Hi all.....just thought I'd post what I have experienced regarding building a zero deck slant for a street only engine.
The build used some 198 rods,the early smaller dish turbo pistons,3.445" bore.
The head has engnbldr intakes,a nice set of standard size exhausts and hardened seats. The chambers were well polished and ports cleaned up...just a nice home port job.
Cam is basically a 208@.050" grind similar to the Pacer Aussie grind
I enlarged the dish in the pistons to give me 9/1 comp without milling,the block needed a .020" skim to make zero deck.
The rest is all the usual,2bbl carter,stock exhaust manifold,HEI etc etc.
To my relief I feel that all the mucking about was worth it...Detonation resistance is remarkably improved. Using the same dist from the old engine there is no detonation and I'm running 12.5 degrees static. The old engine pinged with the same curve at 7. The curve in it is what is posted here ,with the reduced slots in the governor. I can't remember the total figure exactly,it's been 4 days....that's too long for my head this time of year,but 32 total without vac connected rings a bell?
The cam is extremely quiet on recommended lash of .012" and .016" . I'll be doing hot settings when I retorque the head shortly,but it idles like a stocker and produces solid torque from around 1500. If anyone in OZ needs a cam ground see Tighe cams....nice work.
I really wasn't expecting the detonations tolerance to be as good as it is. Sure it's zero deck,but it's far from having any appreciable quench. I can only assume the dish design pistons concentrate more combustion closer to the plug and the higher ring grooves may also help!
The engine also runs much cleaner. Originally the points ignition,stock rebuild by a well known place here in Sydney was putrid...start the engine in the garage and you had to move it out ASAP ...put HEI on it and it improved a lot,but this engine had an oily cylinder after only 2000 miles which didn't help,but with the new engine is definitely cleaner,the garage doesn't stink after a few minutes running and then drive the car out.
The turbo pistons also have a really nice compact design and better ring pack,ring sealing was very good,even for a new build yet to be fully run in.
It definitely runs better,no race car,but good solid torque... And spins very well,great throttle response for a long stroke engine..From memory the Pacer engine was 185HP? I'd put this thing at that without any issue...maybe more. All testing carried out using butt dyno....

Nice, sounds like a nice "up to date"/modern slant build!!!!

Groovy. Got detailed specs on the VF Pacer cam?

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Too many people who were born on third base actually believe they've hit a triple.

So how close to 0.000" is 'zero' in this case? And did you mill the piston dish in a specific manner, like towards the plug or evenly all around? Sounds like a worthwhile build.

Zero is zero. After I got the block decked I dummied up the assembly and skimmed maybe .005 " max off a couple of pistons to make them all zero deck height. The dish depth was .180" from memory,roughly 2" diameter. I did not make the dish deeper,but I did increase the diameter to make 9/1 comp...think it was 11.5 cc dish from memory. I don't have the build sheets in front of me so I'd have to confirm that,but it is round,did it in a lathe so nothing too exotic.
Dan....I do have a very comprehensive spec sheet on the cam. After it was ground he cam doctored it and sent me the complete readout....I think it had durations and lifts measured at .050" increments....buuuut...I'm living in two states at the moment and of course the data is in Sydney. I'll be down there again mid Jan at the very latest,as soon as I get my hands on it I'll email it through to you!

Sounds like a successful build. Congrats and enjoy the ride...

Lou

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Home of Slant6-powered fun machines since 1988

I have always liked the "long rod" SL6 combo... those longer con rods improve a number of design "compromises" the factory made when they turned the 170 into a 225.
The lighter pistons, thinner rings and improved rod ratio you get really help the engine "spin" better... plus the work you did on a dished piston helps promote better combustion.
I just wish there were more 198 rods out there...
Thanks for the up-date,
DD

Thanks very much everyone ....It's a shame somebody doesn't do a Budget I beam rod for the slant ,I know K1 / Molnar do a rod at a decent price,but a cheap OEM style deal would probably appeal to a lot of slant builders....oh well

I think there would be more of a market for a new forged Slant 6 piston to fit on stock 225 rods. If you are going racing the K1/Molnar is already available.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Excellent