A few questions about the mk30h

[Silas_53A]

Ok, I have a couple questions here outa curiosity.

The mk55h is still a legal race engine in both mod and SO classes but the mk30h is only allowed in mod, why? Were they too different from the current C engines were the 55hs are quite similar.

I saw a 30h mod at kingston NH last year and it had megaphone exhausts. were the 102/302 mods use tuned sliding exhausts, why not use two tuned exhausts, one for the top two and another for the bottom two.

[DiGia54D]

Bob Gollars Merc had 2 sliding pipes and when it was running years ago. It was super fast. Merc C's are a lot of work. Trying to find parts are scary. I had them on my Merc in 92. When the 102's and then 302 were aloud in mod they could only have a tuned exaust. Plus there are probably only 2 0r 3 Mercs around that might get Clark or Vanover.

[sam]

I saw a 30h mod at kingston NH last year and it had megaphone exhausts. were the 102/302 mods use tuned sliding exhausts, why not use two tuned exhausts, one for the top two and another for the bottom two.

The port duration used on the 30's is not very effective with expansion chambers. The exhaust duration is too short for the pipe to compensate for.

[Dave M]

Still The Fastest

Are the old Mercs. Given the rules as they are right now in MOD only, a Merc would beat a Yamato every time if someone could manage to find the proper parts. There is a special block that not very many were made that made Gary Miller's C Mod Merc scream and Bob Gollers merc. Terry Witham ran Gary Millers C Merc on the runabout I believe and went undefeated for many many years.

They opened up the rules for the C Mod Merc to the point that if someone wanted to build one and had the knowledge and time, money, and place to do it right, it would be a barn stormer.

First find the block.................

[T Chance]

First find the block.................

Dave, You've got one. Remember the Merc C-Mod I sold your dad in 1970 and he went out and set a record with it the very next weekend? Pure stock with pipes. - Tim

[Dave M]

Yup

Dave, You've got one. Remember the Merc C-Mod I sold your dad in 1970 and he went out and set a record with it the very next weekend? Pure stock with pipes. - Tim

Sure do. Not sure what happened to that block over the years.

[Silas_53A]

Is it any actual 30h block thats seem to run good like that? or is it mark30 blocks from 19XX-19XX that seem to be the best?

Also does anyone know if there is any specific reason why they are no longer allowed in the C stock class or is it that people just stopped using them so they took them off the list.

Also, I know the 44xs/55h foot are the same internal just different molds, is the 25xs/30h foot the same?

[DiGia54D]

In Stock, Sam Hemp and Matt Dagastino Were Super fast with there Mercs against the 102's. But after a couple of years Mercs were eliminated do to parts available. I am sure if most of our races were on courses as big as Wakefield, Mich. Those same 2 mercs would still win alot of races.

[Larry Mac]

Well I wish someone would tell me about this magical 30 ci Merc block that would smoke the Yamatos. Yes Terry Witham had a good C Merc and he smoked us in the runabout but he wasn't any faster than we was in the hydro. We are close to the yamato but not quite there and yes we have the parts but I guess I don't have the right block or knowledge to make it happen.
Larry McAfee

[Team B&H]

No, the Mercs weren't eliminated from Stock because of parts availability although you couldn't just go down to your dealer and get most of them. It was simply because Matt and I had better rigs at the Nationals. Once there were more Yamato owners in the class, someone figured out the power of the ballot. They had a proposal to eliminate the Merc and the votes to do it. I had one of the first 102s and while it was nice on short courses, it handled like sh-t compared to the Merc.

And handling is the big advantage of the Yamato in CMH. Its lower and with 4 blade props you can get the still fairly klunky gearcase more out of the water. We (Brian Palmquist and me) were always faster with the Merc but the Yamato wins on the race course. Even now, we can't go as fast with the Yamato as we did with the Merc 10 years ago, but the Yamato is best on the race course.

They have liberalized the Merc port rules so maybe a Merc could be built now but what's the incentive when we win with the Yamato anyway? We keep hearing from blowhards (no, not Larry or Kevin) here on HR about their new super 30-Hs but never see them at the Nationals.

Who was the last guy to win the Nationals in CMH with a Merc and why did he switch to a Yamato for the next year?

[David_L6]

Who was the last guy to win the Nationals in CMH with a Merc....

Sam Hemp?

[bh/]

Cmr ?

George Luce's Merc impressed me with his speed at Jesup, but got DQ'd [for jumping?]. Will be interesting to see how he goes at the Nats in CMR.

We were hoping this one might be ready for the NATS,
but the speed is not quite there, yet.
Would the high 60s be even close in CMR today ?

[Dave M]

Well

IN case Sam just called me a blowhard, not sure yet (typical Hemp response) We have not run the C Merc for quite some time. Back in the mid 80's or even before was the last year Dad ran the class (Mod Only). We have the trophies in the basement to prove he had the highpoint championships and National Titles for a great many years in that class alone. The old "CUS" boat as we called it.

Larry, it is the two port blocks.

And Sam is wrong on the fact they can't get around the race course today. He is 100% correct that back then they could not. With the rules allowing the use of gearboxes other than Merc it is very possible for a Merc to ET. The gear ratios are unlimited with today's gearboxes.

Of course all of my responses are based on the Mod version of the engine, not a stock version.

[Team B&H]

No, David, I was not refering to you- can't remember you saying much about a C Merc before this. There was a guy bragging about his Wizard block C like the Wizard block was something special and some guy from the left coast. But never seen them win the Nationals

[Tim Weber]

Sam,

Dave Bryan won CSR with a wizard block at the Bakersfield nationals in the early 80's.

Sam, if you still have the 30H mod, will we see the return of the C-monster?
I think your old rig could still win the big one.

Tim