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Misfire when cold

I don't know specifically if AA1car is a reputable source, but it sounds reasonable enough to me, and reasonable enough to spend the few dollars to get double platinum plugs.

Well they tried, but they got it wrong... sort of.
Quote AA1car link: Copper core standard plugs and copper core single platinum spark plugs are not designed to withstand this reverse polarity firing and will suffer premature gap growth due to center electrode erosion.

On standard single platinum plugs, the exposed center core electrode is (the single) platinum, not copper. Using standard single platinum plugs you will have no additional center electrode erosion compared to double platinum plugs. You may get a little extra lifespan out of double platinum but the increase from copper to single is much more than from single to double.

Platinum on the ground electrode is what usually makes it double platinum... the ground electrode wears out nowhere near as fast as the center electrode, so they leveraged the long wear of platinum or iridium to make the center electrode platinum first, especially if a fine-wire design. A fine wire copper center electrode would wear out so fast that I'm not aware of any consumer applications for it.
 



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@masospaghetti

Message Received - watching the thread and rootin' for ya'!

Follow up with updates as you see fit.

Good Luck and Happy New Year!
 






What engine do you have? I bought the coil for my ohv from amazon too. It’s the DGE446.

Also, what cps did you install? I’m thinking of replacing mine since I’ve had trouble with it’s connector corroding in the past.

Yep, same one...DGE446 for the OHV engine. I used the Standard Motor Products CPS PC250, was about $14 on Amazon. Magnet is definitely stronger than the old one.
 






Wow, someone said that coincidence doesn't exists. But I'm struggling searching for info on my 96 OHV ex. It's also having trouble with a "cold" start -sometimes it happens midday with higher temps-.

I crank it, it has a rough start briefly, some vapor in the exhaust, coolant smell all over the place and losing like a cup on the reservoir deposit every 2 or 3 days with the regular use of the truck.

I brought the truck to a test with pressure in the radiator and it showed that the coolant will enter the combustion chamber under pressure, adding vapor on the tail pipe.

I haven't checked the spark plugs yet, will do soon, but my first guess was a busted head gasket. Now that I'm reading this thread, I'm getting a bit worried about what should this be. It only has 90k and a cracked head will be a killer. I don't live in the US so getting reliable new heads its a pain.
 






Yep, same one...DGE446 for the OHV engine. I used the Standard Motor Products CPS PC250, was about $14 on Amazon. Magnet is definitely stronger than the old one.

Good to know. I ordered the standard motor products PC250T, it was $12 on amazon.
 






Looks like my coolant level is still dropping but its hard to tell, since it varies a bit with temperature. If its using coolant the consumption rate is really low. However, the "misfire" is still there, and if I am still losing coolant that means either 1) K-Seal or 2) major repair work.

Looks like it would probably be about $600 in remanufactured heads, or $2200 or a remanufactured engine. I think I can do the work myself either way. I'm tempted to just replace the heads since the motor otherwise seems healthy - have recently done the rear main, and put in a new timing set -- but 250K miles is a lot. Thoughts or opinions? At this point since this is a second vehicle, and I can have it out of commission for awhile, I don't think I will be going the K-Seal route.
 






Looks like my coolant level is still dropping but its hard to tell, since it varies a bit with temperature. If its using coolant the consumption rate is really low. However, the "misfire" is still there, and if I am still losing coolant that means either 1) K-Seal or 2) major repair work.

Looks like it would probably be about $600 in remanufactured heads, or $2200 or a remanufactured engine. I think I can do the work myself either way. I'm tempted to just replace the heads since the motor otherwise seems healthy - have recently done the rear main, and put in a new timing set -- but 250K miles is a lot. Thoughts or opinions? At this point since this is a second vehicle, and I can have it out of commission for awhile, I don't think I will be going the K-Seal route.

I wasn’t losing a huge amount of coolant either when I had warped heads and a misfire, but it still filled with enough coolant to misfire on startup. If you can live with exhaust gas in the coolant but no coolant in the cylinder then k seal is a good idea. It stopped the coolant from getting into my cylinder but the piston blow by was too strong and exhaust gas still got into my coolant, and being my daily driver I wasn’t ok with that.

At this age, I would rebuild the entire engine. I would have but I’m in my last year of school and can’t afford it. So I went with new heads and fuel injectors for now. Hopefully you don’t have a leak in the heads somewhere and it’s something else.
 






have recently done the rear main, and put in a new timing set --

Heads.

I would.

Have you tried a compression check?

Actually you could have a local shop, hot dip, pressure check & re-deck the old heads then redo the valve stem seals and regrind the valves.

You have the top off the engine so you could get a good look to see if cylinder wall crosshatch is still there.

If it is I would think you are good for a while.

Regards,
Chris
 






For anyone who loses coolant and has a cold misfire:

My 2000 OHV had a misfire on cylinder 4 when it would start cold. Sometimes it would happen just a few hours after turning it off, sometimes it wouldn’t happen at all, even after being off all night. But it would return internmently. My coolant was disappearing and I had air in the coolant system. I used k seal and it stopped the misfire since no more coolant was getting into the cylinder. Coolant has silicates, sand, which plug very tiny holes. But exhaust gases were still getting into the coolant.

I wasn’t burning coolant anymore but I didn’t want to risk complete head gasket failure, so I had the heads replaced and discovered that the head surfaces and gaskets had warped. I’m planning a full rebuild in the next year or two with a 4x4 auto conversion. Since I plan on keeping the vehicle. Note that my engine passed compression tests even with the warping.

Had the same problem.
I have 10K miles on the K-seal. I say 100% try it, nothing to lose, my coolant looks great. I read stuff like that is installed in the factory on some cars (may be products designed exclusively for the industry and not retail). Problems with those products happen when you have a filthy cooling system that was neglected for 10 years.

I would have fixed the heads but the truck is rusty and with inspections it could fail and have to be scrapped. It is a tough decision for a 20+yo truck, but if I had a rust free CA truck I would have paid 600 for the heads and parts to do it right.
 






Heads.

I would.

Have you tried a compression check?

Actually you could have a local shop, hot dip, pressure check & re-deck the old heads then redo the valve stem seals and regrind the valves.

You have the top off the engine so you could get a good look to see if cylinder wall crosshatch is still there.

If it is I would think you are good for a while.

Regards,
Chris

I did a compression test last month. All cylinders were within about 10 psi of each other.

If the crosshatching was gone, would you still run the motor? or pull it and replace it at that point?
 






At this age, I would rebuild the entire engine. I would have but I’m in my last year of school and can’t afford it. So I went with new heads and fuel injectors for now. Hopefully you don’t have a leak in the heads somewhere and it’s something else.

I'll keep checking around, local machine shop wants $3200 for the rebuild -- maybe it's the part of town I'm in but it seems everything is vastly overpriced here. Rockauto has ATK rebuilt engines for about $1800 shipped but it doesn't say it uses the new "improved" head, also I don't know anything about ATK. They also have Ford remanufactured engines for about $2500 shipped.

Had the same problem.
I have 10K miles on the K-seal. I say 100% try it, nothing to lose, my coolant looks great. I read stuff like that is installed in the factory on some cars (may be products designed exclusively for the industry and not retail). Problems with those products happen when you have a filthy cooling system that was neglected for 10 years.

I would have fixed the heads but the truck is rusty and with inspections it could fail and have to be scrapped. It is a tough decision for a 20+yo truck, but if I had a rust free CA truck I would have paid 600 for the heads and parts to do it right.

I'm a bit worried K-seal would plug up my heater core or cause other damage. It's actually a rust-free NC truck, body is in great shape, needs paint (I have another thread about that - trying to find an economical way to repaint) - but also it's near impossible to find the 4x4 4-door 5-speed combo. Just installed a rebuilt transmission and the transfer case was rebuilt about two years ago.
 






Had the same problem.
I have 10K miles on the K-seal. I say 100% try it, nothing to lose, my coolant looks great. I read stuff like that is installed in the factory on some cars (may be products designed exclusively for the industry and not retail). Problems with those products happen when you have a filthy cooling system that was neglected for 10 years.

I would have fixed the heads but the truck is rusty and with inspections it could fail and have to be scrapped. It is a tough decision for a 20+yo truck, but if I had a rust free CA truck I would have paid 600 for the heads and parts to do it right.

K seal is good stuff. My coolant had been flushed on time before my misfire, I think that’s the reason my vehicle started to develop leaks around the cooling system. But depending on how big the leak is, k seal can’t stop exhaust blow by from getting into the coolant.

It was an easy decision for me as I’m keeping this truck. As far as rust goes, my manifolds came off after soaking them overnight with penetrating oil.
 






Rockauto has ATK rebuilt engines for about $1800 shipped but it doesn't say it uses the new "improved" head, also I don't know anything about ATK. They also have Ford re-manufactured engines for about $2500 shipped.

Just want to help clarify the Rock Auto/FORD re-manufactured engine they are offering for $2,500.

It's incorrectly listed.

Rock Auto lists it as a "long block" (block & heads), when in reality it's a "short block" (block without heads).

If you check/GOOGLE the FORD parts number for what RA is offering, you'll see that FORD lists it as as short block.

Hope that helps -
 






Rockauto has ATK rebuilt engines for about $1800 shipped but it doesn't say it uses the new "improved" head, also I don't know anything about ATK. They also have Ford re-manufactured engines for about $2500 shipped.

Just want to help clarify the Rock Auto/FORD re-manufactured engine they are offering for $2,500.

It's incorrectly listed.

Rock Auto lists it as a "long block" (block & heads), when in reality it's a "short block" (block without heads).

If you check/GOOGLE the FORD parts number for what RA is offering, you'll see that FORD lists it as as short block.

Hope that helps -

Good catch!! That's a huge mistake on RA's part.
 






Rockauto has ATK rebuilt engines for about $1800 shipped but it doesn't say it uses the new "improved" head, also I don't know anything about ATK. They also have Ford re-manufactured engines for about $2500 shipped.

Just want to help clarify the Rock Auto/FORD re-manufactured engine they are offering for $2,500.

It's incorrectly listed.

Rock Auto lists it as a "long block" (block & heads), when in reality it's a "short block" (block without heads).

If you check/GOOGLE the FORD parts number for what RA is offering, you'll see that FORD lists it as as short block.

Hope that helps -

Does Ford still reman these engines? If they do I’ll definitely purchase a short block from them in the future.
 






If you have good compression and you are not burning any oil I would let it run.

I just use the factory crosshatch as a visual indicator of how things are going.

If you have the heads off you can see anything abnormal.

For instance my 98 with a 302.

It's been an ongoing project for years. But just redoing each section one piece at time.

A while back, I had done heads, cam, pulled the engine and re-gasketed the bottom end, exhaust and a mild to aggressive tune for for what I had.

I let my son drive it.

He got too aggressive on the gas one day goofing off with his friends and blew the top off of #1 piston.

When I pulled the engine again and broke it open all cylinder walls looked great except for #1....

So now we are back to square -1.

Always wanted a 331 anyway. 347 was more than what I needed.
 






Just an update, I've been keeping an eye on my coolant level and it's still dropping slowly, so I am biting the bullet and pulling the heads. I've checked for slow external leaks, used the AC Delco radiator stop leak tablets. Sometimes it will still misfire when cold so I am convinced beyond any reasonable doubt the head is cracked. So far I have two new heads coming and a new gasket set with head bolts.

What are thoughts on reusing the hydraulic lifters, rocker arms, and pushrods?

Pushrods are cheap, but the cheapest name brand set of hydraulic lifters (Melling) are about $29 each at RockAuto - not an insignificant amount of money for a set of 12.

Enginetech lifters are about $11 each, but I've heard Enginetech doesn't make any parts and therefore these are basically white box parts with questionable quality.
 






I re-used mine and everything is fine. The parts had around 250,000 miles on them. I would have replaced them if I was looking into a long term repair, but I see a 5.0 swap in the future. I would have just rebuilt the entire engine but I only need it to last till next summer.
 






Made some good progress today. Got both heads off, and as I suspected, the head of cyl #4 was cracked. It was hard to tell at first because of the carbon build up.

IMG_20191207_113655.jpg


My work bench and how I'm keeping things organized. Gotta make sure those pushrods and lifters go back in the same spots:

IMG_20191207_113620.jpg


IMG_20191207_113625.jpg


The bores of cylinders 1 & 2 look pretty good to me, still can see the cross hatching. Cyl 4 and 5 don't look quite right. Can't feel anything with the fingernail though. Going to let the bores soak with a bit of carb cleaner and ATF, maybe scuff up cyl 4 and 5 with some green scotchbrite and see how it looks.

Cyl 4:

IMG_20191207_113721.jpg


Cyl 1:

IMG_20191207_114113.jpg


Overall this was not an "easy" job but not terrible either. One of the more fun jobs so far, everything came apart pretty easily, much more fun than taking out a transmission.

New heads from Promaxx should be here tomorrow.

IMG_20191207_113639.jpg


IMG_20191207_113704.jpg
 



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Nice. My heads were pretty bad. This is the result of the vehicle sitting for a year before I got it and overheating a few years later. This valves were bad. The heads weren’t cracked but they did warp.
0E6D20B9-9213-4E9D-966E-19D199256F86.jpeg

9C98698A-6D8F-4FF7-BBB0-EB51C4149CDB.jpeg

54058638-25D3-4A17-A101-23F9AFED7F88.jpeg
 






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