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Post by Deleted on Jul 7, 2014 8:56:30 GMT
Well done Alan. Keep burbling! Sounds like your wife may have been talking to you? Good advice!
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Post by Welsh Warlock on Jul 7, 2014 9:07:35 GMT
I'm almost looking forward to tearing the engine down. May do it bit by bit over the week nights but then, having gathered all of the gaslets and fluids, I want to set aside a day and possibly a weekend to rebuild the engine slowly and meticulously.
I don't want to have to do it again if I can help it.
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Post by guidedog on Jul 7, 2014 10:47:28 GMT
We will watch with interest.Bon Chance
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Post by enigmas on Jul 7, 2014 11:03:21 GMT
When you get the rotating and reciprocating parts to whomever is going to check the balance, it would be great to find out where or what is/was causing the imbalance.
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Post by Welsh Warlock on Jul 7, 2014 14:39:54 GMT
I agree. That was the reason I didn't just go down the balance rout and rebuilt in case it was just the piston issue.
I hope when I take the parts along that I will be able to stay while he balances them. Would be interested to see the process and establish the exact issue. Maybe then I can see what the 'professional' who built the engine has to say about it. I'm sure he won't offer any recompense and I'm not expecting any but how he deals with any issues found will be interesting.
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Post by Welsh Warlock on Jul 7, 2014 21:05:19 GMT
Engine and gearbox separated and garage tidied away ready for stripping!
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Post by Welsh Warlock on Jul 13, 2014 21:53:40 GMT
Spent Saturday stripping the engine.
The pistons, conrods and caps weighed as units were all within 4 grams on a mass of 1.25 kilos per assembly
I now have a block with just the cam and crank in and I'll be ringing the balancer tomorrow to make an appointment.
All gaskets have been obtained so build up should be fairly quick once done.
ETA: Time permitting of course.
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Post by djm16 on Jul 13, 2014 22:51:29 GMT
Having gone this far, I would get everything individually to better than a gram not just as a unit. That way you will have an engine as smooth as silk (or expire in the process)
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Post by Welsh Warlock on Jul 14, 2014 18:40:55 GMT
I'm going to see the engine balancer on Friday and have arranged to take the day off to spend with him.
He reckons he will have been the one who balance it in the first place and is interested to see if he can find the problem.
Looking forward to it now.
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Post by Colin McA on Jul 15, 2014 13:14:05 GMT
Keep ploding away buddy.
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Post by Welsh Warlock on Jul 15, 2014 15:39:04 GMT
Nil carborundum illegitimi!
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Post by Deleted on Jul 15, 2014 18:15:20 GMT
Well fingers crossed Alan. Be prepared! He was the one who balanced it in the first place?.......
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Post by Phil Nottingham on Jul 15, 2014 19:11:39 GMT
Well I did the Sciences not ancient arts so I should not know what that means
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Post by Welsh Warlock on Jul 15, 2014 21:06:35 GMT
Well fingers crossed Alan. Be prepared! He was the one who balanced it in the first place?....... When I spoke to the chap he was mortified at the prospect that one of the engines that he PROBABLY balanced was vibrating and is happy to work with me to track down the issue. He said he will know if he has been there before just by looking at it. He has a great reputation and is the brother or a well known V8 specialist (not the one who built the engine)who is well known in the TVR world so has a vested interest in getting this sorted. I took the crank out of the block this evening - nothing untoward found. I am looking forward to Friday and hope to be able to shed some light on the issue. Meanwhile my continued thanks to those who have been supportive. [/quote]
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Post by enigmas on Jul 15, 2014 23:01:26 GMT
Good luck with the investigation. I'm looking forward to the discovery of the gremlin too.
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Post by Welsh Warlock on Jul 18, 2014 13:39:05 GMT
Well, I'm back from the balancers.
What a great experience that was. Very 'Man in a shed' but the level of skill is second to none.
He knew straight away what the problem was and someone earlier almost hit the nail on the head.
This is as I understand it:
The 3.9/4.2 engine has balancing issues that the other variants don't have due to an issue from when the development work was done. How does he know? Because the company his brother used to run, and for whom he worked, did (at lease some of) the development work on the engine. Land Rover took the specs they supplied but forgot to make specific allowances for the bearings in the balancing.
Since Rover didn't realise this until type approval had been completed, it was then too late/too expensive to rectify so they tried to overcome the issue by balancing taking out the imbalance by compensating in the flywheel and pulley.
Hence it matter little on other varaiants of the engine if you swap flywheels and pulleys but on the 3.9 engine it is important that either the engine is kept with its original flywheel and pulley OR that they are balanced separately and latterly as a unit for fine tuning.
Because I was never going to use the original flywheel I would always have had a problem putting the flexplate onto the engine eve if I had used the original pulley.
As I was there and had already committed to spending the money, although there is a cheap fix, he did the full balance of each component and then as a unit.
Each piston, Rod/pin, the crank, flexplate and front pulley were balanced individually and the crank/pulley/flexplate as an assembly.
Now just a matter of rebuilding it and seeing if it all works.
Balancer reckons it should be smooth as silk.
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Post by p5bdownunder on Jul 18, 2014 13:57:56 GMT
Well, I'm back from the balancers....... Great update and (hopefully) good news too! Keep us posted..... Stu
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Post by guidedog on Jul 18, 2014 15:57:57 GMT
That's great news Alan. It sure must nice to see a light at the end of the tunnel
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Post by Welsh Warlock on Jul 18, 2014 16:01:24 GMT
Might be a while until I get time to rebuild due to other stuff an I won't really have anything to report until its in and running.
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Post by Deleted on Jul 18, 2014 16:15:22 GMT
Sounds good!
Finally!!
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Post by Welsh Warlock on Jul 18, 2014 18:19:06 GMT
Not counting my chickens just yet chaps but fingers crossed eh?
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Post by Colin McA on Jul 18, 2014 22:08:38 GMT
Interesting conclusion. One of them things that those on the know, know.
Give it to the wife to put back together on her holiday...
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Post by Welsh Warlock on Jul 19, 2014 12:36:04 GMT
It would appear that a lot of people that think they are in the know aren't as much in the know as they think they are!
I'd love to give the engine to Alison to assemble but there are 2 problems with that:
1. I am spending the day replacing rear discs and pads on her Audi - not as easy as you might think. Needs the bearing races swapping and the ABS rings - and if she can't do that then no hope of her rebuilding the engine and: 2. She'll be in Scotland house sitting for someone! I assume someone's nephew will be taking her out for dinner while she is there and while his significant other is away?
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Post by Colin McA on Jul 20, 2014 19:42:11 GMT
I will print this out in lieu of a permision slip.
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Post by Warwick on Jul 24, 2014 3:40:19 GMT
The 3.9/4.2 engine has balancing issues that the other variants don't have due to an issue from when the development work was done. How does he know? Because the company his brother used to run, and for whom he worked, did (at lease some of) the development work on the engine. Land Rover took the specs they supplied but forgot to make specific allowances for the bearings in the balancing. Since Rover didn't realise this until type approval had been completed, it was then too late/too expensive to rectify so they tried to overcome the issue by balancing taking out the imbalance by compensating in the flywheel and pulley. Hence it matter little on other variants of the engine if you swap flywheels and pulleys but on the 3.9 engine it is important that either the engine is kept with its original flywheel and pulley OR that they are balanced separately and latterly as a unit for fine tuning. Alan, I think this is a fundamentally important piece of information, that could easily become lost or difficult to find with the passage of time. Perhaps you should create a new thread, titled something like "Using 3.9 & 4.2 engines" and outline what you have discovered, and include a link back to this thread so the background is available. And then that thread should be made a sticky.
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