Longblock problems
06-07-2009, 09:29 AM
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Longblock problems
I've had a Tomahawk 37 (1989) for six years without engine problems. The old owner or the owner before him changed one of engines out so one is the orginial (the one that have stopped working). The broken one is with serial #14015445 and heads #6272990. The working newer one with serial # 10237297, heads dont now the number but square ports. No idea of what type of cams but not roller in either. Just got a longblock delivered block serial #10114182 head #10114156, S&S rebuilt no roller cam. Is told that it is 360hp. Have now learned that the working one is a Mark VI 96-96 and realized that was what i should have bought I think. The dealer dont sell Mark VI longblocks with square ports and I would like to minimize the parts to convert to a Mark VI. I had the heads done this winter but the old one's wasnt in that good condition I was told. I can return the longblock. Now to the question.
Can that rebuilt longblock produce 360hp? What does the Mark VI engine that I have produce in hp? If I would like to rebuild to get some more hp around 400hp instead of the original 365, what should i do and think of when I by a new longblock today? I really would like the engines to look the same when I am ready to sell her.
Can that rebuilt longblock produce 360hp? What does the Mark VI engine that I have produce in hp? If I would like to rebuild to get some more hp around 400hp instead of the original 365, what should i do and think of when I by a new longblock today? I really would like the engines to look the same when I am ready to sell her.
Last edited by wperson; 06-07-2009 at 01:57 PM.
06-07-2009, 05:53 PM
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wp,
First of all, just so you know, your terms are kind of confusing. The numbers you have listed are not "serial" numbers, they are "casting" numbers and only identify the block and head castings. There is no way to tell the HP of the engine from these numbers
What you really need to do is try to find someone to sell you or build a matching engine to your one good one. You need to get the casting numbers of the heads, they are under the valve covers. It would be real nice if you can determine the camshaft also but that will require partial disassembly of the engine.
You really do not want the new engine to make more horsepower than the one good one that you have, they need to be matched. The ideal thing to do is get in touch with the previous owner and see if there is any way to find out exactly what the good engine is. Are there any tags attached to it that might identify it ? Either on the valve covers or down on the lower area of the block near the starter or oil filter. If it is a remanufactured engine there should be a tag on it somewhere.
You may be better off working with a local builder to get what you need.
Where are you located ?
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
First of all, just so you know, your terms are kind of confusing. The numbers you have listed are not "serial" numbers, they are "casting" numbers and only identify the block and head castings. There is no way to tell the HP of the engine from these numbers
What you really need to do is try to find someone to sell you or build a matching engine to your one good one. You need to get the casting numbers of the heads, they are under the valve covers. It would be real nice if you can determine the camshaft also but that will require partial disassembly of the engine.
You really do not want the new engine to make more horsepower than the one good one that you have, they need to be matched. The ideal thing to do is get in touch with the previous owner and see if there is any way to find out exactly what the good engine is. Are there any tags attached to it that might identify it ? Either on the valve covers or down on the lower area of the block near the starter or oil filter. If it is a remanufactured engine there should be a tag on it somewhere.
You may be better off working with a local builder to get what you need.
Where are you located ?
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
06-08-2009, 04:23 PM
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Sorry Bill for the late reply.
I'am located in Gothenburg Sweden, the time difference is a problem to read and reply. Just had the engine taken out tonight (serial C334066).
There aern't many builders here in Sweden and fewer now what they are talking about when I adress my problem.
I didnt have time to have a look at the serial on the heads on the working engine. The boat is imported so I really can't get in touch with previous owners and the last owner wasn't much of a mec guy so there is no info there either. I didn't find any tags at all, so the cast numbers is all I got. Where do I find the camshafts name or number? Do I have to take the cam out to identify it?
This is how I think, when I have a working Mark VI engine with
high performence heads, that i remeber I read on the heads when I had them rebuilt this winter. I then buy a new rebuilt Mark VI (GMC-454MRLB Marine CHEV 97-96 454/7.4 8 390hp 6200$ here in Sweden) so I can use the boat this season.
Next winter I can pull the old Mark VI and set it up with the same camshaft that the new one has. Don't you think the would be pretty much the same after that?
More questions? Will the Rochester I have today make a 454MRLB(roller cam) go to lean? What other parts do I need to the longblock?
I have figured that I need new valvecovers, oilpan with matching oilstick, flywheel, and frontcover.
You have to excuse if my spelling is wrong sometimes.
Look forward hearing from you Bill.
I'am located in Gothenburg Sweden, the time difference is a problem to read and reply. Just had the engine taken out tonight (serial C334066).
There aern't many builders here in Sweden and fewer now what they are talking about when I adress my problem.
I didnt have time to have a look at the serial on the heads on the working engine. The boat is imported so I really can't get in touch with previous owners and the last owner wasn't much of a mec guy so there is no info there either. I didn't find any tags at all, so the cast numbers is all I got. Where do I find the camshafts name or number? Do I have to take the cam out to identify it?
This is how I think, when I have a working Mark VI engine with
high performence heads, that i remeber I read on the heads when I had them rebuilt this winter. I then buy a new rebuilt Mark VI (GMC-454MRLB Marine CHEV 97-96 454/7.4 8 390hp 6200$ here in Sweden) so I can use the boat this season.
Next winter I can pull the old Mark VI and set it up with the same camshaft that the new one has. Don't you think the would be pretty much the same after that?
More questions? Will the Rochester I have today make a 454MRLB(roller cam) go to lean? What other parts do I need to the longblock?
I have figured that I need new valvecovers, oilpan with matching oilstick, flywheel, and frontcover.
You have to excuse if my spelling is wrong sometimes.
Look forward hearing from you Bill.
06-08-2009, 08:31 PM
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wp,
You really should pull the cam to get the number off it, but you might be able to get close by just measuring the lift at the end or the pushrod or at the lifter if you have the capability.
Your plan with another engine sound ok, but I would try to get one with heads that are as close a match as possible to your existing ones. If your good MKVI engine has square port heads, you really need to get a replacement engine that also has square port heads.
If your Q-jet came off the 365 hp engine, it should be pretty close but might need the jets and metering rods to richen it up a bit, especially the secondary metering rods.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
You really should pull the cam to get the number off it, but you might be able to get close by just measuring the lift at the end or the pushrod or at the lifter if you have the capability.
Your plan with another engine sound ok, but I would try to get one with heads that are as close a match as possible to your existing ones. If your good MKVI engine has square port heads, you really need to get a replacement engine that also has square port heads.
If your Q-jet came off the 365 hp engine, it should be pretty close but might need the jets and metering rods to richen it up a bit, especially the secondary metering rods.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md
