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V-8 Engine Tech

440 engine and gearbox split apart with a siezed engine

Mopar Big Block Talk

by interceptor1021 » Fri Apr 13, 2018 6:20 pm

Good afternoon gents, I am now a little less stressed as my engine was seized so solid I was beginning to think that it had seized due to lack of oil but today after much soaking in diesel I have managed to free off one piston and its just rusted in.
All three rings totally rusted with the oil ring been the worst. its taken a gentle chiselling to get the rings off and all have broken and will be replaced.

My next problem: the con rod is completely seized on the gudgeon pin. With a mallet I can move slightly but its rotating in the piston and I expected it to be free on the conrod with a interference fit in the piston and as it seems to be stuck to the conrod I cant knock the gudgeon pin out of the piston. I am almost sure the other 7 will be the same. These have also been soaked in diesel and I have also applied heat but nothing. The workshop manual mentions fully floating but there is nothing visable to stop the pin sliding out if they are indeed fully floating.
Any advise welcome.
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by cannonball » Fri Apr 13, 2018 7:54 pm

The Gudg pin is a press fit in the conrod and the piston should slide float on the pin,
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by interceptor1021 » Fri Apr 13, 2018 8:58 pm

cannonball wrote:The Gudg pin is a press fit in the conrod and the piston should slide float on the pin,

Thankyou sir, thats a relief.
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by interceptor1021 » Thu Apr 19, 2018 4:33 pm

Hi guys, At last all the pistons are out. The cam shaft was also seized along with the timing chain, fuel pump and distributor drives so new parts ordered and the gearbox off to a specialist for new plates and check over. Now I have a bare block which is going to be steamed cleaned and I thought about painting the block but not sure what colour. Was the original colour black?
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by grottenolm » Thu Apr 19, 2018 6:52 pm

The turquoise colored blocks - coming from Chrysler - were painted black by Jensen. I also painted it black obviously with a special paint for engines.
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by interceptor1021 » Fri Apr 20, 2018 8:15 am

grottenolm wrote:The turquoise colored blocks - coming from Chrysler - were painted black by Jensen. I also painted it black obviously with a special paint for engines.

Great thankyou, I wondered why there was 2 layers of paint on a untouched engine
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by interceptor1021 » Fri May 11, 2018 6:06 pm

Gentlemen, I now a fully rebuilt engine and gearbox which I have put together on a test bench so I can make sure everything does what its meant to do.
Does anyone know what kind of compression readings I should be getting with using the starter motor as I am only getting 55 psi on all 8 cylinders which seems low.
all the timing is set up and plugs removed.
Regards Michael
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by Kevin Birch » Tue May 15, 2018 6:51 pm

That is very low, but did you do the test with the throttle wide open, to allow the air in and turn the engine over three or four times on each cylinder. The fact that it is even across all cylinders is good, but should be at least double the reading I would have thought. Can you borrow another tester just in case.
If you work it out, the cylinder at rest would be 1 bar pressure, if you have an 8:1 compression ratio, then you should see 8 bar with a tester, or 116PSI as 1bar = 14.5 psi.
I would expect a new build engine to have slightly less compression, as the rings won't have bedded in yet, but not that low. Did you stagger the gaps in the rings so they are 180 degrees opposite each other, if they are on the same side of the piston, this will allow gasses past.
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by interceptor1021 » Thu May 24, 2018 7:47 am

Kevin Birch wrote:That is very low, but did you do the test with the throttle wide open, to allow the air in and turn the engine over three or four times on each cylinder. The fact that it is even across all cylinders is good, but should be at least double the reading I would have thought. Can you borrow another tester just in case.
If you work it out, the cylinder at rest would be 1 bar pressure, if you have an 8:1 compression ratio, then you should see 8 bar with a tester, or 116PSI as 1bar = 14.5 psi.
I would expect a new build engine to have slightly less compression, as the rings won't have bedded in yet, but not that low. Did you stagger the gaps in the rings so they are 180 degrees opposite each other, if they are on the same side of the piston, this will allow gasses past.

Hi Kevin, Thanks for the reply. All rings are staggered and carb fully open. I have now put oil in and rotated the engine allowing a flow so I can turn the engine faster without the worry of metal on metal with no lubrication.
I have after many rotations on the starter managed to get readings of 70 psi across all eight which is encouraging but odd, never had this before. I have been advised all is ok and once running and hot the reading will improve as you say with bedding in.
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by rta50car » Thu May 24, 2018 10:05 am

Just wondering if you replaced pushrods. 2 or 3 thou difference in length from original could be enough to effect full valve face closure tdc and therefore your compression psi. Personally you should be getting more like 120/130 psi

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