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2008 Suburban HD - 8.1L swap (frankenburban 2.0)

fidelity101 said:
in other news of "I'm a dumbass"

I believe some of my issues is my PCV routing setup and probably had an impact on the tune/caused some lean issues. I need to throw these valve covers away and start over, anyone need these fancy baffles?



This is how I had it.

1576954539_proper-pcv_mmthumb.JPG





but this mimics the 6L setup which I thought was okay, but its not...

Realizing I need to get air intake suction from the crankcase I neglected completely this orifice:

1592495321_sdfkjsagsdfg_mmthumb.JPG


there is a NPT port here plugged that is for the medium duty vehicles - they use this port for an oil drain on the air compressor that is attached to the accsesory drive, it runs on the oil from the big block. So effectively I need to do this:

uc


and tune it properly instead of driving it around all the time and mucking with orifice sizes/etc...

but one still the question remains, what size tubing should this be? Its a 1/4" NPT port in the front and a 3/8 NPT in the back, the stock PCV was only a few millimetre port in the throttle body and bottom side of intake manifold. The inlet and outlet of the catch can is also 3/8s"
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I have mine plumbed like this and used a PCV valve at the front of the intake.
 
Rick Capito said:
I have mine plumbed like this and used a PCV valve at the front of the intake.
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which way? the 6L style or using the oil drain plug on the intake manifold routed to the rear intake port?

does it matter where the PCV valve should be? I always see them on the crankcase side from old SBCs/etc with just a host going into drawn air (vacuum)
 
fidelity101 said:
which way? the 6L style or using the oil drain plug on the intake manifold routed to the rear intake port?

does it matter where the PCV valve should be? I always see them on the crankcase side from old SBCs/etc with just a host going into drawn air (vacuum)
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I used the oil drain you can see it in this pic but ended up turning it to the drivers side and the other pic my catch can is behind the power steering reservoir.

IMG_0788.JPG

IMG_0929.JPG
 
Rick Capito said:
I used the oil drain you can see it in this pic but ended up turning it to the drivers side and the other pic my catch can is behind the power steering reservoir.

View attachment 343755

View attachment 343756
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ahh gotcha, I can't tell from the photos - my premium membership lapsed a while back and I sold my K20 burb a few years ago so I never bothered to re-up but people had been interested in this swap so I kept the data here for others. if you don't mind can you email them to me? fidelity101 @ gmail.com
 
Another correction/update. This is a big issue with the 8.1 vs the 7.4. GM says their timing cover fits but really doesn't tell you anything important or relevant because it needs to be modified to fit.

if I teardown the motor I could replace the reluctor wheel on the crankshaft, and use the appropriate PSI 8.8 or IC bus sensor and plus the cost of the overhaul which sounds terrible... this would be the best approach but it is also more involved and costly. The whole front cover has been leaking because its meant for a 454 not a 496 so the oil pans are different, a 454 oil pan would solve my dilemma but it wont mount to the block due to the mounting spacings/locations.


So the timing cover needs to be modified, again poorly described within a paragraph within the 8.1 performance book:

uc



what its trying to say is that this cavity in the GM performance front cover needs to be filled so it can match with the 8.1 style oil pan and gasket.

uc


see how the oil pan gasket basically will just flop around in there? it should ride the edge like you see on the bottom cover, there is a good witness mark for the seal.

either a bunch of RTV or JB weld some aluminum in there so that the cavity is filled and is flush with the pan gasket allowing the pan to work. I have struggled with this issue since the start of the swap and poured too much money into this only to realize this is a terrible idea.

I'm beginning to wonder if I really even needed to trim the balancer shaft per their 'instructions' as well.

here is a comparison across the pans. left is modified, middle is stock and the right one is an umodified GM one.
uc


so ignore all the other garbage I talked about in previous pages in relation to the timing cover and oil pan.
 
I think you still would have had to cut down balancer if using front mount wheel. I cant find my notes to say exact measurement, (oily scrap paper burried someplace lol) but the 8.1 balancer stuck out exactly the thickness of that reluctor wheel too far. Maybe you could use a 7.4 pan gasket as a template, cut out shape of radius out of aluminum and press it in there with some jb weld, then 8.1 gasket should seal against it. Or can you cut section from 8.1 stock cover and make it fit in groove?
 
Drtrider82 said:
I think you still would have had to cut down balancer if using front mount wheel. I cant find my notes to say exact measurement, (oily scrap paper burried someplace lol) but the 8.1 balancer stuck out exactly the thickness of that reluctor wheel too far. Maybe you could use a 7.4 pan gasket as a template, cut out shape of radius out of aluminum and press it in there with some jb weld, then 8.1 gasket should seal against it. Or can you cut section from 8.1 stock cover and make it fit in groove?
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yeah I think so too, just frustrated with GM at the moment. Its like every 2 years I have a major overhaul to do. I have spent more summers fixing chevy trucks than actually working on the race car that the truck is used to tow to events, very backwards situation right now...

The current plan is to have a friend machine a piece of aluminum to fit in the groove and he can likely weld it in there too.

new engine is currently at home, found a low mileage engine from a wrecked truck not too far away:
uc

here we go again! :(
uc


uc

sketchyness is critical but I did it similar to this last go around too...

uc

ta ****ing da, and nobody got a crunched finger, also seatbelts are very strong
 
and about a month later it is in with all the proper parts swapped over, just waiting on fedex to deliver the final puzzles pieces because I neglected to keep my oil cooler line fittings and hoses from the core assuming they would be the same but they are less than 1.5MM difference in diameter! what a joke!

sometime 2003 this happened so this is an FYI for you. be sure to double check the year of your radiator/oil cooler/oil cooler fitting combo before installing everything.
 
fidelity101 said:
and about a month later it is in with all the proper parts swapped over, just waiting on fedex to deliver the final puzzles pieces because I neglected to keep my oil cooler line fittings and hoses from the core assuming they would be the same but they are less than 1.5MM difference in diameter! what a joke!

sometime 2003 this happened so this is an FYI for you. be sure to double check the year of your radiator/oil cooler/oil cooler fitting combo before installing everything.
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doin egr delete?
 
this truck "originally" had an 04-06 style 8.1 it so it had no EGR, yes this has been long removed from this engine but what does EGR have to do with oil cooler lines?
 
well its fixed, drives good and plenty of power, borderline idle oil pressure though however it meets the GM spec.

if anyone wants this truck send me a PM $12,000 comes with winter wheels/tires as well, no roof rack/camper box. my zip is 48328 engine has warranty until December 3rd 2020.

truck currently has 91K miles on it
 
I know you are frustrated, but if its not making noise that 10 psi at idle is probably fine. My brother in law bought a uhaul truck to convert to flatbed to haul steel on and it has 10 as well as do many of them. Not sure why, but it has been super reliable and doesnt use much oil and is quiet as can be. Just a thought, might be okay.
 
Drtrider82 said:
I know you are frustrated, but if its not making noise that 10 psi at idle is probably fine. My brother in law bought a uhaul truck to convert to flatbed to haul steel on and it has 10 as well as do many of them. Not sure why, but it has been super reliable and doesnt use much oil and is quiet as can be. Just a thought, might be okay.
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yeah don't care anymore, ive over it I'm buying a new truck with a warranty. I'm tired of missing race events due to a non functioning tow truck or having to do constant repairs on a vehicle that isn't 100K miles yet. I like racing, not working on tow trucks.
 
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