This is a question about a non accord vehincle,

Let's say:

two engine:

-one is a 1.3L the other is a 1.5L
-both blocks are identical, uses same parts except one is about a few cm shorter.
-uses same pistons, but the 1.5 rods are slightly longer and (which makes it a 1.5)
-the 1.50 crankshaft has a higher lift for the extra cc's
-head is the same with both

so I would like to know if it would be possible to machine a metal plate so both blocks will be the same height, adding the extra 1 - 1.5 centermeter (to make it a 1.5), use the slightly longer rods and crankshaft with the higher lift

will this work without blowing up or damaging anything?

I posted here because I always get answers and good advice here

And can you please explain your opinions, thanks

 

While I couldn't tell you specifics but don't people stack or use thicker/thinner gaskets between the block and head to accomplish this for compression?

 

maybe if you got a plate cnc made to match the top of the block and used a gasket on both sides. but you would have to get the size exact. IMO it would be easier to just swap in a 1.5. but i dont know. GL either way.

 

It's do-able (I suppose) but I would think that the complications and durability issues would far outweigh any benefit.
You'd be dealing with:

Dual head gaskets (one above, one below your spacer plate.
You'd have issues with Timing Belt length
Coolant passages and plumbing issues
Piston configuration (custom set)

Just the pistons would be a real problem. They would have to be configured such that the rings would never rise higher than the original deck height and would have to be machined lower on the piston skirt.

a D18 would be a far less contencious avenue to explore

P

 

yes they do but it's not to lower compression but to add about 200cc's


both use the same pistons, the 1.5 timing belt would be used

yes it would be cnc to match the block

 

That's what I figured, in essence you're just asking if you can toss on a rather thick gasket as what P mentioned. Two gaskets with a machined extension in the middle. I wouldn't see why it wouldn't work.

 

would the gasket between the plate and the block get burnt? would i really need pistons with a different ring level?

 

I have seen weld on deck plates to create a taller deck Height. Engine builders have been doing it for years to build stroker engines. But you will need a longer stroke crank, longer rods, or move up the piston wrist pin location to keep stock compression. How much longer all depends on how much you ad to the deck height.

 

The issue (one issue) will be how high are the top piston rings at TDC. They would have to be below any gasket, at the highest right at the top of the original block casting. If the piston tops then protrude above the deck (or the squish is less than the spec min clearance), then thicker gaskets or even in some cases stacked gaskets could posssibly be used (a custom made thicker gasket would be more reliable than stacked gaskets, maybe a solid copper plate gasket).

I've done this (extra thick custom gasket) on an engine when the machinist became over-enthusiastic when machining the deck, resulting in protruding pistons (they'll never find the body...).

A 'deck plate' could be made that 'extended' the bore higher if the rings were going to rise above the top of the existing bores, but it would need to be fitted without a gasket and the 'bore extension holes' would need to be honed to match the original bores exactly (don't want a ring 'catching' on any join). Such a plate would want to be made from a similar metal to the block or liners, i.e. cast iron, but even then it might be scary engineeering with different expansion rates etc.

If you use a stroked crank with longer rods then you'll make the problem even worse, i.e. the piston will rise even higher than with the stock rods. It's possible to use a stroked crank with shorter rods (and / or pistons with less crown to pin distance), which can keep piston TDC height the same as stock, but will lower BDC height. It also increases rod angularity and changes piston accelerations and 'dwell at BDC and TDC, all of which might (or might not) present tuning and reliability issues.

You do need to know what you're doing when stroking a motor, and be willing / able to pay for it. I can't see that what you seem to be considering would be remotely worthwhile given the probable problems and expense. Why not just use the larger engine???

 

man... that sounds so smart I kinda need parts broken down for me

well what i was actually seeing is if a plate was made to near identical specs of the 1.5, with the timing belt, rods, and crankshaft from the 1.5 will it make it a proper 1.5

 

The cubic capacity is dictated purely by the bore diameter and the stroke, so if you can get it to work with the longer stroke (without falling apart) it will be a "proper" 1.5 litre engine (there is no such thing as an 'improper' capacity, it is what it is...).

The question is; why not just use the larger engine? It will be cheaper, more reliable (probably), and much much easier. I woudn't be at all surprised if having the plate made to custom spec didn't end up costing near to, as much, or more (by itself) than just buying a whole second hand 1.5 engine...

 

^^^x2

Most stroker deck plates are created for an engine that does not have a taller brother in it's family. Yours would obviously be a custom one-off. If there is already a 1.5L engine and all you are trying to do is create that exact same engine using it's shorter brother. You would be better off buying the taller block. Unless you have free access to the materials, a CNC machine and a very good aluminum welder. Then it might be a little bit cheaper. You still have to buy all the 1.5L internals though.