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Swap questions

P

Phillapierre

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Hey guy,

Long time reader, I have a couple decision to make on a swap. First the two beast being swapped.

1) receiver. 1996 p-32 motorhome with sidemount turbo GM-4. 130000km. Blow-by. 4l80e trans. Draft tube for crank case vent. Single t sat. A/c deleted. Custom oil cooler and line.

2) Donor. 1997 GMC 3500 pick up manual trans with Tuna can crank case ventilation. 160 000km and 400psi cold compression

The decision I have not made yet are.

1) draft tube or tuna can
2) dual thermostat or single thermostat.
3) to rering or not rering

Should I buy a second turbomaster and swat the GM-8 in place of the GM-4.

Any other thing I should pay attention to.

Thanks
 
Last edited:
Running the cdr vs open air venting is an emissions issue.
The best option if legal in your area is to use a catch can without a cdr as it will stop all the oil fumes and vent nothing. Provent 200 is the best fit for this engine I found as off the shelf unit.
Pulling the crankcase into a vacuum of approximately 8” is highly desirable, but hard to achieve.
Just venting to atmosphere will allow the oil fumes to be lost to atmosphere and therefore you are loosing oil. No vacuum is achieved and possible a slight pressure which is bad for oil seals and fights the engine loosing power and mpg. This also means you are killing polar owl trees or something like that, so be careful of regulations before acting.

What waterpump you are running can be as important if not more important than thermostat crossover.
If serpentine belt, you want the pump with spin on fanclutch and only one heater hose connection to it that gets fed from the crossover.
If dual thermostat then use a restrictor in the heater hose. If single stat crossover then it needs to be the block off type.
 
The draft tube was installed like that from the factory so it is definitely legal.

I’m wondering what’s vest for the engine. Not sure I understand how to pull a vacuum with a catch can.

I will install a new water pump, clutch and d-max fan but still wonder wich system to use as I’ve got both on hand. Single and dual. The belt is the typical serpentine Micro-v.

Thanks for the reply
 
Yup to all above options. Catch can vs cdr is he cdr is designed to have less vacuum pull from crankcase at higher rpm, which is opposite everything learned in race engines as well as hyper milage tests on all engines.
Blowby occurs most and bottom of piston crankcase pressurization occurs more at high rpm than low. The only reason the cdr cuts at higher rpm is because it can suck the oilpan dry between oil changes.

Another place you could run the catchcan output is drafting from exhaust post turbo.

Read up on oil dry sump systems and gained power from crank case vacuum to get all details
 
One more thing for the list.

Look for a better intake system. Goal here is to have the intake pressure (post compressor) match the exhaust pressure (pre turbine) as closely as possible where a 1:1 ratio is ideal. IIRC, Quadstar was in the process of making a better setup, but have not tracked its progress.
 
Still pondering on all these answer. My original idea was to use the GM turbo. The intake on the motorhome is unique to this application and pretty well done with a lot less restriction then the pickup intake. I will try to install the round filter element airbox whom should help that as well.
 
You are going through a lot of work, valued at $1000.00, or more to just swap engines. Before you drop 10 cents on the donor engine make sure the mains are not cracked.

Since you are there a deglaze and new rings. You were going to run it with old rings so just a re-ring is good for at least 60K miles. Gapless rings make a big difference in blowby AND oil changes going longer than 2500 miles. Yes, RTFM it's 2500 miles on HD use oil changes! :eek: The oil in my gapless ring 6.2 was clean for 3000 miles not Soot Black after the 1st start after an oil change. UOA was good at 5000 miles. Formerly conventional rings oil was overdone at 3000 miles.

Cam bearings are a good thing to inspect while the engine is out before it gets hot and your oil pressure goes through the floor. A HV oil pump is a good thing to have.

Bunch of cooling system advice above that's all good, but, the exhaust is a BIG part of what keeps heat in this engine to start with. Yes, I am talking about the GMx Asthma Attack turbo GM decided to use on this engine. Bluntly the turbo plugs the exhaust over 2200 RPM and holds a bunch of power robbing "lock the cooling fan up" heat in the engine. Oh Yeah... it also falls flat on its face over 2200 RPM as well.

For this high load applications like motorhomes many have found big improvements in MPG with a non GM turbo. I have personally used a huge ATT turbo towing going from 7.5 MPG to 10.4 MPG towing the grades in AZ. Same route 550 miles a day.
 
Just answering the draft tube question. Will diggest the other afterward. Every picture I’ve seen of 6.5 MH of this year had the draft tube weather the owner was Canadian or American. The only difference between Canadian and American vehicle at the moment are daytime running Light.

What I’m more interested in is the durability and reliability of the different system. I do like the oil catch can one and will consider it.

Anyone ever tried one of the Provent copy out there at 1/10th the price.

Thanks for all the comments.

Another question. With the engine out and the oil pan off, how hard is it to do ring. Removing the engine will be the fartest I’ve been mechanicaly.

Thanks for all the comments
 
Removing and installing engine in an rv can be more labor than the rv costs. over $10,000 is not surprising. It all depends on how your rv is built. That is one issue. Make sure you are covered there first.

Doing rings isnt hard, but you need an large assortment of tools, really watch YouTube videos before just guessing if you can do it.

There are other catch cans out there. Provent works very well. You would have to find people that bought multiple types to compare them. I searched and couldn’t. What I did find is provent USED to make more simple ones and progressed to what they have now. Their tech support folks explained higher percentages of captured oil mist from their older designs to the current.

There is diy ones on here. I copied someones fairly close and ran it on my Mercedes diesel. Worked ok for a bit but failed later.
 
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