4a. Won’t start after full rebuild. Any ideas what to check next pse?

[Michel Higuet]

13 hours ago, keith1948 said:

Hi Michel

Earlier he had a multimeter giving wrong readings. Just because it is new doesn't mean it reads correctly and easy just to try on a different engine to make sure it is giving somewhere near accurate readings and not leading us down a route that is not relevant.  Just asking the question on valve seat lapping. Again eliminating something easy to cross off the list. As you say unlikely to affect all 4 cylinders but not impossible. And no I wasn't going to suggest piston rings missing.

You are probably right to suspect setting of TDC is wrong and valves opening and closing at wrong time.

Keith

The multimeter was not correctly employed, reading 8 ohm would invite to check the battery indicator of the Fluke. Piston ring missing was a joke from me of course. But regarding the problem I always go to what seems the cause of the problem, I hope for him it is the camshaft... 

Edited November 28, 2023 by Michel Higuet

[Michel Higuet]

13 hours ago, Andy Moltu said:

Checking your cam timing is a relatively quick process (if it's incorrect, re setting it is a bit more complicated as you will have to remove the timing cover and set the timing).

A TR4 standard cam should have no1 inlet fully open on the mid point of the lobe 110degrees after TDC.

Check crank tdc. Attach a timing protractor to your crank when in this position. Rotate the crank 110 degs and no 1 inlet should be fully open. There is a good but quite long video here.

+1

And with my post I write a monstrosity and nobody warned me...

"the high point of the inlet pushrod cyl 1 must be at 127° " of course not, camshaft is a 17/57- 57-17 so the highest lobe is at the half the cam duration 17°+180°+57° thus 249/2 = 124.5°   

Yes but the cam start 17° before TDC so high lobe at 110°. 

Edited November 28, 2023 by Michel Higuet

[Michel Higuet]

13 hours ago, Rob Salisbury said:

Dead easy way of checking if you are in the right valve timing ballpark  .... take all the plugs out and remove the rocker cover, find top dead center on the induction stroke,  (Cylinder no.1 inlet valve opening, exhaust valve closing) then turn the crank back 45' (assuming a standard cam 17/57/5717) the inlet valve should now be closed, adjust the valve gap to around 2 thou then put in place the thinnest feeler gauge you have, now wind the crank on towards top dead centre and where that thin feeler becomes tight is where the cam clearance ramp has been taken up and valve lift has begun, this obviously is quite inaccurate but if you can judge halfway between 45' and 0' then it's just over 20' and heading towards the point at which the valve should be opening and will give a clearer picture of where to go next.                                                                                       Cheers Rob 

Yes it will give a good indication indeed

Very bad indication is as previously stated "the rockers are in balance" ( 19 Nov Yes Roy, both rockers are free when the rotor arm points to pushrod tube one. ) because it's mean the pushrods are on the lowest of the cams :

Inlet valve is on his cam lowest after 254° for the following 466°

exhaust vale is on his cam lowest after 466° for the following 254°

So for 212° of the crankshaft they are both at their lowest... And that is what I presume is the cause of the problem is the degreeing of the camshaft.

Edited November 28, 2023 by Michel Higuet

[Michel Higuet]

17 minutes ago, Michel Higuet said:

Yes it will give a good indication indeed

Very bad indication is as previously stated "the rockers are in balance" ( 19 Nov Yes Roy, both rockers are free when the rotor arm points to pushrod tube one. ) because it's mean the pushrods are on the lowest of the cams :

Inlet valve is on his cam lowest after 254° for the following 466°

exhaust vale is on his cam lowest after 466° for the following 254°

So for 212° of the crankshaft they are both at their lowest... ( in fact I need to subtract the 34° of the overlap so really is 178° )  And that is what I presume is the cause of the problem is the degreeing of the camshaft who cause a very bad compression so no vacuum. I have not seen much motor who give not even a cough with "eazy start".

 

Edited November 28, 2023 by Michel Higuet

[BlueTR3A-5EKT]

34 minutes ago, Michel Higuet said:

 

Does this help you Michael?

https://www.blocklayer.com/degree-wheel

 

[Michel Higuet]

58 minutes ago, BlueTR3A-5EKT said:

Does this help you Michael?

https://www.blocklayer.com/degree-wheel

 

Easy if you have a different cam ( fast road for eg. ) and you don't want to calculate yourself, you can print the wheel but degree wheel is cheap and more rigid. In both the annoying is the fixing of the wheel and fixing a fine metallic point.  Of course here you can print a very big wheel and have to wait for the delivery of the item. 

So useful that it corrected my previous addition... :-)

[Michel Higuet]

15 minutes ago, Michel Higuet said:

Easy if you have a different cam ( fast road for eg. ) and you don't want to calculate yourself, you can print the wheel but degree wheel is cheap and more rigid. In both the annoying is the fixing of the wheel and fixing a fine metallic point.  Of course here you can print a very big wheel and have to wait for the delivery of the item. 

 

It set the wheel for my Piper fast road cam 26-66 66-26  and the centre lobes are the same 110° the difference is longer intake & exhaust duration and overlap of course.

Edited November 28, 2023 by Michel Higuet

[Michel Higuet]

3 hours ago, Michel Higuet said:

+1

And with my post I write a monstrosity and nobody warned me...

"the high point of the inlet pushrod cyl 1 must be at 127° " of course not, camshaft is a 17/57- 57-17 so the highest lobe is at the half the cam duration 17°+180°+57° thus 254/2 = 127°   

Yes but the cam start 17° before TDC so high lobe at 110°. 

 

[BlueTR3A-5EKT]

22 hours ago, Michel Higuet said:

Easy if you have a different cam ( fast road for eg. ) and you don't want to calculate yourself, you can print the wheel but degree wheel is cheap and more rigid. In both the annoying is the fixing of the wheel and fixing a fine metallic point.  Of course here you can print a very big wheel and have to wait for the delivery of the item. 

So useful that it corrected my previous addition... :-)

The benefit of the 'blocklayer' printable disc is that you can size it to glue to a CD.

[Steven Whitaker]

I’ve been working away this week so nothing done until now.  Rad drained and removed and timing cover off tonight so I’m going to redo the valve timing and go from there.  The compression tester is a used one borrowed of a friend so I’ve ordered my own ready to compare if I still have low comp after I redo the valve timing.

I”m hoping it’s wrong valve timing..

[Michel Higuet]

9 hours ago, Steven Whitaker said:

I’ve been working away this week so nothing done until now.  Rad drained and removed and timing cover off tonight so I’m going to redo the valve timing and go from there.  The compression tester is a used one borrowed of a friend so I’ve ordered my own ready to compare if I still have low comp after I redo the valve timing.

I”m hoping it’s wrong valve timing..

It will be interesting before any adjustment to read the actual degree value of the camshaft, If you don't have forget to put the piston rings ( joke ) it will be the valve timing.

If my count is right on 4T cycle of 720° during 180° the rockers are in balance, so a lot of margin for a "good" valve timing indication. My idea is the timing is very in retard, in the suction phase the inlet valve open very late the piston was already in is down run so suck not muck than in the compression phase the inlet valve close when the piston is already very high and thus compress not much too. 

In the very unlikely event that this is not the problem you should consider hiring the services of an exorcist :-)

If this is the problem, after rebuilt, inject a little "easy star"t and you will hear it talking ( very short ) for the first time or maybe much longer if the carbs are almost ready.

 

[Steven Whitaker]

Who wants to buy a tr4?  

 

So, first job this morning was to find TDC on cylinder 1 and mark the crank pulley with the timing cover on.  Done.

Next job was to set the cam / valve timing so I followed the instructions in the Triumph TR4a manual as per the photos, after I had set the valve gaps, and followed this sequence to the letter.  I dug out the old cam and crank chain wheels with the idea being that, if I’d got the cam in the right place, the old wheels with their alignment marks would line up.  I can see tell tale marks on the back of the cam wheel where it mated with the cam, so I thought, if I refit the cam wheel to the same original place the lines on both sprockets (noting the centre punch mark) will be in line.  But, lo and behold, the lines did not line up on the cam wheel.  The line on the crank wheel did align to the centre of the cam though, so at least tdc is correct….

So now, I’m utterly confused.  I’ve just managed to borrow a cam tiiming wheel with graduations, but need some advice on what to do next.  Turning the cam is a sod with the valve gaps set.

Have to say, I did find the manual a bit confusing and wasn’t expecting the extra sequence on the second photos, as this seemed a bit odd.  Is the manual correct?

I thought my above idea would be simple, but obviously not.  I’m starting to wonder about letting someone else do this now, as Kim losing the will.  But I really do prefer to sort it myself.  I’m sorry that we are on page 8 now.  I’m feeling rather embarrassed, but i must get it sorted.  I’ve never used a cam wheel before but guess this is the next step in this journey.

Cheers All,  Steven.

Thnaks, Steven.

 

 

[Steven Whitaker]

On 11/25/2023 at 4:31 PM, Michel Higuet said:

If your camshaft adjustment is/was ok the high point of the inlet pushrod cyl 1 must be at 127°  

Interesting link, everything you need to know.

 

 

On 11/25/2023 at 4:31 PM, Michel Higuet said:

If your camshaft adjustment is/was ok the high point of the inlet pushrod cyl 1 must be at 127°  

Interesting link, everything you need to know.

 

Thanks, but this is for a tr6 so I got confused!  And my head is on so I can’t follow this method.

[Steven Whitaker]

On 11/27/2023 at 8:52 AM, Andy Moltu said:

When checking TDC it doesn't matter if you have no1 or no4 firing or on the exhaust stroke. The crank is in the same position. 

It does matter for checking ignition timing as the cam rotates once for every 2 rotations of the crank.

Understood, thanks.  I set the tdc of cylinders 1 and 4 with the tool in the plug hole on cylinder 1.

[Rob Salisbury]

Hi Steven, You want to set the cam without the rocker shaft in place, instead you need a Dial gauge resting on top of No.1 cylinder's inlet push rod with this you can move the cam to  find the highest point and then set the crank to 110' past Top Dead Centre,    ... also have a read of Dave Vizards book Tuning Triumphs over 1300cc (pages 98- 102) (Google)     gives a full description of how to set the cam using my preferred method of finding the exact point of valve lift (17' before TDC).                                                          Cheers Rob  

[Steven Whitaker]

3 minutes ago, Rob Salisbury said:

Hi Steven, You want to set the cam without the rocker shaft in place, instead you need a Dial gauge resting on top of No.1 cylinder's inlet push rod with this you can move the cam to  find the highest point and then set the crank to 110' past Top Dead Centre,    ... also have a read of Dave Vizards book Tuning Triumphs over 1300cc (pages 98- 102) (Google)     gives a full description of how to set the cam using my preferred method of finding the exact point of valve lift (17' before TDC).                                                          Cheers Rob  

Thanks.  So is the method in the workshop manual which I followed no good?

[trchris]

Hi Steven

so you have number 1 at TDC and number4 valves rocking? If so remove the new crank and cam sprockets replace with the original ones time using the original marks carefully remove and replace with your new ones along with the chain without turning either crank or camshaft

Chris

[Rob Salisbury]

34 minutes ago, Steven Whitaker said:

Thanks.  So is the method in the workshop manual which I followed no good?

It will work, but may be subject to an error of plus or minus 5', install figure of 110' method is good but subject to a small bit of variation 'cause you are measuring on a curved surface, whereas Vizard's method finds the precise point of start of valve lift, doesn't matter what cam you have so long as you have the timing figures for that cam, worth pointing out that you can slightly vary a cam's timing (advance or retard) by decreasing or increasing the tappet gaps.   

[iain]

This is what I would do to check, valve timing, then ignition timing. 

1. Find TDC for No1 piston…..ignore everything else until this is accurately found. Timing chain off.

2. Find the point of balance for nos  7/8 valves as per the WSM by rotating the cam. Number one cylinder valves are then on the firing stroke.

3 Refit the timing chain as accurately as possible. Re mark your timing gears.

4. Check the position for the distributor drive and ensure that is in the correct position. Drive slot on the correct side and distributor inserted such that the rotor arm is pointing at No1 plug.

Iain

Ps if I’ve missed something I’m sure someone will correct me.

This will be close enough to check everything is ok.
(By using a Degreeing wheel you can get the cam timing very close to spec but then have to set the timing events consistent with the cam manufacturers specification)

 

Edited December 2, 2023 by iain

[Steven Whitaker]

1 hour ago, trchris said:

Hi Steven

so you have number 1 at TDC and number4 valves rocking? If so remove the new crank and cam sprockets replace with the original ones time using the original marks carefully remove and replace with your new ones along with the chain without turning either crank or camshaft

Chris

Hi Chris.  I understand what you’re saying but with cyl 1 at tdc, and cyl 4 valves rocking, the lines on the old chain wheels don’t line up!

[Kiwifrog]

Was the engine running before you rebuilt it? If you have never had the engine running I would not rule out the marks on the old sprockets being wrong

[Rob Salisbury]

1 hour ago, Steven Whitaker said:

Hi Chris.  I understand what you’re saying but with cyl 1 at tdc, and cyl 4 valves rocking, the lines on the old chain wheels don’t line up!

Maybe check the markings on your old cam, I seem to remember the Standard 4 Pot cam being 307036, but you may have a reground one or a non standard profile, for instance, I have an old , worn out SAH26 profile ground on a standard 307036, it is however marked as SAH26 on the end. 

[Steven Whitaker]

1 hour ago, Kiwifrog said:

Was the engine running before you rebuilt it? If you have never had the engine running I would not rule out the marks on the old sprockets being wrong

The history is unknown, but the chassis was caked in oil!

[John L]

Steven.

When you set the tappet settings as per your manual, on valves 7 and 8, and turned the crank with the chain still attached, to give both rear valves, one closing and one just about to open, where was the #1 piston?  was it at TDC or not, that's all you needed to tell us.

We are trying very hard for you to follow exact instructions and give us answers, one by one, then we can help.

Where was the # one piston? if it wasn't at TDC, was it before TDC or after TDC? either you got the cam timing wrong, or its not a standard cam. 

John

[Michel Higuet]

Ok I stop here because it becomes a duck soup...

Steven has already difficulty with one method to degree the camshaft and here we give him 3 different method with mixing the advises.

He found the true TDC ok but then a real mechanic would have to know the actual degree of the camshaft just to know how much dephasing it was and a very good indication the cause for the 50psi. It was not done! It was still easy, only to position the degree wheel, position the at TDC Cyl 1 firing and READ the wheel...

I thing Steven is not up to make a job like this one and the avalanche of different advices here only makes it more confusing for him. Better for him to ask somebody to do the job.

I stop...