79 Bay Window Bus Square Port Heads

What is WRONG with some people?!?!?!?

I started pulling the heads off the 79 bus engine in my garage. The engine turned freely so I was wondering just why the thing was given up on. Now I know.

Stupid mechanics. Or DPO`s. Either/or.

When I got the head off, it was obvious the combustion chambers had blown out all around the head. And there was a combination of combustion residue and cooked oil in the combustion chambers, the head around the cylinders, and the first couple fins on the cylinders. I found that each cylinder had 2 gasket rings, one bent or broken, and one mostly round.

Someone tried to fix leaky piston rings by adding an additional set of head gaskets!

The valves are nice, there are no cracks in the 3/4 head (I haven`t pulled 1/2 yet), so someone blew it. Sigh.

What`re these heads worth? I have no use for square port heads...

GWB: Top End Refresh

ARCHIVE- GWB Top End Refresh

• Don
• Mon 18th June 2007, 8:12 am

In the beginning...

After the last breakdown, I decided it was time to do a top-end refresh. Goals were:

• Remove heads to fix stripped studs


• Hone cylinders


• Re-ring pistons


• Inspect heads and case for cracks and such

So the decision at this point was whether or not to drop the engine. I decided to leave it in the bus.

I pulled off the carbs and intakes, fan shroud, and tinwork. Dropped the exhaust system and removed the bumper (for ease of accessing the muffler bolts).

Heads

Pulling the heads was a breeze! The only hiccup was the right head had to go down out of the engine compartment instead of up. Big deal.

For this project I picked up a cheapo craptastic 120v 70a arc welder for $80 from Pep Boys. The idea was to weld nuts to the snapped studs to get them out. After much fumbling and one garage fire (!) I got the job done:

(The holes are from trying to drill it out... The steel those studs are made from is HARD!)

I pulled they cylinders off next. Checked for out-of-round (no issue there) and honed them. Then I got one of my new 94mm 2.0 piston rings. Put it inside the cylinder to check gap... It overlapped! Huh?

2.0 Rings by Cofap

A quick micrometer check showed I have 93mm 1800 pistons and cylinders, not 94`s.

Work came to a screeching halt.

I ordered a set of 93mm 1800 rings and got them a couple days later. Work resumed the next weekend.

Inbetween here somewhere I decided to paint my pushrod tubes. Not for looks (nobody but me will see `em), but because I want to easily see and trace any oil leaks I develop. I soaked them in parts dip 12 hours, rinsed them, then hit them with a wire wheel. There was some surface rust on them that needed to be cleaned off.

I then primered them with white Rustoleum, and painted them the next day with white Rustoleum Professional. Not as smooth or shiny as other paints, but the "professional" line has proven itself to me as a tough paint for rattle can...

A few surprises awaited me during the head inspection.

First, one of the heads had a slightly sunk valve and a welded crack:

It seems to me that the sunk valve MAY be from the repair, and the seat is just a bit lower than it should be. If so that`s great. But I`ll be watching that valve closely...

The other surprise was a head gasket:

I`ve no idea just how that happened. It`s like the gasket was sucked into the combustion chamber. A couple mm`s of the gasket are missing, presumably shot out the exhaust long ago.

Pistons and Cylinders

I decided to do away with head gaskets altogether. As has been discussed ad nauseum, the VW factory instructed its dealers and rebuilders to NOT use a head gasket, instead lapping the cylinders to the heads and using shims at the bottoms of the cylinders. So I did the same.

Nice thing about the Victor Reinz gasket sets, is they come with both head gaskets and barrel shims. So I could be prepared regardless of my decision.

I cleaned up the cylinders, checked of out of round (less than .2mm at the biggest difference... looks good to me), honed them to remove the glaze present in the cylinders, lapped them to the heads, and set them aside.

The piston rings were all chrome rings, shiny and in excellent condition. The gaps were even well within specs. However, one ring was snapped: The #4 bottom compression ring. I have no idea how that ring could just break, but it happens to be on the same cylinder as the sucked in headgasket. So all bets are off there...

Using the broken pieces of the old ring and a soft brass wire brush, I cleaned out the piston grooves. Only that one piston had anything in the groves to speak of and needed use of the ring. The rest just needed some light brushing and carb cleaner.

Installing the new rings was kind of a PITA with the pistons still attached to the rods, and the engine still in the bus. Took an extra 2-3 minutes per piston in this condition. So again, no big deal. I forced oil into the ring grooves and smeared it around the pistons, especially on the skirts. Did the same to the cylinders, and using a steel band style ring compressor got the cylinders over the pistons. Smooth as silk, once I realized I should wipe the oil off the compressor BEFORE putting the ViceGrips on it... heh.

I got the heads back on and cross-torqued them. This involves torquing opposite studs. Example: forward center bottom stud on the right, forward center bottom stud on the left. Rear corner top stud on the right, rear corner top stud on the left. The theory is that it reduces strain on the case and helps the studs stay torqued. The heads will be retorqued again when I`m ready to begin reassembly of the valve train. This is a week later, so the heads, cylinders, and case should have had a good chance to settle. This should avoid the necessity of retorquing the heads a few hundred miles down the road.

In the meantime, I pulled the top of the right hand carb off. The symptoms of my last breakdown were fuel starvation, but fuel is flowing smoothly from the tank, through the filter, and out of the fuel pump. So the problem MUST be in the carbs.

Here`s what I found:

Obviously, I`ll be tearing the left carb down as well, just to make sure those chunks of rubber aren`t in both carbs.

Jets (per markings):

Right Carb

• x127.5


• 140

This is where I`m at today, January 20, 2006. Tomorrow I get to see if I can`t finish...

GWB: Dropped Seats Suck

ARCHIVE
Great White Bus
1st Engine Drop

Dropped Seats Suck

At the end of the summer of 2005 I started noticing a serious loss of power, and valve adjustment checks showed the #1 cylinder had a sunk valve seat. Another Type 2 listmember had sent me a 1700 cyl head a while back so I tackled cleaning it up and making sure the valves sealed.

The Windex Test

First thing I should mention is the "Windex" test. What`s a Windex test? Flip the head combustion chamber up. Stick objects underneath to make the head level, and pour Windex into the combustion chambers. Don`t have Windex? Use water, gasoline, etc. Whatever. I just happened to have Windex handy when I initially tested this head.

What you`re looking for is any of the solution leaking past the valves. In my case, one of the intake valves was leaking a measurable amount out the intake port. If it leaked this much Windex at zero compression, imagine how much combustion is getting out at 7:1 compression!

Inspecting the 1700 Head

When I discovered my sunk valve seat, and checked my bank (nada), I decided to see what could be done to the head I was sent. It didn`t have sunk valve seats and the valve tips were all within a 1/4" of each other.

Cleaning Up

Off to PepBoys for some tools. I picked up a valve spring compressor, valve lapping compound, and lapping tools. Total around $20.

I pulled the springs and checked the rock of the valves in the guides first. Barely noticable. Sweet, no new guides needed. But when I pulled the valves out there was a HUGE amount of carbon buildup on all the valves, especially the intakes. I found the source of my leak.

I put a brass wire wheel on my drill press and cleaned the carbon off the valves and set them aside, matched with their springs and retainers, marked to replace them in the same cylinder. Then I went at the seats with a brass wheel on my Dremel. I went through 3 wheels before I was done. That carbon is TOUGH. But I got everything cleaned up.

Lapping The Valves

The lapping compound sold at Pep Boys consists of 2 parts: Coarse and Fine. Obviously you want to use the Coarse compound to cut any large bumps, and use Fine to finish and reduce the scratches.

I spent about 15 minutes per valve for each compound. The valve face and seat were beautifully smooth. Not polished, but absolutely smooth to the touch, and no scratches or gouges were visible. I then cleaned everything up with carb cleaner to make sure none of the grit from the compounds was left behind.

Reassembly

I soaked the springs and retainers in Parts Dip for a few minutes, wiped down, and then wiped with motor oil to resist rust. Reassembly was the same as assembly. Everything went together smoothly with no problems.

The head now passed the Windex test with flying colors. I even tried filling the combustion chambers with carb cleaner (a much thinner solution) and again no leaks found. The head was ready to rock!

Dropping The Engine

We had pulled Troy`s engine a couple weeks before and it was easy as pie. Not so on the GWB. And here`s why:

It`s barely noticable, but the skirt between the fan shroud and the bumper is actually pushed in about two inches. I know, two inches isn`t much. But in this case it was enough to keep the engine from coming out smoothly - The shroud was hanging on the skirt! By the time we figured out that we weren`t going to get the engine out with the shroud on, it was too late. We couldn`t get the engine back on the tranny either!

After much finangling and use of my new three foot pry bar (and destruction of that pretty blue finish on the fan shroud) we finally popped it loose.

Blocking Cooling Airflow

Once it was out, we found some interesting things:

From left to right:

• Spark plug and socket resting on the head over the #1 cylinder


• Handfulls of gunk blocking airflow
• More gunk

It`s a wonder the engine ran at all! This just shows the durability of the Type IV engine...

Pulling The Head

So off comes the head! Well, not quite... I pulled the valve train off the passenger side head, then undid the nuts in the reverse of the torque sequence. I wasn`t worried about the head warping, but didn`t want to unevenly stress the studs and, by extension, the case. I was planning on reusing the pistons and cylinders, using the new 1700 piston rings I bought to tighten things up.

The head did NOT want to come off. I thought this was odd considering the 1700 used copper head gasket rings, instead of lapping the cylinders to the heads. This should have been a warning flag...

After much beating with a rubber mallet, the head finally came off... With the cylinders attached! More beating to get the cylinders free. Then I found there were no gaskets. Strange, but a rebuild is to be expected at some point during 30-some years on the road.

Hmm... The combustion chambers on the head look larger than the ones on my 1700 head. I test fit one of the cylinders to my 1700 head, too big! I grab one of Troy`s 2.0 heads and test fit... Perfect. Ahhh... The engine was upgraded to a 2.0 at some point. It makes sense, since it doesn`t really cost much more to cut the case and head for 2.0 cylinders. It`s what I would have done if I was doing a complete rebuild.

But this left me in a conundrum. I couldn`t use my 1700 rings, and I couldn`t use my 1700 head. The rings weren`t a deal breaker, but the head was. I didn`t have a 2.0 head handy. But Troy did! He has 2 78`s and one engine is torn down for a rebuild. So I got to use one of his heads.

Reassembly

I lapped the cylinders to the loaner 2.0 head using the same lapping compounds I used for the valves. I spent about 20 minutes on each cylinder, and cleaned up with carb cleaner. I put the cylinders back on the pistons and studs (using Troy`s handy ring compressor) and then lined up the head.

Everything went back together nicely. Did the two stage torque on the head nuts and reinstalled the valve train. I then tackled cleaning up the mess on my engine. Grease, oil, dirt, gunk, etc, all needed to go away. I used lots of Purple Power and the garden hose. The engine practically shined after that.

Back Into the Bus

Putting the engine back into the bus, even without the fan shroud, was not easy. Apparently during the prying-banging-cursing session getting it out we bent one of the studs. I was determined to get things back in though, so after much finangling and sweet talking the engine finally slid home.

After hooking the intake and exhaust back up I hit the starter. It barely coughed and died. I was flipping out. Turns out I had forgotten to adjust the valves on the head I just put on. Oops. A quick valve adjustment later and the bus ran tight!

Test Drive

I let it warm up a bit then drove around the block. Aside from clouds of white smoke from the exhaust, it ran strong. Nothing really dramatic but smoother and more consistent power.

Obviously the mixture is off. Also, I forgot to hook up the booster line to the metal pipe in the engine compartment. So there was a great big vacuum leak. I hooked everything back up, but still getting smoke.

I decided to go ahead and head home and play with the carbs later. When I got to adjust them, they balanced easily, and I was able to make the smoke go away. Still not really dialed in, but solid.

We`ll have to see how things go over the winter...