Cam timing without timing marks?

[Oom_Paul]

Hey all,

As above? Any ideas on how to do cam timing with no timing marks whatsoever? PO has removed both the cam belt covers and the ignition timing mark bracket. :sigh::sigh::sigh:

I marked TDC with the head off, but how do I find the correct position for the camshaft before fitting the cambelt? :hmm:

On a more positive note, I have at last got the head on and I hope to have the engine refitted by tomorrow evening! :woot:

Cheerio from South-Africa!
Justus

 

[Pete Whitstone]

A degree wheel...

Hey all,

As above? Any ideas on how to do cam timing with no timing marks whatsoever? PO has removed both the cam belt covers and the ignition timing mark bracket. :sigh::sigh::sigh:

I marked TDC with the head off, but how do I find the correct position for the camshaft before fitting the cambelt? :hmm:

On a more positive note, I have at last got the head on and I hope to have the engine refitted by tomorrow evening! :woot:

Cheerio from South-Africa!
Justus

On the crank pulley, with a dial indicator fitted to a valve, would be the normal way to time a cam in this situation. But that's difficult to do when the engine is in the car. Not impossible, just difficult. Do some youtube searches for "degreeing a cam" and you will find the technique.

Pete

 

[jvandyke]

there's a still a mark on the cam pulley of course (?), replace the belt cover with the little marker on it! is this a 1500? (it's not on the plastic cover but the metal backing plate/belt guard) if you put the crank pulley pointers back on, verify exact position off flywheel or other method, it's "adjustable" and can be off which would cause you headaches if you set ignition timing by a mis adjusted guide (ask me about 4 blown head gaskets!!)

 

[JimD]

Year and engine info

Please post some info on the year of your X and the engine size... 1300 or 1500. Is it the original engine? Are South African Xs euro models or US spec? If possible, post some pictures of what you are looking at. The more info you can provide, the better we can help you.

 

[EricH]

As above? Any ideas on how to do cam timing with no timing marks whatsoever? PO has removed both the cam belt covers and the ignition timing mark bracket. :sigh::sigh::sigh:

If you had a 1300 motor and cam pulley, this would be easy - the cam timing mark is on the snail mount. But if there's an ignition timing mark bracket to remove, it's a 1500 and the cam timing mark is supposed to be on the metal bracket that mounts the timing belt cover. I'd seriously consider buying this bracket if it' s missing - you'll want a timing belt cover one of these days, and not having a cam timing mark is going to be a real pain.

 

[Oom_Paul]

More details:

Sorry guys, I should have known to post more details from the start. Here goes.

Short version:
--> 1500 X1/9 block
--> 1500 X1/9 crank (as far as I can tell)
--> 86mm bore
--> Nissan SR20de pistons
--> Uno Turbo (MKII) conrods
--> Uno Pacer (1400) head
--> Uno Pacer camshaft (standard cam)
--> Garrett T25 BB Turbo (off a Nissan 200SX) - 0.6bar
--> Uno Turbo Intake Manifold
--> Custom Intercooler
--> Custom exhaust manifold
--> Custom freeflow exhaust
--> Spitronics engine management




Long Version: :woot:
I bought Brutus a few months ago as a fun little runabout/project, instead of buying something boring like a VW Polo. He was fitted with a Uno Turbo head and camshaft as well as some turbo off a Volvo. PO promised me reliability and economy, I suspected otherwise but I was in love, so I bought him anyway. :nuts:

Problems started immediately, smoked like hell until the turbo got warmed up. Used water and overheated intermittently. I replaced the turbo (with the T25) and the smoking stopped. Happiness, for a bit :sigh: The overheating got worse and I suspected a headgasket.

Compression test revealed a leaking headgasket. I took the head off and found worse. Head cracked in at least 5 places (into waterjacket and between exhaust and intake valves) and a badly worn camshaft (all lobes worn and 2 exhaust lobes basically MIA).

Reaction-->
Sourced a head that would work (Uno Pacer 1400) and a matching camshaft that apparently works well with a turbo (also off a Uno Pacer). Managed to figure out what pistons were used in the engine by the PO (Nissan SR20de) and concluded that he wanted to use them to drop the compression ratio for the turbo (he was boosting 1bar when I bought the car and had gone as high as 1.6bar). I sourced some new oversize pistons (SR20de, 86mm) and had the blocked bored to match.

Crank also had to be reground undersize and new bearings were sourced. I did some work on the head (light polishing and porting) while I waited for parts. Sorted out the cooling system to work with the new head (thermostat housing works differently from X1/9) and plumbed in some watercooling for the turbo. I also did some other bits and pieces like find a flatter oil filter housing that, when mated to the oil cooler manifold, can actually be replaced without pulling out the motor. :woot:

Right now the bottom end is assembled and the head is assembled with new valves and torqued down. Everything feels and looks good. Finding a cam cover locally is all but impossible so I don't think that's really an option. Buying a dial gauge appeals to the engineer in me but I would really like to get Brutus back on the road asap! I guess jvandyke's signature applies

Thanks for the replies so far!

 

[Oom_Paul]

Wow, long post above^^ :geek:

Some pics of the engine:

 

[EricH]

Buying a dial gauge appeals to the engineer in me but I would really like to get Brutus back on the road asap! I guess jvandyke's signature applies

If the camshaft is a split overlap (intake opens the same number of degrees before TDC as exhaust closed after TDC) as are most of the stock and performance SOHC cams available in North America, you can dispense with the degree and dial indicator.

With the cam box out off the motor and on a flat surface, cam lobes for #4 cylinder pointing up.
1) take a cam bucket with a shim on in it, put it into the well for #1 cylinder exhaust valve.
2) Rotate the camshaft counterclockwise until the cam lobe contacts the shim. Mark the position of the camshaft index pin against the cam housing at that point.
3) Now use the same cam bucket with the same shim, put it to the well for #4 cylinder intake valve.
4) Rotate the camshaft clockwise until the cam lobe contacts the the shim. Mark the position of the camshaft index pin against the cam housing at that point.
5) Try this a few times, to be sure that you're getting repeatable results.

With a split overlap cam, the correct TDC position will be with both cam lobes pointing down and the index pin midway between the two marks. If you repeat this procedure for #1 cylinder, you should find a TDC position that is exactly 180 degrees out, and that would be a good check.

The rest of your motor is sufficiently far away from stock that there's no particular reason to expect that the stock cam timing is going to be optimal anyways... so I'm not sure that I'd be worrying about a few degrees off in the cam timing, not until I had the car running and felt like playing with the cam timing. It can wait, but I'd be considering an adjustable cam pulley at some point, just to facilitate experimentation. Looking at JvanDyke's signature, I'm inclined to think that correct can wait

 

[Oom_Paul]

Thanks Eric!

I'll be following your suggestion for now and start playing with the cam timing once the car is running again. :dance: