Recently came about a 1098 engine and box (with a 12G295 head ) at a scrapyard which I bagged for next to nothing
It’s seized so will need a rebuild. Are there any obvious upgrades I could do whilst I’m in there? If it needs boring out etc, what’s the max I could take it to and what cc/pistons would this give me with the 295 head?
The long stroke of the 1098 makes it more tolerant of a wilder cam than the other small bores. Doesn't Vizard even say the 648/9 is a good cam in a 1098? Certainly a 286 over a 266. lighten the flywheel, get it to about 10:1 and it will be a nice engine in a moke.
I found getting hold of decent pistons tricky, but eventually found some flat top ones from a company in Australia of all places. The part number was KR18520, the same as the original Powermax design they were built to.
I could not fault my 1098 motor, it was fitted with 12G295 head, 510 cam and 1-25 twin stombergs. Plenty of torque and despite the cautions regards the long stroke was reliably free revving
I have a 1098 with:
+080 flat top pistons (1166cc from memory)
266 type cam
12G202 head with bigger valves, porting etc (higher spec than a stock 295)
I’ve been really happy with it, it’s been really smooth and lots of low down grunt. I have an rpm limiter as part of the electronic timing box, and it’s surprising how often it’ll spin up to the limiter when you are having fun driving
Read this by Keith Calver. https://calverst.com/technical-info/eng ... potential/
I've just built a 1098 +0.100" and followed keiths build.
A local specialist has just built a 1098 with 68mm pistons from Keith and it's putting out about 75 bhp.
I’ve built a 1098 with a skimmed 295 (otherwise standard) and a 997 spec cam. Hoping to see at least 55 HP but plenty of torque. Gearbox is a four sync wand with a 3.2:1 FD in it. Should make a good motorway mini.
The 1098 in the Hornetto is taken out by +.100" using the CST pistons, which is 1186. Combined with a mildly worked 12G295 and a Piper 255, it will pull trees over.
It's quicker and more sparkly with a 3.1fd than most 1275s with a 3.44fd.
The ultimate build would be with the 68mm pistons - I've used them in a 998 which is a rev monster so in a 1098 should be most agreeable.
I'd say with the longer stroke its worth getting the internals balanced and make sure your damper is in good condition. I've put together a few 1098 engine using the Calver oversized pistons and have been really happy with them. The first two used MiniSpares EVO cams and one of Keiths heads which both revved really well. The most recent one uses an alloy Speedwell head (brought up to 295 spec) and a 255 cam which at the moment I'm not 100% happy with, hopefully as session on the r-road in a few weeks will make the world of difference.
AndyB72 wrote: ↑Tue Apr 05, 2022 10:10 am
I'd say with the longer stroke its worth getting the internals balanced and make sure your damper is in good condition. I've put together a few 1098 engine using the Calver oversized pistons and have been really happy with them. The first two used MiniSpares EVO cams and one of Keiths heads which both revved really well. The most recent one uses an alloy Speedwell head (brought up to 295 spec) and a 255 cam which at the moment I'm not 100% happy with, hopefully as session on the r-road in a few weeks will make the world of difference.
I've gone down a similar route with +0.100" KC pistons.
I've gone with the 255 cam matched to one of Keith's heads and a recurved distributor.
Keith ask me for a 202 or CAM head to modify as either offered better modifying options than a 295.
I'm wondering if the Speedwell head is maybe not as well suited to this build as one of Keith's bespoke heads.
Be very interested in any RR readings you will have.
I've gone down a similar route with +0.100" KC pistons.
I've gone with the 255 cam matched to one of Keith's heads and a recurved distributor.
Keith ask me for a 202 or CAM head to modify as either offered better modifying options than a 295.
I'm wondering if the Speedwell head is maybe not as well suited to this build as one of Keith's bespoke heads.
Be very interested in any RR readings you will have.
[/quote]
I don't think the Speedwell head is quite up to the iron heads Keith produces, although it was Keith that checked over and fiddled with the speedwell head for me. I think maybe the 255 cam is a bit too mild compared to the MiniSpares EVO cams, it ticked over much better but doesn't want to rev as freely at the top end.
AndyB72 wrote: ↑Tue Apr 05, 2022 5:05 pm
I've gone down a similar route with +0.100" KC pistons.
I've gone with the 255 cam matched to one of Keith's heads and a recurved distributor.
Keith ask me for a 202 or CAM head to modify as either offered better modifying options than a 295.
I'm wondering if the Speedwell head is maybe not as well suited to this build as one of Keith's bespoke heads.
Be very interested in any RR readings you will have.
I don't think the Speedwell head is quite up to the iron heads Keith produces, although it was Keith that checked over and fiddled with the speedwell head for me. I think maybe the 255 cam is a bit too mild compared to the MiniSpares EVO cams, it ticked over much better but doesn't want to rev as freely at the top end.
[/quote]
Maybe Keith can clarify why he recommends the Piper 255 over the evo001. I put an evo001 in my wife's 1330 convertible (MG Metro head) and it made 90bhp.
Maybe Keith can clarify why he recommends the Piper 255 over the evo001. I put an evo001 in my wife's 1330 convertible (MG Metro head) and it made 90bhp.
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It was me that choose the 255 cam, I'd read rave reviews about it. It certainly has great road manners, just not quite as buzzy up the top end which I like. Will see after the r-road when I start to thrash it a bit more
Bore the block
Fit the oversize pistons and balance the crank, rods and flywheel.
Choose a cam.
Choose a head either 295 or 202. I have some forged S rockers.
Choose a carb. Twin SU ok?
) at a scrapyard which I bagged for next to nothing 
