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Popped the heads off my 91’ 5.0 to see what I was working with. Not sure what it means but there is a ton of junk in the cylinders also some oil. Besides that they are clean and the pistons seem ok.

What do you guys think? I’m a ok to keep going with this engine? Is it too early to tell? Pictures attached

Any advice is welcomed.
 

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Spammer Hammer
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Are you asking about the cylinders or piston tops? Lots of carbon buildup. Check the cylinders for roundness and lip at the top. Refresh it and go if it’s good. What do you want to do with it?
 

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Oil consumption. Probably from worn valve guides. Could be worn rings and cylinders but I'd check the valve guides and seals first. A lot easier then tearing the shortblock out and apart.
 

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Lots of carbon which you can clean up. All but impossible to tell about the cylinders. You need to/have them mic'd.

Allen
Ok so it’s just carbon that’s good. Yes I definitely need to check the cylinders.

Are you asking about the cylinders or piston tops? Lots of carbon buildup. Check the cylinders for roundness and lip at the top. Refresh it and go if it’s good. What do you want to do with it?
Both I guess. No lip at the top of the cylinders. Atleast not one that I’m able to feel. I just want to have it be a reliable engine. Not looking for more hp. Just want to make a run good.

Oil consumption. Probably from worn valve guides. Could be worn rings and cylinders but I'd check the valve guides and seals first. A lot easier then tearing the shortblock out and apart.
Could the rings and cylinders be worn after only 80k miles? Also I was going to continue tearing the block apart is that not necessary?

how do you check the valve guides and seals? I believe I know what your talking about.

My first engine I’ve ever torn apart, don’t really know what I’m doing but I guess that’s how you learn.
 

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A quick way to see if the heads are the problem. Look into both the intake and exhaust ports at the back of the valve heads. If they have a build up of crud, mostly likely they are the problem. It's deposits from oil getting by due to wear. Especially on the intake valves since they don't run as hot and burn the junk off. Next would be or have a shop remove the valves and check for wear.

I'd suggest cleaning up a cylinder or two and post a couple pictures so we can see better. Typically these motors will easily go 200K miles and still show some honing marks. When @2nd 66 took the heads off the 118k mile GT40P I picked up for him he said the cylinder walls looked brand new.
 

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Discussion Starter #9
A quick way to see if the heads are the problem. Look into both the intake and exhaust ports at the back of the valve heads. If they have a build up of crud, mostly likely they are the problem. It's deposits from oil getting by due to wear. Especially on the intake valves since they don't run as hot and burn the junk off. Next would be or have a shop remove the valves and check for wear.

I'd suggest cleaning up a cylinder or two and post a couple pictures so we can see better. Typically these motors will easily go 200K miles and still show some honing marks. When @2nd 66 took the heads off the 118k mile GT40P I picked up for him he said the cylinder walls looked brand new.
Ok I’ll clean one up and post a few pictures. I mean if I could get away with not having to take the bottom end apart i would be very happy. Glad to here they run a good awhile.

Now I’ve heard gt40p heads a lot on this forum. I think this calls for a google search.
 

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Ok cleaned up a cylinder and looked at the areas you mentioned.

Regarding the exhaust and intake ports in the head: they are a bit yellow and there was a small amount of rust looking built up. Almost looked like the gasket. But it was just sitting there. I nudged it with my finger and it all fell out. Not sure if that is what you are talking about.

I cleaned up a cylinder and it looks really good (I think) there is a tiny bit of corrosion but you can’t feel it with your fingers. Still no lip. No dings or anything. And when I rotate the crank it turns super smoothly.
 

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Now I’ve heard gt40p heads a lot on this forum. I think this calls for a google search.
Ford started putting the 5.0 motor in Explorers in 1995. They put on improved cylinder heads and better intake. These parts were used on some early 90's Mustangs as the GT40. It made 240 hp. In the Explorer with a milder cam and very restrictive exhaust made 200 hp. In midyear of 1997 Ford had to modernize the GT40 as it wasn't able to meet new emissions standards. Ford spent a lot of money designing a modern cylinder head for a limited amount of production. As a result the best Windsor head. Over the older Mustang E7 head the GT40P head is probably worth about 30 hp. But like any factory cast iron head by the time you rebuild any factory cast iron head and maybe a little performance work you have a good down payment on a set of aluminum aftermarket heads. However if you find a good used set of heads and use them as is, they can make a very cost effective upgrade for a mild Street motor on a budget. Of course there is a hitch. To improve combustion effiency Ford changed the angle of the sparkplug. They're more perpendicular and many headers won't work. Some will. So if you haven't bought headers and you're planning on buying them, that's fine. If you already have headers and they won't work it doesn't make much sense to buy new headers or the GT40P head. All the conditions must be right.

I'm running a GT40P motor in my 66. I knew the pitfalls and I didn't have headers. So I sold a set of GT40P heads I was going to use on another motor. I sold them for $525 and used that money to buy a low mileage GT40P with all the EFI stuff and trans for $450. Sold off what I didn't want for $175. So you see I actually made some money.

I put on a swap meet intake $80, used Edelbrock 600 $125 and a used Mustang 5.0 cam $60. Supposedly this combination is worth about 300hp. I can't say if that is true or not but I can say it runs very, very well! I made a post on my swap.
 

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Discussion Starter #14
Ford started putting the 5.0 motor in Explorers in 1995. They put on improved cylinder heads and better intake. These parts were used on some early 90's Mustangs as the GT40. It made 240 hp. In the Explorer with a milder cam and very restrictive exhaust made 200 hp. In midyear of 1997 Ford had to modernize the GT40 as it wasn't able to meet new emissions standards. Ford spent a lot of money designing a modern cylinder head for a limited amount of production. As a result the best Windsor head. Over the older Mustang E7 head the GT40P head is probably worth about 30 hp. But like any factory cast iron head by the time you rebuild any factory cast iron head and maybe a little performance work you have a good down payment on a set of aluminum aftermarket heads. However if you find a good used set of heads and use them as is, they can make a very cost effective upgrade for a mild Street motor on a budget. Of course there is a hitch. To improve combustion effiency Ford changed the angle of the sparkplug. They're more perpendicular and many headers won't work. Some will. So if you haven't bought headers and you're planning on buying them, that's fine. If you already have headers and they won't work it doesn't make much sense to buy new headers or the GT40P head. All the conditions must be right.

I'm running a GT40P motor in my 66. I knew the pitfalls and I didn't have headers. So I sold a set of GT40P heads I was going to use on another motor. I sold them for $525 and used that money to buy a low mileage GT40P with all the EFI stuff and trans for $450. Sold off what I didn't want for $175. So you see I actually made some money.

I put on a swap meet intake $80, used Edelbrock 600 $125 and a used Mustang 5.0 cam $60. Supposedly this combination is worth about 300hp. I can't say if that is true or not but I can say it runs very, very well! I made a post on my swap.
I’d be happy with 225 hp. The stock of this motor. I really don’t want to dump money into it. Which apparently isn’t necessary given the the gt40p heads aren’t to expensive. But I really just want to get this engine running reliably and Carbed. My plans are run this engine as long as possible. Then build a 363 on a dart block. Boosted of course!

What did you think of the cylinders? I posted some pics above.
 
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