Hello all my first post is a question but hope to post many answers to in the future.

I am building a 2.1 ZVH from a blacktop (series 3), but have a couple of questions.

• I have now broken two torx bits trying to take the Zetec head off. Can anyone recommend a torx set.
• I intend on using c20let pistons for a C/R of 7.4/1. My question is when I take my con rods to the machine shop how much do I ask them to bore out the small ends too.
• Do I really have to block that middle water way off or will the 1.9 CVH head gasket hold it.
• The water pump hole is different because the blacktop uses a external water pump. Is it ok to just mount the conversion plate to the block and cut the correct size hole out.
• It there any other differences to the ZVH process when using a black top engine compared to the silver top engine.
• Different oil pump is used and thus the filter might foul in the engine bay. I was going to use a oil cooler set, would this stop the problem allowing me to use the original pump?

Sorry for being so long but there is not to much info out there for the blacktop ZVH conversion.

Thank you for your time.

Bob.

 

I've never broken a torx bit on taking a zetec head off - even really old rusty munters. Are you using the right size and a suitable breaker bar?

Pistons: assuming you're keeping the standard rods, then they should measure the pin of the piston and ream the rod to a suitable interference fit, and then fit them for you.

You can use the earlier water pump with a suitable hole in the block, or go electric.

Sure, using a remote take-off for the oil filter would move that obstacle away, but I doubt it'd be a problem as it's in a much better location on a black top (eg, like how a cvh has it)..

 

When I bought the torx set off the car boot I knew something was fishy. Lesson learnt.

Thank you for your reply

 

the water pump hole can just be enlarged to fit a cvh water pump, no need for a plate!

the oil filter is on the block, not the pump, so there will be loads of clearance there.

only thing i'd be concerned about is using the blacktop rods... they're no good for the LET pistons. you need silver top ones for it you need about 0.0015 nip on the pins if the machine shop really need to know, but to be honest, if they couldn't work it out for themselves i wouldn't be using them!

 

Thank you so much!!

Look forward to getting it upand running!!!!

 

Whats the difference in the rods then?

 

The length and the small-end size.

 

speak to www.powerconversions.co.uk they know how to sort the rods out, they build these on a regular basis

 

With the small end being bored out anyway, would the only problem be the length?

So the question is...

What is the difference in the length?

Thus should be able to work out the new C/R using c20 let pistons and if the outcome is unacceptable look at different piston options.

I think using silver top con rods, c20let pistons and a bore of 86mm the C/R is around 7.4/1

Would like this a tad higher but not much 7.6 to 8 would be nice for better throttle response.

 

It's actually more like 7.6:1 on an un-skimmed head with C20LET's...

I wouldn't worry too much about response.. it's great with a suitable turbo (et, T34)..

The black top rods are much longer, to the point where you'd most likely get positive deck protrusion with these pistons. I'm not sure i'd want to ream out those rods by 2mm either.

 

Fail enough point. Silver top con rods it is then!
Anyone have some laying around?

When you add it all up does it make ŁŁŁ sense to buy silver top rods to have them modified, for them to be a weak link in the chain.

 

The deck protrusion should anyhow be around the head gasket thickness minus 0.8mm to make the combustion chamber work as it should.

 

What

We are talking about turbo application here.

Or am i getting the wrong end of the stick? (Which i often do)

 

What JesseT is correct - on a properly engineered engine, you will have a suitable squish area which requires the pistons to sit proud of the block deck by a blueprinted amount.. However you can't really do that with the LET pistons as the main reason they're used for turbo zetecs is because they sit so far down the hole its the only way they give you the reduction in compression ratio.. It's not ideal and it's crude, but it works!

 

So this is why you see pistons with a concave look to them or am i knot following?

Must say people I have learnt alot in this thread so I would like to say thank you to you all. I am very impressed.

If I get this working it will be amazing. My first engine build!!!

Does any one have any recommended reading material about engine building as I find it a fascinating subject?

 

Another reason to use concave/dished pistons is that one usually want's to maximize the distance from the piston top to the first piston ring. On the other hand it's better to use long rods and have the pin higher up in the piston. So everything is a compromise. The black top has 3.0mm longer rod and the pin is 3.0mm higher in the piston. This is the reason not to mix and match.

On the other hand, if we are talking only hemi CVH heads, they don't really have any squish area at all. So I guess the LET pistons are ok for ZVH if the compression ratio is ok.

 

what oil filter should i use on my 2ltr zvh?

 

ive got a set of silver top rods if you are still looking mate?

 

what oil pump have you used?

 

dont know vulcan engineering have built it im sure he said a stubby mondeo filter.

 

Halfords pro tools have a lifetime warrenty on them, so if its breaking through them, try a hal-pro one and if it breaks too it'll be replaced free.

JAmes.

 

Well I am getting a set out new tool out of machine mart with Life time warranty so that zetec head is coming off.

How Clarke5700 how much are you moving your con rods on for?

I will be sticking with the standard Blacktop oil pump with an oil cooler attached.