Jump to content

Recommended Posts

Have completed the refurb of the H4 carbs and fitted them but the car won't  start.

I haven't touched the ignition at all.

Timing checked OK,spark at each plug, firing order correct, plenty of petrol getting to carbs( I had trouble with leaks at the banjo bolts) but car won't start. Pistons move freely in the carbs,have swopped the plugs,still won't start , not even firing.

Have left the battery on charge but stumped by this.

Any suggestions?

Thanks Eddie 

Link to post
Share on other sites

Assuming H4s are much the same as H6s....

I had trouble starting the car after sitting for a while  last winter.It would turn over but sounded rough as a badgers...the cause was the choke skicking open on one carb....the jet is lowered when you pull the choke which allows more juice to flow.Mine stuck open due to dried out cork gaskets sending too much juice when not required, a new SU kit sorted the problem.You can check with a mirror if the jets return once the choke is released or perhaps easier to see if filters removed.Take a plug out and see if it is wet.

Also if you fit new needles they are not meant to be seated in the piston before tightening up the screw...apologies if too basic.

Link to post
Share on other sites

Eddie, have you read this article about fitting the needle.

http://sucarb.co.uk/technical-h-type-carburetter-reassembly

 

Lots here from MGA Guru on H type carbs.   https://mgaguru.com/mgtech/carbs/carb.htm

Edited by BlueTR3A-5EKT
Link to post
Share on other sites

Thanks for the replies

Definitely petrol in bowls, I  had a few leaks and was surprised how tight everything needed to be to stop leaks,  especially the banjo bolts . Thought I had centred jets OK but now one piston drops with a clunk and the other slightly quieter.

However plugs don't seem to be very wet after cranking many times.

I will try some easy start tomorrow to see if I  can get it going.

Thanks again Eddie 

Link to post
Share on other sites

Have you pulled the choke out all the way?  It can be very stiff on the sidescreen cars if that is what you have, so you think it's fully open but actually it's only half way.   That makes all the difference for starting. 

Link to post
Share on other sites

Ian Vincent,

See BlueTR3as reference to the SU bible.

It is too easy to insert the needle too far into the piston and nip it up which results in running rich as the needle then sits too high in the jet orifice.

I found that if you hold the needle between thimb and forefinger, at the shoulder of the needle, you can then lower the piston on to it and tighten the wee grub screw to hold it in place.......then all you have to do is set the jet height correctly (SU sell small spanners to adjust the jet height which makes life easier).

John S

Link to post
Share on other sites

How old was your petrol when you tried to start the car? I put new fuel in the filter bowl after allowing some fuel to run though the system. It sometimes still needs some QuickStart to help get things going. The problem gets worse with the age of the fuel. The fuel when old looks yellower and less clear.  
May be a contributing factor. I have changed all sorts of components to try to get the car to start better after a lay off and it was the petrol all along. 
hope this helps. 
Keith

Link to post
Share on other sites

Keith,

It might have been the petrol. I've read that the ethanol attracts water and maybe I had some at the bottom of the tank. The car had become more difficult to start over the winter and I didn't take it for a run so the petrol at the bottom of the tank  wasn't getting used.

Just tried it today and it started first time and I haven’t adjusted anything from when it wouldn't start so hopefully everything is OK now.

Eddie 

Link to post
Share on other sites

Car starts fine now but I am having a problem with petrol leaking at the carbs. 

I have tightened the banjo bolts as tight as I can and the float chamber bolts underneath seem to be OK now but needed excessive  tightening.

However I have petrol leaking past the jets. I have used the 2 viton o rings in place of each Cork seal to make the seals ethanol proof but they seem to be leaking and these can't be tightened up.

Anyone else have this problem with H4 carbs.

Thanks Eddie 

Link to post
Share on other sites
1 hour ago, RogerH said:

Modern plugs do not like getting or sitting with damp plugs.

I;ve gone back to Champion L87 plugs as the NKG's didn't last any time at all.

 

Roger

Going back to the time when to own a TR4 meant you were only 25 years away from what was a new car, buying NKG spark plugs (the dyslexics friend lol) was reckoned to be the way to get TRs to run without fowling when they got hot...and then cold. 

At that time I worked for a Leyland truck dealership and enquiries to mechanics at the local Mann Egerton dealership workshops situated at Triumph road (nicely named), came up with the opinion that there was NO difference between the performance qualities of Champion or the more correctly named NGK plugs. HOWEVER there was an opinion that the qualitive difference was down to... quality testing. ie the NGKs were MUCH more rigorously tested. Meaning many more failures for NGK within their factory gates as against the Champions expiring in service on customer cars on the A38 somewhere between Lichfield and Burton (for owners below Watford Gap that's ...in the North). Whether now NGK has rescinded their aggressive testing regime (alleged) and now like Champion their testing is carried out by their customers is unconfirmed.

Mick Richards        

Link to post
Share on other sites

Hi Mick,

 from what I have heard; because modern car engines are seriously lean burn there is no need for excessive glazing on the ceramic body.

So, our very wet engines get the plugs damp and that soaks into the ceramic - not good.

About 4 years ago (in Ireland) I was having horrid trouble with the NGK's. They were lasting about 500 miles or so.

Back home I changed to the Champ 87 and now getting about 5000 miles.

It could be rhubarb but......................

 

Roger

Link to post
Share on other sites

Had same problem on one carb.

Sorted by replacing dried out cork seals with new cork seals soaked in oil for a day or two.

My undersranding was that folk used the teflon rings to get a better longer lasting seal, not because of ethanol.....Wine bottles are sealed with cork and some of them have over 10% ethanol, hic.

Check your needles are inserted correctly.

Check your jets are set to the correct height below the bridge, have a look with the filters off.

Check that when you release the choke that the jets return to the correct height....again look with filters off.

The SU web site has excellent diagrams and info for assembling the carbs.

Good luck, you will sort it eventually.

John

 

Link to post
Share on other sites

Most of the NGK problems are down to fakes that are widely circulating within the aftermarket sales industry Im afraid.

New NGK have always had a problem with fouling if run too rich, I usually use an old set for initial startups until tuning is corrected then fit the hew ones, thats been the case for probably 30 yrs now.

Stuart.

Link to post
Share on other sites
  • 2 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.