Washed it, now it lacks power
Turbo Mini Forums

Gave the mini a spring clean yesterday.
Washed it, checked the plugs, cleaned the air filter, and did a compression test (just got given a tester)

Plugs looked nice colour but were a tiny bit oily on 2 and 4, and compressions were 120,110,75,110. Put a bit of oil in number 3 and it went up to 105.

It's a 1275 N/A with an SU. http://www.turbominis.co.uk/forums/index.php?p=vt&tid=326405

Couple of questions...
I had the bores honed and replaced the pistons with a brand new set only in august (about 2500 miles ago) would the rings have gone already? and...
Presumably me washing the car didn't suddenly make the rings go, so why does it run so much worse now?

The difference in running is that it lags before picking up any power and doesn't pull as much. I didn't touch the timing or mixture. and the plugs are on the right way round.

Edited by dan187 on 3rd Apr, 2010.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Have the valves been re cut?

check the coil connections aren't damp. If you have hosed it through the grill they may be damp and your ht could be shorting out.

As above, check all the ignition electrics for water and damp ingress. Also check inside the dizzy cap etc.

Water on elecytics as both above but the change in compression from 75 to 105 on No3 implies rings are damaged, did you do the test with the engine hot ???

But they are all very low anyway.

In your "build thread" you show you did some work on the chambers but did you have the head skimmmed afterwards to compensate for the metal removed ???

Re. the one low reading, did you gap the new rings when you had it honed ???

Schrödinger's cat - so which one am I ???

On 3rd Apr, 2010 Sprocket said:

On 3rd Apr, 2010 Rod S said:
Water on elecytics as both above but the change in compression from 75 to 105 on No3 implies rings are damaged,

I beg to differ I reckon its valve seal. The additional oil will also help seal the valves. With such a varience in compression pressures I put that down to valve seal, which is why I asked the qiestion I did

If your wife wants to learn to drive, don't stand in her way.

Fair point but oil normally seals the rings first - unless loads has been put in.

It could also be a broken ring/rings in just one cylinder, which is why I asked about whether the test was done hot and whether the rings were gapped properly when rebuilt :)

Also, the work was only done in Nov 2009 so a bit early for a valve and/or seat to burn out ??? (assuming the valves were lapped after the head work).

Schrödinger's cat - so which one am I ???

if it were a valve the compression would not have come up

my opinion is the rings iam afraid

Wow, thanks for all the replies.
ok, first i'll clear a few things up...

Car rebuild was finished September 2008 but new pistons put in August 2009.
When rebuilt in 2008 the head was skimmed to compensate for chamber work. CR is about 12:1. and valves were lapped in.
Just checked with the old man, he thinks I did check the piston ring gaps when putting the new ones in (i can't remember)

Compression test was done with engine warm (not that hot tho, i'll do another) only put a dashpot size amount of oil into the bore when checking.

Also I have noticed that in the mornings from a cold start the engine is more difficult to start and will kick out a fair amount of white smoke if not just left to idle, it is fine when warm or other starts later in the day.

Edited by dan187 on 3rd Apr, 2010.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Head gasket?

high cr and pump fuel = hard to start did on my mates 1380 anyways. possibly head gasket?

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

i can always pop up to you and have a gander if you like for a second oppinion as im close by :)

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

it could be the head gasket, this needs looking at first!

Edited by BENROSS on 4th Apr, 2010.

Agreed, white smoke would indicate water so either theres a lot o condensation or the HG is on its way out

right, cleaned the dizzy cap and sprayed wd40 on all the bits and leads. Runs much better now (as it was before I washed it) cheers guys.

As for the compression...
The water level in the rad has never gone down, so it doesn't appear that anything is flowing out of it.
I do get mayo in the rocker cover but i've always put that down to condensation, since i mainly get it in winter and it happened before this head gasket.
The white smoke i thought may be leaky valve seals or stems but Andy could be on the mark considering the mayo.
Would the head gasket blow through to the oil reservoir? I do seem to use a fair bit of oil and not a lot appears to leak out onto the garage floor.

Thanks for the offer paul, i'll see how I go. I may not have time to take a proper look at it before I go back to uni on sunday.

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

which sunday do you mean i only live in old town your only 10mins from me with my driving lol :) so if you had a spair half an hour i dont mind poping over

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

Schrödinger's cat - so which one am I ???

1275 N/A Sprite, 998 T2 Turbo Mayfair
1275 EFi Turbo

Still say thats a valve

Tight tappet on No 3 ?.

On 5th Apr, 2010 Sprocket said:
Still say thats a valve

Edited by Rod S on 6th Apr, 2010.

Schrödinger's cat - so which one am I ???