View Full Version : very quick TDC question
jeffchiz
2nd December 2009, 11:15
basically im swapping my rallye head from my 106 to my vtr and my vtr head on to my 106 so i wanna know how to put my head/engine at top dead center so i can take it off and change
Scott_GT
2nd December 2009, 18:35
Easy, basically take the head off, turn the engine over and put a 6-8mm pin into the side of the gearbox which locks the flywheel, theres only one place on the flywheel where it will lock into to hold it and that will be TDC.
The hole for the flywheel is on the front of the engine where the gearbox mates to the engine.. pretty hard to see as its only a 8mm ish hole..
jeffchiz
2nd December 2009, 21:31
i thought you had to put it at TDC when the head is on? then put a pin in the head to lock it there, then if they are both locked at TDC then i dont need to time the head up again?
jeffchiz
3rd December 2009, 00:45
some one must know? I'm guessing you put a socket and ratchet on the cam pulley and turn the engine/cam over until you get to TDC? in the cam pulley there is a hole I'm guessing this is where you put the locking pin? does this hole line up with a hole on the block? and when these two holes are lined up it that the only possible way for it to be at TDC? also say if i do take the heads off and they aren't at TDC how bad will this be for my car if i try to start the engine and it isn't timed up properly can i do serious damage to my car?
VTRelite
3rd December 2009, 00:53
If it is not timed then you will get the pistons crashing into the valves my friend
jeffchiz
3rd December 2009, 01:29
If it is not timed then you will get the pistons crashing into the valves my friend
thats not good :S ive seen the how to guide on changing a cylinder head on the vts engine it says to put a locking pin through the cam pulley in to the cylinder head is this the same on my vtr/rallye head i would have thought if these two holes are lined up then it must be a TDC?
LeeM
3rd December 2009, 08:39
theres a hole in the flywheel which matches a hole on the front of the block. by lining that up and putting an allen key through the holes this locks cylinder one at tdc.
jeffchiz
3rd December 2009, 11:55
ok brilliant ill do that then so when i remove the head i must be very careful not to turn the cam?
jeffchiz
3rd December 2009, 12:10
can i turn the engine over and put it at TDC when the head is on?
Stevo123
3rd December 2009, 13:31
You can also lock the valvetrain/head/cam at TDC with a 10MM drillbit (mk2) or 8MM ish on Mk1 through the cam pully into the side of the head. When reassembling the engine the bottom end will be at TDC and the top end will be at TDC also. After fitting the new cam belt you can remove the 2 drill bits.
jeffchiz
3rd December 2009, 16:19
You can also lock the valvetrain/head/cam at TDC with a 10MM drillbit (mk2) or 8MM ish on Mk1 through the cam pully into the side of the head. When reassembling the engine the bottom end will be at TDC and the top end will be at TDC also. After fitting the new cam belt you can remove the 2 drill bits.
yes thats the way i was gonna do it :D so basically i turn the cam pulley untill the hole on the pulley and the hole on the head line up then thats deffently 100% at TDC?
jeffchiz
3rd December 2009, 17:56
anyone lol i just need a yes or a no to put my little head at rest lol
wolfie3291
3rd December 2009, 18:07
yes you can time up your engine to TDC but ONLY when the head is on only unless you have a special tool to stop the cylinder liners poping out when you turn it over with the head off. the engine can only be timed up 1 way. you need to pin up both cam and crank shaft like you would doing a cambelt so you know the correct pistons are at TDC and make sure when you put the rallye head on that is timed and pinned up correctly to our your lovely new head will have broken valves quickly depending on how far out your timing is.
its best to time up the cam shaft 1st to know the crank is in the correct position before pining up the crank to because even if you pin up the crank 1st the cam could still be out of line with the timing pin hole by 180 degrees.
jeffchiz
3rd December 2009, 20:21
ok cool so if i line the two holes up and put a drill bit in the head and do this with both heads then i can just lift the heads off and place them on the engine then bolt them back down and they should be timed up properly
luthor1
3rd December 2009, 22:19
Haven't read the whole lot because I'm pissed bu thought I'd throw in my 2 pence :)
set all 4 pistons half-way up the bore, this way there is NO way you can bend valves.
Fit head.
Set head cams to the timing positions.
Move crank to TDC
tighten belt.
Jobbed. Simplez :)
Andy
raunchz
3rd December 2009, 22:20
Haven't read the whole lot because I'm pissed bu thought I'd throw in my 2 pence :)
set all 4 pistons half-way up the bore, this way there is NO way you can bend valves.
Fit head.
Set head cams to the timing positions.
Move crank to TDC
tighten belt.
Jobbed. Simplez :)
Andy
Not bad for a drunk man :P
jeffchiz
3rd December 2009, 22:44
Haven't read the whole lot because I'm pissed bu thought I'd throw in my 2 pence :)
set all 4 pistons half-way up the bore, this way there is NO way you can bend valves.
Fit head.
Set head cams to the timing positions.
Move crank to TDC
tighten belt.
Jobbed. Simplez :)
Andy
only one problem i dont have a clue how to set the cams to the correct timing positions :( im about to cry its so confusing im trying to find the simplest way possibile which i would have thought would be to just line the holes up on the head and pulley then swap heads and it should all be at tdc can it be done that way or not :( lol and yea im pretty impressed with that considering ur pissed lol
jeffchiz
5th December 2009, 18:19
rite im just gonna line up the holes and if anything goes wrong im blaming all of saxp lol
raunchz
5th December 2009, 18:23
its a vtr so all you've got to do is stick an allen key in the botton end timing hole until it locks that, then put an 8mm bolt in the camshaft sproket to lock that - job done
jeffchiz
6th December 2009, 13:40
its a vtr so all you've got to do is stick an allen key in the botton end timing hole until it locks that, then put an 8mm bolt in the camshaft sproket to lock that - job done
thanks for your help mate really appreciate it x
Slugshead
6th December 2009, 14:39
Theres locking holes for the cams aswell mate, cant remember which end it is, the fly wheel or the cam end but the square pin thing out of a door handle locks it perfect
jeffchiz
8th December 2009, 04:19
Theres locking holes for the cams aswell mate, cant remember which end it is, the fly wheel or the cam end but the square pin thing out of a door handle locks it perfect
which square pin thing??
raunchz
8th December 2009, 08:16
Theres locking holes for the cams aswell mate, cant remember which end it is, the fly wheel or the cam end but the square pin thing out of a door handle locks it perfect
which square pin thing??
The locking hole is in the camshaft pulley end for the head, it uses an M8 bolt to lock it off (the square thing being referee to is 8mm too)
He's just refering to another tool that can be used to lock the head off at tdc
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