Last chance saloon, getting the engine running properly

[RobinTR6]

Anyone reading the threads from me recently will know Ive had few issues. I'm now at the stage when I have two choices

 

1. Put a bomb under it (at least I'll get some satisfaction)
2. Back to first principles and check everything..not nice

Option 1 whilst attractive is probably not on. So option 2.

 

Ive had various issues with the dizzy and PI system bleeding, I believe they are now sorted.

 

After all the faffing about the car was starting easily, running a bit lumpy but when accelerating it was 'holding back' all the way thru the rev range, as if it was missing of lacking petrol. Revs fine in the garage to 4k (new engine build didnt want to go to hard till she's run in).

 

Been thru the PI system with Neil Raven Smith and we concluded that shes not suffering from a lack of petrol. Injectors all popping fine, spark on all cylinders, when test driving increasing the petrol with the choke lever slowed her down so no lack of juice.

 

Advance seems OK as witnessed with timing light. Fiddle'd with timing both retard and advance no improvement , usually worse, timing set static with test light on dizzy. Redone valve timing a 3/4 times, notably each time quite a few needed redoing valves needed adjusting from 15/20 thou back to 10, I'm assuming thats just because its all new and settling down.

 

Dizzy cap replaced numerous times , I have 3, and rotor arm, also have 3 (one dizzy doctor), no change, points changed, condenser changed also numerous times, even tried another coil.

 

Having run out of ideas (AGAIN) decided to recheck stuff. MU off again, separated mu from dizzy drive, all seemed as per brown book, drive offset facing engine, dizzy rotor arm about 7 pm, reconnected and retest with hole on no.6 about half way open. TDC identified, valves on NO.1 both closed, No.6 on the rock. Worth pointing out that she was set at the port just opening before and now set with port about half open . Now really misfiring as if shes 180 out, starts quickly and but wont rev at all then dies.

 

So, Im thinking have I done something fundamentally wrong putting in new camshaft (BTW its a CP cam from Moss with a CP head rebuilt and a CF engine ex USA). The reason I question this is

 

1. tried about every thing else
2. does seem timing related (however cant find anything electrical)
3. When I last did the MU timing she should have gone back to starting fine and running OK till driven as per above, not missing badly and backfiring and not revving.
4. Its as if something fundamental on the timing setup isnt what it looks like , ie when No. at TDC the crank and cam arent where I think they are. These were lined up with the pin holes on the sprocket and crank as brown bible, if they were off what would symptoms be
5. I know that the crank pulley marker is OK at TDC NO.1/6 as this was done with a DTI when the head was off.

Off with her indoors for the weekend taking my computer and Brown bible

 

FYI, MU pushing 100+ at idle and about 85/90 when driven (have gauge), pump off a relay connected direct to battery and getting 13.5 volts , oil pressure all fine, gearbox works, clutch works, axle seem OK , electrics all working, brakes working , so having done all that I'm gutted II cant get her to run as she should.....

 

HELP....

[AlanT]

What's the state of the exhaust system?

What are the air filter arrangements?

[RobinTR6]

Exhaust is a used stainless standard system with cast manifold, all generally good condition.Exhaust gaskets all new, its blowing down by the gearbox a bit so I'll need to address that, clamp may need moving or tightening. Standard plenum, front box and air filter etc, again all good condition. BTW Inlets, injectors, MU, and Lucas pump and filter and pipework .all recon'd with new pipes throughout.

[Mike Grimwood]

Have faith Robin I converted an American engine to British PI and it works well.

You go into detail about timing etc, but at TDC does the rotor arm point to number 1?

Is the PI system new or second hand?

Are you getting between 100 and 110 PSI at the metering unit? If not the pump or PRV needs attention. Do you get a drop in pressure when cranking (best done without the dizzy cap off) if you are getting a drop it can be down to 90 PSI then the relay is wired incorrectly.

Are you getting a perfect conical shape at the injectors? Take care of the exhaust manifold.

 

[Peter Cobbold]

All your spark timing to date, both static and strobe depends upon TDC being correct on the crank pulley.

You can do a quick test by rotating the disy to give optimum tickover rpm, ignoring timing marks. Does that cure the lack of power?

 

The dial gauge method might appear to be the most precise, but may not be as the piston around TDC spends a lot of degrees moving up/down very little indeed. It can be done but crank must be to and fro'd several times to get close to true TDC. But its very easy to check TDC#1 now with a piston stop screwed into the plug hole. Half way between the two positions is true TDC. Reset spark timing. If the error between DTI and piston stop method was large, say 5 deg, it could also have affected cam timing and a small performance hit at higher rpm.

Edited April 17, 2014 by Peter Cobbold

[RobinTR6]

Peter, faff'd about with DTI quite a few times till I eventually settled on the TOP, it was easy as engine was out and head off. When shes was running setting the timing using the 'twist the dizzy' method used and lots of different setting tried, no change. I'm concerned that when redoing the MU timing it went from running to backfiring indicating that something I'm using to get the TDC and cam set is not what I think it is. How can I verify that the cam relative to the crank is setup OK ?

[Peter Cobbold]

When #1 is at TDC firing - NOT just both valves shut - rockers 11 and 12 should be swapping over, 'on the rock'.

Edited April 17, 2014 by Peter Cobbold

[marko]

80 - 90 PSI is not enough at the metering unit...It should be a constant 105 PSI.

 

Adjust the Pump / PRV or junk the Lucas Pump and put something decent on it....

 

Or bring it up to us!

 

[Peter Cobbold]

Maybe its air. Are the butterflies opening fully? Try it with air filter off. Mouse nest in inlet hose?- straws again.

Peter

[BlueTR3A-5EKT]

Was troubled by a TR6 once that had a complete new stainless exhaust system fitted but ran like a bag of poo. Would not rev under load. It ran a treat before being touched, and the exhaust was the only item touched.

Went through the 'rubbish new stainless exhaust must be blocked' conversation. plus the MU has gone wrong and the injectors have blocked and the timing slipped while it was parked.

 

The solution was simple - refit the down pipe gasket so the holes for the pipes lined up.

Try it, the gasket can be fitted in two ways or 90 degrees out.

 

Went a treat after that.

 

Peter W

PS Robin, I have a new (GEG 724) exhaust down pipe gasket if you need one.

 

PPS Is the LT electrical side of the coil wired correctly? CB or - (negative) should be the white wire with black trace going to the distributor. Simple to see and check. This causes the coil not to give a nice fat spark, if wired the wrong way round. Lots on here about coil wiring previously.

 

PPPS I have had a TR2 with the cam timed a tooth out. It idled OK but had flat performance up to 4000 then picked up and ran. It used to spit fuel back out the carbs as it was revved, and fluffed as you drove it under load.

Edited April 17, 2014 by BlueTR3A-5EKT

[RobinTR6]

Answers in sequence:

 

1. at TDC No.1 valves both closed and valves at No.6 'on the rock'
2. I can recheck TDC when home again , car missing big time not a little when pushed , also sounds like its hunting a bit at idle and lower revs
3. Marko, Lucas pump , MU, injectors all refurbd. At idle shes running 105 PSI, and when pump first turned on before starting same, when driven its dropping to the 85/90 level. Spoke to Neil Raven _Smith about this and he doesnt think thats the issue, especially when choke is pulled it get worse, ie holding back more as if shes overfuelling. He also gave me some other things to try toprove that shes not suffering from fuel issues , they all worked. I do have another pump, also refurbd. I have cranked up the PRV but pressure doesnt rise. My question would be why would the pressure drop when driving if the pump does 105 psi at idle and is getting 13.5 volts when engine running
4. Hoses all look fine and butterflys opening properly, idle a bit rough but they are recond and havent yet got any carbon etc to seal
5. Did once have a mouse nest in the air demist system with enough seeds to feed him all winter , unfortunatley he was dead, did smell awfull and took quite a time to find him in there.....
6. Exhaust worth a look so will investigate, Ill check downpipe gasket but pretty sure its ok and then remove rear box and ensure its clear
7. Peter thanks for the offer, let me check. The earth from the dixxy goes to the negative of the coil and the white 12v + from ignition to + side of coil so think this is OK
8. Peter, Im wondering about the cam alignment. Is ther a way to test this without taking the fron cover etc off.....

BTW guys am away till Easter Sunday but keen to have some ideas to try.

 

Marko, if I cant sort this you may well get a visit (unfortunatley for me Im in harrow so she will need a tow/flatbed to get to you.......), thanks for the offer (PS am desperatley trying to stay with Mr Lucas for my pump), even managed to get it mounted on the chassis where people put their Bosch stuff, all with stainless hoses....

[Guest ntc]

Anyone reading the threads from me recently will know Ive had few issues. I'm now at the stage when I have two choices

. Redone valve timing a 3/4 times, notably each time quite a few needed redoing valves needed adjusting from 15/20 thou back to 10, I'm assuming thats just because its all new and settling down.

 

 

 

That should not be the case.you have checked the pushrod length ?

[RobinTR6]

Neil, checked all the pushrods before installing cant remember then length but they were all the same and the correct length for the CP head.

[Guest ntc]

Robin

Be sure they are correct, you maybe bending them with valve binding.

[Denis]

I once had curious lag and a reluctance to rev...which turned out to be a vacume pipe that had collapsed in the middle! Pull it off and blow through it !

 

If you read my recent '5 Cylinder Woes' thread ? I went all through the H/T & L/T...Refurbed Dizzy...Injectors, Refurbed M/U... yet still had an intermittant misfiring, now cured with a new Coil !

 

Also, I note you say your Rota points at 7pm at TDC...When my (standard CP engine) is at TDC...my Rota's pointing at No.1 in Cap...at 5 o'clock, and runs fine, static and under load all the way (I never exceed 4,500rpm these days)

Edited April 17, 2014 by Denis

[Peter Cobbold]

Robin

Tried hot wiring battery live to coil ? - to eliminate the ig switch and loom and starter solenoid connection to coil ( IIRC)

Also bypass the inertia cut out switch to the fuel pump - its by the wiper motor, connect the wires together.

 

This is odd: "When shes was running setting the timing using the 'twist the dizzy' method used and lots of different setting tried, no change." Do you mean the tickover speed did not reduce either side of an optimum position of the disy? If so, that suggests to me the spark timing is badly out. Redetermine the TDC with a piston stop*. TDC has never been checked since you had the head off. This graph shows relative errors for the two methods ( post 342):

http://forum.205gtidrivers.com/index.php?showtopic=105821&page=18

 

 

*Piston stop for TDC - steps 3 to 5 here:

http://www.motoiq.com/MagazineArticles/ID/2284/PageID/4012/How-To-Degree-Cams.aspx

 

Peter

Edited April 17, 2014 by Peter Cobbold

[RobinTR6]

Peter, ok will try hot wiring but already proved all six firing with a strobe light timing light. Moving dizzy did increase and reduce revs and notably advanced timing measured on timing light when advanced. So think that's operating as it should. Advance spring seems fine and you canoe rotor arm a bit and basrplate moves freely.

[alanwcoote]

Dont know if relevent but had issues with my 6 similar to this. Part of the cure was dizzy primary spring damaged and secondry stretched + dizzy main shaft worn. All referbed by Martin ( dizzy doc ) never looked back.

Reflective Patch

[Tim D.]

I take it that the compression is ok across all cylinders ?

Tim

[RobinTR6]

Dizzy is rebuilt by a Tr specialists, compression not tested. I don't have the kit. Engine rebuilt by PO so anticipated basics ok. Engine seem to have plenty of go at low revs, ill see if I can get a tester but feels like timing related still

[Phil Kirk]

Robin it is worrying that the valve clearances are changing I would suggest that you need to find out the reason for this before going ahead and changing things elsewhere.It might be the cam followers are sticking. Sorry to say but you might need to pull the camshaft and start over and has Neil has pointed out the pushrods may have bent.

 

Best of luck Phil

[Peter Cobbold]

Dizzy is rebuilt by a Tr specialists, compression not tested. I don't have the kit. Engine rebuilt by PO so anticipated basics ok. Engine seem to have plenty of go at low revs, ill see if I can get a tester but feels like timing related still

Robin

From your post 17 I'm now convinced its not spark timing. If the centrifugal advance stationary is fine (according to the strobe) it will also be fine under load, driving - there's no load-sensing built into it.

Time to move on, so to speak.

[Peter Cobbold]

Along with Neil and Phil I'm veering towards camshaft.

If the camshaft bearings bored in the block are worn you might get variable tappet clearances.

 

If PO had badly mistimed the cam such that it allowed valves to kiss pistons >>> bent pushrods, valves. A badly advance cam could allow piston to contact an inlet valve- but the damaged valve would cause backfiring in the inlet - not a symptom. A really badly retarded cam might have allowed piston(s) to hit a exhaust valve that was too late closing

So which tappet clearances were fluctuating? My guess would be exhausts

A badly retarded cam will impair cylinder filling worst at higher rpm, and engine may not seem too bad at lower rev range.

So check this using your DTI on #1 and determine if valve lift agrees with spec in relation to crank. You are looking for a big cam timing error!

Damaged valves should also show up on compression tests.

[Mk1PI]

http://club.triumph.org.uk/cgi-bin/blogs/blogview.cgi?blog=494120#1

 

My valve clearances kept getting wider - this is what I found - combination of poor NOS core and too hard valve spring (I am guilty) your version may vary but it's not uncommon unfortunately.

I though wishbone classics followers were meant to be the dogs danglies - now using a set of Clancy followers from Jon Wood.

Edited April 18, 2014 by Mk1PI

[Peter Douglas Winn]

I don't know if this is of use.

Lucas engineers had a kit to test the injection system. It consisted of a Vacuum guage and a Presuure guage. Both of them had a pipe that was long enough to put the gauge under the wipers wilst driving. Hence the fuel pressure at the MU input and the vacuum at the manifold could be checked. You need 104 psi to run properly. The car will start with 95psi. The fuel presuure must stay constant at all times.

 

You can run a PI when the dizzy is 180° out.

 

The return must dribble. Blow down the return and get somebody to listen if there are air bubblrs in the tank. The return pipe often gets squashed during installation of the other pipes under the bodywork.

 

If pulling out the choke does not change anything then it normally means the fuel supply is on its limit!!!

Peter