Hercules
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Post by Hercules on Oct 31, 2009 11:35:46 GMT 2
I had to re-con my Lada's head due to bent valves after the timing tensioner shoe broke. The engineering place that did the head suggest that I replace the valve guides with solid brass guides used in the BMW728 motor because they are better than the cast iron guides of the Lada. The only mod on the BMW guide is that they had to be machined shorter and the circlip groove had to be added. I also used the BMW valve stem seals because they are of a better quality as the Lada seals. It work perfect and I'm very happy with mod after doing nearly 15000km already and no problems. The guide part no. is RVG24002 and is available from Midas.
Regards.
Hercules.
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Post by danie on Oct 31, 2009 13:32:28 GMT 2
Well, you can never go wrong with German technology...........mixed with a bit of "Boer maak n plan" technology - and sharing information on this Forum, our Ladas can only get better..........
Thanks Hercules
Danie
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Post by hotstuff on Nov 5, 2009 0:01:44 GMT 2
ok and what did this mod or fix up cost you if i may ask, as and when it happens to me i will be porting and gas flowing with powder cote as well. and info or experience on that with the lada
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Hercules
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Lada - your peace of mind to take on the world's vast landscapes.
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Post by Hercules on Nov 5, 2009 19:12:36 GMT 2
Mike the cost do redo the head is as follows.
From agents: - Headset______________________R1100.00 - 4 x Inlet valves________________R700.00 - Timing chain tensioner shoe______R398.00 - Damper shoe__________________R203.00
From Spare Shop: - 4 x BMW Guides________________R100.00 - 4 x Bmw Valve stem seals________R60.00
Alum Welding of head____________R140.00 Machining and head assembled_____R580.00
Plus a full major service.
Regards.
Hercules.
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Post by hotstuff on Nov 5, 2009 19:54:32 GMT 2
THNXS HERCULES not to bad could save a bob or two if i do most of the work....
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Post by danie on Nov 29, 2009 17:36:24 GMT 2
Just some information regarding Lada Cylinder Head Bolts:
Although the service manual clearly indicates that the cylinder head bolts can be re used, I am aware of a rumour in South Africa that the cylinder head bolts are "stretch bolts" - and therefore should never be re used, after removal - because, (according to the rumour) it will snap during the torque process. I have also been told that the cylinder head bolts should never been re torqued after a "running in" period, because it will snap.
I once verified this information at another international Lada forum, and it has been confirmed that the Lada Cylinder Head Bolts are definately not "stretch bolts"- one owner confirmed that he already used the same bolts over and over again.........without any problems.
To my mind the head bolts should rather be replaced if the threads are rusted, and when / or if one really battles to loosen the bolts. If the bolts are really tight, it might be weakened when loosened, and should rather be replaced.
I also cannot see any reason why the bolts should not be re torqued after a "running in period". As said before, Ladas are not rocket science technology.........
Regards
Danie
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Hercules
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Post by Hercules on Nov 29, 2009 19:42:05 GMT 2
Danie, I also could not get any info that the head bolts are stretch bolts that were fitted in RSA. The fact is that not one Lada were assembled in RSA but that all vehicles docked fully assembled. I also did spoke to Jan at Centurion Lada at the time then I did do my head, and he re-insure me that I can used the bolts as-long as that they still are the required length as that is specified in the manual, which is not in excess of 120mm. When they are longer than 120mm, the bolts bottom and broke during the torque process. That is the main reason why head bolts broke on Lada's after re-using over and over again. When measuring my head bolts, they measured only 116mm and it was the second time that this head was re-con. After removing the head, I noticed that in the past their was work done on the head before I bought the car. The cam was also modified because the valves open 9.8mm instead of the standard 8.9mm. I also noticed a huge difference in low ref. acceleration in comparison with other Lada's I did work on.
The bolts are very tight when loosening them, but if looked at the torque spec, you will notice that the bolts are at a very high torque setting, and do not required any re-torque after running-in. The torque spec is as follows:
Step 1 :- Tighten 20 N.m Step 2 :- Tighten 85 N.m Step 3 :- Turn the bolts 90 degrees Step 4 :- Turn the bolts again 90 degrees.
If looked at these specs, the bolts are actually torque in excess of 130 N.m, which is very high on a aluminium head, and do not required any re-torque after running-in. To re-torque the head bolts after running-in will require to remove the complete cam shaft and cover to get access to the head bolts as they are underneath the cam housing and cannot be reached with the cam housing fitted in position.
After talking to the engineering place which did the head, they also confirm that the torque spec. is very high for a aluminium head. I think the torque spec. is so high for the reason that the head does not require any re-torque after running-in due to the difficulty to access the bolts once the cam is installed.
Regards.
Hercules.
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Post by danie on Nov 29, 2009 20:22:16 GMT 2
Thanks for your reply Hercules - your explanation definately make sence, and do clear a lot of uncertainty regarding this issue.
Regards
Danie
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darryn
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Post by darryn on Oct 30, 2010 9:57:57 GMT 2
Nou het ek k@k...
Last night whilst coming back from Roodeplaat my engine just went "whump" and stopped. I convinced myself I had run out of petrol (I was close to going into reserve, but I don't trust my reserve warning yet), so I ran 3km to a garage to get some fuel and back. Put fuel in. Nothing. Lots of starter motor wailing. So I checked the electrical stuff. No loose connections. No leaks. Nothing. So I called the Cavalry, and my boet came out to have a look. We tested the cables and the coil. All fine and in working. Then we tried to crank the motor with the distributor cap off. The rotor wasn't turning. He said that it looks like my timing chain broke. I still have to open the cover to see if this is the case, but I'm almost too scared.
I the chain broke while under load then I'm "proper f**ked". It looks like I'll have to get this bunch of mods done to my head if the worst is true.
I'll let you all know how it goes.
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Post by Charles on Oct 30, 2010 10:31:16 GMT 2
Dis n kak ene. I hope it didnt do too much damage. When last did you adjust your timming chain? When adjusting my chain it didnt go very tight. I have the tappet cover off so i stuck a screwdriver behind the shoe and pushed it the tightend the tentioner. much better but not as tight as i want it. can the spring in the tensioner go soft?
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Post by marius on Oct 30, 2010 10:33:46 GMT 2
Hi Darryn You are having a lot of trouble with RPG lately IF it is the timing chain I would think it is actually a fairly easy repair. However it is very unlikely to brake - but if I remember correctly you did make some kind of repair on it - could be just that. Hopefully you will be sorted soon. Regards Marius
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Post by danie on Oct 30, 2010 10:35:58 GMT 2
Hi Darryn I am crossing fingers and toes that the chain did not break. Maybe the link that you have made to replace the original missing small link plate was not strong enough Regards Danie
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Post by ronnie on Oct 30, 2010 11:15:22 GMT 2
Hi Darryn
I will keep my fingers crossed that there is not much damage.
Ronnie
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Post by ronnie on Oct 30, 2010 11:19:20 GMT 2
Hi Charles
When I tightened mine it felt tight to me but after I adjusted it there was a big difference, it really was tight. I would assume any spring under tension will over the years weaken.
Ronnie
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Post by Charles on Oct 30, 2010 11:42:48 GMT 2
Hi Ronnie
Did you adjust it like they say on baxters site or is there another trick?
Charles
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Post by ronnie on Oct 30, 2010 13:26:37 GMT 2
Hi Charles
I adjusted it as per Baxter`s site.
Ronnie
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Post by Charles on Oct 30, 2010 14:12:47 GMT 2
If i ever have to pull the front covers i will make a auto tensioner. A spring tensioner like some cars have on their cambelts. I think with a rolling tensioner (i think thats whats it called, like the one bobby made) will work nice with a strong pull back spring. Imagine you never have to adjust your timing chain again.
Charles
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Hercules
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Post by Hercules on Oct 30, 2010 20:25:27 GMT 2
hi Darryn.
Sorry to hear about the problems again. Hope it is not to serious.
Firstly, it is unlikely that the chain can break unless the master link ( if equipt with ) came loose, but can happen. Take the tappet cover off and see if the chain is still on the cam drive gear. If not the chain is broken. Secondly, the drive shaft of the oil pump broke or thirdly the distributer shaft snap.
If the chain did broke, you had to take the head off and re-con the head as the valves will be bend. If it is no2 or 3 it is fairly easy to repair by just replace the oil pump or dissy. Good luck and hope the damage is not to serious.
Keep us updated.
Regards.
Hercules
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bobbyd
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Post by bobbyd on Oct 31, 2010 7:09:40 GMT 2
The one I have still needs to adjusted like an original, it just removes the slider from the equation
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Post by Charles on Oct 31, 2010 9:56:55 GMT 2
I know bobby. im just thinking of putting a spring on it so its auto adjusting
Charles
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Post by danie on Oct 31, 2010 10:38:41 GMT 2
I think with a rolling tensioner (i think thats whats it called, like the one bobby made) will work nice with a strong pull back spring. Charles Hi Charles In a Lada's case (with Bobby's mod) I think it would actually need a "push forward" spring. Danie
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bobbyd
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Post by bobbyd on Oct 31, 2010 11:03:08 GMT 2
I know bobby. im just thinking of putting a spring on it so its auto adjusting Charles Thats a step in the right direction!
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Hercules
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Post by Hercules on Oct 31, 2010 11:58:35 GMT 2
Hi All.
Bobby's rolling tensioner will work very well with a hydraulic tensioner as used by the Lada with the Sequential Fuel Injection System (MPI). You don't need to adjust the tension again as it it done by the engine oil pressure everytime you start and drive the vehicle. (See the workshop manual page 193 - 194.)
Regards.
Hercules
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Post by Charles on Oct 31, 2010 12:22:55 GMT 2
So a good idea would be a rolling tensioner and auto tensioner from a FI model. Then fit a t piece at the oil pressure switch wit a pipe going to the tensioner. Does anybody know how much those tensioners are?
Charles
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darryn
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Post by darryn on Oct 31, 2010 14:28:11 GMT 2
OK- I took the cover off and yes, the chain broke. It broke just before it got over the tensioning shoe. My boet said something about it might not be so bad if it broke in a part of the cycle where it is not under so much tension, and when looking at the diagram in the exploded drawings, it looks as if just after the crankshaft sprocket is a "not so high tension" spot. Am I being a bit too optimistic here? Am I going to have to take the head off come hell or high water? I've already emailed Ventz for prices and a list of all the things he thinks could been busted up. I'm not completely sure of the mechanics involved here, but is the chain breaking very much the same as when Hercules's tensioner shoe broke? Will it do the same damage?
And if so, do I have to lift the whole engine to get the head off or can I do it with the engine still in the engine bay? I'm asking because if I need to lift the engine, then I need to start planning to where I'm going to have the Lada towed. I certainly can't afford to send this to a mechanic so I'm going to have to do it myself.
I guess it's time for another adventure...
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darryn
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Post by darryn on Oct 31, 2010 14:36:32 GMT 2
Never mind about my second question- the manual says I can take the head off with out lifting the engine. Whew.
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Post by danie on Oct 31, 2010 18:47:11 GMT 2
I think installing Bobby's rolling chain tensioner, by following Ahma's instructions regarding the chain tension at the next Youtube link, is the way to go:
My only concern about the rolling tensioner though - I assume the gear rotates on a bearing - if so, the bearing should be of excellent quality, and should be replaced every now and then. A bearing failure could obviously cause problems as well.
Danie
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Hercules
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Post by Hercules on Oct 31, 2010 18:50:49 GMT 2
Hi Darryn.
It is the same as when the tensioner shoe broke due to the fact that the cam go out of timing or stop rotating. The valves that is open will all be bend as the pistons still move up and down till it stops.
Regards.
Hercules
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Post by ronnie on Oct 31, 2010 19:10:21 GMT 2
Hi Darryn Hope the damage is not too bad. Looks like you have had to learn quickly how to fix a Lada. That is the one good thing that comes out of the problems. Ronnie
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Ventzel
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Post by Ventzel on Oct 31, 2010 22:28:36 GMT 2
I've never seen broken Lada timing chain in my life. But may be I'm lucky. Or the chain is ............... replacement.
V.
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