Turbo 200 cast iron X-flow

[Anonymous]

I am organising the rebuild of my motor which has a holset turbo with a compressor similar to a TO4b S3 compressor(small for a TO4) cam is gas research stage 1, about .450 thou lift and around 260 degree. Straight LPG, very early model gas research 350 cfm mixer. Redline Torker manifold. Ford truck intercooler cut down to 100cm x32cm x4cm (it fits between the lights on an XB with the narow section of the truck end tanks, like it was designed for the job, very happy.)

I have the machining costed and most of the parts. I have questions about 2 things:

1. I will buy ACL's Race 9411 pistons (8.5cc) bowl giving about 8.3 to 1 with my 60 cc heads and zero deck. Bore is currently standard (worn) is 30 thou a safe overbore? The cylinder walls look pretty thin in these blocks.

2. Valve springs, I want the lightest springs that will control the stock valves up to 6000 or slightly beyond. Anyone got any experience?

 

[Anonymous]

No takers re recommended valve springs?

 

[Anonymous]

dependin on boost 30thou over should be ok unless if it was previously bored.

you might encounter simmilar head problems as the crossflow guys, blowout on no.6. but the 200 is different so maybe not. :roll:

On the topic of valve springs id use some aftermarket clevo ones pressure maybe 120-130lb remmember your running Boost it drops abit. they may not be the lightest things but will be fine on 6500 revs . they fit p'fect on alloy head crossflow so should fit on yours. good luck

 

[Anonymous]

Crane 893 are an okay spring. 120 lbs seat and 380lbs/in gain which is still reasonabley high. You will need to buy springs and retainers as they are a double valve spring. These will set you back about $300-400

I also have a set of springs which I was using on my engine up until a a month ago.

These are a double valve spring with retainers. I bought these Springs from Ian Moody who invented the ultraflow manifolds and they worked beatifully with my 230° advertised duration camshaft. There was no fretting marks under the seats when I removed them so they have never valve bounced. I have revved the engine to 5900 at times also. He had these springs wound because all of the crane springs etc were very stiff. I don't know the rate of these but they installed at 90 lbs with the spacers and shims I have with them.

I am selling these with the retainers and shims etc for $120. My engine only travelled 2500kms with these springs and they are only being replaced because I changed my 230° advertised cam for my new 256° advertsed cam and solid lifters.

As for the 0.030" bore you will be fine. My engine is running 0.040 and I have used 20 psi boost and made 400 rw hp with my setup before the new cam and inlet manifold.

Also I blew two head gaskets in my developments and both times it was cylinders three or four and it blew out into the pushrod gallery. I could see the buckled gasket out in the gallery before I even ripped the head off. Crossflow engine will always blow the gaskets on the cold side of the engine which is the inlet side. The gaskets do not bond to the surfaces as well on the cold side of the head.

I would suggest o-ringing the block when you rebuild the engine. The only reason you should blow a head gasket is from pinging. A good tune up is important but at some stage it is likely that you will get a hot day or bad fuel and pinging will occur. The o-rings will help you survive these bad days!