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Discussion Starter #3
I have been looking at replacment piston options and found a piston that will give a 2.2 engine with 22 wrist pin but the compression height is much lower. Longer rods is one option or I could take advantage of the lower compression height and go the whole hog a fit a stroker crank.

Weighing up my options at the moment on how to build the engine. I was initialy just going to use one of my 8 bolt engines and build a basic 2.1 lump with very high compression and run lpg only. As both the 8 bolts I have still run very well I thought I'd make it a bit more of a chalenge and build up a 6 bolt engine.
 

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I recommend against using the 8-bolt rods in a performance application -- they are both heavier and weaker than the 6-bolt rods. You can substitute rods from the '80-'83 B21/23 (marked "M") for those. They are also heavy, but much stronger.

I've built a fair number of engines with 93mm pistons (2174cc), and I don't think I'll do any more. Even if the cylinder wall thickness is still adequate at that bore, it becomes difficult to seal the coolant passages between the block and the head. There just isn't much metal left between those passages and the cylinders. I've had no such problems with a 92mm bore.

For a stroker, I've done a 92mm x 85.1mm engine (2263cc) by offset grinding a crank, and using off-the-shelf Eagle H-beam rods for Chevy LS1 with custom pistons. That was less expensive than using ready made pistons and having custom rods made up. That may be different in the UK.
 

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Discussion Starter #5
I've built a few engines with 93mm pistons and not had any major issues with sealing the coolant passages - having said that I had problems with one but changing the gasget sorted it and at the time I just put that down to a faulty head gasget. I've got 5 or the late 8 bolt engines and a good spare crank but want to see what I can do with a 6 bolt.

For the LPG engine I will most likely go with a 92mm bore, I have considered offset grinding but not sure it would be worth the hassle.

Do you know how much material you can grind off teh top of teh block? I've only ever taken a small amount before to clean things up. The pistons I have found need around 8mm taking off to sit flush.

Custom rods and pistons are very expensive over here and very hard to find anyone who will make them.
 

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I cut one block down far enough that it skimmed off the top of the VOLVO B20 in the casting, but that's still not nearly as much as 8mm. I don't know, sorry.

I have pistons made by Ross Racing, and I know they will ship internationally. They are somewhat expensive, but very high quality. You could check with them for what it would cost.
 

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You MIGHT be able to drill and tap the headbolt holes deeper. About 7/16" thread engagement will give you all the strength you can get. Be SURE you tap 7/16"14-UNC and NOT M12-1.75. With larger bores and larger bolt holes you could run into headgasket leakage EVEN if you use the right metric bolts. The similarity of these two sizes can be a real death trap!
 

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Has anyone here had experience with VPD (Vintage Performance Development)? They sell stroker cranks, their own cams, and a lot of other goodies to approach the 200 hp mark. They also sell Mikuni conversions, and claim that they are far better than Webers (not a huge surprise). I want to build a potent but yet streetable B20 for a 223, and VPD appears to be good--but I don't know anyone with personal experience.

Dan
 

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Has anyone here had experience with VPD (Vintage Performance Development)? They sell stroker cranks, their own cams, and a lot of other goodies to approach the 200 hp mark. They also sell Mikuni conversions, and claim that they are far better than Webers (not a huge surprise). I want to build a potent but yet streetable B20 for a 223, and VPD appears to be good--but I don't know anyone with personal experience.

Dan
Start a new thread re your B20 build and we will point you to viable parts sources to include established firms/individuals that provide head/block work.

Thanks.

George Dill
 
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