Opinions on rusty engine cradle

[JohnZ]

Hi there! My dear VIN 3305 is undergoing a clutch replacement, with all the "while you're in there" stuff being replaced!

My cousin is a professional mechanic and he is performing the job for me, and the thing is going surprisingly straightforward! It just needed to be replaced, along with all the clutch related things!

But an issue has come forward, as usual when you deal with DeLoreans! we found out that the lower part of the frame, sustaining the engine, is very rusty, to the point in which some parts are slowly rotting...

Luckily the rest of the frame, at least the visible portions (to be honest we inspected it thoroughly), is in pretty good shape and we're happy with it!

So a question bugs us: what do we do to address this problem? It's there a way to reinforce the thing? Or to replace that part with the help of a professional welder?

Any suggestion is appreciated! (Frame off and total frame replacement is out of question)



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[David T]

It looks a lot worse than it really is because all of the epoxy is coming loose. Remove all of the loose epoxy so you can do a proper assessment of the damage. If the metal is not too bad, at least stop the rust by using a product that can convert the rust like POR 15. In areas where the metal is rotted through the only repair is to cut it out and replace it. You can section pieces out and weld in new metal, it is just 16 GA CR sheet metal.

[cdrusn]

+1 to David. Scraping off the epoxy coating that is peeling off will reveal what needs to be done. In no way does the frame need to be replaced but welded in patches might be in order. I'm wondering
if it is this bad in this location what about the rest of the frame. When I do rust patches I find, I start with OSPHO rust killer (ACE hardware), the POR 15 (Amazon) then gray Rustoleum.
Seems to work well for me but you still need to annually do a frame inspection from the inside out. Get a camera from Harbor Freight and go into the voids around the engine cradle, use
Eastwood internal frame spray even if you don't see rust.

[JohnZ]

Thanks to you both guys! Very informative answers indeed!

As for the welding: do you think that we have to cut the rotten parts and replace them with fresh steel, or do we need to stop the rust with all the products you told me and then reinforce the old bits with new steel "wrapped" around the old material?

My doubts are related to the fact that I don't want to "weaken" the structure by splicing sections that are meant to be in one entire piece by design...

I hope I explained myself!

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[David T]

Thanks to you both guys! Very informative answers indeed!

As for the welding: do you think that we have to cut the rotten parts and replace them with fresh steel, or do we need to stop the rust with all the products you told me and then reinforce the old bits with new steel "wrapped" around the old material?

My doubts are related to the fact that I don't want to "weaken" the structure by splicing sections that are meant to be in one entire piece by design...

I hope I explained myself!

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You don't "wrap" or cover over the rot, it will just continue to spread. Unless you remove a very large piece and leave the rest completely unsupported, it is OK to cut the rot out, make a template up out of cardboard, trace it out onto metal and weld it in. In some cases instead of replacing a lot of small pieces you do a major repair and replace a whole section. It is a judgement call as to how to do this using experience. If you are not comfortable doing this you should seek out someone who can either help you or do the work for you. In general you try to do the smallest repair you can but sometimes it can make sense to do one large repair fixing a bunch of small spots at once.

[outatym2001]

According to this YouTube video here is why you should not use POR 15 and the video is titled, ?If You Think POR 15 is Good Paint? Watch This Video! Paint Testing Eastwood, KBS, POR15, and More.?
The YouTube channel is called Repair Geek.
DO NOT use POR 15 for rust protection.
If you do not believe me then fast forward near the end of the video at 39:35 for a complete breakdown of the nine products tested.

The best is listed first on the list.
Mastercoat AG111 which is a black top coat for the Mastercoat Permanent Rust Sealer which is silver.
Raptor Liner.
Mastercoat Permanent Rust Sealer silver.
POR 15 with Topcoat
Eastwood Rust Encapsulator Platinum
KBS
POR 15
Bill Hirsch Miracle Paint
Rustoleum.

[dn010]

The few times I used POR-15, it really didn't do anything and I had rust all over again after a few months. I switched to KBS and have had no problems. I coated the frame of my 57 Cadillac 16 years ago with it and it still looks damn good even after driving it on salted roads in New York. I used their tank sealer kit and that also, 16 years later, has passed the test of time. Yes, I prepped everything I was coating in POR-15 and KBS correctly, it was not a matter of bad prep work, it was just that POR-15 sucks.

[David T]

I have used POR-15 and it seems to work for me. I coat it with paint after it dries. Maybe that's why I get good results? The POR-15 does a decent job converting the rust but I don't think it protects well from future rust so I cover it (seal it) with a layer of paint to prevent moisture from getting through. Of course if you live next to the ocean you may need to use something better than POR-15. The epoxy paint did well too but it eventually becomes brittle, cracks, and allows moisture to get to the base metal. Nothing lasts forever. The "Gold Standard" is to cut out ALL rust and replace it with fresh metal. Since that is not always practical we resort to methods to stop the rust but "Rust Never Sleeps"! BTW, most of these products say all you have to do is remove the loose rust and clean the surface. I try to wire brush as much of the rust off as I can. Maybe that is also why I get better results?

[Timeless]

The few times I used POR-15, it really didn't do anything and I had rust all over again after a few months. I switched to KBS and have had no problems. I coated the frame of my 57 Cadillac 16 years ago with it and it still looks damn good even after driving it on salted roads in New York. I used their tank sealer kit and that also, 16 years later, has passed the test of time. Yes, I prepped everything I was coating in POR-15 and KBS correctly, it was not a matter of bad prep work, it was just that POR-15 sucks.

I spoke with KBS at SEMA last year and they said they were working with DMC to provide a frame coating product to color match the original epoxy color. I'm willing to try KBS on my car's frame but I have good luck with a rust converter and the POR-15 aerosol product. Granted, my frame is in great condition.

[dn010]

I have used POR-15 and it seems to work for me. I coat it with paint after it dries. Maybe that's why I get good results? The POR-15 does a decent job converting the rust but I don't think it protects well from future rust so I cover it (seal it) with a layer of paint to prevent moisture from getting through. Of course if you live next to the ocean you may need to use something better than POR-15. The epoxy paint did well too but it eventually becomes brittle, cracks, and allows moisture to get to the base metal. Nothing lasts forever. The "Gold Standard" is to cut out ALL rust and replace it with fresh metal. Since that is not always practical we resort to methods to stop the rust but "Rust Never Sleeps"! BTW, most of these products say all you have to do is remove the loose rust and clean the surface. I try to wire brush as much of the rust off as I can. Maybe that is also why I get better results?

If my memory is fine, both POR-15 and KBS suggest to use a top coat over their rust sealing products otherwise their coating would fade, especially if exposed to sunlight. Might sound odd for a frame to be exposed to sunlight but all you have to do is open a hood on a sunny day and it's enough to hit the frame, or have a tire off with the sun in the right spot to hit the frame. My original deLorean frame was removed, had the rust cut out, I had grafted on a new front end, any areas of surface rust and repair was then sandblasted, then cleaned/degreased-etched- POR-15 painted and then top coated. After a few months of driving, there were many areas of rust already developing. Huge difference compared to the control arms that were just hit with a rattle can and are all surface rust now so you can really see what difference the coating makes.

I did the same thing to my Cadillac frame, only this frame needed no repair and I used KBS on it. It was removed, stripped down, needle scaled, surface rust sandblasted as much as possible, cleaned/degreased-etched-painted with KBS and then top coated. It spent longer in New York than the DeLorean and there are very few areas that developed a spot of rust or two after 16 years, likely from rock or road debris chipping the coatings.

For the D, I ended up getting a frame from vin 712. I did the same thing on that stripping areas of rust, sandblasting, cleaning and KBS coated that one. I painted over that as well. I'd like to say that was 8 years ago now and no rust on it at all, even living/driving by the Gulf of Mexico.

I've tried POR-15 on a few different frames and parts and they all somehow developed rust quickly. Just my experience and I have never suggested using POR-15 after those experiences.

As far as getting the original color, sure, it would be nice to spray it once and have it done but I'd still suggest top coating over the KBS in the color you want, just to give it extra protection and prevent it from ultimately fading which is inevitable regardless of which company you use.