19 replies to this topic

[lawrie124]

I've posted in this section as I'm not sure "ragging your 998cc mini around a track flat out in 2nd gear for 15 laps" warrants a post in the main problems section!

 

My two main problems are the water getting red hot (up to H on the temp gauge) and more worrying is that I am losing about 250ml of oil into the catch tank off the main breather.

 

It's basically a 998cc with little in the way of modification, and being run at 6,000 rpm in 2nd gear for about 6 minutes.

 

Timing is about standard, and it's not running lean judging by the colour of the plugs which are brown/slightly sooty.

 

Using decent millers oil, but not sure what grade (will find out).

 

I'm thinking I can cope with the hot running by perhaps adding a heater matrix under the bonnet (O/S) to tap into the (already in place) heater take off on the head. It's the loss of engine oil that is worrying me; I've already destroyed one +60 block due to piston circlip letting go and scoring the block and piston, and now the next block is displaying similar symptoms. grr...

 

Anyone else relate to this any any suggestions?

 

cheers

 

Mike

 

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[leaky]

Got an alloy rad?

[summs116]

get a 2 core super cool rad and have a pipe welded into the top so you can run a pipe from the heater tap intp the rad and run water wetter,put a thermostat removal plate in,and it should run around 80-85 deg top,

i done 5 years with that set up and was revving to 7700rpm on the oval.

 

as for the oil breathing sounds like rings are worn

[lawrie124]

Got an alloy rad?

 

nope, lots of scrap ones though!

 

Can you buy alloy rads second hand for 99p on ebay?

[lawrie124]

get a 2 core super cool rad and have a pipe welded into the top so you can run a pipe from the heater tap intp the rad and run water wetter,put a thermostat removal plate in,and it should run around 80-85 deg top,

i done 5 years with that set up and was revving to 7700rpm on the oval.

 

as for the oil breathing sounds like rings are worn

 

we don't run posh rads as inevitably they soon get smashed. The heater 'tap' now runs into the rad, and it's got a blanking plate in the thermostat hole.

 

out of interest, how do you get 7,700rpm out of a mini engine?

 

... and not liking the idea of worn rings, given it's only been out for 3 races.

[summs116]

Well I ran a clubman and tried my best not to hit anything,
If its getting that hot it's probably glazed the bores and started breathing heavy, I've found that when the temp goes higher than 84.7 it started to lose power and I lossed 3 bhp when it hit 87deg.

I had a worked crank with modded rods all shot peened and short skirt pistons,a 266/mg metro cam with a custom made cam gear to run the timing out differently as standerd cams run between 1500-5500,so we moved it up so the range was 3000-7500,as thats were your racing revves are.compression raised head work and modded carb and needle,
It help the I work after school at a place with a engine dyno and spent hundreds of hours on it with dad and the engine builder,
Had a 4.1 diff on 10s with a tight shimmed diff,and a set of custom made drop gears,that's all I can remember as that was 15-18 years ago

[leaky]

 

Got an alloy rad?

 

nope, lots of scrap ones though!

 

Can you buy alloy rads second hand for 99p on ebay?

 

 

 

Very good point. I put a cheap alloy rad off ebay in the clubby and it works a treat. Not as cheap as 99p though.

[lawrie124]

 

 

Got an alloy rad?

 

nope, lots of scrap ones though!

 

Can you buy alloy rads second hand for 99p on ebay?

 

 

 

Very good point. I put a cheap alloy rad off ebay in the clubby and it works a treat. Not as cheap as 99p though.

 

 

Fair point John; there is a place up thame way that does good alloy rads at sensible prices; gonna get some for the road cars but not for racing!

[lawrie124]

Well I ran a clubman and tried my best not to hit anything,
If its getting that hot it's probably glazed the bores and started breathing heavy, I've found that when the temp goes higher than 84.7 it started to lose power and I lossed 3 bhp when it hit 87deg.

I had a worked crank with modded rods all shot peened and short skirt pistons,a 266/mg metro cam with a custom made cam gear to run the timing out differently as standerd cams run between 1500-5500,so we moved it up so the range was 3000-7500,as thats were your racing revves are.compression raised head work and modded carb and needle,
It help the I work after school at a place with a engine dyno and spent hundreds of hours on it with dad and the engine builder,
Had a 4.1 diff on 10s with a tight shimmed diff,and a set of custom made drop gears,that's all I can remember as that was 15-18 years ago

 

That is a might impressive spec but we run virtually standard, and I appreciate the point about not hitting anything but I'd still rather not scrap a #50 alloy rad.

 

Will take the head off later this week and check out the bores.

[summs116]

I was in a standered class but every 1 bent the rules so we just bent them a little more.
Do a loss compression test first befor stripping.and see where the breathing happining

[lawrie124]

I was in a standered class but every 1 bent the rules so we just bent them a little more.
Do a loss compression test first befor stripping.and see where the breathing happining

 

thanks, but you are going to have to explain that. I've got a compression tester which I know how to use, but don't understand the 'loss compression' bit.

 

thanks for the assistance.

[summs116]

You need to buy the kit but what you do is turn the engine to cylinder 1 to the bottom and make sure the valves are both shut and fit the kit to cylinder 1 and force air into the cylinder through the plug hole and it registers a loss of air.you have a bit even with a fresh new build. But it say with instructions. You can sometime here the loss if you remove the dipstick or even though the carb/exhaust if a valves gone and feel air coming out of the other plug hole if a head gasket gone between cylinders.

[lawrie124]

ok; understood. Many thanks

[leaky]

 

 

 

Got an alloy rad?

 

nope, lots of scrap ones though!

 

Can you buy alloy rads second hand for 99p on ebay?

 

 

 

Very good point. I put a cheap alloy rad off ebay in the clubby and it works a treat. Not as cheap as 99p though.

 

 

Fair point John; there is a place up thame way that does good alloy rads at sensible prices; gonna get some for the road cars but not for racing!

 

 

 

O really. The ones on ebay have mixed reviews. I think I paid about £80 for it and its been fine but someone has said theres split after a year. Mines been on longer then that now though. I'm pretty sure Harri has one on mollie as well.

 

Let me know how much these ones you found are though. Need one for Jennys 1293!

[Sam]

definately run a heater matrix as a second radiator.

 

I've always run with the standard rad, and with a matrix plumbed in aswell I haven't had any problems for years. I kept the thermostat too, and made sure it was warm before the start of the race.

Edited by Sam, 11 June 2013 - 05:41 PM.