head bolt change

hello ,

i had a broken impeller (plastic bag on the stern drive ) and so 2 head gaskets to change .

my engine is volvo 4.3 gl a .

do i need to change the bolt head ?

thank you , have a nice day

greg from france

Always good practice to replace head bolts... especially with "modern" engines. BTW, Many years ago I had the same thing happen to me. Except I caught it before I had to change the head gaskets... I had modified that boat for thru transom exhaust, and you can hear on a thru transom exhaust when the water flow stops.

My solution on that boat and all subsequent boats I've owned is to have the water inlet thru hull with strainers. In my current boat, I have an external "wedge" style inlet strainer. Never clogs ( 12 seasons) ... no filter baskets to empty or have corrode, no filter cover gaskets to leak or filter covers to get cross threaded/improperly seated.

See attached for what I followed on mine. Be careful as to choice of hole size on the strainer mesh, several are available.

http://bertram31.com/proj/tips/strainers.htm

thank you for your answer !
nice and good idea !!

on my next boat : working on it (windy 22 sport ) = thru hull exhaust (and in water : swiss laws on lake leman) !

after this problem , i made a little electric circuit :

using a switch coming from mercruiser : it cuts ignition and i add a circuit with relay for of big electric pump . if it s too hot , the engine stop and the pump starts .

sorry for my english

frenchy greg said:

thank you for your answer !
nice and good idea !!

on my next boat : working on it (windy 22 sport ) = thru hull exhaust (and in water : swiss laws on lake leman) !

after this problem , i made a little electric circuit :

using a switch coming from mercruiser : it cuts ignition and i add a circuit with relay for of big electric pump . if it s too hot , the engine stop and the pump starts .

sorry for my english

Click to expand...

Yes, you can do that, however in my career as a design engineer, I found that solutions that prevented problems in the first place, worked better than those that delt with the aftermath.

Re: your English.... waaay better than my French

Re: Exhaust thru hull. Volvo drives have an undersized port size for V8 engines, so i went thru hull. Here in New Jersey, they also have laws about thru hull exhausts and as a result my thru hull exhaust setup includes a pair of fiberglass marine mufflers inside the boat (tight fit!!!) and exhaust ports that are the recommended distance above the water line.

do i need to change the bolt head ?

Click to expand...

Nope,..... Chevy head bolts are still durable,......

They just gotta be perfectly clean, 'n the threads coated in sealant,.....

bondo said:

Nope,..... Chevy head bolts are still durable,......

They just gotta be perfectly clean, 'n the threads coated in sealant,.....

Click to expand...

re: "Chevy head bolts are still durable,." WOW!!! at least something is.. Thanks for the correction.

bondo said:

They just gotta be perfectly clean, 'n the threads coated in sealant,.....

Click to expand...

I'll add that the sealant also provides some thread lubrication for when tightening these bolts to the correct torque value.

I did this same job last summer, have a few tips to make it easier/come out better

1) clean clean clean the outside of the engine before taking things apart
2) find a way to label parts and wiring, do not trust to memory, take cell phone pix of wiring connections, linkages, etc.
3) an electric impact gun works well for removing stubborn head bolts.
4) the intake can be stubborn, you may need to find a way to pry in the front or rear seam (that’s sealed with RTV) without doing damage (screwdriver padded with electric tape).
5) After removing the heads, take them to a machine shop for magnafluxing
6) after you get them back, clean the block deck surface and remove all old gasket material carefully. Measure warpage using a straight edge, it should be less than .003”
7) clean out the bolt holes with compressed air and solvent and clean the threads with a thread chaser
8) clean the threads on the bolts as well as you can, if they are too rusted, then replace them. I used APR bolts for the heads and intake
9) before installing the heads make sure each head bolt threads all the way in, if not find out why and rectify.
10) when installing the heads and intake use proper marine gaskets like Fel Pro
11) adhere to torque specs closely

Torque down bolts in 3 phases and follow sequence carfully

And don't forget the sealant on the bolts. Be careful when resetting the intake, I used a bit of Permatex to hold the intake gaskets in place (and also on the water passage area).

louc said:

And don't forget the sealant on the bolts. Be careful when resetting the intake, I used a bit of Permatex to hold the intake gaskets in place (and also on the water passage area).

Click to expand...

ok


for the torque , i ve found :


sequence with degrees
or
and sequence with torque


Here is the sequence

Preferred Method is as follows

• All bolts first sequence 22 ft. lbs.
• Long Bolt Final Pass in Sequence 75 degrees
• Medium Bolt Final Pass in Sequence 65 degrees
• Short Bolt Final Pass in Sequence 55 degrees

Optional Method

• First Pass in Sequence 26 ft. lbs.
• Second Pass in Sequence 44 ft. lbs.
• Final Pass in Sequence 66 ft. lbs.

Well done keep us posted

can i use without trouble : the optionnal method ???

Yes, you can just follow the bolt sequence EXACTLY

my fel pro kit is already in my garage .

when i read , for the bolt and the sealant : it s like on my cj5 and its hurricane !

the head s are since tuesday 19th at the machine shop

for the block , a friend of mine gave me a special tool to be sure that is ok , for me and him = ok

all my bolts are very nice (fresh water and after using the boat = trailer with all the drains open)


to hold intake gasket , i ve done like that when i change the intake for a 4bbl this spring


i ll hope you ll understand what i say

Well done and good luck