Engine fun

Decided to strip down the top end of the 106 engine todays. It's always had a slight misfure and it's a bit smokey on startup so decided it was about time I did something about it.

So after much messing about I wipped the head off today and started stripping it down. Unfortunately due to the weather and lack of space in my garage I had to take the head indoors to clean it up - so here's how our dining room table currently looks:

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It's like being a student again!! And the other half can't moan cos it's all from her car!! In fact she's been doing a great job of helping - she knows how to use a valve spring compressor now :)

But I'm glad I took it all apart, as the valves are seriously coked up. But I'm popping over to Dad's tomorrow to clean them all up, as my cordless drill here isn't man enough for the job!! Managed to clean the cylinder head though and that's come up pretty well. Also the valve stems seals were rock hard, as were the inlet manifold seals so they're all changed now. And when I took the rocker cover off I realised why it sounded to tappety - some of the rockers must of had about 3mm of play in them - bit more than the

0.2/0.4mm they should be. Hopefully I'll be able to adjust them ok when it all goes back together!!

I've also got a new cambelt (obviously), tensioner, water pump and headbolts to go on - for once there's been no expense spared.

So I'm hoping that this overhaul will result in a much smoother and potentially more powerful engine. Fingers crossed!!

Reply to
Carl Gibbs
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wow thats almost a mod post! personally i'd be to scared to take anything like that apart cos i know i'd f*ck up putting it all back! plus the BM is no doubt about 10 times more complicated than your 106 i bet lol

Reply to
Vamp

Hope you are going to lap the valves in too as this actually will result in smoother running and more power.

Go get a valve "sucker" stick and some grinding paste from your local motor factors...

Otherwise taking it all apart was almost pointless.

Reply to
Burgerman

burgerman you know far to much shit bout shit you know!

Reply to
Vamp

Cleaning all the crap out and replacing leaky seals is pointless?

Reply to
DanB

Not necessarily. Unless you are assuming some, or all of the valves are leaking? Having said that, having got that far I'd probably give them a quick lap just to make sure they're not. Mike.

Reply to
Mike G

I bow to your superior knowledge :-) I'd just have loved getting the stem seals done on my old 405 heh, it used loads of oil!

Reply to
DanB

Just about. The seals stop a bit of smoke on start up thats all. The carbon causes little trouble. Its not exactly in the way.

Making the valves seal properly is far more important. It will run like a new motor. And it only takes an hour. You may also need a cheap valve spring compressor but its well worth it. Even on a NEW engine because they dont have the time at the factory and just cut them and fit them. Results in a less than perfect seal even from new.

Just ad the paste, stick valve back in hole and rotate back and forth with sucker thing. Once you have a nice mat grey ring right aroung the valve and the seat about 2mm wide you are done. Wash in wd 40 as you go and its obvious when they are done!

Reply to
Burgerman

I have never seen ANY valve that seals properly in any motor I ever took apart. And thats quite a few! Including a brand new Suzuki GSX 1100 EF motor. That had about 75 miles on it.

The manufacturers just use an aluminised coating on the seats and hope they bed in. They do more or less but never as well as if you just lightly lap them in by hand.

If you dont believe me take your next head that you removed and fill the ports with parafin and watch it leak or in some cases gush through! Then try it after you properly lap them in... If you get it right none will be apparent at all for about 5 mins. Then only a tiny weep caused by the cappiliary attraction.

The difference when you start it up is always apparent. Anyway its good to know its done and that you didnt have any leaky valves! Its theraputic.

Reply to
Burgerman

Of course I did! All done this morning with a sucker stick and some grinding paste. Head's now nice and shiney (well kind of), with all new seals and gaskets. I really could have done with replacing the inlet valves as the ends of them have been knocked out of shape and are a bit tight coming out of and going back into the head. But once back in they were ok, so should hopefully be fine. This probably wasn't helped by the rocker clearances being so big! So here's how the head looked after some drill and sucker action:

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Unfortunately GSF have given me the wrong waterpump, so the car is still in bits. By the time I realised it was past 4pm so Halfrauds was closed. Doh. So gonna have to take the afternoon off work tomorrow to finish it. But we're on the home straight now, and I've quite enjoyed it (apart from the aforemention c*ck up).

Reply to
Carl Gibbs

Emery paper and patience!

But once back in they were ok,

Large valve clearances actually help with power. You lose a tiny bit of lift and a bit of duration but you avoid loads of useless crank rotation degrees where the cam is on the "quieteniung" ramp. This bit is designed to give valve seats an easy time and to make less noise. But it means the valve is neither far enough open to flow any gas but open enough to stop the engine doing much work. A valve needs to be either open or shut. All the time it spends doing neither properly means its just in the way. Larger running clearances helped power usually. The valve gets banged off the seat suddenly. Sounds like a diesel though.

Then it will run like a new one! Makes you feel like throwing a set of rings and shells on too doesent it... And skiming a mm or so off the head for a bit of free extra power...

Reply to
Burgerman

I've taken quite a few apart myself. You can usually see if a valve is not seating well by an inspection of the seating faces. Maybe not as perfect as a valve that has just been lapped, but good enough to not be a problem, but I'm not trying to start an argument. I just don't believe there is any significant difference, performance wise, between a just lapped valve, and one that is not obviously leaking.

Agreed. As I said, I would lap valves. 1) because if they are seating quite well it only takes a few minutes, and, 2) if the tappet clearance is set by shims you might as well set them with well seated valves. I would also fit new springs if there was any shortening of the existing ones. Maybe not if the car was an old banger though. Mike.

Reply to
Mike G

Well there is a difference but if its not leaking much the difference is small. But while the heads off its daft not to do it!

But you missed the main reason. Its very theraputic. And when you drive it you know its right!

Reply to
Burgerman

Yep certainly sounded rough, but that makes sense. But an extra ~3mm of clearance - surely that's far too much?

Heh, if it was worth a bit more I might, but at the end of the day it's only an old banger. I reckon I've lost a fair bit of compression from all the carbon deposits I've removed though so a skim might have been a good idea ;)

Reply to
Carl Gibbs

Yep!

Reply to
Burgerman

I read somewhere that after a period of running, valves in a new engine will have lapped themselves in due to rotation in their seats.

Reply to
Mark W

Wheras in reality the exact opposite seems to happen. Even more so with uleaded fuel and harder seats. Ye very olde softe ones sort of seated themselves as the valve sunk into the head. So now perfect sealing from new is more important than before. And good lapping and sealing is labour and time consuming so its skipped. We rely just on accurate machining and an aluminised coating on the valves thats soft enough to seal while they bed in. In practice its good "enough" for most usually. However...

When you remove a valve and look at the seat area its always black and or pitted and always leaks some - at least the exhaust valves do.. Some more than others. When you start to relap a valve the first thing that happens is that you start to cut through the black "scale" on both the seat and the valve. After a couple of minutes and a wash in parafin you will see that the new cut area is in patches on both the seat and the valve. Not complete rings Proving that the thing was thrupeny bit shaped (ask you dad) and that the seat was also not properly round when you started..

If you keep lapping all the new mat grey areas eventually form a full ring in the seat with no gaps, and also on the valve itself. NOW it will seal.well.

Reply to
Burgerman

Got the correct water pump, and the engine is now all back together and seems to be running better than before. I think the engine is quieter after resetting all the valve clearances, but it's hard to tell because the exhaust manifold is blowing slightly, but I couldn't be bothered to fix that tonight, so that'll be a job for tomorrow. At least it can now be used for the commute tomorrow!!

Only managed a drive round the block tonight, but I'll take it out for a proper drive in the next few days, but at the moment it looks like the overhaul has been a success! Sweet :)

Reply to
Carl Gibbs

Well done dude :-)

Reply to
DanB

I thought only Tom Jones fans did that sort of thing. Is there something you're trying to tell us?

Reply to
Clive George

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