1725 Engine Rebuild.

[Mike O'D]

I am getting ready to do a rebuild of my 1725. I know there are a lot of possible enhancements out there, so I'm looking for some feedback to determine what is worth doing.

KB grind on the cam - what does it do for you? Does anyone have data like dyno before and after?

Visard mod - I assume it reduces the compression ratio because you are making the chamber larger. Are people adjusting for that or just leaving it as is? Any data before and after?

Other things to consider?

Thanks.

Mike

 

[Ken Ellis]

Chevy rod conversion can save a lot of weight on the rotating assembly.

On edit... I see you mentioned that already elsewhere...

Here's chapter and verse on the Vizard mod: http://sunbeamalpine.org/2010/08/26/vizard-mod/
I think there has been discussion of flow bench work, too, but I don't remember the participants.
Flywheel lightening is a another mod, if you want to go there.

 

[Tom H]

Vizard Mod, bored 0.040" or 0.037" , Chevy rods, increase stroke by 0.100, while regrinding crank to match Chevy rods, custom pistons to achieve desired Compression Ratio, added bore and match increased stroke. KB Grind,

Tom

 

[Jimjordan2]

Only thing I have to say is $$$$$ vs hp increase and performance. Once I started looking into actually doing this, I think I was looking at about a $5000 engine or more. I agree with all the improvements, but sheesh lots of money. Oh, and I still had to assemble all the parts myself. Yikes!!!!!!!

 

[Mike O'D]

Thanks for the information guys. Tom - one of these days you need to hit the dyno with your car to see what it's putting out.

Mike

 

[chazza]

"Once I started looking into actually doing this, I think I was looking at about a $5000 engine or more. " Jimjordan2

That seems to be about the normal price over here. I have just finished assembling a Rover V8; machining was $3500, parts at least $1500. Most of the machining cost was fitting new liners.

Reducing the mass of the connecting-rods and the flywheel, seem to me to be well worth doing.

Or if you want an engine which really is fun to drive behind, get a 1600cc,

Cheers Charlie

 

[alpine_64]

Charlie, while there is some compartaive pricing for different locations ( as in local living costs)... You need to think 5k usd vs 5k aud ... So that engine is about 7k+/- aud.

That said for very nice work and lots of good balancing and new parts and head work i think aud 7500 for a 1725 would be realistic... A stock rebuild would run 4500 easy.

 

[67brg]

I am getting ready to do a rebuild of my 1725. I know there are a lot of possible enhancements out there, so I'm looking for some feedback to determine what is worth doing.

KB grind on the cam - what does it do for you? Does anyone have data like dyno before and after?

Visard mod - I assume it reduces the compression ratio because you are making the chamber larger. Are people adjusting for that or just leaving it as is? Any data before and after?

Other things to consider?

Thanks.

Mike

I have done both to my Alpine. The kb grind is very streetable and my car seems to be more torquey (if that is a word). I also had to bore it 30 over because of a broken piston gouge and installed new pistons that have a flat top instead of a dish like the original. This raised the compression up a little after the Visard head mod. I don't have any specs but can tell you by the seat of my pants it is way more powerful than before the rebuild. Car idles with a notable lope and really sounds nice. Makes me feel like I'm driving a really potent machine. lol

 

[RootesRooter]

On my SV, the KB cam, Vizardized head, balancing and a slightly lightened flywheel work great. SV's trannies have a bit of a gap between 2nd and 3rd, where I used to have to wind it up a bit before shifting to 3rd. That gap has disappeared with the extra torque. However, I would use flat-tops next time like 67brg, instead of shaving the head to bring the compression back up to stock, where I'm almost touching the threads for the side chamber bolts.

 

[Mike O'D]

Thanks for the additional input guys.

Mike

 

[jumpinjan]

Vizard chamber mod & flat top pistons are the way to go.
Jan

 

[65beam]

Jan,
What happened to all the parts for the engine Stockman built a few years back? It was never installed in a car and he disassembled it.

 

[Thor 1211]

Where can you get flat top pistons for the 1725 motor. I've looked all over but can only find the dished ones.

 

[Tom H]

You can get custom pistons pretty reasonably priced from Venolia Pistons in CA