Mercruiser 454 timing chain

[BERTRAM42]

Gentlemen

Replacing my 1991 7.4 ltr timing chain. Mercruiser part 75588T is indicated and no longer available.

What is equivalent timing chain and gear set that I can use?

Is this a flat tappet engine and would a double roller set fit under stock cover?

Thank you
Paul

 

[achris]

It's a GM part, don't buy from Mercury, buy it from a quality GM parts supplier...

Try Summit Racing, they list dozens... And as you're not going over 5,000rpm, you don't need a double....

 

[Scott Danforth]

your original chain was a mehling part purchased originally by GM and used in the Tonawanda engine plant.

check prices, a double roller may be less money than stock simply because of the volume of the double rollers.

yes, you can get just about any of them to fit under the stock timing cover on your Gen V motor

 

[tpenfield]

When I re-built my 1991 Merc 454, I think the timing chain was a Mehling brand. You should be able to get all of the parts from the engine industry suppliers rather than through Mercruiser.

Here is the original Timing set . . .

.
Here is the replacement set. I got a lot of parts from Summit Racing . . as Scott mentioned.


.
Looks like I did go with the double link chain . . .

I assume your engine is the "Mark IV" Block, being a 1991 :noidea:

Here are a few of the parts I bought . . .

 

[BERTRAM42]

Gentlemen

Thank you for your responses. I will most likely go with a double roller since you have indicated it will fit under stock cover which I am also replacing.


FYI Chris
I have a 1968 20 Bahia Mar which is my next project rebuild. It was my first boat since 1985 and its time for a complete redo. Will post some pictures when started.

 

[achris]

...FYI Chris
I have a 1968 20 Bahia Mar which is my next project rebuild. It was my first boat since 1985 and its time for a complete redo. Will post some pictures when started.

:thumb: Look forward to seeing them.

 

[BERTRAM42]

Well saga continues....removed cover and discovered different looking existing camshaft gear. The original engines were 1991 sent back to jasper. These motors were jasper rebuilds done 2007. This engine is missing the tag in the rear. I can see the two rivits were it was. No other casting numbers. They are high performance heads either 360 or 400 HP.

The camshaft gear is slotted which appears to be used on later generation engines. 1996 to 1999. I have attached picture.

Any help appreciated. I am going to check other motor to see if tag is still on or any other #s.

 

[BERTRAM42]

Head casting # 14097188
In search found 14097088, rectangular port, open chamber,
gen V, 454/502 HO, 118 CC chambers
1991 and up

No listing for 188???
Pictures attached

 

[BERTRAM42]

Identified cloyes C3216 which appears correct for this engine.

 

[Scott Danforth]

you are over-complicating things. you can take a timing chain from a short deck big block made today and install on a motor made in 1964....... and visa versa.

doesnt matter if there is a slot or a hole for the alignment pin

 

[BERTRAM42]

Scott
Appreciate the response.

However, I purchased a comp cams 2110 set and the mounting holes for the camshaft pully do not align when I install with pin in hole?? And I am installing in correct direction with timing mark facing me and its labeled front.

I am not at boat at moment but will check again to see if im losing my mind!!!!

Thank you
Paul

 

[Scott Danforth]

thats a generic comp cams BBC timing chain.

what doesnt align? you have the lower sprocket set at 0 degrees, correct?

 

[BERTRAM42]

Picture shows new cam shaft gear in front, old one behind.
I will look to see if there is block numbers/tag on other engine still in boat.

 

[BERTRAM42]

Engine has a roller cam, can see them thru front port. Must be newer generation block??

 

[76SeaRay]

I don't know if this applies to your engine. I am building up a 1996 5.7L and went to a double roller cam. On this engine, you have to grind down the front edge of the oil channel bosses behind the top of the cam gear or the chain rubs on the boss. Make sure you check clearances for the cam chain all the way around and, if a roller cam, check the clearance of the cam retainer bolts with the back of the cam gear. Like I said, don't know if this applies to your engine...

 

[Scott Danforth]

I don't know if this applies to your engine. I am building up a 1996 5.7L and went to a double roller cam. On this engine, you have to grind down the front edge of the oil channel bosses behind the top of the cam gear or the chain rubs on the boss. Make sure you check clearances for the cam chain all the way around and, if a roller cam, check the clearance of the cam retainer bolts with the back of the cam gear. Like I said, don't know if this applies to your engine...

shouldnt have had to do any grinding on a Gen VI