Tell me it's not true!!!

[Anonymous]

Earlier today I read on this thread that at TDC the pistons can be as much as 175-thou or more down in the bores. When I first read it I thought, nah...can't be! But I just happen to have my 250 minus head sitting on the engine stand so decided to take a look after work today. Here's what I saw...the piston crown was 3mm (~120-thou) down the bore at TDC!

I thought I was going to vomit! There is a beautiful flat quench-wedge cast into the head, but the piston doesn't come anywhere near close enough to take advantage of it. To make matters worse, I measured the head gasket at .049". It'll crush a bit, but that still leaves the slugs a good 160-thou down the bores.

Okay, I'm going to need some help with this one, 'cuz there is no way on God's Green Earth that I am going to put this abysmal piece of (expletive deleted) in my Mustang!

I'm hoping you Ford I-6 experts can point me to better pistons that will utilize the quench pad. Any suggestions? Remember, this is a turbo-LPG engine, so CR is not as critical as it would be with gasoline.

Thanks in advance!

 

[Anonymous]

Actually, the thought just occurred to me that the very fact that this is a turbocharged LPG engine might mean that quench is not as critical as it would be in a gasoline engine. After all, the draw-thru turbo assures a truly homogenous mixture...

Any thoughts about that issue?

 

[Anonymous]

XTaxi, XEcUTE, Dean, Deano etc. etc. has mentioned several times that the 6.00" 2.5L HSC rods from a Taurus would be the perfect swap for the 250s.

DB.

 

[Anonymous]

255 V8 pistons are a direct fit and have a taller compression height. 1.55" IIRC. I used them in my last 250.

 

[Anonymous]

Okay, you see me exposed as a complete dupe...

I have just returned from the shop where I confirmed that I was sold a "bill of goods" when I bought this "250"...

It is a 200. I just measured the bore at 3.68" and the stroke at 3.91".

For the past three years I have wondered why I have run into problem after problem adapting this "250" to the 250-in-a-200 slot. Now I know...

FWIW, here are the casting numbers...

Block:
D8BE
6015
JA

Head:
87BE-6990-AB
7K27

Can anybody confirm the particulars on this engine?

TIA,

 

[Anonymous]

Stan,

the 250 has a 3.91 stroke and the 200 3.121" stroke. right?

 

[Anonymous]

Yep - a 250

Uhh, that engine had cast steel rods originally. Hope you changed them. I wouldn't use them in a turbo app......

 

[Anonymous]

My bad...sorry about the mistype above!

I just did a quicky remeasure with a machinist's rule, and got about ~80mm...which is about 3.12". A 200, right?

 

[addo]

Count the water pump bolt holes. Hey, if it's a 200, I have an idea about something that may suit you...

 

[Anonymous]

What's your idea, Addo?

 

[addo]

There is an extra 221 motor and Oz specific parts currently in the SF area... I can PM you more details if you want.

 

[MustangSix]

D8 BE-JA should be a 250.

If it has the small block bell pattern and four water pump bolts, that cinches it.

255 pistons are 1.585" vs 1.50" CD. The 2.5 HSC rods would bring the stock pistons up. But if you did that, the CR would be pretty high.

I'd run the short pistons as is with CNG.