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#1 10,000 mile "temporary" engine update

Posted: Sun Sep 22, 2019 4:41 pm
by politeperson
Thought I would take a minute to examine the 1967 short block engine now it has completed 10,000 miles. Yes I cannot believe it has gone so quickly. I haven't really had to touch much for a long time, it has all been pretty reliable.

Shame it is so good really, as I am taking it all out to put the original long stud engine back in! The original has had a complete rebuild, slightly up on compression with a big vale head, D - type cams and a very special Neil Brown engineering cylinder head. This new engine will be dressed with all the fuel injection and exhaust manifold you see here.

After running it in on SAE 30 for 500 miles, the engine has had three oil changes running on 20w50 mineral oil. Oil consumption has been pretty minimal between changes.

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The oil in it is now 4,000 miles old and it still looked pretty clean this afternoon.

Coolant is clear blue and up to the correct level. It is now three years old so due for a change. The brake fluid is also clear but due for a change too as it is also three years old.

Plugs look OK. Thought I would check the compression, all cylinders are showing around 180 psi + - 3psi. This is on 8:1 pistons, as for some reason I was paranoid about pinking. It is a very smooth, powerful and economical engine however, even with the lower compression pistons. We even saw 28mpg on trip to London.

It has been putting down 225ft-lb at 1,000 rpm on injection, rising to 374.5 ft-lb 372 n/m at 3,400 rpm.

Flywheel was 263bhp @4250rpm, 229.2 bhp at the rear wheels.

Oil pressure is a rock solid 50 psi hot at idle. It rises to around 65 psi of the mechanical gauge.

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The rear oil seal is dripping a little bit on the "upgraded" modern seal kit. It is no better than a correctly rope seal really. I will replace it soon.

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So all in all, the temporary engine has proved quite successful.

#2 Re: 10,000 mile "temporary" engine update

Posted: Sun Sep 22, 2019 11:57 pm
by PeterCrespin
Front and rear ‘carbs’ are fractionally weaker than the middle. How would you trouble shoot that if you ever wanted to? I assume you could try to see if the mixture follows swapped-around injectors or plugs? ECU signal and fuel pressure must be identical and 180 +/- 3 psi suggests mechanicals are also very consistent.

#3 Re: 10,000 mile "temporary" engine update

Posted: Mon Sep 23, 2019 6:21 am
by chrisfell
Will you be keeping the engine as a spare or letting it go?

#4 Re: 10,000 mile "temporary" engine update

Posted: Mon Sep 23, 2019 11:11 am
by politeperson
Hello Peter, yes I could swap the injectors and see what happens. They are Mini Cooper S and readily available on the Bay.

What I really need to do it check all 6 butterflys are still synced with my flow meter and feeler gauge. That is the more likely culprit. It is pretty easy to do. Must get my meter back off Richard some time.

Chris, the short stud motor is already spoken for I am afraid.

When it comes out, I will check the valve clearances(one sounds a bit loud) and do the oil seals. It is being dressed up in a slightly more traditional fashion with triple SUs and a 123 tune distributor. It will be interesting to see how it performs, all other things remaining equal.

#5 Re: 10,000 mile "temporary" engine update

Posted: Tue Sep 24, 2019 2:08 pm
by Woolfi
"It is being dressed up in a slightly more traditional fashion with triple SUs and a 123 tune distributor. It will be interesting to see how it performs, all other things remaining equal."
This would be really interessting to know.
Maybe (? ? ?) the rampipes I can see on the picture are a little bit short. The distance between the valve and the end of the trumpet must "fit" to the revs of the highest power. There are formulas to calculate this.
If you check a Mercedes SL 300 Gullwing you can see, that the 6 pipes between the injcetion-sampler and the cylinder head is longer.

Regards Wolfgang Gatza

#6 Re: 10,000 mile "temporary" engine update

Posted: Sun Sep 29, 2019 7:53 pm
by politeperson
Hello Wolfgang, sorry your reply dropped through the cracks.

Yes, I could try longer rampipes, might just do that. Might increase torque.

It is just a matter of getting value for money.

Like many things in life the cost increases per unit as the units gets bigger.

In other words, in XK terms, taking an engine from 200 to 220 bhp is much cheaper than taking an engine from 260 to 280 bhp.

There comes a price where you reach the maximum point on the value for money/performance efficiency curve. I suspect the engine in the silver car is about there value wise.

I will be very interested to see how the old motor (2017!) performs on SUs.