ATK Engines.

[Roger Straker]

2 years into a 40 Mark 1 build and two weeks before a booked a UK IVA test my engine decided it didn’t want to turn over very well. An internal inspection with an endoscope revealed water droplets on the pistons and rusty colouring around the top of all 8 bores. The engine, a 365 bhp 302 with a Quickfuel (Holley) carb is only 18 months old and has run for less than 3 hours.
It was a crate engine supplied by ATK Performance Engines of Texas who have not been very helpful. The engine is only warrantied in the USA and the fault was apparently caused by me because I did not check the head bolts after 500 miles and only used water in the cooling system. Left with the choice of returning the engine to Texas with all the time and cost involved or strip it myself and have it rebuilt in the UK I opted for the latter. To my surprise the headgaskets are fine and show no sign of leakage. The two ali heads have been pressure tested and are fine. From what one can see of the bores with the pistons still in there is no sign of physical damage. So a lot of head scratching as to how water could have got into all eight bores.
The engine is now at a specialist who will fully strip it and hopefully rebuild it in the new year.
In the meantime does anyone have any ideas or had this problem before?

 

[colin artus]

I suspect that you have a leak at the intake/head interface that is allowing water to be drawn into the plenum area of the intake manifold itself; this would explain the presence of water in all the bores. Replace the intake gaskets and refit the intake. To make sure it's leak free you can pressurize the water system while wielding the endoscope.

 

[Roger Straker]

Thanks for the response Colin. I forgot to mention that the head/manifold silicone gaskets looked ok but it has made me think about the integrity of the inlet manifold. The bores have got to be honed and new rings fitted which means a total strip down but I will think about pressure testing it when its complete.

 

[colin artus]

Check the manifold fit all round in a dry assembly. You can use the cork end seals to get the height correct ( then throw them away and use silicone rtv). I've had an new Edelbrock manifold that was a problem fit in the past so a problem there is not unheard of.

 

[Bill Kearley]

My thot is. With that few hours, has the engine been subject to any drastic temp changes and how was it stored ( condensation ) could it caused the droplets you mention?

 

[Walter Williams]

4000 MILES ON MY ATK 347 AND NO ISSUES..

 

[Ken Roberts]

I could see repetitive temporary heating of a unheated garage, so you can work on it in the winter, scenario causing it.

 

[Roger Straker]

Thanks for the responses but the car and engine are in a heated garage so no condensation.

 

[Jason Lycett]

Hi Roger. I bought a built motor from the states and found on my engine that the intake manifold bolts had almost no torque on them. The gaskets tend to collapse quickly and you have to retorque them. Im very lucky water didn't get into my engine because I spotted the problem. As has been suggested, get rid of the end seal cork gaskets and use a good Rtv like Loctite black, then go back over it after 24 hours or so and keep the torque up. I seem to remember around 18 lb/ft is correct but check with you manifold manufacturer.

 

[Paulbav]

Hi Roger. I bought a built motor from the states and found on my engine that the intake manifold bolts had almost no torque on them. The gaskets tend to collapse quickly and you have to retorque them. Im very lucky water didn't get into my engine because I spotted the problem. As has been suggested, get rid of the end seal cork gaskets and use a good Rtv like Loctite black, then go back over it after 24 hours or so and keep the torque up. I seem to remember around 18 lb/ft is correct but check with you manifold manufacturer.

I agree I’ve just retorqued my inlet bolts after 500 miles and they were surprisingly lose.

basically everything comes lose after 500 miles in a GT40

 

[Roger Straker]

Hi Jason and Paul. Thanks for the info. Thats really useful to know. A little bit of water could creep past the silicone without marking it in the short time I had it running. Stupidly I didn't cheque the torque on the manifold bolts but they did come out rather easily. Despite having to do a complete strip and hone I hope that was the problem because anything worse is going to be expensive!!!!