Running very Rough

RoyLuke

Well-known member
Apr 18, 2007
261
11
Hello All;
I put together a 4.0 Petrol engine from various spares left over from previous engines for my old Disco 1.
It cranks but runs very rough. There is even what sounds like metal to metal noise.
The engine skips on at least one cylinder.
What would be a good troubleshooting sequence?
I don't want to put a lot of money into this engine because I don't think it will last anyway.
This is engine change # 3. The last engine "threw a rod" and totally destroyed the block. This is the last block I have.
Next time I am putting the Chevy conversion in.

Roy

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Flyfish

Well-known member
Oct 29, 2004
1,402
212
52
St. Louis
Check firing order? Verify spark at all cylinders? Crank sensor good? Inspect all teeth on reluctor wheel? Etc…
 
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RoyLuke

Well-known member
Apr 18, 2007
261
11
The spark plug wires are a bit old (13 years). Maybe it is leaking to cause disrupted firing of the cylinders?
 

Flyfish

Well-known member
Oct 29, 2004
1,402
212
52
St. Louis
The spark plug wires are a bit old (13 years). Maybe it is leaking to cause disrupted firing of the cylinders?
Always a possibility. You can test them with a multimeter. I would check everything until you find the problem. But after 13 years, it’s probably time to refresh a few things regardless.
 
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discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
The spark plug wires are a bit old (13 years). Maybe it is leaking to cause disrupted firing of the cylinders?
Always a possibility. You can test them with a multimeter. I would check everything until you find the problem. But after 13 years, it’s probably time to refresh a few things regardless.
Wait, you rebuilt this engine and it has 14 year old spark plug wires on it?

Never mind.
 

RoyLuke

Well-known member
Apr 18, 2007
261
11
Well that’s just because it’s a shitty engine design. It’s not a workmanship issue, just shitty engineering
I agree. Rather than trying to piece together this engine I should have done the Chevy convesion.
 

discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
Exactly ! That is why I need a war-plan to troubleshoot.

Yep, if you bolted in a Chevy engine and did all the adapters you would need to hook it up, then found a place to mount your new ECM and all new harness, and got that to play nice with your Lucas security system, plumbed any modifications you need for the cooling system, adapt a p/s pump and a/c compressor, bend your custom exhaust and figure out what coil springs will hold up your new curb weight at the correct height.
That would have probably gone much more smoothly and way less problems than you had with this old Buick V8 piece of shit. Pulling it out and putting it right back where it was originally. That’s way harder.
 
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terryjm1

Well-known member
Jan 23, 2011
1,486
375
While only 7mm, I purchased close out Borg Warner ignition wires from rock auto super cheap. I bet they still have some. I was ordering filters for my GMC and decided for $5 to add them to the cart as it didn’t add any shipping cost. I figured worst case I could use them on my TR8 as it isn’t temperamental about plug wires.

If you are trying to be frugal, maybe it’s an option?

They are on my current D1 project and seem to perform just fine. To quote a friend, “It runs smooth like a Toyota.” Who knows how long, though. However, when I worked in an auto parts store, literally decades ago, Borg Warner was considered a good quality line.

On a related note, I replaced every gasket and seal (and of course head bolts) on that engine which only had 26,000 miles but sat untouched inside a D1 stored outdoors for over 10 years. It had a mouse nest under the intake manifold and they had eaten the ignition wires. It looked like hell from the outside but was like new inside. Well, one intake valve was pitted and I replaced it along with the valve springs as I assumed some of them were compressed for those 10 plus years and that couldn’t be good. Valve springs and valves are not expensive.

This is my first D1 with an engine not a diesel and not with a ton of miles. I have had the engine together and installed for quite a while but only recently got the rest of it roadworthy. I was very surprised how much power it has compared to my high mileage D1. If I hadn’t installed it myself I wouldn’t believe it is only a 4 liter. I am assuming the main difference is the camshaft isnt well worn like the high mile one. I have put together other Rover V8 engines but they were installed in much lighter Triumphs. A 4.0 in a 2200 pound car is quite enough. So, until now I didn’t have a good feel for how a 4.0 should perform in a D1. Frankly, with the manual transmission, it has all the power I want. I have only driven it 22 miles and it is already my favorite D1. The diesel is cool but it is slow. The high mileage automatic, well, my wife can drive it as it is an automatic.

I have another project D1 that is believed to have a recently rebuilt (it looks the part) engine with 4.6 internals. It needs a bunch of suspension work before it hits the road. It will give me a nice comparison when I do get it on the road. It has super scary death wobble at present.
 
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