What cam for original poor man stroker. RENIX?

Newbies, and basic Stroker Recipes... Get started with your first stroker here!!
Post Reply
Supakas
Posts: 5
Joined: January 13th, 2024, 10:31 am

What cam for original poor man stroker. RENIX?

Post by Supakas »

Greetings from Europe !

Im building 89 Wrangler YJ. (sit 7 years under the tree) It has 4.2 AMC 258. Its running now, but its very tired. So im gona stroke it !

So i have complete 4.2 AMC 258 and 88 4.0 from XJ.

Idea:
4.2 3.895" Crank. - problably needs machining.
4.2 Rods. - have them cheked
sealed power 677 pistons .030 over
New rings,bearings etc.
New injectors.
Stock head (DIY port it? ) , intake , exhaust. Bore TB.

Im aware of the big quench problem but for me to order custom pistons and use 4.0 rods is out of the game because of the cost.(shiping etc.)
I dont see detonation problem an issue because we have high octane fuel.

Machining is cheap- i can deck it down .040 ? shorter pushrods?

So my question is, what cam i should buy for this combination ?
Closest dealer is selling Melling MC809 - so this would be the cheapest option. But im willing to go the right way.

And i know. HO engine would be nicer, but in europe we dont have junkyards full of 4.0HO-s so it is what it is. ( Had do buy full XJ to get this engine)
Im not looking 300HP monster. Just a little HP boost with stuff i already have.

Sorry for my bad english , and thank you for this community !

Few pictures if someone cares:


Image
Image
Image
Image
Image
User avatar
Cheromaniac
I live here
I live here
Posts: 3177
Joined: March 8th, 2008, 12:58 pm
Stroker Displacement: 4563cc
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Cyprus
Contact:

Re: What cam for original poor man stroker. RENIX?

Post by Cheromaniac »

The Melling MC809 is the same spec as the stock cam but if you want a mild performance increase, Russ can supply you with a lower lift version of the CompCams 68-232-4 that allows you to retain the stock valve springs.
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car :mrgreen:
Supakas
Posts: 5
Joined: January 13th, 2024, 10:31 am

Re: What cam for original poor man stroker. RENIX?

Post by Supakas »

Thank you Cheromaniac.

'What can you suggest from the shop?
Maybe something i can find in europe from parts dealers ?

In overall.
Should i deck the block down ?
Supakas
Posts: 5
Joined: January 13th, 2024, 10:31 am

Re: What cam for original poor man stroker. RENIX?

Post by Supakas »

Some math:

Stroke: 3.895
Rod: 5.875
677P piston height: 1.585
Jeep 4.0 Deck height: 9.450

Deck clearence : 0.043

Compression calc :

Bore: 3.905 inches
Stroke: 3.895 inches
Combustion Chamber: 60cc dremel it to 60 ?
Deck Clearance: .043 inches
Gasket Thickness: .039 inches
Dome/Dish/Valve Relief: 15 cc

Static Compression Ratio 9.36 : 1

Dynamic Compression Ratio 6.92 : 1


In case of stock chamber size
Static Compression Ratio 9.74

Quench: 0.08199999999999999 ? :)


Am i correct ? Considering high octane fuel in europe. 98 equivalent to 93 in US. Seems okey and safe ?
User avatar
Cheromaniac
I live here
I live here
Posts: 3177
Joined: March 8th, 2008, 12:58 pm
Stroker Displacement: 4563cc
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Cyprus
Contact:

Re: What cam for original poor man stroker. RENIX?

Post by Cheromaniac »

The original poor man's stroker in my Jeep was almost exactly that spec except for a 3.895" bore (square engine), 677P pistons with dish increased to 17.7cc, and a 58cc combustion chamber. The static CR was 9.25:1 with a deck clearance of 0.045" and a quench of 0.088" (0.043" head gasket).
I had absolutely no problem running it on 95 RON octane fuel (91 US) and that was using the stock Champion RC12LYC spark plugs (not colder plugs).
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car :mrgreen:
Supakas
Posts: 5
Joined: January 13th, 2024, 10:31 am

Re: What cam for original poor man stroker. RENIX?

Post by Supakas »

Great. Ordered the pistons.
I also managed to find 1720 head.- can i still use stock intake and fuel rail or it will choke the good flowing head ?
If im looking to delete EGR system- should i change timing on cam ?
Problably going with the Melling MC809.
User avatar
Cheromaniac
I live here
I live here
Posts: 3177
Joined: March 8th, 2008, 12:58 pm
Stroker Displacement: 4563cc
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Cyprus
Contact:

Re: What cam for original poor man stroker. RENIX?

Post by Cheromaniac »

The HO head will require an HO intake manifold and throttle body for best results. As for the cam, install it straight up.
Supakas
Posts: 5
Joined: January 13th, 2024, 10:31 am

Re: What cam for original poor man stroker. RENIX?

Post by Supakas »

What should the bore clearence be?
On the package it says min 0.0001 inch.
User avatar
Cheromaniac
I live here
I live here
Posts: 3177
Joined: March 8th, 2008, 12:58 pm
Stroker Displacement: 4563cc
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Cyprus
Contact:

Re: What cam for original poor man stroker. RENIX?

Post by Cheromaniac »

It'll be whatever the piston manufacturer specifies 'cause the type of material used makes quite a difference. Hypereutectic pistons require the smallest clearance from the bore since they have the lowest expansion rate.
Post Reply

Who is online

Users browsing this forum: Ahrefs [Bot] and 4 guests