205 block engine build

[richardm6994]

20 hours ago, LewisH said:

I have worked out cam timing by finding TDC, zero'ing timing disk, then turning crank clockwise until I reach 108 deg (FR33 cam), then setting cam at this point with inlet cam lobe on no1 cylinder pointing to the sky...is this correct? At this point the rotor arm is pointing to no1 lead.

 

I could be misunderstanding what you're saying here....but inlet cam lobe pointing to the sky?? this sounds wrong to me.

The lobe should not be pointing skywards at 108 degrees....instead, at 108deg, the intake lobe should be pointing the opposite direction and pushing the rocker downwards, which in turn pushes the valve stem downwards and opens the valves.

Basically at 108deg, your intake number 1 valve should be at it fullest open position....

To me, your description of the number 1 intake lobe pointing towards the sky sounds like the intake valve would be closed at 108 instead of fully open?  

 

[LewisH]

4 hours ago, richardm6994 said:

 

I could be misunderstanding what you're saying here....but inlet cam lobe pointing to the sky?? this sounds wrong to me.

The lobe should not be pointing skywards at 108 degrees....instead, at 108deg, the intake lobe should be pointing the opposite direction and pushing the rocker downwards, which in turn pushes the valve stem downwards and opens the valves.

Basically at 108deg, your intake number 1 valve should be at it fullest open position....

To me, your description of the number 1 intake lobe pointing towards the sky sounds like the intake valve would be closed at 108 instead of fully open?  

 

Oh. Looks like I have totally misunderstood the term "maximum lift on inlet valve". Doh! 

Thanks Richard, I'll give this a go tomorrow just in time for the great weather...

[IanS]

Being a 4 stroke engine the inlet valve will be both fully open and fully closed at 108deg depending on it being the inlet stroke or the power stroke.

[richardm6994]

43 minutes ago, IanS said:

Being a 4 stroke engine the inlet valve will be both fully open and fully closed at 108deg depending on it being the inlet stroke or the power stroke.

Very true, however the valve only reaches its fully open position for only a fraction of the rotation, whereas it is at its fully closed for a significant amount of rotation….meaning a lot more chance of inaccuracy trying to set timing with the love pointing skywards…not to mention the dti would have to be perfectly positioned over the centre line of the camshaft and perpendicular to the centreline for this to stand any chance of being accurate…

It is far more accurate and easier with a dti to set the 108 crank angle at the valve fully open position than it is to try and set it all at 1 rotation further along when at fully closed…hence why the established process of cam setting is determined by when the valve is fully open.

dti on the valve spring collar to measure fully open.

 

[IanS]

I agree and have always set the cam by measuring movement of number 1 inlet valve.

The pinto has unusual cam to valve geometery as the followers rock on pillers set to the side resulting in changing timeing when lift is changed. This is a complex situation but the cma manufactured will have known about.

[Bob Tucker]

https://rimmerbros.com/ItemFiles/Manuals/Kent Cams Fitting and Timing Instructions.pdf

[Foz]

I know cam timing is important for best performance but, unless it's a long way out, I doubt it's the cause of the engine not starting.   My pinto ran with the cam pulley 1 tooth out following a belt change - it  started up OK and it was only when I drove it that I could tell I'd cocked something up.

[richardm6994]

Ultimately though, with any engine problem diagnosis, work your way through all possibilities and make sure you eliminate each one properly….in this case, it’s obvious cam timing has not been set properly so I would be starting with getting that corrected first before moving onto the other potential possibilities.

[Snapperpaul]

Sorry I’m late to the party. 
camshaft rotates at ½ crank speed so you can be 180 degrees out which I think you are. You should have a little valve lift (open) at TDC and maximum valve lift (open) at the prescribed degrees ATDC.

doing it by eye is not accurate but you would be somewhere near.

Never run an engine until you have turned it over by hand.

a DTI gauge is required for accurately finding actual TDC as the piston stops moving at TDC for around 5 degrees, TDC is in the middle of the dwell. On the degree wheel turn engine until DTI stops moving (DTI down plug hole to touch piston near TDC) mark, carry on until piston moves, mark, TDC is the centre of the 2 marks, reset degree wheel.

move DTI to valve spring retaining cap

I check both lift at TDC and lift at cam designated max lift degrees ATDC

Edited May 13, 2023 by Snapperpaul

[LewisH]

So I've checked and double checked cam/ignition timing, it must be close enough to run. I've taken the carb off and given it a good clean, a bit gunky but not too bad...yet still I'm getting exactly the same issues. Very difficult to start and once running it won't idle and just dies.

I'm now thinking is this potentially leaky valves on the head giving low compression?

I've rebuilt the bottom end but didn't think to check how the valves were sealing. Given that this was an ebay engine purchase, probably should have checked this before slapping the head back on. 

I've got an injection head being refurbished/machined by Burtons at the moment, but was hoping to do the running in miles with the existing head whilst I wait for the refurbed one.

Is there an easy way to check for vavle leakage without taking the head off? I don't know if my symptoms are a result of low compression but running out of ideas here.

 

Edited June 7, 2023 by LewisH

[Foz]

A compression test is the easiest way, assuming you can get your hands on a compression tester.

Pull all 4 plugs out, put the tester in a plug hole and spin the engine on the starter with the throttle wide open.  Repeat for the other cylinders and then compare the readings.  should be somewhere around 12 bar but that will depend on lots of factors, it's more important that all 4 cylinders are pretty much the same.

Steve

[LewisH]

New head has arrived at last, but in taking the old head off I accidentally dropped one of the m6 bolts that holds the plate on the back of the camshaft down an oil-way in the block. I've tried fishing it out with a magnet but no joy.

I assume it's now sitting in the sump...question is, do I need to take the sump off and get this out? Or can this sit in the sump without causing an issue?

Pic attached of where the bolt has gone.

[Snapperpaul]

People have left stuff in the sump but you’ll always know it’s there. You could try a large magnet under the sump to see if you can get it near the magnetic extending pickup or near the sump plug, you could fit a magnetic sump plug and hope but I would drop the sump.

hard lessons learnt there, plug all the holes before you do any work, that also includes inlet and exhaust ports and when the head is on the oil drain holes when working on that.

[Bob Tucker]

A magnet down the hole restricts the area you are "fishing" in the sump.

Assuming there is no oil in the sump, remove the drain plug and systematically move a telescopic magnet from side to side and backwards and forwards to cover much more area., but It will still leave some of the sump uncovered.

[nelmo]

Does that gallery definitely go through to the sump? Might be a kink which may mean the bolt is just sitting there and that could be bad for oil pressure.

Have you tried just turning the block upside down? Might just drop out?