My G54B toast ?

[Out Getting Ribs]

Hi, guys,

So... I need a second guess... I'll try to keep this short. Mine is a D50 89' 4x4 with the G54B. I bought it 2 months ago knowing the head gasket was blown and had to be replaced. I've not removed the head yet but I ordered a small bore camera to look inside the cylinders. I think not only the head is gone but also the block looks toasted but I'm not a pro so could you guys give me your opinion?

These are the links for the videos I took, sorry for the quality, the steadiness and my face. I was trying the get an overview of the cylinders but it was not easy. Also a picture of the sparkplug if it can help in any case.

Cylinder #1 : https://youtu.be/YdioWYR03JU
http://www.mightyram50.net/vbulletin/attachment.php?attachmentid=26855&stc=1

Cylinder #2 : https://youtu.be/0z55KMRKgZc
http://www.mightyram50.net/vbulletin/attachment.php?attachmentid=26856&stc=1

Cylinder #3 : https://youtu.be/McEKgVCTtJg
http://www.mightyram50.net/vbulletin/attachment.php?attachmentid=26857&stc=1

Cylinder #4 : https://youtu.be/WaIXsQHhF50
http://www.mightyram50.net/vbulletin/attachment.php?attachmentid=26858&stc=1

Cylinder #1 & 4 looks OK but if you look closely there something that look like a crack on the #1. Would it be possible the block be cracked between two chambers considering what you see on all the videos...!?
Cylinder #2 is the worst, look like there is metal bits in there, parts disintegrated from the head?
Cylinder #3 looks better than the second but there black spots on the walls, from overheating?

Most of the walls have vertical mark which I think is a pretty bad sign...

I'm pretty bummed tbh, I feel dumb not doing this before ordering parts, brake, alternator and other stuff. My plan was to, worst case scenario, take the head to a machine shop during the winter if warped or if not salvageable buy a new non-jet head. Now it seem like the whole thing would need to got out and it's not the same deal. I've considered swaping the engine at first for a 4g63 but KM145 you know... or maybe swap the head... In any case, it involve a lot for now and I was hoping to at least get the truck back on the road with the current engine for a little while.

The truck runs, I've started it for about 3-5 minutes twice, seemed like there was a power loss but it was at low speed and I kept crossing my fingers its was only a matter of cleaning the carb or broken vacuum lines.

Anyway, pretty disappointed right now but maybe you guys have a different opinion on the state of this engine and have suggestions for me if you had to be on this situation. Let me know.

Thanks,

[FMS88]

Have you check the compression of each cylinder? That's the first step when internal problems are suspected. A low reading will point to the cylinder or cylinders that likely have a problem and suggest where to look when you remove the head and the blown gasket. I couldn't see much in the video, but with the head off it will be easy to assess the block's condition and then judge if there's damage or if what the scope showed was mostly just wear and tear. I bet the block will be in better shape than you fear. However, expect to replace the head. They crack easily, especially those with jet-valves.

[Out Getting Ribs]

I was planning to do a compression test when I will do the brake in the next two weeks, we'll see. I'll post the results here and following steps. I was just wondering if you guys could give your 2cents from my videos. I just hope at least the block is fine... I think a fellow member here said that they could withstand a lot.

[geezer101]

Biggest worry with 4G54 blocks are cracks in the top deck of the block around the head bolt holes. I've commented a number of times that a healthy 4G54 bottom end will be good for 600 hp - a healthy bottom end. High mileage or poorly maintained engines will have their lifespan drastically affected. The weak links in the block are balance shaft bearings. These things are exposed to way more rpms than the crank and rods and when they fail, it causes a domino effect of oil pressure loss. They are noisy (they make a weird rumbling noise and vibration but your engine will be dead by the time you hear or sense that) The balance shafts can be deleted from the 4G54 but it takes some effort and thought (rotating shaft bearings to block oil passages to maintain oil pressure, modified timing chains, modified oil pump shaft...) Pros - improved throttle response, weak link removed from oiling system. Cons - change in harmonic vibration at certain rpms (it would pay to weight match every rod and piston assembly to reduce harmonics)

From your videos - some light scoring on the bore walls isn't a deal breaker but without removing the head, it's just guessing how deep the scoring is. The footage of #2 cylinder is concerning. You are right - it looks like chunks of debris have been bouncing around the combustion chamber and ripping up the upper section of the cylinder wall (it does look like fragments sitting on the piston) No obvious signs of the crown of the piston breaking apart so what the source of the debris is...? There appears to be quite visible uneven clearances between the piston tops and cylinder walls which indicates high wear.

*don't know what to make of the 'cracks' in #1 video. They appear to be below the head gasket so I doubt these are a source of coolant loss etc :scratchheadyellow:

[Out Getting Ribs]

Thanks Geezer. The gap between pistons and walls is pretty concerning. I just realized I switched videos of cylinders #1 and #4 on YouTube. You can the the crack I was talking about on video #4. Here is a picture : 26860

[tortron]

https://m.aliexpress.com/i/32860508996.html?gatewayAdapt=Pc2Msite

Some if those and a rering. Depends on the block and head tho

[geezer101]

Yeah that doesn't look good either way. If that is a gouge in the bore, it's a serious one. If it is a crack, you're looking for another engine... At this juncture the only option you have is to pull the engine and take it apart. You may get lucky and it's all cosmetic damage (this will still require sending the block through a machine shop and ordering a stack of new parts to reassemble it) I would start hunting down a replacement engine to be honest. One that is still in good running condition. Do a couple of tests on it like leakdown and compression, buy a new water pump and timing chain kit, replace a few seals etc before installing it so you know you won't need to touch it for a while.

[Out Getting Ribs]

Aight, still gonna do a comp test and remove the head to have a better look but yeah your just confirming what I thought. Astron engine will surely be hard to find here and Ill have to import it. The swap gonna be sooner than planned hehe. Still gonna try to find something that could mate with the KM145 but that a subject for another post I guess (information that prove to be hard to find). Thanks again Geezer and all, your help is mucho appreciated. Maybe I'll post pic of the block and head while removed just to have another second guess...

[geezer101]

Are Ram50's and other Mitsubishi/Dodge trucks that uncommon that you aren't able to source one from a yard? That's rough. The 2.6 engine found it's way into a lot of vans and cars etc. Might have to think about looking for a different source to get a donor engine or block.

[Out Getting Ribs]

Yes sadly, cars here don't last long. I'm 30 and the first time I saw this truck on the street was about 6 months ago and that's why I started lookin for one of these on marketplace. At the time , there was only another one on the West coast in British Columbia and I live in Quebec. The other one was mine and you may have seen the state of it on my first post hehe that's the best I could find. I have better chance lookin for a decent replacement on the other side of the border.

[SubGothius]

See the 4G54 section here under the green Applications bar to see other models that used the same basic engine:

https://en.m.wikipedia.org/wiki/Mitsubishi_Astron_engine#4G54

[geezer101]

So... this is something I have thought about a bit and could be a viable option. The 4G54 and the 4G64 both share the same transmission mounting pattern. You 'could' neanderthal tech a 4G64 (which is a fuel injected engine) to run a vacuum advanced distributor and intake manifold/carb from a G63B engine. It would be better to use a Weber carb like the 38DGES instead of the kinda crap Mikuni factory carb. Bonuses - timing belts and general maintenance on the 4G64 is a cake walk. The 4G64 2.4 is a much newer engine which means easier to source parts and will be more efficient. Only other thing you will need to factor in is a matching exhaust manifold for the 2.4 and the starter motor. The 2.4 should be lighter and more throttle responsive than the 2.6. The 2.4 was used in the Mighty Max and a bunch of Mitsubishi vans so the odds of finding one is in your favour. Going carb will eliminate the headaches of electrical system mods and adding the EMS/electric fuel pump and high pressure lines etc. I think it's plausible, but if any members have added input on this idea please add your insight on it :)

[Out Getting Ribs]

That idea is really interesting since that would give the opportunity of putting something newer and more reliable on this sweet truck. So basically a 4g64 would bolt on the KM145 or I can expect to have to buy a bell housing adaptor ?

[geezer101]

Nope, same transmission mounting pattern used for the 4G54 and 4G64 so no adapters. KM145 is a wide block pattern, the G63B 2.0 is a narrow block for mating to a KM132. Thanks for making things confusing Mitsubishi :rolleyes:

[Out Getting Ribs]

Hi, I'm kind of getting this thread back from the dead. After looking at swap options for my blown g54b, I've stumbled on one of forum member who swaped his 90' 4x4 with a 6g75, the build is insane... Does anyone knows if any 6gXX would bolt to my existing km145 drivetrain of I would need to change for the something like the V5MT1 ? Thanks,

[pennyman1]

you need to change the tranny to the V5MT1 for the 6g72/75 swap - the bell housing bolt patterns are different, and not removable.

[Out Getting Ribs]

Thanks for the answer Penny. That's what I thought, a V5MT1 may prove to be harder to find than another block... I've done some Marketplace and found a 99 Galant with 120k (km) on it, thing is that the 2.4 in it is technically a 4g64 but the narrow block variant... I find it pretty hard to know in which models it was the wide block version... Is it me or this information is kind of difficult to source ? I understand that I can find the engine application on wiki or forums but it's pretty hard to know if it is a wide or narrow block variant. As I understand it right now if I go with the 4g64 and want it to mate my km145 I need to find a Mitsu Expo or another MM.... Ouch.