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Discussion Starter #1
Found a 93 Mark VIII DOHC localy for a good price awhile ago. Contacted the guy today and found out he had sold it, but the guy found water in the engine so he returned it. The original owner of it tore into it to investigate and found some water had cept into the intake manifold. So he will now sell it to me as a $100 core, but it is a complete engine. Figured it is well worth it and I will do a compression test, and a leak down to make sure. Overall dont think the water could have done any major damage and I am also considering possibly forged internals so if I want to get blown down the road I can.

Should I be concerned the water may have found it's way into other areas of the engine? I plan on ripping the heads off and checking a few other areas, but figured for the price I cant go wrong. The block alone should recoupe my loss, worst case.
 

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Screw-Rice said:
Overall dont think the water could have done any major damage and I am also considering possibly forged internals so if I want to get blown down the road I can.

Should I be concerned the water may have found it's way into other areas of the engine? .
Well excluding rusting the cylinder bores, corroding the piston tops, rusting the piston rings, rusting the valve stems, rusting the timing chains/crank shaft/rods...

I wouldn't run an engine that has had water in it. :beek:

But a lot depends on where the water was!! :thumbsup:

But $100 for a complete DOHC core engine is a good price. But I would consider it a core and not try to run it. But you never know... I know a lot of people that have run "junk yard engines" and not had any problems... :thumbsup:
 

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the water should not be a problem , if you completley dissabesmble it , do not do a compression check, if there is water inside , you will damage it.
 

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Discussion Starter #4
The water only made it to the manifold (I was told, I will know when I check it). He also said the water didnt have any kind of rust in it (been a dry winter, right now this is only like our 4th snow fall). I will avoid doing a compression check though, thanks.
 

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well

just the block is worth a little more than $100 and the heads are worth a couple hundred, you can't go wrong. But rebuilding it would be a wise investment. That way you have no questions about it being dependable. Also the early mark engines had problems with the valve springs breaking and things like that. Being a 93 motor...it's probablly got lots of miles as well.
 

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Discussion Starter #6
The engine had 60k on it (was a low mile car then got totaled) before it was pulled. It would be nice though knowing that I know what condition it is in since I rebuilt it...and am hoping I can find room in a tight budget for some LT's and maybe Cobra manifold.

If I pull the heads and find no water, do I need to be concerned about the shortblock? 99% sure I am going to rip it apart anyway though.
 

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I'd pull the heads, and pop the oil pan. That will tell you everything you need to know. (But keep in mind.... head bolts are not reusable (and cost $60 on up). :bawling:
 

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If you went through the trouble to pull the heads off and I was you I would take the head to an engine shop and have the valves seated and guided and new valve seals and a good shop will surface the heads to make sure there flat. They will also get you the new head bolts and gaskets need if you want the to. But you got a great deal.
 

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If your serious about a DOHC swap it's a good deal. I'd rebuild it completely forged, that way you have a brand new forged engine for under $2000.
 

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also

don't forget that the early mark viii engines were prone to breaking valve springs, so you should have them replaced while you have it taken down.
 

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which valve spring do you recommended?

thanks.
 

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well

If you're only going to be keeping the motor build up mild...say 450 hp or less then the 96+ ford behive springs work very well and are decently priced. However if you want something that will handle lots of abuse and a pretty serious power adder later on, then go with the comp cams setup. But which ever way you go, you'll be happy to always know that you won't be doing the swap later on with the motor in the car. If the motor has 100k or more miles on it I'd also recommend swapping the lifters (tensioners) and followers on the heads as well. Some....not all....mark viii's have problems with the tensioners and or the followers failing either due to wear or pluged oil holes in the tensioners due to either too heavy of oil or improper maintenance. This will cause a loss of use of a valve or two on the affected cylinders. I'm about to pull the cam covers on my 97 because it's tapping and I'm pretty sure that this is the cause.

Now don't get discouraged. We're only telling you the things that we recommend because we don't want you to perform the swap and immediately have problems with the motor. NOTHING is worse than doing all that work and then not being able to enjoy it once it's done...or being plagued with drivability or reliability issues down the road. I know that you like most of us are most likely on a budget. And as so I also know that you probablly want to just jump into the project with wrenches flying, but NOW is the time to wait a little longer and do this right. You need to sit down and plan out what all you want this car to do. If you want it to run low 13's and still be a daily driven car then you need to build it accordingly. If you're happy with mid 14's then you can spend less, but you should spend the time to build for reliability. These motors are known to last 300k+ miles with proper maintenance...but you don't know how it was treated for that first 100k...so take your time and plan it all out.

Other areas of concern:

oil pump gears...weak points in all 4.6 motors if you want to make lots of power.

all gaskets and seals

main and rod bearings...if they're worn...replace them and have the crank and rods checked at a machine shop

freeze plugs...it only takes one going out to overheat and potentially destroy your investment

transmission...can it handle the extra power???

bushings and balljoints...if your front end goes out while driving you'll loose everything, maybe even your life

I appologize for going on and on, but I'd hate to read on here in a couple of months that you're DOHC powered mn-12 was parked due to lack of preparation. Also if you think you want to make more power down the road then by all means OVER BUILD the engine now to prevent from having to do it later.

Justin
 

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Discussion Starter #13
Thanks for all the great info. Would have replied sooner but recouping from a snowboard injury.
 
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