Getting my sprint block bored. Does anyone have a deck plate?

[roger440]

As per the title, getting my block bored, but, ideally id like to do it with a deck plate fitted for the best result.

Has anyone got one? Does anyone actually bother on these engines?

Happy to rent/ hire etc.

[soe8m]

I guess you have to send your engineblock to NL then. First a skim of the deck with the engine clamped in the main bearing bore to have the deck flush with the cranckshaft bore and then a bore with the deck plate. Our deckplate is as large and alloy as a cylinderhead and torqued the same way so with the actual head torqued down your bores will be perfectly round.

Jeroen

[roger440]

I guess you have to send your engineblock to NL then. First a skim of the deck with the engine clamped in the main bearing bore to have the deck flush with the cranckshaft bore and then a bore with the deck plate. Our deckplate is as large and alloy as a cylinderhead and torqued the same way so with the actual head torqued down your bores will be perfectly round.

Jeroen

Thanks.

Too complicated sending back and forth.

Ive just done it without

[soe8m]

99,99% does without and it goes fine. When you have some time left you could torque only a head on the engineblock and measure the bores from the cranckshaft side and see the cylinders are marginally oval now. Nothing to worry.

Jeroen

[roger440]

99,99% does without and it goes fine. When you have some time left you could torque only a head on the engineblock and measure the bores from the cranckshaft side and see the cylinders are marginally oval now. Nothing to worry.

Jeroen

Do you have any thoughts on piston to bore clearance. Book says 1 thou for a standard engine. But this will be making circa 190bhp. Should i increase it do you think?

[soe8m]

The size should be determined by the piston manufacturer. AE and I believe Mahle have the bore size on the piston box for that particular piston but all manufacturers will have their own tolerance as not every piston is made of the same material.

Jeroen

[Carledo]

99,99% does without and it goes fine. When you have some time left you could torque only a head on the engineblock and measure the bores from the cranckshaft side and see the cylinders are marginally oval now. Nothing to worry.

Jeroen

Do you have any thoughts on piston to bore clearance. Book says 1 thou for a standard engine. But this will be making circa 190bhp. Should i increase it do you think?

Unless you are going drag racing or drifting, the standard 1thou should be ok. Horsepower is less of a controlling factor than operational heat range, if it's gonna get properly hot from competion use, might be worth adding another thou. I recently watched an American guy building a V8 Mopar engine for dragstrip work and he built it quite deliberately with around 5thou of slop in the pistons, far too much for a road car but necessary for that application. (Uncle Tony's Garage on Youtube a real down-home, low budget car builder, great fun watching his low cost, low tech cars going far quicker than they have any right to, yes, and sometimes blowing up!)

Steve

[roger440]

The size should be determined by the piston manufacturer. AE and I believe Mahle have the bore size on the piston box for that particular piston but all manufacturers will have their own tolerance as not every piston is made of the same material.

Jeroen

Absolutely!

I dont know where the pistons are from, but they are cast, and have 90.28 stamped in them. Other than that, i have nothing to go on. In the previous block, they had 4 thou clearance!!

Given it will do the odd track day, and it will be making good power, thats where the concern came from.

I dont want to go any bigger than i need to. But 1 thou is very tight.