Replacing 4G64 piston rings - what else should I do?

[Intrepidor]

HI all, I’ve got a 6-bolt 4G64 engine in my ’91 Delica van that I’m trying to fix up enough to get back on the road. I’m working on rebuilding a replacement engine that’s outside the van, so just trying to understand what kind of work I need to do to bandaid the current one. The van runs and drives, but had a rough idle, white smoke on acceleration and went through about a quart of oil every fill up. I did have a shop do some testing awhile back, and this is what they told me:

As far as the engine goes it has good compression on all cylinders. It looks like all cylinders are leaking a little bit into the crankcase with cylinder 3 being the worst with about 24% leakage. This is most likely due to bad piston rings at this age and mileage.

So I know I need to replace the piston rings, but based on the above are there other basic items I should be looking into?

 

[dwb]

It's not as simple as just replacing rings. You're performing a full rebuild at that point.

 

[97egl]

So you are rebuilding a different engine for the van but are trying to keep the one in the van going in the meantime?

If so I would try pulling the plugs on the engine and pour a cleaner like berrymans or seafoam into the cylinders and let it sit a day or two. Change the oil and add 1 qt lucas oil when doing the oil change. Then put a rag over the plug holes and crank it to clear the cleaner out of the cylinders. Pop the plugs back in and go drive it. It will smoke while the cleaner burns off. Once the smoke clears up drive somewhat aggressively to try and get a good amount of heat into the pistons which will hopefully loosen up the rings if they are stuck.

Hopefully this helps you. I've had pretty good luck extending the life of poor compression engines by doing this. If you don't want to pour anything down the cylinders just adding lucas should help a little with the white smoke and oil consumption.

 

[1990TSIAWDTALON]

Run Sea Foam in the oil for an day before you change the oil. It is a cleaner/solvent. Not something to leave in, just something to bust up crud just before an oil change. I do it to my old LS Chevy truck to try and keep the lifters from being noisy on first startup.

 

[Intrepidor]

Appreciate all the replies, as this seems much easier than taking the engine apart I've used Sea Foam for years on our '82 VW Westfalia and it's always kept it happy.

So you are rebuilding a different engine for the van but are trying to keep the one in the van going in the meantime?

Yes, because we're also doing a camper build and I need it for supply runs, and to test the camper out. I'm teaching myself how to rebuild the other engine(s) but no idea how long that will take since I'm a novice at this and have the luxury of time, so just want to get it road-worthy for now.

 

[97egl]

Appreciate all the replies, as this seems much easier than taking the engine apart I've used Sea Foam for years on our '82 VW Westfalia and it's always kept it happy.

Yes, because we're also doing a camper build and I need it for supply runs, and to test the camper out. I'm teaching myself how to rebuild the other engine(s) but no idea how long that will take since I'm a novice at this and have the luxury of time, so just want to get it road-worthy for now.

Just to be clear this may or may not work and if it does work it is more so just a band-aid to the situation and is not a long term fix. Sounds like you understand that but just wanted to clarify.

Also not sure where you got the engine from that you are rebuilding but the 4g64 does come in a couple different style blocks so you'll want to make sure you have the correct block before rebuilding it. There's a wide block and narrow block. Not trying to add any confusion but if the engine you are rebuilding didn't come from the exact same vehicle you may want to check into that. I'm sure a much more knowledgeable expert can chime in on this. I am by no means an expert on the 4g64 wideblock and RWD variants.

 

[1990TSIAWDTALON]

Good advice, thanks @97egl !!!

 

[Intrepidor]

Just to be clear this may or may not work and if it does work it is more so just a band-aid to the situation and is not a long term fix. Sounds like you understand that but just wanted to clarify.

Also not sure where you got the engine from that you are rebuilding but the 4g64 does come in a couple different style blocks so you'll want to make sure you have the correct block before rebuilding it. There's a wide block and narrow block. Not trying to add any confusion but if the engine you are rebuilding didn't come from the exact same vehicle you may want to check into that. I'm sure a much more knowledgeable expert can chime in on this. I am by no means an expert on the 4g64 wideblock and RWD variants.

Yep, a band-aid is what I'm looking for mainly to be able to drive it around this summer and fall a bit. Engine rebuild is my long term solution.

I've actually got 2 replacement engines that both came out of Delicas. One is a low-mileage 7-bolt 4G64 I purchased that came from a Japanese-spec Delica, but when it came time to install it, the install shop discovered a spun balancer shaft. The 2nd engine is a 6-bolt 4G64 from a US-spec van sent as a "replacement" for the first but it's higher mileage than the other one and would need a rebuild anyway. I'm using that one to practice on.

We've since moved far away from any install shop that will touch it if it ain't a Ford or a Chevy, so I'm taking my time and learning to rebuild it myself.

 

[97egl]

Yep, a band-aid is what I'm looking for mainly to be able to drive it around this summer and fall a bit. Engine rebuild is my long term solution.

I've actually got 2 replacement engines that both came out of Delicas. One is a low-mileage 7-bolt 4G64 I purchased that came from a Japanese-spec Delica, but when it came time to install it, the install shop discovered a spun balancer shaft. The 2nd engine is a 6-bolt 4G64 from a US-spec van sent as a "replacement" for the first but it's higher mileage than the other one and would need a rebuild anyway. I'm using that one to practice on.

We've since moved far away from any install shop that will touch it if it ain't a Ford or a Chevy, so I'm taking my time and learning to rebuild it myself.

Sounds like you're all set then. I never know how much someone knows that's posting on here so I try to give as much info as possible.

Years ago back when I had my first dsm I rebuilt a spare 7 bolt engine I had picked up for my 94 eclipse. Unfortunately for me I bought a 2g 7 bolt and after rebuilding it realized I didn't have anywhere to bolt motor mounts

 

[pauleyman]

Yep, a band-aid is what I'm looking for mainly to be able to drive it around this summer and fall a bit. Engine rebuild is my long term solution.

I've actually got 2 replacement engines that both came out of Delicas. One is a low-mileage 7-bolt 4G64 I purchased that came from a Japanese-spec Delica, but when it came time to install it, the install shop discovered a spun balancer shaft. The 2nd engine is a 6-bolt 4G64 from a US-spec van sent as a "replacement" for the first but it's higher mileage than the other one and would need a rebuild anyway. I'm using that one to practice on.

We've since moved far away from any install shop that will touch it if it ain't a Ford or a Chevy, so I'm taking my time and learning to rebuild it myself.

The spun balance shaft can be dealt with. Doesn't necessarily make that engine worthless or more difficult to deal with.
As far as band aid I would try the suggestions above. Nothing to lose.
I suspect you are using this car for utility but that things looks like it would be a hoot in modified form. Is that a w5m33 trans?

 

[Intrepidor]

The spun balance shaft can be dealt with. Doesn't necessarily make that engine worthless or more difficult to deal with.
As far as band aid I would try the suggestions above. Nothing to lose.
I suspect you are using this car for utility but that things looks like it would be a hoot in modified form. Is that a w5m33 trans?

Yep, and according to the seller it's only got about 40K miles on it, and they already did a timing belt service before sending it.

It's utility for now, but our plan is to build a camper in the back for overlanding. It will eventually replace our 2WD VW Westfalia because we kept getting stuck . Don't know off the top of my head what the trans is, but it's basically a Mitsubishi Pajero but in van form, so they can definitely hold their own off road.

 

[DSMPT]

Don't know off the top of my head what the trans is, but it's basically a Mitsubishi Pajero but in van form

I think Delica star wagons are not full time 4wd. The trans may be a V5M21 rwd based part time 4wd.

 

[Intrepidor]

I think Delica star wagons are not full time 4wd. The trans may be a V5M21 rwd based part time 4wd.

Yep, that's the correct trans. So they're normally in 2WD but then have selectable 4WD hi/lo (using the old school manual shifters of course!). Some of the "premium" models like our Super Exceed also came equipped with an LSD.

 

[NextLevelDelica]

I think Delica star wagons are not full time 4wd. The trans may be a V5M21 rwd based part time 4wd.

Thats exactly right. ^^
Id like to find some information regarding which wide block turbo engines from the 4G family would mount to the V5M21.
Do you know which came as a wide block? & Where Should I look for this type of info?
Modifying engine mounts for the subframe is not out of my scope but if would be nice to match bellhousing mounts at least.

Ive turbo'd my 4G64 8V and its been fun. Sitting at about 165HP to the crank. [Woohoo] Much better than <110-ish

However, I'm wondering if finding a salvage DSM may speed up my next swap. I know some externals may need to be changed over but if I can nail the prep & start with (some) mount-ability, Id be super happy.
Thanks for any support with this

 

[Intrepidor]

Nice to see another Delica here - 165hp sounds fun! I'm considering doing that to my build, but I'm in very rural Michigan and can't find anyone who will touch the rebuild, so will probably end up doing it myself. Unfortunately it keeps getting pushed off so not sure when I'll get around to it.

To bad Idaho is so far away - I've got an extra 4G64 just sitting in my garage that I probably won't use.

 

[NextLevelDelica]

Nice to see another Delica here - 165hp sounds fun! I'm considering doing that to my build, but I'm in very rural Michigan and can't find anyone who will touch the rebuild, so will probably end up doing it myself. Unfortunately it keeps getting pushed off so not sure when I'll get around to it.

To bad Idaho is so far away - I've got an extra 4G64 just sitting in my garage that I probably won't use.

Its quite fun with a turbo but its been a steep learning curve to program my fuel and timing maps. The bottom end was all holding 120 psi in the beginning. Slowly but surely with some detonation being the culprit, Maybe some over fueling (especially after the 272 cam), the front two cylinders are at 95 psi. Lots of blow-by. Given the position of the piston ring seat in the stock 4G64, it was bound to happen. Currently adding a quart per week and draining my intercooler of oil... some via the BOV.
Somehow, the van still holds temp and feels decent headed downtown the road!
I'm looking to either buy or rebuild a stronger short block. Im thinking about some JE pistons and eagle rods. [Suggestions much appreciated] The crank should be just fine with new bearings all around. It's nitride coated & forged, I believe.

What would you like for your 4G64 you have there? Is it the one from the US Spec Mitsy Van?
Cheers

 

[Intrepidor]

What would you like for your 4G64 you have there? Is it the one from the US Spec Mitsy Van?
Cheers

Unfortunately I have no idea where the engine came from as it was offered as a "replacement" for the original one I bought. Seller claims it came from a Delica and has 160k km on it, but I have no way to verify that and don't trust the seller, considering he sold me a "running" engine that actually came DOA with a spun balancer shaft. I've been using it as a practice engine before doing the actual rebuild, so on second thought you might be better off finding one closer that's in better shape

 

[NextLevelDelica]

So you are rebuilding a different engine for the van but are trying to keep the one in the van going in the meantime?

If so I would try pulling the plugs on the engine and pour a cleaner like berrymans or seafoam into the cylinders and let it sit a day or two. Change the oil and add 1 qt lucas oil when doing the oil change. Then put a rag over the plug holes and crank it to clear the cleaner out of the cylinders. Pop the plugs back in and go drive it. It will smoke while the cleaner burns off. Once the smoke clears up drive somewhat aggressively to try and get a good amount of heat into the pistons which will hopefully loosen up the rings if they are stuck.

Hopefully this helps you. I've had pretty good luck extending the life of poor compression engines by doing this. If you don't want to pour anything down the cylinders just adding lucas should help a little with the white smoke and oil consumption.

Thanks for this internal cleaning idea. I had some luck the other day with another vehicle I'm working on. Carbon buildup and a bad ring seal on cyl2 must have cleared up a bit because now she's running like a gem.
Do you ever run a zddp additive? Ive heard max concentration for an older 90s engine would be around 1800-2200ppm. Thoughts?