High milage Terminator compression test

I had a friend selling his cobra with 140k miles on it, so we did a compression test. Here are the results


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xsellr8 said:

I had a friend selling his cobra with 140k miles on it, so we did a compression test. Here are the results


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That was a awesome demonstration of a compression test. What is actually perfect compression 170 or 180? If so, it didn’t loose that much over 14/15 year span.


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NasteeNate said:

That was a awesome demonstration of a compression test. What is actually perfect compression 170 or 180? If so, it didn’t loose that much over 14/15 year span.


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Yeah, I’ve seen people report 165 +\- 10, so not bad at all. Not sure if being 8.5:1 lower compression engine has an effect, but good to see a supercharged engine still going strong!


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First time seeing something like this done. What happens when it fails a compression test? What needs to be done?

Z06 said:

First time seeing something like this done. What happens when it fails a compression test? What needs to be done?

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Could be a multitude of things. I've run a cylinder leakdown test previously when I detected lower compression on a cylinder or two to help identify where the problem is. But bottom line, you're most likely going to be tearing into the motor if you have low compression in order to remediate it.

paluka21 said:

Could be a multitude of things. I've run a cylinder leakdown test previously when I detected lower compression on a cylinder or two to help identify where the problem is. But bottom line, you're most likely going to be tearing into the motor if you have low compression in order to remediate it.

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Thanks, I hope I never gotta do one of those to any vehicle.

There was a guy on here with 300,000+ on his 03.

Z06 said:

First time seeing something like this done. What happens when it fails a compression test? What needs to be done?

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On a supercharged car you’re likely to lose compression from detonation taking a chunk of the piston, a lean condition melting and deforming the piston, or burned up rings.

This other GT I tested was not as lucky

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RedRocketMike said:

There was a guy on here with 300,000+ on his 03.

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@hotcobra03

Pretty sure he's over 400K now!

I ran into a guy in LA that had a compound setup on stock short block with e85 and well past 150k on the clock, said he's never had a problem with it. They hold up pretty good and were well designed factory with good tolerances and really good hardware for the time, what more would you expect. I tore into an LSA crate with a friend of mine put in a s14 he built for drifting a couple years back and it didn't even hold up by the time he sold it for another project. Ford did it right.

SVTFastBack said:

I ran into a guy in LA that had a compound setup on stock short block with e85 and well past 150k on the clock, said he's never had a problem with it. They hold up pretty good and were well designed factory with good tolerances and really good hardware for the time, what more would you expect. I tore into an LSA crate with a friend of mine put in a s14 he built for drifting a couple years back and it didn't even hold up by the time he sold it for another project. Ford did it right.

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I’m convinced if the engine is well fed they are very durable. Most failures I see are from detonation or melting a piston from a lean condition and everyone blames the pistons lol


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xsellr8 said:

I’m convinced if the engine is well fed they are very durable. Most failures I see are from detonation or melting a piston from a lean condition and everyone blames the pistons lol


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Yep, because an all too common theme I see is money spent on a good blower, or spinning the snot out of the stock blower to make as much boost as possible and cheaping out on the fuel system. Let's run a ton of boost on a $100.00 set of eBay fuel injectors with a fuel pump maxed out.


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Kind of depends on the mentality of the owner as well by playing cheap and getting expensive results when going the more reasonable route of better fuel and fuel delivery so you can play with timing more aggressively and fuel maps with good power gains. I've never been a fan of the big boost or none at all methodology and see how far you go on stock maps and stock hardware when you know you're playing hot potato by yourself with a hand grenade. Then again i'm excessive and scope the bores while doing compression checks on a normal basis just to make sure the walls are not getting torn up and ring integrity looks intact regardless of what the test initially results, then again I live smack dead in the middle of the Mojave desert where vapor locks a *unt. Safety first.

wow..

no comment on video..

at 419k..

I'm seeing 180 to 195 psi..

6,7,8 have been reading this since replacement head..

cyl 6 piston has hash marks from exhaust valves dropping..200k since last work..

passenger side head is still original 4 thread..

using Castro gtx with stp oil treatment since new..

hotcobra03 said:

wow..

no comment on video..

at 419k..

I'm seeing 180 to 195 psi..

6,7,8 have been reading this since replacement head..

cyl 6 piston has hash marks from exhaust valves dropping..200k since last work..

passenger side head is still original 4 thread..

using Castro gtx with stp oil treatment since new..

Click to expand...

sounds like a completely different story if you’ve had the engine apart.. what car, what compression ratio, what work to the heads, performed hot or cold, temp outside ...many factors can change results- you can’t get caught up on specific psi. You need to pay attention to percentage drop among all cylinders.

The main thing here is the car was running consistent. with 8.5:1 CR you shouldn’t be seeing such high numbers. You may have done something incorrect- maybe even sprayed fuel into the cylinders when cranking OR even adding oil to the cylinders can increase the results. Your heads may be leaking oil into the cylinders


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xsellr8 said:

sounds like a completely different story if you’ve had the engine apart.. what car, what compression ratio, what work to the heads, performed hot or cold, temp outside ...many factors can change results- you can’t get caught up on specific psi. You need to pay attention to percentage drop among all cylinders.

The main thing here is the car was running consistent. with 8.5:1 CR you shouldn’t be seeing such high numbers. You may have done something incorrect- maybe even sprayed fuel into the cylinders when cranking OR even adding oil to the cylinders can increase the results. Your heads may be leaking oil into the cylinders


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Click to expand...

really?

2003 cobra motor..stock..

head was new out of box ford complete..bolt and go..

block has never been touched

some pics to keep it honest..looks like we used the same guage..

tell your buddy,,run 3 full tanks of gas with stp fuel treatment..
his numbers should climb,

why? dirty motor..

when I did my head ..I noticed intake runners were baked black as we'e. valve stems..nothing would remove it..I had blower off weeks after,and noticed...runners and valves looked new...I was amazed...

Thanks for posting. I actually have a buddy interested in the same car. I'll pass this along.

Why not do a leak down test also?

There was a guy on modularfords years back that had 120,000 miles on his motor. Bone stock. The car was still running 10.0's with a whipple. Pretty impressive if you ask me.