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Lifter Question

fastjeff said:
1986 Mercruiser 305 cube, 230 hp engine. Does it have roller lifters or flat tappets?
Click to expand...

Due to the year, and assuming that it has not been modified, it most likely has flat tappet hydraulic cam followers.

Questions:
Why are you asking?
Are you planning to replace them?



.
 
Not sure if pulling a valve cover would allow me to see what type lifters it has.

Stock, unmolested motor.

I want to know if a ZDDP additive is needed.

Jeff
 
May have answered my own question via an Internet search (Wiki):

For 1987, Chevrolet once again made some revisions to increase overall reliability, many of them borrowed from the TBI L03, which was to replace the LG4. The coil-in-cap HEI distributor was retired, and an all-new electronic distributor design was used. The intake manifold to head bolt pattern was redesigned to improve gasket integrity - four of the center intake manifold bolts were drilled at 72 degrees instead of 90 degrees for the cast iron cylinder heads. Changes to the valve covers were also made. "ribbing" was added to the top of the valve covers to increase surface area, acting as a heat sink. To improve intake gasket sealing, the mounting bolts were relocated to the valve cover centerline, placing all sealing pressure evenly upon the mounting flange perimeter... thus these became known as "centerbolt valve covers", first introduced in 1985 on the LB4 4.3L V6 and the Corvette a year earlier (the aluminum cylinder heads used with the Vette were the first to have the centerbolt valve covers). Another improvement was utilization of a hydraulic lifter/roller camshaft on most '87 LG4's. Some early engines have lifter retainer provisions, but utilize the older, non-roller camshaft. 1987 would also be the last year for the LG4 production, however a run of LG4 engines was made to supplement the carry-over production for the 1988 Monte Carlo and the 1988 Chevrolet Caprice.

Jeff
 
Jeff

Apples to Oranges....

1986 mercruiser marine egnines were NOT center bolt valve covers and also were two piece rear main seal.
Now there could be a few late year engine that were the center bolt one piece rear main seal.
If you look at how the parts lookup by year. 1987 is seperate.

I personally have friends with 1986 year mercruisers. I my self have a 1987.
they are not the same....as i describe above.
If your engine is unmolested and is a 1986 it should be flat tappet. Two piece rear main seal and non center bolt valve covers.

End of story......

For many years marine engines were/are about one to two years behind GM production for autos......
 
Jeff, I just popped in to see if any more info has been added to your thread.

I agree with Jack "For many years marine engines were/are about one to two years behind GM production for autos".

I found this in a Chevrolet Automotive Forum.

In 1986, GM (Chevy) started with the 1 pc rear main seal, but left the standard 4 bolt flanged valve covers and the flat tappet cam in these engines.
In 1987 GM changed to the centerbolt valve covers and roller cam.
I spent many years working at parts stores selling replacement motors (and taking cores back), working on F-bodies and then did a few years at Jegs in tech support (for anyone who wonders who I am and how would I know).
However, the 1986 block castings are not setup for the roller cam.


 

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  • SBC 2 pc vs 1 pc rear main seal explained 2 .jpg
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fastjeff said:
My motor has center bolt valve covers.

The plot thickens...

Jeff
Click to expand...

As I said """""Now there could be a few late year engine that were the center bolt one piece rear main seal.""""

Post the serial number that is the only way to tell
 
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