RS Motorsport :: Classic Speed Restored

I have just fitted my new cossie engine into my MK!.

It runing very hot. I have removed the themostat to assist and bypassed the heater in an effort to remove any blockages. I think i have all the air our of the system, not sure how to prove this though.

The carbs are new 45mm 152 matched pair with standard jets at the moement until i get the car to the dyno.

I was hoping to get a few miles on the clock perior to the dyno run but im concerned that it runner to hot and will damage the engine.

Any assistance would be appreciated.

Which head gasket did you use and what are you using for coolant

Hi Danny,

Its a standard composite head gasket. approx CR 10.3

At this point the coolant has not additives.

Ian

Is it a pinto or a YB gasket as the coolant passages are slightly different and when you say hot, how hot and what sort of gauge are you using and where is it in the head

It is a YB gasket.

When i say hot the headers were glowing cherry red when attempting to run the cams in. The new paint has blisterd on the engine bay inner wing.

Im using an electric gauge that is head mounted. The temp seems to level without a thermostat at around 90. But i havent ran it for that long stationary to confirm if it will surpass that point. I have taken it for a run and the temp was quick to fall away only to rise sharply again when parked back in the shed. I am running a thermofan and radiator was fine when running the pinto hard at track events.

I dont have a temp gun. however the rocker cover is very hot to touch shortly after starting and the rad is also the same within minutes.

Im running a pinto dissy. Will this give me different timing (retarded)and therfore hot ?

When i shut the engine down it alsmost seem light a flame has just been snuffed and it give a small puff from i think the exhaust.

Depending on what the coolant temp was before the you removed the t/stat and if you were running an alloy radiator I wouldn't be overly concerned but to be honest what you're actually seeing is a lean mixture and another reason why I only run in engines on a dyno as to be honest you don't need to run the cams in just make sure it doesn't idle under 2000rpm and make sure the ignition hasn't got more than say 30degrees total timing
I only start the engines long enough to make sure that it runs and has oil pressure as I wont start it again until it's on the rollers and has load and with a lambda up it's arse

Ok great thanks. I intendt to take it to the shop on Tuesday. I can trailer it i guess.

The rad is alloy and i expect the mixture is lean as you mention. Im not sure how i can restrict the advance on the dissy but i will check what i have when i fire it up again.

Thanks again

Ian

Don't fire it up again leave it until it's on the rollers

Have you done your research for what jetting your going to use for the 45's. I wouldn't turn up at the dyno without a good selection of jets and chokes. Somewhere around on the internet there is a handy reckoner for jetting weber's and dellorto's for a given cylinder size and rev range.

I ran a pinto dizzy recurved for 32 degrees total advance but as the engine was low compresion that was ok'ish. Remains to be seen how it goes on the new build.

Definitely don't start it again until you can measure the A/F ratio on the dyno.

Thanks guys, I have the car ready again for the dyno.
I think i will ttrailer it as suggested.

I also found this handy guide

http://cnx.org/content/m37431/latest/

Don't use that handy guide for selecting emulsion tubes.

When the exhaust gets hot most of the times the ignition timing is way too late, resulting in a burning mixture in the exhaust.

How many turns do you have the idle mixture screws out ??
I've found that I had run the '152' carbs out around 5-5.5 turns to stop the headers glowing at idle, off idle it was fine.
This is on a Pinto, but still should work on a YB.

Clayton

just a maybe ??? but have you checked & set the float levels correctly ??

Hi Clayton,

I have the idle screw out around 4 turns now for the best idle to date.

I havnt check the float levels as the carbs are new. Never really give it thought.

Dyno tomorrow, so hopefully it will all be sorted. Fingers crossed..

Ian

Good luck,

Hopefully it's something simple and cheap to fix.

Matt

well i got the car back from the duno and the temp has definaetly dropped off around the exhaust.

It ran nicely for the approx 80km trip home with the water temp running at around 70 degrees on the open road.

However i have now refitted the thermostat and it holding steady around 88 degress even when out on the open road. Funnily the thermostate i fitted was 88 degrees.

Is this what i should expect ? Im sure the pinto used to fluctuate 5-10 when on the open road.

If the radiator and t/stat are doing their jobs it shouldn't fluctuate
How much squirt did it make