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I have discussed this in my build thread but thought I'd maybe get more answers here.
I am doing my first ever timing belt change on a Peugeot 205 with the TU3 engine. I locked the camshaft sprocket with a drill bit and the flywheel with a bolt prior to removing the old belt. I slipped off the old belt and renewed the waterpump and tensioner pulley. I then connected the new belt and tightened up the tensioner pulley. I was struggling to get the tensioner pulley tight but eventually got it sufficiently tight that I could only turn the belt about 90 degrees. So I unlocked the camshaft sprocket and flywheel and turned the engine by hand.
Rookie error was here - I turned it by the camshaft sprocket rather than the crankshaft sprocket. It was tight and difficult to move but it did move without massive force, but it was jumpy/slow/felt like it clicked into place rather than turning smoothly. I probably turned it about half a revolution. The belt loosened off from doing this and I struggled to get it tight again.
I've now from a bit of googling realised I should have taken the spark plugs out before turning by hand.
I'm concerned that a) I've lost timing as it may have jumped a few teeth and b) possibly damaged valves / pistons? (I've watched some videos now to better understand the insides of the engine and realise why I shouldn't have turned the engine by the camshaft...).
Problem is the engine doesn't have timing marks and there isn't a locking bolt visible on the crankshaft so I can't see how to check if timing is correct?
Is my only option to tighten it back up and try turning it by the crankshaft and see if it turns without interference? Could I damage the engine using modest force by hand? Is there another way to check timing (remembering my obviously very rookie mechanical skills)?
Or do I just give it a whirl and hope my engine doesn't explode when I turn the key for the first time and if it does scrap the car, write the 1600 quid it owes me down to experience, sell my tools and PCP a Dacia Sandero?
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Rich
Club Retro Rides Member
Posts: 6,235 
Club RR Member Number: 160
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Remove the spark plugs, retime the engine removing the belt if necessary and never ever turn and engine over by the cam sprocket or rotate it backwards unless the manual specifically states to do so. I can’t really image what you’ve done wrong on a TU motor other than jump the teeth in the belt forcing the engine round via the cam sprocket.
Do not ‘just give it a whirl’ unless you are 110% the valve timing is correct as you will just trash your valves, and possibly guides, and I’ve even seen these engines snap the keyway out of the cam pulley when the belts let go. If in doubt, seek professional assistance here. I’m all for learning and enhancing skill set but a timing belt replacement isn’t a job you can substitute built up knowledge with enthusiasm on.
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Last Edit: Dec 6, 2020 23:23:19 GMT by Rich
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Thanks. Removing the belt to retime the engine is fine, but my problem is I don't know how to - there are no timing marks?
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Rich
Club Retro Rides Member
Posts: 6,235
Club RR Member Number: 160
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Thanks. Removing the belt to retime the engine is fine, but my problem is I don't know how to - there are no timing marks? No, you are right, there are no timing marks. The engine is timed via pins in the camshaft pulley and flywheel, as you said in your post earlier. To ensure the crank pulley is correctly set as it’s easy to accidentally ‘feel’ the pin into a lightening drilling, you may gently rock the crank back to ensure it is correctly locked. If it rotates more than a fraction it isn’t in the timing pin hole in the flywheel. |
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Rich
Club Retro Rides Member
Posts: 6,235
Club RR Member Number: 160
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If you’d like to PM me an email address I can send the specific timing instructions from Autodata to you tomorrow as it seems you are getting muddled in your HBOL going on your readers rides thread.
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Thanks. Removing the belt to retime the engine is fine, but my problem is I don't know how to - there are no timing marks? No, you are right, there are no timing marks. The engine is timed via pins in the camshaft pulley and flywheel, as you said in your post earlier. To ensure the crank pulley is correctly set as it’s easy to accidentally ‘feel’ the pin into a lightening drilling, you may gently rock the crank back to ensure it is correctly locked. If it rotates more than a fraction it isn’t in the timing pin hole in the flywheel. Okay - so take belt off, turn cam pulley to align locking hole and lock cam pulley, try and lock fly wheel, slowly turn crank until I can lock fly wheel (as you can't see through the locking hole)? |
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If you’d like to PM me an email address I can send the specific timing instructions from Autodata to you tomorrow as it seems you are getting muddled in your HBOL going on your readers rides thread. Great thanks just did! |
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Rich
Club Retro Rides Member
Posts: 6,235
Club RR Member Number: 160
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No, you are right, there are no timing marks. The engine is timed via pins in the camshaft pulley and flywheel, as you said in your post earlier. To ensure the crank pulley is correctly set as it’s easy to accidentally ‘feel’ the pin into a lightening drilling, you may gently rock the crank back to ensure it is correctly locked. If it rotates more than a fraction it isn’t in the timing pin hole in the flywheel. Okay - so take belt off, turn cam pulley to align locking hole and lock cam pulley, try and lock fly wheel, slowly turn crank until I can lock fly wheel (as you can't see through the locking hole)? More or less. Further points to note; you won’t be able to turn the crank or cam 360 degrees without the belt fitted without the pistons coming into contact with the valves, which leads to point 2; the crank or cam can be rotated backwards with the belt removed to align valve timing, counter rotation is only not permissible with the belt fitted as it may unload the tensioner and cause the timing to slip. Will email tomorrow. |
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Last Edit: Dec 7, 2020 0:15:10 GMT by Rich
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Okay, noted; thank you. There is a bit of an oil leak in this area too so will try and locate that as well when I have the belt back off. Do you know if there are any common culprits? It looks like it could potentially be from the head gasket - this is the coolant post drainage, is that scum possibly oil? I didn't think so initially...:  If it is the head gasket, Google suggests its a common problem and is usually minor. Might be okay to leave then? Evidently a head gasket replacement may be beyond my technical abilities... |
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Some good news - I tensioned the belt, removed the spark plugs and VERY SLOWLY turned the engine by hand (by the crankshaft this time!). It turned easily and I got it back to the camshaft locking position with no metal on metal contact. So I locked the camshaft and the flywheel and took the belt and tensioner off.
Two bits of bad news:
- It seems the crankshaft is not actually locked - can move it a little both directions with the belt off. So need to find the timing again.
- The belt was fouled with oil. The one I took off wasn't, so wonder if it got touched by oil when refitting (it is quite oily down there). I'm going to have to clean the engine up and try and find the source of the oil leak. Is it safe to liberally apply Gunk degreaser and/or brake cleaner, and then lightly hose it down?
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If it's eaten the head gasket you probably should replace it while you're in there. I've only ever done head gaskets on pushrod engines which are quite hard to get wrong. The thing that has always scared me about doing a head gasket on an overhead cam engine is setting the timing afterwards which you're already learning to do so you're half way there. You might as well give it a go. Best of luck.
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To be honest, if the head gasket needs changed I might wimp out and get a mobile mechanic to do it. I assume with the belt etc already exposed he could whip the head off, change the gasket and sort the timing in no time at all ...
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Rich
Club Retro Rides Member
Posts: 6,235
Club RR Member Number: 160
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The crank will rock a little when locked. It isn’t a ‘rock solid’ lockup. The head gasket will leak oil from the high pressure cam feed on the head to block joint, only cure is replace. If you are unsure of the cam belts installation and want to head done too now would be the time to ‘call it’ and get a mobile tech in to do it if you have lost confidence. These engines are fabulously simple to work on but everyone has a point where they are outside of their comfort zone. Don’t be ashamed of that. I will still send the data tonight for you however.
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Thanks. This is just a cheap project car that I am unlikely to do more than 1000 miles a year in and so ideally I wouldn't be spending a lot getting a mechanic to do the head if I could get away with it. Would it be a dreadfully bad idea to clean up the engine, fit the belt, and leave the head for now, and keep an eye on oil levels? From my searching it seems that the oil leaks out the engine at this point but doesn't tend to leak elsewhere and mix with the coolant...? It wouldn't be a massive amount of work to strip the camshaft covers and belt off and get the HG done in the future if needed.
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Rich
Club Retro Rides Member
Posts: 6,235
Club RR Member Number: 160
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Thanks. This is just a cheap project car that I am unlikely to do more than 1000 miles a year in and so ideally I wouldn't be spending a lot getting a mechanic to do the head if I could get away with it. Would it be a dreadfully bad idea to clean up the engine, fit the belt, and leave the head for now, and keep an eye on oil levels? From my searching it seems that the oil leaks out the engine at this point but doesn't tend to leak elsewhere and mix with the coolant...? It wouldn't be a massive amount of work to strip the camshaft covers and belt off and get the HG done in the future if needed. You are right with your assumption that normally the oil just leaks onto the alternator with no other ill effect. You are ok to leave it if there are no other symptoms and you are ok with topping it up regularly. |
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To lock the crankshaft at the flywheel you can use a drill bit or bent piece of steel, from memory it’s 6mm and fits into a hole in the flywheel through the block casting. It should only have a little bit of movement.
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