Flat Spot

[david painter]

I have spent quite a bit of time with Renzo on this one. Seems the initial problem on this was the advance curve was way out. Chris solved this part of the problem he had a spare unit fitted a Electronic ignition to it and sent it to Malta. The housing that it bolts to in the block is cracked think I might be able to sort that bit got one on a old MGA block. Carbs wise the front carb is broken around the throttle spindle hole but does not seem to be sucking air. Renzo has found that the oil in the front carb dashpot seems to keep disappearing ( maybe a cracked housing) . He has swapped the dash pot and damper assembly off a known good car. His car now he reports runs correctly. The carbs are Twin HS don't know if they are original TC ones or from a MGB as I have been looking at this via Wattsapp video message. However the carb bodies will be same as MGB so fairly easy to find. jetting and needles may differ slightly. He would however like a original TC Air box assembly to bolt to the carbs with the alloy adaptors as he only has 1970's style pancake filters fitted at present so will need the complete assembly. I am sure Renzo would really appreciate any help in locating as set. Both Chis and Myself have his Contact details should you wish to contact him . Thanks on behalf or Renzo
Dave

[LORENZO73]

Dear David, thanks alot for the information you gave me. I don’ t have words how to thank you and chris for all the help you both gave me. Thanks to both of you now the car is running quite well. I really appreciate that you asked for the original TC Air box assembly on my behalf i really appreciate. Renzo

[LORENZO73]

hi gil, yes you’re right without them i don’t know what i will have done. They are a god send. Renzo

[LORENZO73]

Hi Guys,
yesterday i go for a ride, i make 67 kilometres and it run very well.
The little think that she make is, when i am in traffic for a few minutes, she give me 2 or 3 missing when i go for acceleration, other problems is finish no misfire no flatspot, she run very well.

Many thanks
Renzo

[LORENZO73]

Hi Guys,
After a big search, we find the cap of distributer missing her contacts. Now the engine finally is settled. i want to tell a big thanks to chris weedon that he put me in a right position, and find everything that i want , also a big thanks for David Painter, because without those two right persons the engine stay in a big problems.

So now i make about 400 miles, and i find that is two low that marina, because she before have a diesel engine.
Chris told me to check refs on it, and to check the refs on my other my marina TC that i have the EPW 709K that is original from factory. I find more difference and chris told me that my marina have diff and gearbox for a 1.3 engine, after i send him the readings of refs and miles.

I try to find a diff of 1.8 with 3.63.1 ratio. About gearbox i don't now what i am doing, because i make everything new on it, and she's coming very well.

Many thanks
Renzo

[MarinaCoupe]

So if anyone has a spare 3.63:1 differential, in good condition, ready for Renzo to fit, then message him or me. He’s not looking for something that needs reconditioning first.

[MarinaCoupe]

One for the FMM Brains Trust - I have some ideas, but need to share, to see what others think could be the problem.

Lorenzo has a genuine green TC that he bought off eBay UK and shipped to Malta. He also has what was originally a Maltese built genuine Diesel car that he has had totally rebuilt and painted metallic red. The car is fitted with a 1.8 Super engine, but TC carbs. It’s been the discussion point for much of this topic and he has now got the engine running quite well. He has noticed that for a given kph/mph reading the two cars seem to be running at significantly different revs. The wheels & tyres are the same so no effect on the gearing.

Green TC at 75kph in top gear - 2500 rpm
Red Super at 75kph in top gear - 3000 rpm

Green TC at 30kph in first gear - 2900 rpm
Red Super at 30kph in first gear - 4000 rpm

My first thought was that the Red TC was running a higher diff ratio and I assumed that the Green TC had its standard 3.63:1 diff.

On the strength of this Renzo has sourced a 3.63:1 had it checked over and today had a mechanic strip out the diff from the Red car, only to find that the car already has a 3.63:1 diff fitted.

To say the least, I am confused, two 1800 engines in top gear, with the same differential should give the same revs at the same speed.

My only thought is that the red car has the wrong speedo drive wheel, so it is under reading the actual speed. Or put another way, to get the speedos to read the same indicated speed, you are revving higher and actually travelling faster than indicated (I had this on my Stag until I changed the speedo drive).

My idea to test this is to get someone to drive a modern car at say 60kph and follow in both the red and the green cars, to see what their speedos say and then compare.

Has anyone any other thoughts that we can check on please?

[david painter]

Why not just drive the car with the sat nav on displaying speed the GPS speed would be accurate
Dave

[MarinaCoupe]

Good idea David - Renzo have you got a SatNav?

[david painter]

You should be able to download a app for your mobile
Dave
https://apps.apple.com/us/app/speedomet ... d557871911
https://www.androidauthority.com/best-s ... id-789270/

[LORENZO73]

Hi chris, David,
I don't have NavSat, but i think my friend have one.

My mechanic, ask me thoose two engines are the same? I told him no, are the same but with different camshaft, the red one have a camshaft for 1.8 super, and the green one, have a camshaft of 1.8 TC.

So he told me, thoose have a consumption of fuel different, because have different camshaft and distributer.
He think this problem is from different camshaft and distibuter, and he told me as well the two carbs on the red is for nothing, because two carbs want a different camshaft.

I am not a mechanic, but when i drive the two ones, i find more difference in speed. Last time i go in a street, without cars and people, i put them on the second gear gas down, the red one gave me 60khm, and the green one give me 100khm.

Many thanks for everyone answers
Renzo

[drinud]

100kmh in 2nd gear seems to be a lot. What do you guys think?

[david painter]

I agree with Chris that indicated road speed is different in each car we need to establish what is the correct road speed then it is possible to pinpoint the problem, engine spec ie cams carbs wont alter indicated speed in top gear as its direct dive if axle ratios are the same. The fault must lie in indicated road speed either faulty speedo head or incorrect drive gear. I can get you correct part no for a MPH speedo but have no data on a KPhH one
Dave

[balmy]

There are several decent speed apps you can use on your phone Renzo instead of a sat nav.


Sent from my iPad using Tapatalk

[LORENZO73]

hi everyone,
thanks all for your help. Just want to ask you, the sat nav or an app on the mobile they will give me bought accurate speed. But to know how much reafs the engines are doing, shall I use their own reafs counters?ù
Renzo