Questions about repowering my 28 Bertram

scenarioL113 · Post by **scenarioL113** » Jun 3rd, '08, 19:41

I know this is site is for the 31's but the 28's are similar and I am sure we are on common ground.

First off I have decided to repower my 28 with a pair of 4bt 150hp cummins. I have just finished rebuilding them and am going to drop them in some time this summer.

Money is tight and I cant get crazy with every single thing being replaced. I decided to keep the velvet drives but I needed to replace one of them with a 1:88 to one unit which will turn opposite the input for counter rotation. Both engines are standard rotation. I figure this will allow me to keep my current shafts and placement will be the same for the trans. The 4BT Cummins are not big boys but I am sure they will push the 28 just fine.

If I would have went with 200 plus hp diesels I would have had to go for bigger running gear etc...

So far with the engines AND rebuilding BOTH, replacing one trans I am only into the repower for just under $6,000.00.

My factory wiring is in decent shape and I am soldering and heat shrinking all the connections that were connected via terminal connectors. The terminal connectors, I believe were mainly to supply the lower station with whatever the upper station had, I no longer have the lower station so I figure I can remove whatever connections that were originally setup for the 2 stations.

I was wondering if anyone out there has their 31 powered with 6BT which are identical to the 4BT except they have 2 more cylinders setup. I was wondering how the ignition need to be set up on the diesel and if anyone uses pull cables to shut them down.

Any suggestions or input would be great.

In Memory Walter K · Post by **In Memory Walter K** » Jun 3rd, '08, 21:55

I have 6BT 210's in my 31. I have 1 3/8" shafts. I have key switches and the engines start and stop instantly when I use them. There is a pull shut-off on the engines, but used only when (and if) off your shut-off module fails. Walter

scenarioL113 · Post by **scenarioL113** » Jun 3rd, '08, 21:57

Is that shut off module wired under the injection pump?

In Memory Walter K · Post by **In Memory Walter K** » Jun 3rd, '08, 22:06

Screws right onto it with a threaded post and nut that a power wire goes on. It's not a big module. When powered, the tip pops out and stops up the fuel line so no fuel reaches the injectors.

Rawleigh · Post by **Rawleigh** » Jun 4th, '08, 09:58

Vic has 6BT's. I think he says that the 4's vibrate a lot more than the 6's.

In Memory of Vicroy · Post by **In Memory of Vicroy** » Jun 4th, '08, 11:54

Yeah, the 4s vibrate pretty good at low speed. Walter, if I remember correctly the fuel solenoid is spring loaded and power keeps it open, cut the power and the spring closes it shutting off the fuel flow. I have on/off keyed ignition switches and separate start buttons. The keyed switches are prone to fail if water gets down in them, so a CX shot now & then is a good idea.

UV

Hyena Love · Post by **Hyena Love** » Jun 4th, '08, 13:18

I have two BW out of my 28 in my garage. 1.5 to 1, as I recall. One has a fresh rebuild. Let me know if you could use one or both of them.

Ironman · Post by **Ironman** » Jun 4th, '08, 13:37

Those 4bs are some great motors...

& real good on fuel.
Wayne

r2d2 · Post by **r2d2** » Jun 4th, '08, 14:37

I've got a lot of experience with 4BT's in 28.
1.The solenoid in the CAV pump needs to be charged for the engine to run. The 12V pull the plunger back. The plunger can be removed and you can use manul levelr to shut off. Usually there a swicth on the dash to energize the ignition ciruit and the plunger.
2. The 4bt is a very tall engine. Even with a ZF 220A (10 degree down angle) the engine deck had to be rasied. So with a straight marine gear I don't think they drop in with out some major surgery.
3. 18x19 props would provide a good crusie at 21 knots or so. Usually
100 nautical mile required 80 to 90 gallons of diesel.

Hyena Love · Post by **Hyena Love** » Jun 4th, '08, 17:29

Shiat - I forgot all about the plan to run straight gears. Yeah, raise the deck a good bit with BW's. It makes the step down into the cabin more like a leap. Plan to add another step. And, then the hatch to the cabin becomes a head banger. Can only raise it so far til it hits the flybridge seat back. Plan to make the hatch a remove and stow deal.

On my '72 hull, and an 8 degree down angle tranny, the engine hatches would not close on that engine.

Now, with some revisions to shaft angle, and/or some tunnels, sure. But, make the shaft angle too shallow, and you can't swing the prop you need with a 1.8 to 1.

scot · Post by **scot** » Jun 4th, '08, 18:35

I "hear" that the 4B should be set up at a fairly high idle to eliminate the exessive vibration, which is said to be the worse at lower idle speeds. I have a Twindisc MG5010A gear in a current boat that is 8 1/5" long, has a 10 degree down angle. (that's the size gear you need) The OEM manual on the gear said it could be shifted "up to" 1100 rpm max. You may want to varify this on whatever gear you end up with to avoid damaging your gears by increasing the idle speed.

I like the 4B at 155hp, said to be indestructable at that power level. I really like the $$$ you are getting it done with.

PS..the 28 hull is nothing like the 31, 25 or 20 (Ray Hunt designs). It's more akin with the 26 or 33 Berts, more deadrise, a sharper keel and a much longer entry angle.

Good Luck and let us know how it works out.

r2d2 · Post by **r2d2** » Jun 4th, '08, 23:33

If you use the Barry mounts there is very little vibration transmitted.
The 4BT is indestuctable provided it has the new stlye heads and is never
overheated. It has a very small expansion tank. I'd love to try the 4B 250 in a 28.

mike ohlstein · Post by **mike ohlstein** » Jun 4th, '08, 23:53

r2d2 wrote:The 4BT is indestuctable provided it has the new stlye heads and is never overheated.

And the new, non melting injector tips.....

r2d2 · Post by **r2d2** » Jun 5th, '08, 05:36

mike ohlstein wrote: And the new, non melting injector tips.....

Mike,
I think that was only a problem on the 4B 250. The Bosch injector tips were a problem and they tried a number of solutions.
Did they ever really fix it?

mike ohlstein · Post by **mike ohlstein** » Jun 5th, '08, 06:56

I believe that you're right, and I believe that it's fixed. I certainly don't hear about it any more....

Hal · Post by **Hal** » Jun 5th, '08, 10:45

I ran a 28 with 180hp Yanmars for a couple of years and all I can tell you is that you're going to be the slowest boat ever created. You'll be lucky to get up on full plane with that little power and without tower and additional weight, I'd be surprised if you could get more than 13 knots.

Mine had a tower and genset and running with the pyrometers pegged at 1100 degrees typically produced 14kt cruise loaded and maybe 16 light.

Good luck, but I think you're building a very fuel efficient trawler.

r2d2 · Post by **r2d2** » Jun 5th, '08, 14:10

I ran a 28 with 4BT's for five years.
No tower or genset.
It would cruise 20+ knots all day long.

dougl33 · Post by **dougl33** » Jun 5th, '08, 16:17

At what HP? I was also thinking that 150hp was pretty light for a hull that has similar weight and dimensions to a 31.

r2d2 · Post by **r2d2** » Jun 5th, '08, 16:44

The 4BT's (CPL 741) put out
130 BHP for medium continuous
150 BHP for intermittent

Todd · Post by **Todd** » Jun 5th, '08, 19:11

I have yanmar 170's in my 28 and run 20 knots with a full load no problem. No tower though. The thought of a tower on a 28 is scary.

r2d2 · Post by **r2d2** » Jun 5th, '08, 20:03

dougl33 wrote:At what HP? I was also thinking that 150hp was pretty light for a hull that has similar weight and dimensions to a 31.

It's just at the limit. The boat needs to be pretty light.
Bimini vs. hard top
No tower etc.
In NC waters, most of the time you can't run a 28 much above 20 knots w/o getting beat up.... Especially in a SW wind and chop..........

Just letting the person who started the thread know it can be done.
That's all...........
It's a bare bones rugged setup that'll fish.

scenarioL113 · Post by **scenarioL113** » Jun 5th, '08, 20:13

Thanks guys for the replies.

I do not have a tower and this info has been helpful, I am going to do this with alot of trial and reeor, I will see how much the deck nds to be modified after I get the motors in. I know they are tall but I will figure it out.

I prefer to stay with the velvet drives unless I can come across a set of twin disk at a good price.

I am pretty good at making things work so we will see how it goes.

Can we post pics?[/img]

scot · Post by **scot** » Jun 5th, '08, 20:23

but I will figure it out.

That's the attitude!!!! I'm betting you will figure it out and make it work.

Food for thought: the Twindisc 502, 5010A, 5011A or ZF220's are 10" shorter than a reduction BW gear, that could make your life much easier....but hey I'm a big fan of "run what ya got".

You have to be careful on these boards because much of our well meaning advice will break "your" bank, not ours...LOL.

CaptPatrick · Post by **CaptPatrick** » Jun 5th, '08, 20:46

scenarioL113 wrote:Can we post pics?

See the Links & Images Sticky...

scenarioL113 · Post by **scenarioL113** » Jun 5th, '08, 21:25

Thanks Scot, I appreciate all advice even if its what I dont want to hear.

I took measurements of my v8 gassers 350cid mercruisers and from the centerline of the crankshaft to the top of the heat exchanger is over 21 inches, the measurement on the 4BT is within an inch of being the same, now I am sure that the advice here is accurate since others have done the same with 4bts in B28's so it is hard to argue.

It looks like it would be close, I plan on putting the v/d's exactly where they were (in the boat) when attached to the v8's and where ever the 4bt's line up is where they are going sit. My heat exchanger when on the v8 is slightly higher than the rear valve cover on the 4bt. It would seem the clearance problem would occur towards the front of the engine since it is a big square. The problem would definately be worse on the 6BT.

Anyone that has or had this setup what was the clearance issue, was it the heat exchanger expansion tank? Was it the valve covers?

scenarioL113 · Post by **scenarioL113** » Jun 5th, '08, 21:54

Here is a few pics:

scenarioL113 · Post by **scenarioL113** » Jun 5th, '08, 21:59

Getting a good deal on a pair of 4bt cummins running but needing rebuilding 3,000.00

Cummins factory parts for the rebuild both total $2500.00

Pair of Velvet drives 1.91 (only need one) $300.00

Having a Dad thats rebuilding them for free and helping you with the job......

PRICELESS!!!!!

r2d2 · Post by **r2d2** » Jun 5th, '08, 23:44

scenarioL113 wrote:.....
Anyone that has or had this setup what was the clearance issue, was it the heat exchanger expansion tank? Was it the valve covers?

You'll have one major issue. The height. You'll need to chop the step up deck and raise it some 4 or more inches.
Also your port expansion tank will bump into the stairwell.
But you can shave the stairwell frame to get it to fit.
There should be plenty of room on the front to the bulkhead but I'm assuming you've already removed the belt guard.
Next you may be tight on the rear bulkhead. At least we were with ZF 220A's..............
A couple other things. We had no problems with 1 1/4 shaft.
Also I forget the size of the mixing elbow (3 1/2 or 4), but you can run that size exhaust all the way with inline veratone muffler and have no back pressure issues.
I hope when you rebuilt you have the heads with 7mm injector tips.
If not you'll sooner or later be switching them out. The heads with 9mm tips just plain suck.
Anyway hope this helps you out with your project. I wish circumstances had been different and still owned one.

jspiezio · Post by **jspiezio** » Jun 6th, '08, 09:00

Cool, good luck with her.

Rawleigh · Post by **Rawleigh** » Jun 6th, '08, 12:11

Nice hoist!! And in your back yard too!! That should help with the turn around time on the overhaul!! Well, maybe not, it didn't work for Thudd!

Hyena Love · Post by **Hyena Love** » Jun 7th, '08, 08:47

Add in space for insulation. Both the heat and the noise is way different that Chevy 350's.

Plus, those hatches flex a good bit with weight. So, that 1/4 inch of clearance can mean hatches rubbing on a vibrating engine when weight is applied (coolers, people walking on them or climbing the ladder).

Seriously, there are guys that can't even get the air cleaners on V8's to fit without cutting the engine hatches.

Only good news is if already have a high deck. I have heard of them, but never seen them. Not sure whether mine was a high deck model, but it sure did not seem like it.

One thing I have come to understand on this board, and lord knows I have learned a ton, is that learning from the mistakes of others is a heck of alot cheaper than learning from my own mistakes. These guys saved my bank roll on more than one occassion by saying - Hey, stop right there. That shiat don't work. When I have disregarded that advise, thats when the big bills came due and payable.

Thus, I have concluded that one ignores the input of the "been there, done that" crew on this board at one's own peril.

scenarioL113 · Post by **scenarioL113** » Jun 7th, '08, 12:01

I am leaning towards laying the engines in and see exactly how much clearance that will be needed and where.

I was thinking if possible the hatch covers themselves could be cut and extended like a box. Then they could still lay into deck like original but they would have to be placed in and not attached with a hinge anymore. My friends 30' Chris Craft Tournament is kind of like what I am talking about.

I sat many hours on those engine covers trolling bass, they are kind of like a big seat.

Time will tell, the engines aint going in for atleast a month or so.

Face · Post by **Face** » Jun 9th, '08, 13:59

I have a 28 with 2 4BT's in it, well technically they are going back in shortly. I have been restoring this boat for about two years now and will have it put back together in the coming months (hopefully by mid-july). When I got the boat it had already been repowered, in 1989. I haven't run the boat yet but have been assured by others with these motors that it will cruise around 20 knots. My engine boxes were not modified but I'm not sure if the shaft log was altered. I will post some pics here when I get a moment.
-Joe

scenarioL113 · Post by **scenarioL113** » Jun 11th, '08, 17:51

Face, what trans are in your B28?

pics would be great.

Frank

Face · Post by **Face** » Jun 16th, '08, 08:52

Transmissions are ZF 220A's. PM me for more details. Here are some pics.
-Joe

[/img]

scenarioL113 · Post by **scenarioL113** » Dec 26th, '10, 15:38

scenarioL113 wrote:Getting a good deal on a pair of 4bt cummins running but needing rebuilding 3,000.00

Cummins factory parts for the rebuild both total $2500.00

Pair of Velvet drives 1.91 (only need one) $300.00

Having a Dad thats rebuilding them for free and helping you with the job......

PRICELESS!!!!!

Dont mean to dampen anybodies mood but my best friend in the world who is pictured in this post unexpectedly and very suddenly passed away this past Tuesday.

Love you Dad! I couldnt have done the repower without you!

In Memory Walter K · Post by **In Memory Walter K** » Dec 26th, '10, 18:15

So sorry to hear that news. He'll be with you every time you turn the key and those engines turn over. Our condolences. Walter

Rocket · Post by **Rocket** » Dec 26th, '10, 18:55

I think it is pretty cool that your best friend in the whole world was your Dad. I bet he thought that was pretty cool too. It gives me something to aspire to with my 7 year old boy.

My condolances, I am sure it really hurts, but the joy you had will outlive any sorrow to come.

Tony Meola · Post by **Tony Meola** » Dec 26th, '10, 19:52

Sorry to hear about your loss.

I was the same way with my Dad. I was with him the day he purchased the boat. We picked it up together and ran it home. We fished together every weekend. He started taking me fishing with him when I turned 5. I still remember all of those trips, the party boats, my first time night bluefishing.

After he passed I kept the boat. Great memories, and whenever I am on it, I feel like he is looking over my shoulder.

I am sure you will have a great number of fond memories.

John F. · Post by **John F.** » Dec 26th, '10, 20:13

Sorry to hear of your loss.

Ed Curry · Post by **Ed Curry** » Dec 26th, '10, 20:22

My thoughts and prayers to you and your family. Looks like he was a helluva guy to have as a dad.

gplume · Post by **gplume** » Dec 29th, '10, 22:04

My condolances as well....Make him proud and finsh it up right....best way you can honor him.

All the best
Giff

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Questions about repowering my 28 Bertram

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