe that if you switch to a Type 1 based engine, you will be very sorry.
_________________
69 road Bug 2110
73 Squareback - 2L, T4, Automatic W/ AC
Gone, but many fond memories 69 Baja Bug 2010 - 5 Rib Bus Transaxle
Gone but not forgotten 72 Baja Bug 2010
My builds
T4 into Squareback http://www.thesamba.com/vw/forum/viewtopic.php?t=458944&highlight=
Auto Trans Rebuild http://www.thesamba.com/vw/forum/viewtopic.php?t=516066&highlight=
AC in Squareback https://www.thesamba.com/vw/forum/viewtopic.php?t=...highlight=

[oprn]

[jpaull]

[oprn]

I have been wondering the same as you. More torque is generally associated with a long stroke and smaller bore but the type 4 is the opposite. I know the heads flow much better, is that it?

And yes there is a big torque advantage with the type 4 engine!

[Alstrup]

A 66 hp bus type 4 makes approx 10% more torque than a 1600 dual port type 1 and peaks approx 200 rpms higher.
An 80 hp 1700 makes about 30% more torque than a 1600, but again peaking about 300 rpms higher.
A 2 liter bus engine pulls a good 40% more torque than a 1600, but peaks at the same rpms
A euro spec 2,0 914 pulls approx 50% more torque than a 1600, again peaking 3-400 rpms higher.
So the term torque monster is not what I would use about them. That said, if you take an 80 hp 1700 and couple it to a 3 rib transmission you would probably feel that if you did not know better. An 80 hp 1700 pulls about 1000 rpms more rpm. and therefore have a wider work zone so to speak. That is probably what you fell.
A built type 4 can be made to bleed a lot of torque. So can a type 1. The main difference is that the type 4 can handle it much longer than the type 1.

[Multi69s]

The problem is that most doubters or unbelievers have never done a side by side comparison between a Type 1 based engine versus a Type 4. I can also tell that no one read my Type 4 engine installation into a Squareback thread that is my signature (its a sticky). I really don't give a rat's fart about published numbers, but I'm more concerned about drivability. I used to build screamers, but those days have passed. If I want an adrenaline rush, I just jump on my dirt bike (a TM 300EN that produces 55HP).

In my write up I compare my 69 road bug that has a 2110 with a Scat ultra light crank, Carrillo Porsche length rods, a 110 cam and dual Webers 44s against my Type 4 build. It is in a Squareback with a 3 speed automatic transmission, plus air conditioning. So right there I am talking more weight, and we all know that an automatic trans (especially a 3 speed) is not setup for performance, so the Squareback is at a disadvantage from the start.

The engine is also very mild. Its a 2 liter with 1700 heads, and a Scat C25 cam.

I live in the San Joaquin valley, which means that any road trip I take involves going through a mountain range. Not trying to be condescending, but for those of you that live back east, what you call a hill, we call it a slight incline. For those of you that live in CA you know what I am talking about ( the Grape Vine, Pachinko Pass, etc). Yet it is these hill climbs where the difference really shows. When we do a day trip, we always take the Square, because we get a lot of stares, and people thinks it looks really cool.

When we go its me and my wife plus two kids and a dog. also the front trunk and back storage area is full of ice chests, beach stuff extra cloths etc. So when we go, we are really weighted down. So what am I getting at? with my bug with the 2110 and two people, if I get behind slow moving cars or Semi's and loose speed, I have to down shift to build my speed back up. However in the same situation with my fully loaded Squareback, it just pulls. In fact the transmission doesn't even kick down to second. So yes in comparison the Type 4 engine is a TORQUE MONSTER compared to a Type 1 based engine. In fact the difference is like comparing a gas Truck to a diesel. I should know because this is how I roll when I go for a week of adrenaline fun in the desert (sometime I take a Baja, others our dirt bikes).

_________________
69 road Bug 2110
73 Squareback - 2L, T4, Automatic W/ AC
Gone, but many fond memories 69 Baja Bug 2010 - 5 Rib Bus Transaxle
Gone but not forgotten 72 Baja Bug 2010
My builds
T4 into Squareback http://www.thesamba.com/vw/forum/viewtopic.php?t=458944&highlight=
Auto Trans Rebuild http://www.thesamba.com/vw/forum/viewtopic.php?t=516066&highlight=
AC in Squareback https://www.thesamba.com/vw/forum/viewtopic.php?t=...highlight=

[oprn]

I for one am not doubting that they do produce more torque, the question remains - WHY?

[Multi69s]

Just to dispel another myth. Using the engine oil to heat your VWs really does work.

When we hit the desert in December, Night temps will drop to 25 degrees, and day temps 40 if we are lucky. Yet with this setup, we are toasty warm.
_________________
69 road Bug 2110
73 Squareback - 2L, T4, Automatic W/ AC
Gone, but many fond memories 69 Baja Bug 2010 - 5 Rib Bus Transaxle
Gone but not forgotten 72 Baja Bug 2010
My builds
T4 into Squareback http://www.thesamba.com/vw/forum/viewtopic.php?t=458944&highlight=
Auto Trans Rebuild http://www.thesamba.com/vw/forum/viewtopic.php?t=516066&highlight=
AC in Squareback https://www.thesamba.com/vw/forum/viewtopic.php?t=...highlight=

[Multi69s]

[jpaull]

[Alstrup]

Hey Multi69. Nice solution with the A/C. I have never seen that before. Cool, - litterally

WRT the type 4 seeming/being more torque oriented than the type 1 has one immediate explanation. That is that the I/E ratio is almost 10% less than the type 1 (stock) which helps tremendeusly in making better torque in the low to midrange rpms.

Now, with your set up there are 3 obvius reasons to why you have a torqey type4 and that you feel it so much compared to the type 1.

1. The type 3 Aut transmission is very low geared (3,91 final) which makes the engine rev just shy of 3300 @ 60 mph with stock tyre dia. (Assuming that you are using the factory type 3 Aut.) That will easily compensate for the engine having to pull the A/C and then some. So you have a lot of power reserves below driving rpms. Also with the Aut. The engine will almost always be in its comfortzone due to the converter.

2. Your 2 liter engine is laid out for torque in more than one way. First, the C25 is a rather mild cam which generally is designed for more torque than hp. Next, the E heads on a 2 liter displacement works very well, with a little more static compression, even better.

3. Last, you are still using heaterboxes. They are only about 1,3" ID, which again aids the exhaust side in not to be over efficient at lower to mid rpms. They will of course also limit the upper rpm power to a certain extend, but not much on such an engine. Think of it this way, you are basicly running a 2 liter with what is equivallent to a 1 3/8" (shorty) header.

With that in mind we compare it to your 2110 type 1.
First you state that you use a W110 cam. It is 1 group above the C25 in the type 4 engine, which will - naturally make the engine "come in" later.
Without knowing your engine I´m pretty sure you have some big valve heads on it, and possibly not that high CR. 44 IDF´s, 1 5/8" header etc etc. Now, I know the W110 is a VERY popular cam, but it is - still - not a cam that produces that much lower end torque as such. If I am right with your heads, and you maybe have had some porting done, there is a reasonably good chance that your I/E ratio is well up in the 70´s possibly even low 80´s. That reduces power below approx 3000 rpm. which again aids in your observasion that the type 1 is not torqey. I will agree with you, it is probably not. But you are really comparing apples to oranges.
I can make you a 2 liter type 1 that will pull the same lower rpm torque as the type 4, but the type 1 wohnt handle quite as high a constant load as the type 4. As I think I wrote earlier that´s where the type 4 really shines and why it was eventually chosen for the busses.
(As a bonus info I can tell you that it was actually in the plans to use the type 4 pwerplant in the type 1 cars too. But the purchase of Auto Union put a stop to that and the Golf was developed out from preliminary plans from Auto Union. I´m sometimes thinking, a Super beetle, with a 412S engine,,,, That would have been a GTI killer in those days and also a true collectors item.( But that´s a totally different story. Back to topic

T

[FreeBug]

[jpaull]

My apologies to Speedster72 for derailing your thread.

Alstrup, Freebug, Oprn, and the others, I started a new topic here regarding Type 4 Torque:

https://www.thesamba.com/vw/forum/viewtopic.php?p=9173678#9173678

If anyone has input on Speedster72's original post feel free to help. Scroll up a few posts to see where it left off with Oprn posting the last on-topic reply.

[Alstrup]

Yes. Got it Jeff.

WRT speedster72
I still say use the W engine. Even with the 34 Solex from the 66 hp engine it will still pull 75ish hp and have more usable power and better fuel efficiency. (You most likely need to rejet)
Use the "P" distributor from the bus engine and check that it has max (30 degrees w.o. vacum) advance at 2800 rpm.

[oprn]

Is the W head not a 3 bolt intake and the CB a 4 bolt? Will that effect what he uses for carburation?

[Alstrup]

No, W is 4 bolt.
The only 3 bolt heads are 2 liter 914´s, which also have a different plug location.