I am starting on a rebuild project on a 616 (1983)engine. This engine has a rebuilt short block with new pistons liners etc. Head and other parts are not done yet.

Since my current engine has a new intake manifold, custom made, and I have adjusted/tuned the IP these will go to the new engine. My plan is to build it to maximum horsepower without adding a turbo. I know this will not be hundreds of horsepower, but I do know that the gains on my current engine have been well worth it. Long term durability is important.

So with goal in mind what cam would you use? Would porting the head be of value? Headers? Any other ideas?

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1977 240D turbo

Two items are needed to make more power, more air and more fuel.

Porting will help, headers will flow exhaust out better.

Cam would certainly help. You might want to contact a cam company to see on a custom cam.

Like Colt Cams. They have a performance profile for a 617. I am pretty sure they might have one for a 616 or can work with you on creating one.
http://www.coltcams.com/

Colt Cams Inc.
2325 264th street
Aldergrove BC V4W 2L5
Canada
Phone: 604-856-3571
Fax: 604-856-3572

Regarding fuel, larger elements (plungers and barrels) for the IP would certainly help. Forum member tomnik has reported great results with his custom elements on an N/A 617.






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1983 123.133 California
- GreaseCar Veg System

Definitely at least run the up-rated cam, springs, levers, and time it in at the most advanced speck, (pre chain stretch).

I have also found that my 616 n/a liked a lot of IP advance on the bottom, so much so that with the advance mechanism advanced the timing it was too much and it did not want to rev, good bottom end torque, but no top end. I want to play with the advance device on my machine to see where it comes in. I would like it to come in real quick to increase the bottom end.

When I had the manifolds off on my 78 616, I was surprised to see how nice the intake ports were designed, didn't have the exhaust off to see the exhaust ports. Be very careful with "porting" as it is real easy to make a port look like it will flow a lot, but in reality, you just killed real life flow capability / velocity. It is like pruning a tree. It isn't knowing what to cut, it is knowing what not to cut if you get my meaning.

My personal opinion is that the biggest bang for your buck would be bigger elements. That, along with what we are discussing privately, will get you a decent running motor.

Depending on your time line, we may be able to work something out in the element department. I will be putting 10mms in my 616 IP this summer, (once my test rig is done), and since you can work with the governor, I would just set the max output, (I hope you saved your rack limiter parts), and let you tune it from there. Just a thought.

It will be a least several months before I have it ready. I would rather take the time to get it just right then hurry it . After all the car does still run good, just uses a lot of oil, so I know that sometime I need to do something.

As for porting, mostly just want to clean up the passages. I need to do some studying on porting before I get into that.

I did save my rack limiter. What size elements would be reasonable? I may look for a spare ip to set up, so I don't have to take my current one off.

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1977 240D turbo

The common element sizes for the MW are 5.5, 8, & 10mm. I originally was going to use 8mm elements, but the availability is sporadic and I did not want to spend time figuring out how to make a part work that I could not get at any time. As a result, I went with a 10mm element, which is a very common size.

Now, it is important that it be understood, that I am altering the helix of the plunger to reduce the capable delivery volume to close to the 5.5mm elements. The goal with the larger elements is not to deliver more fuel, (which they would be capable of), but rather to deliver the fuel in a very short period of time.

I built a turbo MW IP with my 10mm elements and custom injectors, and set the fueling curve to match the turned up 5.5mm IP as close as possible to see how much of a difference the shorter pulse width would make. It was a new animal. Unfortunately, the trans gave out before I could try increasing the fuel, but I was impressed with how it ran with the same amount of fuel it was getting with the 5.5mm elements.

It would clatter when it was cold, and I have an idea on the delivery valves that I will try on my IP, but all in all I was very pleased with the results.

We could look into getting some 8mm elements, I have a guy I think I can get them from for about $75.00 ea, or we could go the 10mm way for an element cost of about $13.00 ea. + I would have to modify them and make new delivery valve holders, (they are different on the elements I chose).

I am also going to modify my IP cam to take advantage of the reduced stroke requirement of the larger elements. I did not have the IP cam modified on the one that I built because the owner did not want to spend the money. I think the modified cam would improve the high speed efficiency of the IP.

Of course we would work out the details privately, but you can get an idea of what would be involved.