Give that slant some more MPG

SixBanger · Dec 4, 2018

I sum myself for what the state of the engine is.

The engine has sufficient compression. He drives okay on both gas and gas. Consumes only little oil by missing valve seals, have been ordered.

No EGR or exhaust system anymore.

I use gasoline as a reference of state of carburetor and adjustment of ignition. Seen that most of you here drive on petrol.
Recently I have the carburetor taken apart and cleaned ultrasonically. New gasket etc in it, I saw that there were some components missing for the acceleration pump (before carb sometimes floats).
Carb adjusted on the basis of manual, adjusting screws 2.1 / 2 CCW
In short, he now runs okay on petrol. Does need a lot of time (+ - 15 km) that it runs well on part load (have a manual choke). When cold, it seems to hold some in with part load (to lean??). This is only while driving on petrol, not on LPG. LPG is starting, running, driving.

LPG system is from Impco. Here you can control the supply of gas through a throttle valve. I have not sat on this yet.

Ignition I have replaced the distribution cap, spark plugs etc. I have not changed anything at the time of ignition.

SixBanger · Dec 4, 2018

I think it's useful if I check the ignition timing.

From the carburetor to the vacuum advance of the distributor, Flashlube is also sucked in.
However, the amount of flashlube is minimal. But with each time move the throttle, both the vacuum is advance and a bit of Flashlube is sucked.
Could it be possible that this affects the vacuum advance? This is not original.

I should say that the connection of the vacuum connection is incorrect.

BudW · Dec 4, 2018

Thumbs up!
That's it.

SixBanger · Dec 5, 2018

Thanks bud.

I intend to make an inlet connection for the flashlube in the older Carburetor Mounting Gasket. This is made of plastic. If it does not work, I can also make a gasket made of aluminum.
I saw on the internet that it is also desirable for this liquid to be injected for the gas valve. So two birds with one stone.

In addition, I am going to look at the timing of the engine.

SixBanger · Dec 13, 2018

Given that I had to disassemble the cylinder head to remove the broken bolt, this offers the possibility to increase the compression of the engine. Like two birds with one stone.

I have now cleaned the combustion chambers. Especially the rooms of cylinder 2 and 6 were dirty. It is also noticeable that the exhaust valve of cylinder 5 has ever been replaced. The outlet valve of cylinder 3 seems to have subsided somewhat. Around 0.5 mm measured between combustion chamber and top of the valve. All other valves contain a size of around 1 mm. After my opinion, this is fine for many kilometers. Currently the engine also uses flashlube to protect extensive valve seat wear.

The head gasket that came off the engine is almost as thick as the new one (1mm).
What strikes me is that in both gaskets no passage for certain cooling water channels. I have shown this with red circles for the gasket, blue circles for the head. Is this fine and has this a reason?

SixBanger · Dec 13, 2018

I have determined the volume of the cylinder chamber. This amounted to a minimum volume of 52 ml.
The packing and the volume above the piston (deck height) provides extra volume of 26 ml.

This equates to a static compression of 8.2: 1.

Specifications camshaft (given from internet) closes the inlet 51 degrees aBDC.
Dynamic compression contains 7.2, which comes down to a dynamic crank pressure of approximately 142 psi, 9.8 bar. This corresponds somewhat to the measured compression (9.5-10.5).

It seems that the head has been little or not flattened for this.

I'm curious which compression ratio is sensible? I would like to increase the compression based on gasoline. Here in Europe, mainly Euro 95 is common. I do not know if this is similar to what you get in the United States as 91 octane?

Later on I intend to adjust the ignition and advance curve. Possibly electronic so that I can adjust it for both petrol and LPG.

I saw a topic on this forum that fellow member had the same question. A compression ratio of 8.7 was recommended here. Can I possibly go higher?

SixBanger · Dec 13, 2018

I am maybe fast! But I think I go with a 1.5 mm cut to 9.0:1 ish static compression ratio. I think this should be a good start point to improve power and efficiency without getting get into trouble.
Today I can bring the head to a specialist in the neighborhood. And I would be able to assemble the whole thing again in the car this weekend.

This was also recommended with the available Euro 95 fuel.
All about the Head... - Slant Six Forum

Oldiron440 · Dec 13, 2018

I photographed this from mopars engine book, it says that a .090 cut on the head will give you a 9.5 cr, I would say that a .060 cut would be 9.0 cr.

Compression ratios are figured with a steel .020 head gasket.
Hope this helps.

Oldiron440 · Dec 13, 2018

I know theres more information on the 6 head milling in the book when I find it I will put it up.
Edit: Ok here's what I was looking for, " to reduce the chamber volume, remove. 0066" from the head surface per 1cc of chamber volume "
Sorry my information is not metric but the /6 is not a metric motor.
That's all I've got...

SixBanger · Dec 14, 2018

Ah okay, so this should go well!

Oldiron440 said:
Sorry my information is not metric but the /6 is not a metric motor.
That's all I've got...

I am currently working to convert the engine into a metric engine. The spark plugs replaced by the European brand Bosch for example.
Now the engine produces no hp and lb-ft anymore, but kW and Nm

For my work I mainly use the metric system. But often combined with imperial units for pipes and couplings.
It is like learning a new language, but designing something completely in another standard units is also an apart. Of course you can convert dimensions for example, but the sense of unity is different.
In your head I can give an idea how big things are or should be, for example, certain machine is going to be. This is something that is learnt with your first language, for me the primair metric units.

Charrlie_S · Dec 14, 2018

Do not use charts for determining how much to mill the head to achieve a specific compression ratio. The charts assume Certain dimensions, that may or may not be correct. Measure what you have now for real dimensions, and CR, then use the formula of .0066 per 1 cc head volume, to determine how much to mill, to get the CR you want. Can't stress enough. MEASURE, MEASURE, MEASURE

PS: Also a slant six head can be milled more then .090, I mill mine between .100, and .120. I know of other slanters that have milled more then that. It is actually possible to mill the head .100 and the block .100, that would give the same result as milling the head .200
Using those numbers and a .041 gasket, stock bore, assuming a deck of .080 (.080-.100 mill), 39 cc combustion chamber (.100-.125 mill) the CR would be 11.7-1 with stock pistons.

SixBanger · Dec 14, 2018

Interesting to see that it is possible to increase the compression even further. But will the CR of 11.7 be paired with a completely different camshaft? I have read on another forum that it is possible to use a 2.2L turbo block piston. In combination with the connecting rods of the 198 slant. Interesting to build a block for real performance purposes. And nice to see that also with this block various adjustments are possible.

During the week I measured a certain size of the block and head. The engine has a considerable deck height. But to what extent do you get into trouble with the valves possibly touching the piston when opening the inlet, for example?

The cylinder head is currently still with the specialist. It took a bit longer than expected, which is not a problem, the threaded rods of the manifolds got in the way.
But are there any adjustments that are easily made on the head when I get it back?

Charrlie_S · Dec 14, 2018

SixBanger said:
Interesting to see that it is possible to increase the compression even further. But will the CR of 11.7 be paired with a completely different camshaft? I have read on another forum that it is possible to use a 2.2L turbo block piston. In combination with the connecting rods of the 198 slant. Interesting to build a block for real performance purposes. And nice to see that also with this block various adjustments are possible.

During the week I measured a certain size of the block and head. The engine has a considerable deck height. But to what extent do you get into trouble with the valves possibly touching the piston when opening the inlet, for example?

The cylinder head is currently still with the specialist. It took a bit longer than expected, which is not a problem, the threaded rods of the manifolds got in the way.
But are there any adjustments that are easily made on the head when I get it back?

View attachment 32648

11.7 CR was just an example to show what could be done, using stock parts. That would only be for very high performance slant six, and it would require a much more aggressive cam. Yes you can also use 2.2 turbo pistons, and the 198 con rods. There are other combinations also. As for piston to valve clearance issues, it depends on the cam, not just the lift, but also, duration, and intake opening point, and exhaust closing point. Again MEASURE.
If you are using a 225 engine, with stock deck height, almost any cam, that is streetable, will not be a problem

Oldiron440 · Dec 14, 2018

There is one thing to consider and that is, if you shave .090 from the head your moving the valves the same amount closer to the piston.

SixBanger · Dec 16, 2018

Given that the cylinder head is still at the machine shop, I checked the distributor. I could easily get it out. I noticed earlier that it looked a bit rusty internally.
The vacuum advance unit seems broken. When I suck on the vacuum connection, it does not work anymore.

This could well explain the higher consumption at part load, highway.
Besides that the Flashlube is also connected to the same vacuum line.

WhatsApp Image 2018-12-15 at 18.53.13.jpeg

SixBanger · Dec 17, 2018

The distributor cleaned and put together. I am thinking to inquire about a digital ignition set. So I leave the faulty vacuum advance unit on it.

Tonight the cylinder head picked up at the machine shop. They have 1.45 mm, 0.057 inch, removed from the head.
In addition, I was told that the head may have leaked during the head gasket. After removing 0.07 mm, 0.00275 inch, the head was completely flattened. This could also see a bit of the soot between the cylinders. So this is also nicely solved.

Tomorrow to install the rest of the parts.

SixBanger · Dec 19, 2018

Currently I have the engine running again. It starts and drives fine.

I have also found a broken drill that has probably been used for drilling the broken bolt in the head. This was in fact in the tap hole of the rear head bolt. I was already looking at why the head bolt did not want to! Probably fallen in after removing the head.

Short video of the slant.

BudW · Dec 20, 2018

If you decide to not use vacuum advance and let a computer take over for ignition timing – I would either reattach the vacuum advance (but leave hose disconnected) OR find a Lean Burn distributor (one that has no mechanical or vacuum advance) and install.
BudW

SixBanger · Dec 21, 2018

Good point Bud. Only do not use the original distributor for the digital ignition. Here the angular rotation of the motor is determined on the basis of a 36-1 trigger wheel.
I leave the original ignition as a backup.

By the way, the trigger wheel will be mounted on the crankshaft pulley. It is still a matter of finding out which method I will fix it.
But I suppose you can easily remove the pulley from the engine with a regular pulley removal tool? Or do you need a variant that is also used for steering removal?

BudW · Dec 27, 2018

Been on vacation for a few days.

This is from my ’77 FSM (Factory Service Manual. I went ahead and made PDF copys from my manual for you (in case you don’t have it):

A person might be able to use a normal balancer tool to remove the balancer with. Install using the balancer bolt might be possible without the official tool. I do not remember installing a balancer on a /6 before – but might have (been 20-25 years ago, so memory cells are not what they used to be).

Checking the timing chain (for excessive play) is always a good thing, if you have the balancer off.
BudW

Give that slant some more MPG

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