I assembled my B18C4 with the high compression ycp type-r pistons and my motor won't turn!

The pistons are touching the head. :-(

The previous owner must had the head milled good for compresson on stock pistons:-(

Is there a solution? :-S

Can I slightly mill the pistons on the edges?
And maybe a thicker headgasket or two OEM headgaskets?

please help me

 

i would first fine out how much the head has been milled and see if the block has been milled also ... once you have those numbers go from there so u can see if a simple thicker head gasket will fix your porblems

 

Where can I mesure how much the head&block was milled?

I will mesure how much the head will need to be rised. I will put some plasticine on pistons and mesaure the thickness.

Can't the pistons be milled a little on the edges?

I am now going to pull the head. - I am glad that I bought ARP headstuds.

Thanks.

 

yes you can mill the pistons but if you dont have to then dont becasue you will have to pull everything apart agian to do it i believe .. if that dont bother you then do it... as for the head part there is a lil area on it where you can check... i personaly dont know how but read it befor , try to google it ... phrase would be probly "how to check if head has been milled on honda" or something along those lines

 

Some news...

I unscrewed the arps and as soon I did that the pistons did not touch the head. The motor spins freely. So there is not a big tollerance issue.

I spoke to an engine builder and he said that I have this problem because of the high compression pistons + 82mm overbore. The solution would be to grind the head=>to widen the combustion chamber to accomodiate the bigger pistons.

I mesaured the distance from the piston at TDC to the spark plug tip and it is 3mm, so I think that he is right and I only have to enlarge the combustion camber, am I right?

 

If your pistons are touching your head, it could mean a few things: your block and/or head has been decked considerably, you're running an LS crank (89mm) with a GSR head that has had some milling/decking. Are you saying that as soon as you released the torque on the head studs that the pistons no longer hit?

 

Get it clayed and it will show you exactly were its hitting. What gas octane are you gonna run with this setup? Youre CR is going to be to high for pump gas unless you run e85 then ure all set.
http://www.c-speedracing.com/howto/claymotor/clay.php

 

Yes!

I will take the mesaurements and produce a photo, then I will post it here for you.

THe motor will be run only on 100 octane gas and the timing will be a little retarded to ensure that the detonation won't occur.

Maybe the 82mm pistons are the only problem because they are hitting on the ends(see picture).

 

I would still clay it to se if you have clerances on the intake and exhaust valves and the top of the pistons to the head just in case.

 

what head are you running?

 

The head is of the motor - B18C4.

I clayed the head and I found the problem: The pistons are touching the head on the sides where the letters and the arrow is stamped.

Pistons sits 0.25mm(0.01") out of the bore

I think that if I just grind the letters ( IN ) and (S + arrow) down, the motor would turn.

Can I grind the letters down or that's not a good idea?

 

The height of those letters is 0.5mm (0.02"). A LITTLE TOO MUCH!

If I tore them down on each piston, the weight will be reduced equally between pistons => I should be good.

Can I grind?

 

are you running the stock b18c crank or an LS crank? If it's the stock crank, I would say someone seriously decked that block of yours if you're running into clearance issues like that.

 

Stock crank and everything. Why is this happening to me:-S :-(


Can I grind the letters OR just buy a thicker headgasket and call it a day!?

 

In all honesty I would install different pistons. Those CTR style pistons don't like the GSR heads (b18c) and there are better performing choices for you. I'd consider JDM ITR, USDM ITR or USDM Pr3 pistons instead. At best, even if you're able to get that engine to run, you'll have to pull a lot of timing to get it to run correctly and last but at the cost of power.

 

If it was that simple...

I really have to get the engine running - I spent a lot of money on the rebuild parts(ALL) and I will be more than happy if the engine would work even if it will be no more powerfull than the original because I will have to pull timing due to detonation.

 

yes you can grind the letters down.

 

Tomorrow I will grind the letters and the arrows down and then torque the head & clayed the engine for the final time to know precisely what headgasket thickness to order.

 

What HG are you running right now? Stock? A cometic HG would more then likely give you the clearance you need.
Stock HG is .026
Cometic HG is .030
OR another choice is the apexi HG @ .050 thickness.

 

Yes, I have the stock headgasket rightnow.

I think that I will run the cometic 0.061" thick HG.

 

I just grinded the letters down. => The engine turns!!! :-D

I also clayed the engine with the original 0.026" gasket and the squish is 0.4mm

So I will order a thicker headgasket and be done with it.

 

may i ask what was your reasoning for choosing ctr pistons?